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[v5] platform: chrome: Add ChromeOS EC ISHTP driver

Message ID 1556976893-19471-1-git-send-email-rushikesh.s.kadam@intel.com (mailing list archive)
State Superseded
Headers show
Series [v5] platform: chrome: Add ChromeOS EC ISHTP driver | expand

Commit Message

Rushikesh S Kadam May 4, 2019, 1:34 p.m. UTC
This driver implements a slim layer to enable the ChromeOS
EC kernel stack (cros_ec) to communicate with ChromeOS EC
firmware running on the Intel Integrated Sensor Hub (ISH).

The driver registers a ChromeOS EC MFD device to connect
with cros_ec kernel stack (upper layer), and it registers a
client with the ISH Transport Protocol bus (lower layer) to
talk with the ISH firwmare. See description of the ISHTP
protocol at Documentation/hid/intel-ish-hid.txt

Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Jett Rink <jettrink@chromium.org>
Tested-by: Jett Rink <jettrink@chromium.org>
---

Submitting the patch to linux-input@ per the discussion here 
https://lkml.org/lkml/2019/5/2/339

The patch is baselined to hid git tree, branch for-5.2/ish
https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish

v5
 - Submitting with all Acked-by & Tested-bys. No other changes.

v4
 - Coding style related changes. No functional changes. Addresses
   review comments on v3.

v3
 - Made several changes to improve code readability. Replaced
   multiple cl_data_to_dev(client_data) with dev variable. Use
   reverse Xmas tree for variable defintion where it made sense.
   Dropped few debug prints. Add docstring for function
   prepare_cros_ec_rx().
 - Fix code in function prepare_cros_ec_rx() under label
   end_cros_ec_dev_init_error.
 - Recycle buffer in process_recv() on failing to obtain the
   semaphore.
 - Increase ISHTP TX/RX ring buffer size to 8.
 - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
   Kconfig.
 - Updated commit message.

v2
 - Dropped unused "reset" parameter in function cros_ec_init()
 - Change driver name to cros_ec_ishtp to be consistent with other
   references in the code.
 - Fixed a few typos. 

v1
 - Initial version

 drivers/platform/chrome/Kconfig         |  13 +
 drivers/platform/chrome/Makefile        |   1 +
 drivers/platform/chrome/cros_ec_ishtp.c | 763 ++++++++++++++++++++++++++++++++
 3 files changed, 777 insertions(+)
 create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c

Comments

Enric Balletbo i Serra May 15, 2019, 12:57 p.m. UTC | #1
Hi,

On 4/5/19 15:34, Rushikesh S Kadam wrote:
> This driver implements a slim layer to enable the ChromeOS
> EC kernel stack (cros_ec) to communicate with ChromeOS EC
> firmware running on the Intel Integrated Sensor Hub (ISH).
> 
> The driver registers a ChromeOS EC MFD device to connect
> with cros_ec kernel stack (upper layer), and it registers a
> client with the ISH Transport Protocol bus (lower layer) to
> talk with the ISH firwmare. See description of the ISHTP
> protocol at Documentation/hid/intel-ish-hid.txt
> 
> Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
> Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> Reviewed-by: Jett Rink <jettrink@chromium.org>
> Tested-by: Jett Rink <jettrink@chromium.org>
> ---

The following patch is queued to the for-next branch for the autobuilders to
play with, if all goes well I'll add the patch for 5.3 when current merge window
closes.

Thanks,
 Enric

> 
> Submitting the patch to linux-input@ per the discussion here 
> https://lkml.org/lkml/2019/5/2/339
> 
> The patch is baselined to hid git tree, branch for-5.2/ish
> https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish
> 
> v5
>  - Submitting with all Acked-by & Tested-bys. No other changes.
> 
> v4
>  - Coding style related changes. No functional changes. Addresses
>    review comments on v3.
> 
> v3
>  - Made several changes to improve code readability. Replaced
>    multiple cl_data_to_dev(client_data) with dev variable. Use
>    reverse Xmas tree for variable defintion where it made sense.
>    Dropped few debug prints. Add docstring for function
>    prepare_cros_ec_rx().
>  - Fix code in function prepare_cros_ec_rx() under label
>    end_cros_ec_dev_init_error.
>  - Recycle buffer in process_recv() on failing to obtain the
>    semaphore.
>  - Increase ISHTP TX/RX ring buffer size to 8.
>  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
>    Kconfig.
>  - Updated commit message.
> 
> v2
>  - Dropped unused "reset" parameter in function cros_ec_init()
>  - Change driver name to cros_ec_ishtp to be consistent with other
>    references in the code.
>  - Fixed a few typos. 
> 
> v1
>  - Initial version
> 
>  drivers/platform/chrome/Kconfig         |  13 +
>  drivers/platform/chrome/Makefile        |   1 +
>  drivers/platform/chrome/cros_ec_ishtp.c | 763 ++++++++++++++++++++++++++++++++
>  3 files changed, 777 insertions(+)
>  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
> 
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 16b1615..5848179 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -62,6 +62,19 @@ config CROS_EC_I2C
>  	  a checksum. Failing accesses will be retried three times to
>  	  improve reliability.
>  
> +config CROS_EC_ISHTP
> +	tristate "ChromeOS Embedded Controller (ISHTP)"
> +	depends on MFD_CROS_EC
> +	depends on INTEL_ISH_HID
> +	help
> +	  If you say Y here, you get support for talking to the ChromeOS EC
> +	  firmware running on Intel Integrated Sensor Hub (ISH), using the
> +	  ISH Transport protocol (ISH-TP). This uses a simple byte-level
> +	  protocol with a checksum.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called cros_ec_ishtp.
> +
>  config CROS_EC_SPI
>  	tristate "ChromeOS Embedded Controller (SPI)"
>  	depends on MFD_CROS_EC && SPI
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index cd591bf..4efe102 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -7,6 +7,7 @@ cros_ec_ctl-objs			:= cros_ec_sysfs.o cros_ec_lightbar.o \
>  					   cros_ec_vbc.o cros_ec_debugfs.o
>  obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
>  obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
> +obj-$(CONFIG_CROS_EC_ISHTP)		+= cros_ec_ishtp.o
>  obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
>  cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_reg.o
>  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)	+= cros_ec_lpc_mec.o
> diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
> new file mode 100644
> index 0000000..997503d
> --- /dev/null
> +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> @@ -0,0 +1,763 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// ISHTP interface for ChromeOS Embedded Controller
> +//
> +// Copyright (c) 2019, Intel Corporation.
> +//
> +// ISHTP client driver for talking to the Chrome OS EC firmware running
> +// on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
> +// (ISH-TP).
> +
> +#include <linux/delay.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/cros_ec.h>
> +#include <linux/mfd/cros_ec_commands.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/intel-ish-client-if.h>
> +
> +/*
> + * ISH TX/RX ring buffer pool size
> + *
> + * The AP->ISH messages and corresponding ISH->AP responses are
> + * serialized. We need 1 TX and 1 RX buffer for these.
> + *
> + * The MKBP ISH->AP events are serialized. We need one additional RX
> + * buffer for them.
> + */
> +#define CROS_ISH_CL_TX_RING_SIZE		8
> +#define CROS_ISH_CL_RX_RING_SIZE		8
> +
> +/* ISH CrOS EC Host Commands */
> +enum cros_ec_ish_channel {
> +	CROS_EC_COMMAND = 1,			/* AP->ISH message */
> +	CROS_MKBP_EVENT = 2,			/* ISH->AP events */
> +};
> +
> +/*
> + * ISH firmware timeout for 1 message send failure is 1Hz, and the
> + * firmware will retry 2 times, so 3Hz is used for timeout.
> + */
> +#define ISHTP_SEND_TIMEOUT			(3 * HZ)
> +
> +/* ISH Transport CrOS EC ISH client unique GUID */
> +static const guid_t cros_ish_guid =
> +	GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
> +		  0xb0, 0xd8, 0x9e, 0x7c, 0xda,	0xe0, 0xd6, 0xa0);
> +
> +struct header {
> +	u8 channel;
> +	u8 status;
> +	u8 reserved[2];
> +} __packed;
> +
> +struct cros_ish_out_msg {
> +	struct header hdr;
> +	struct ec_host_request ec_request;
> +} __packed;
> +
> +struct cros_ish_in_msg {
> +	struct header hdr;
> +	struct ec_host_response ec_response;
> +} __packed;
> +
> +#define IN_MSG_EC_RESPONSE_PREAMBLE					\
> +	offsetof(struct cros_ish_in_msg, ec_response)
> +
> +#define OUT_MSG_EC_REQUEST_PREAMBLE					\
> +	offsetof(struct cros_ish_out_msg, ec_request)
> +
> +#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
> +
> +/*
> + * The Read-Write Semaphore is used to prevent message TX or RX while
> + * the ishtp client is being initialized or undergoing reset.
> + *
> + * The readers are the kernel function calls responsible for IA->ISH
> + * and ISH->AP messaging.
> + *
> + * The writers are .reset() and .probe() function.
> + */
> +DECLARE_RWSEM(init_lock);
> +
> +/**
> + * struct response_info - Encapsulate firmware response related
> + * information for passing between function ish_send() and
> + * process_recv() callback.
> + *
> + * @data: Copy the data received from firmware here.
> + * @max_size: Max size allocated for the @data buffer. If the received
> + * data exceeds this value, we log an error.
> + * @size: Actual size of data received from firmware.
> + * @error: 0 for success, negative error code for a failure in process_recv().
> + * @received: Set to true on receiving a valid firmware	response to host command
> + * @wait_queue: Wait queue for host to wait for firmware response.
> + */
> +struct response_info {
> +	void *data;
> +	size_t max_size;
> +	size_t size;
> +	int error;
> +	bool received;
> +	wait_queue_head_t wait_queue;
> +};
> +
> +/**
> + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
> + *
> + * @cros_ish_cl: ISHTP firmware client instance.
> + * @cl_device: ISHTP client device instance.
> + * @response: Response info passing between ish_send() and process_recv().
> + * @work_ishtp_reset: Work queue reset handling.
> + * @work_ec_evt: Work queue for EC events.
> + * @ec_dev: CrOS EC MFD device.
> + *
> + * This structure is used to store per client data.
> + */
> +struct ishtp_cl_data {
> +	struct ishtp_cl *cros_ish_cl;
> +	struct ishtp_cl_device *cl_device;
> +
> +	/*
> +	 * Used for passing firmware response information between
> +	 * ish_send() and process_recv() callback.
> +	 */
> +	struct response_info response;
> +
> +	struct work_struct work_ishtp_reset;
> +	struct work_struct work_ec_evt;
> +	struct cros_ec_device *ec_dev;
> +};
> +
> +/**
> + * ish_evt_handler - ISH to AP event handler
> + * @work: Work struct
> + */
> +static void ish_evt_handler(struct work_struct *work)
> +{
> +	struct ishtp_cl_data *client_data =
> +		container_of(work, struct ishtp_cl_data, work_ec_evt);
> +	struct cros_ec_device *ec_dev = client_data->ec_dev;
> +
> +	if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
> +		blocking_notifier_call_chain(&ec_dev->event_notifier,
> +					     0, ec_dev);
> +	}
> +}
> +
> +/**
> + * ish_send() - Send message from host to firmware
> + *
> + * @client_data: Client data instance
> + * @out_msg: Message buffer to be sent to firmware
> + * @out_size: Size of out going message
> + * @in_msg: Message buffer where the incoming data is copied. This buffer
> + * is allocated by calling
> + * @in_size: Max size of incoming message
> + *
> + * Return: Number of bytes copied in the in_msg on success, negative
> + * error code on failure.
> + */
> +static int ish_send(struct ishtp_cl_data *client_data,
> +		    u8 *out_msg, size_t out_size,
> +		    u8 *in_msg, size_t in_size)
> +{
> +	int rv;
> +	struct header *out_hdr = (struct header *)out_msg;
> +	struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
> +
> +	dev_dbg(cl_data_to_dev(client_data),
> +		"%s: channel=%02u status=%02u\n",
> +		__func__, out_hdr->channel, out_hdr->status);
> +
> +	/* Setup for incoming response */
> +	client_data->response.data = in_msg;
> +	client_data->response.max_size = in_size;
> +	client_data->response.error = 0;
> +	client_data->response.received = false;
> +
> +	rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
> +	if (rv) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"ishtp_cl_send error %d\n", rv);
> +		return rv;
> +	}
> +
> +	wait_event_interruptible_timeout(client_data->response.wait_queue,
> +					 client_data->response.received,
> +					 ISHTP_SEND_TIMEOUT);
> +	if (!client_data->response.received) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"Timed out for response to host message\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	if (client_data->response.error < 0)
> +		return client_data->response.error;
> +
> +	return client_data->response.size;
> +}
> +
> +/**
> + * process_recv() - Received and parse incoming packet
> + * @cros_ish_cl: Client instance to get stats
> + * @rb_in_proc: Host interface message buffer
> + *
> + * Parse the incoming packet. If it is a response packet then it will
> + * update per instance flags and wake up the caller waiting to for the
> + * response. If it is an event packet then it will schedule event work.
> + */
> +static void process_recv(struct ishtp_cl *cros_ish_cl,
> +			 struct ishtp_cl_rb *rb_in_proc)
> +{
> +	size_t data_len = rb_in_proc->buf_idx;
> +	struct ishtp_cl_data *client_data =
> +		ishtp_get_client_data(cros_ish_cl);
> +	struct device *dev = cl_data_to_dev(client_data);
> +	struct cros_ish_in_msg *in_msg =
> +		(struct cros_ish_in_msg *)rb_in_proc->buffer.data;
> +
> +	/* Proceed only if reset or init is not in progress */
> +	if (!down_read_trylock(&init_lock)) {
> +		/* Free the buffer */
> +		ishtp_cl_io_rb_recycle(rb_in_proc);
> +		dev_warn(dev,
> +			 "Host is not ready to receive incoming messages\n");
> +		return;
> +	}
> +
> +	/*
> +	 * All firmware messages contain a header. Check the buffer size
> +	 * before accessing elements inside.
> +	 */
> +	if (!rb_in_proc->buffer.data) {
> +		dev_warn(dev, "rb_in_proc->buffer.data returned null");
> +		client_data->response.error = -EBADMSG;
> +		goto end_error;
> +	}
> +
> +	if (data_len < sizeof(struct header)) {
> +		dev_err(dev, "data size %zu is less than header %zu\n",
> +			data_len, sizeof(struct header));
> +		client_data->response.error = -EMSGSIZE;
> +		goto end_error;
> +	}
> +
> +	dev_dbg(dev, "channel=%02u status=%02u\n",
> +		in_msg->hdr.channel, in_msg->hdr.status);
> +
> +	switch (in_msg->hdr.channel) {
> +	case CROS_EC_COMMAND:
> +		/* Sanity check */
> +		if (!client_data->response.data) {
> +			dev_err(dev,
> +				"Receiving buffer is null. Should be allocated by calling function\n");
> +			client_data->response.error = -EINVAL;
> +			goto error_wake_up;
> +		}
> +
> +		if (client_data->response.received) {
> +			dev_err(dev,
> +				"Previous firmware message not yet processed\n");
> +			client_data->response.error = -EINVAL;
> +			goto error_wake_up;
> +		}
> +
> +		if (data_len > client_data->response.max_size) {
> +			dev_err(dev,
> +				"Received buffer size %zu is larger than allocated buffer %zu\n",
> +				data_len, client_data->response.max_size);
> +			client_data->response.error = -EMSGSIZE;
> +			goto error_wake_up;
> +		}
> +
> +		if (in_msg->hdr.status) {
> +			dev_err(dev, "firmware returned status %d\n",
> +				in_msg->hdr.status);
> +			client_data->response.error = -EIO;
> +			goto error_wake_up;
> +		}
> +
> +		/* Update the actual received buffer size */
> +		client_data->response.size = data_len;
> +
> +		/*
> +		 * Copy the buffer received in firmware response for the
> +		 * calling thread.
> +		 */
> +		memcpy(client_data->response.data,
> +		       rb_in_proc->buffer.data, data_len);
> +
> +		/* Set flag before waking up the caller */
> +		client_data->response.received = true;
> +error_wake_up:
> +		/* Wake the calling thread */
> +		wake_up_interruptible(&client_data->response.wait_queue);
> +
> +		break;
> +
> +	case CROS_MKBP_EVENT:
> +		/* The event system doesn't send any data in buffer */
> +		schedule_work(&client_data->work_ec_evt);
> +
> +		break;
> +
> +	default:
> +		dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
> +	}
> +
> +end_error:
> +	/* Free the buffer */
> +	ishtp_cl_io_rb_recycle(rb_in_proc);
> +
> +	up_read(&init_lock);
> +}
> +
> +/**
> + * ish_event_cb() - bus driver callback for incoming message
> + * @cl_device: ISHTP client device for which this message is targeted.
> + *
> + * Remove the packet from the list and process the message by calling
> + * process_recv.
> + */
> +static void ish_event_cb(struct ishtp_cl_device *cl_device)
> +{
> +	struct ishtp_cl_rb *rb_in_proc;
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +
> +	while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
> +		/* Decide what to do with received data */
> +		process_recv(cros_ish_cl, rb_in_proc);
> +	}
> +}
> +
> +/**
> + * cros_ish_init() - Init function for ISHTP client
> + * @cros_ish_cl: ISHTP client instance
> + *
> + * This function complete the initializtion of the client.
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
> +{
> +	int rv;
> +	struct ishtp_device *dev;
> +	struct ishtp_fw_client *fw_client;
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	rv = ishtp_cl_link(cros_ish_cl);
> +	if (rv) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"ishtp_cl_link failed\n");
> +		return rv;
> +	}
> +
> +	dev = ishtp_get_ishtp_device(cros_ish_cl);
> +
> +	/* Connect to firmware client */
> +	ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
> +	ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
> +
> +	fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
> +	if (!fw_client) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"ish client uuid not found\n");
> +		rv = -ENOENT;
> +		goto err_cl_unlink;
> +	}
> +
> +	ishtp_cl_set_fw_client_id(cros_ish_cl,
> +				  ishtp_get_fw_client_id(fw_client));
> +	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
> +
> +	rv = ishtp_cl_connect(cros_ish_cl);
> +	if (rv) {
> +		dev_err(cl_data_to_dev(client_data),
> +			"client connect fail\n");
> +		goto err_cl_unlink;
> +	}
> +
> +	ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
> +	return 0;
> +
> +err_cl_unlink:
> +	ishtp_cl_unlink(cros_ish_cl);
> +	return rv;
> +}
> +
> +/**
> + * cros_ish_deinit() - Deinit function for ISHTP client
> + * @cros_ish_cl: ISHTP client instance
> + *
> + * Unlink and free cros_ec client
> + */
> +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
> +{
> +	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> +	ishtp_cl_disconnect(cros_ish_cl);
> +	ishtp_cl_unlink(cros_ish_cl);
> +	ishtp_cl_flush_queues(cros_ish_cl);
> +
> +	/* Disband and free all Tx and Rx client-level rings */
> +	ishtp_cl_free(cros_ish_cl);
> +}
> +
> +/**
> + * prepare_cros_ec_rx() - Check & prepare receive buffer
> + * @ec_dev: CrOS EC MFD device.
> + * @in_msg: Incoming message buffer
> + * @msg: cros_ec command used to send & receive data
> + *
> + * Return: 0 for success, negative error code for failure.
> + *
> + * Check the received buffer. Convert to cros_ec_command format.
> + */
> +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> +			      const struct cros_ish_in_msg *in_msg,
> +			      struct cros_ec_command *msg)
> +{
> +	u8 sum = 0;
> +	int i, rv, offset;
> +
> +	/* Check response error code */
> +	msg->result = in_msg->ec_response.result;
> +	rv = cros_ec_check_result(ec_dev, msg);
> +	if (rv < 0)
> +		return rv;
> +
> +	if (in_msg->ec_response.data_len > msg->insize) {
> +		dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
> +			in_msg->ec_response.data_len, msg->insize);
> +		return -ENOSPC;
> +	}
> +
> +	/* Copy response packet payload and compute checksum */
> +	for (i = 0; i < sizeof(struct ec_host_response); i++)
> +		sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
> +
> +	offset = sizeof(struct cros_ish_in_msg);
> +	for (i = 0; i < in_msg->ec_response.data_len; i++)
> +		sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
> +
> +	if (sum) {
> +		dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
> +		return -EBADMSG;
> +	}
> +
> +	return 0;
> +}
> +
> +static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
> +				struct cros_ec_command *msg)
> +{
> +	int rv;
> +	struct ishtp_cl *cros_ish_cl = ec_dev->priv;
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +	struct device *dev = cl_data_to_dev(client_data);
> +	struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
> +	struct cros_ish_out_msg *out_msg =
> +		(struct cros_ish_out_msg *)ec_dev->dout;
> +	size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
> +	size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
> +
> +	/* Proceed only if reset-init is not in progress */
> +	if (!down_read_trylock(&init_lock)) {
> +		dev_warn(dev,
> +			 "Host is not ready to send messages to ISH. Try again\n");
> +		return -EAGAIN;
> +	}
> +
> +	/* Sanity checks */
> +	if (in_size > ec_dev->din_size) {
> +		dev_err(dev,
> +			"Incoming payload size %zu is too large for ec_dev->din_size %d\n",
> +			in_size, ec_dev->din_size);
> +		return -EMSGSIZE;
> +	}
> +
> +	if (out_size > ec_dev->dout_size) {
> +		dev_err(dev,
> +			"Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
> +			out_size, ec_dev->dout_size);
> +		return -EMSGSIZE;
> +	}
> +
> +	/* Prepare the package to be sent over ISH TP */
> +	out_msg->hdr.channel = CROS_EC_COMMAND;
> +	out_msg->hdr.status = 0;
> +
> +	ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
> +	cros_ec_prepare_tx(ec_dev, msg);
> +	ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
> +
> +	dev_dbg(dev,
> +		"out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
> +		out_msg->ec_request.struct_version,
> +		out_msg->ec_request.checksum,
> +		out_msg->ec_request.command,
> +		out_msg->ec_request.command_version,
> +		out_msg->ec_request.data_len);
> +
> +	/* Send command to ISH EC firmware and read response */
> +	rv = ish_send(client_data,
> +		      (u8 *)out_msg, out_size,
> +		      (u8 *)in_msg, in_size);
> +	if (rv < 0)
> +		goto end_error;
> +
> +	rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
> +	if (rv)
> +		goto end_error;
> +
> +	rv = in_msg->ec_response.data_len;
> +
> +	dev_dbg(dev,
> +		"in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
> +		in_msg->ec_response.struct_version,
> +		in_msg->ec_response.checksum,
> +		in_msg->ec_response.result,
> +		in_msg->ec_response.data_len);
> +
> +end_error:
> +	if (msg->command == EC_CMD_REBOOT_EC)
> +		msleep(EC_REBOOT_DELAY_MS);
> +
> +	up_read(&init_lock);
> +
> +	return rv;
> +}
> +
> +static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
> +{
> +	struct cros_ec_device *ec_dev;
> +	struct device *dev = cl_data_to_dev(client_data);
> +
> +	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> +	if (!ec_dev)
> +		return -ENOMEM;
> +
> +	client_data->ec_dev = ec_dev;
> +	dev->driver_data = ec_dev;
> +
> +	ec_dev->dev = dev;
> +	ec_dev->priv = client_data->cros_ish_cl;
> +	ec_dev->cmd_xfer = NULL;
> +	ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
> +	ec_dev->phys_name = dev_name(dev);
> +	ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
> +			   sizeof(struct ec_response_get_protocol_info);
> +	ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
> +
> +	return cros_ec_register(ec_dev);
> +}
> +
> +static void reset_handler(struct work_struct *work)
> +{
> +	int rv;
> +	struct device *dev;
> +	struct ishtp_cl *cros_ish_cl;
> +	struct ishtp_cl_device *cl_device;
> +	struct ishtp_cl_data *client_data =
> +		container_of(work, struct ishtp_cl_data, work_ishtp_reset);
> +
> +	/* Lock for reset to complete */
> +	down_write(&init_lock);
> +
> +	cros_ish_cl = client_data->cros_ish_cl;
> +	cl_device = client_data->cl_device;
> +
> +	/* Unlink, flush queues & start again */
> +	ishtp_cl_unlink(cros_ish_cl);
> +	ishtp_cl_flush_queues(cros_ish_cl);
> +	ishtp_cl_free(cros_ish_cl);
> +
> +	cros_ish_cl = ishtp_cl_allocate(cl_device);
> +	if (!cros_ish_cl) {
> +		up_write(&init_lock);
> +		return;
> +	}
> +
> +	ishtp_set_drvdata(cl_device, cros_ish_cl);
> +	ishtp_set_client_data(cros_ish_cl, client_data);
> +	client_data->cros_ish_cl = cros_ish_cl;
> +
> +	rv = cros_ish_init(cros_ish_cl);
> +	if (rv) {
> +		ishtp_cl_free(cros_ish_cl);
> +		dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
> +		up_write(&init_lock);
> +		return;
> +	}
> +
> +	/* Refresh ec_dev device pointers */
> +	client_data->ec_dev->priv = client_data->cros_ish_cl;
> +	dev = cl_data_to_dev(client_data);
> +	dev->driver_data = client_data->ec_dev;
> +
> +	dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
> +
> +	up_write(&init_lock);
> +}
> +
> +/**
> + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
> + * @cl_device: ISHTP client device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
> +{
> +	int rv;
> +	struct ishtp_cl *cros_ish_cl;
> +	struct ishtp_cl_data *client_data =
> +		devm_kzalloc(ishtp_device(cl_device),
> +			     sizeof(*client_data), GFP_KERNEL);
> +	if (!client_data)
> +		return -ENOMEM;
> +
> +	/* Lock for initialization to complete */
> +	down_write(&init_lock);
> +
> +	cros_ish_cl = ishtp_cl_allocate(cl_device);
> +	if (!cros_ish_cl) {
> +		rv = -ENOMEM;
> +		goto end_ishtp_cl_alloc_error;
> +	}
> +
> +	ishtp_set_drvdata(cl_device, cros_ish_cl);
> +	ishtp_set_client_data(cros_ish_cl, client_data);
> +	client_data->cros_ish_cl = cros_ish_cl;
> +	client_data->cl_device = cl_device;
> +
> +	init_waitqueue_head(&client_data->response.wait_queue);
> +
> +	INIT_WORK(&client_data->work_ishtp_reset,
> +		  reset_handler);
> +	INIT_WORK(&client_data->work_ec_evt,
> +		  ish_evt_handler);
> +
> +	rv = cros_ish_init(cros_ish_cl);
> +	if (rv)
> +		goto end_ishtp_cl_init_error;
> +
> +	ishtp_get_device(cl_device);
> +
> +	up_write(&init_lock);
> +
> +	/* Register croc_ec_dev mfd */
> +	rv = cros_ec_dev_init(client_data);
> +	if (rv)
> +		goto end_cros_ec_dev_init_error;
> +
> +	return 0;
> +
> +end_cros_ec_dev_init_error:
> +	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> +	ishtp_cl_disconnect(cros_ish_cl);
> +	ishtp_cl_unlink(cros_ish_cl);
> +	ishtp_cl_flush_queues(cros_ish_cl);
> +	ishtp_put_device(cl_device);
> +end_ishtp_cl_init_error:
> +	ishtp_cl_free(cros_ish_cl);
> +end_ishtp_cl_alloc_error:
> +	up_write(&init_lock);
> +	return rv;
> +}
> +
> +/**
> + * cros_ec_ishtp_remove() - ISHTP client driver remove callback
> + * @cl_device: ISHTP client device instance
> + *
> + * Return: 0
> + */
> +static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
> +{
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	cancel_work_sync(&client_data->work_ishtp_reset);
> +	cancel_work_sync(&client_data->work_ec_evt);
> +	cros_ish_deinit(cros_ish_cl);
> +	ishtp_put_device(cl_device);
> +
> +	return 0;
> +}
> +
> +/**
> + * cros_ec_ishtp_reset() - ISHTP client driver reset callback
> + * @cl_device: ISHTP client device instance
> + *
> + * Return: 0
> + */
> +static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
> +{
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	schedule_work(&client_data->work_ishtp_reset);
> +
> +	return 0;
> +}
> +
> +/**
> + * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
> + * @device: device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
> +{
> +	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	return cros_ec_suspend(client_data->ec_dev);
> +}
> +
> +/**
> + * cros_ec_ishtp_resume() - ISHTP client driver resume callback
> + * @device: device instance
> + *
> + * Return: 0 for success, negative error code for failure.
> + */
> +static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
> +{
> +	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> +	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
> +	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> +
> +	return cros_ec_resume(client_data->ec_dev);
> +}
> +
> +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
> +			 cros_ec_ishtp_resume);
> +
> +static struct ishtp_cl_driver	cros_ec_ishtp_driver = {
> +	.name = "cros_ec_ishtp",
> +	.guid = &cros_ish_guid,
> +	.probe = cros_ec_ishtp_probe,
> +	.remove = cros_ec_ishtp_remove,
> +	.reset = cros_ec_ishtp_reset,
> +	.driver = {
> +		.pm = &cros_ec_ishtp_pm_ops,
> +	},
> +};
> +
> +static int __init cros_ec_ishtp_mod_init(void)
> +{
> +	return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
> +}
> +
> +static void __exit cros_ec_ishtp_mod_exit(void)
> +{
> +	ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
> +}
> +
> +module_init(cros_ec_ishtp_mod_init);
> +module_exit(cros_ec_ishtp_mod_exit);
> +
> +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
> +MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("ishtp:*");
>
Enric Balletbo Serra May 15, 2019, 9:23 p.m. UTC | #2
Missatge de Enric Balletbo i Serra <enric.balletbo@collabora.com> del
dia dc., 15 de maig 2019 a les 15:00:
>
> Hi,
>
> On 4/5/19 15:34, Rushikesh S Kadam wrote:
> > This driver implements a slim layer to enable the ChromeOS
> > EC kernel stack (cros_ec) to communicate with ChromeOS EC
> > firmware running on the Intel Integrated Sensor Hub (ISH).
> >
> > The driver registers a ChromeOS EC MFD device to connect
> > with cros_ec kernel stack (upper layer), and it registers a
> > client with the ISH Transport Protocol bus (lower layer) to
> > talk with the ISH firwmare. See description of the ISHTP
> > protocol at Documentation/hid/intel-ish-hid.txt
> >
> > Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
> > Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> > Reviewed-by: Jett Rink <jettrink@chromium.org>
> > Tested-by: Jett Rink <jettrink@chromium.org>
> > ---
>
> The following patch is queued to the for-next branch for the autobuilders to
> play with, if all goes well I'll add the patch for 5.3 when current merge window
> closes.
>

Actually, I reverted this patch and applied v6.


> Thanks,
>  Enric
>
> >
> > Submitting the patch to linux-input@ per the discussion here
> > https://lkml.org/lkml/2019/5/2/339
> >
> > The patch is baselined to hid git tree, branch for-5.2/ish
> > https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish
> >
> > v5
> >  - Submitting with all Acked-by & Tested-bys. No other changes.
> >
> > v4
> >  - Coding style related changes. No functional changes. Addresses
> >    review comments on v3.
> >
> > v3
> >  - Made several changes to improve code readability. Replaced
> >    multiple cl_data_to_dev(client_data) with dev variable. Use
> >    reverse Xmas tree for variable defintion where it made sense.
> >    Dropped few debug prints. Add docstring for function
> >    prepare_cros_ec_rx().
> >  - Fix code in function prepare_cros_ec_rx() under label
> >    end_cros_ec_dev_init_error.
> >  - Recycle buffer in process_recv() on failing to obtain the
> >    semaphore.
> >  - Increase ISHTP TX/RX ring buffer size to 8.
> >  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
> >    Kconfig.
> >  - Updated commit message.
> >
> > v2
> >  - Dropped unused "reset" parameter in function cros_ec_init()
> >  - Change driver name to cros_ec_ishtp to be consistent with other
> >    references in the code.
> >  - Fixed a few typos.
> >
> > v1
> >  - Initial version
> >
> >  drivers/platform/chrome/Kconfig         |  13 +
> >  drivers/platform/chrome/Makefile        |   1 +
> >  drivers/platform/chrome/cros_ec_ishtp.c | 763 ++++++++++++++++++++++++++++++++
> >  3 files changed, 777 insertions(+)
> >  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
> >
> > diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> > index 16b1615..5848179 100644
> > --- a/drivers/platform/chrome/Kconfig
> > +++ b/drivers/platform/chrome/Kconfig
> > @@ -62,6 +62,19 @@ config CROS_EC_I2C
> >         a checksum. Failing accesses will be retried three times to
> >         improve reliability.
> >
> > +config CROS_EC_ISHTP
> > +     tristate "ChromeOS Embedded Controller (ISHTP)"
> > +     depends on MFD_CROS_EC
> > +     depends on INTEL_ISH_HID
> > +     help
> > +       If you say Y here, you get support for talking to the ChromeOS EC
> > +       firmware running on Intel Integrated Sensor Hub (ISH), using the
> > +       ISH Transport protocol (ISH-TP). This uses a simple byte-level
> > +       protocol with a checksum.
> > +
> > +       To compile this driver as a module, choose M here: the
> > +       module will be called cros_ec_ishtp.
> > +
> >  config CROS_EC_SPI
> >       tristate "ChromeOS Embedded Controller (SPI)"
> >       depends on MFD_CROS_EC && SPI
> > diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> > index cd591bf..4efe102 100644
> > --- a/drivers/platform/chrome/Makefile
> > +++ b/drivers/platform/chrome/Makefile
> > @@ -7,6 +7,7 @@ cros_ec_ctl-objs                      := cros_ec_sysfs.o cros_ec_lightbar.o \
> >                                          cros_ec_vbc.o cros_ec_debugfs.o
> >  obj-$(CONFIG_CROS_EC_CTL)            += cros_ec_ctl.o
> >  obj-$(CONFIG_CROS_EC_I2C)            += cros_ec_i2c.o
> > +obj-$(CONFIG_CROS_EC_ISHTP)          += cros_ec_ishtp.o
> >  obj-$(CONFIG_CROS_EC_SPI)            += cros_ec_spi.o
> >  cros_ec_lpcs-objs                    := cros_ec_lpc.o cros_ec_lpc_reg.o
> >  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)       += cros_ec_lpc_mec.o
> > diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
> > new file mode 100644
> > index 0000000..997503d
> > --- /dev/null
> > +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> > @@ -0,0 +1,763 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// ISHTP interface for ChromeOS Embedded Controller
> > +//
> > +// Copyright (c) 2019, Intel Corporation.
> > +//
> > +// ISHTP client driver for talking to the Chrome OS EC firmware running
> > +// on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
> > +// (ISH-TP).
> > +
> > +#include <linux/delay.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/mfd/cros_ec.h>
> > +#include <linux/mfd/cros_ec_commands.h>
> > +#include <linux/module.h>
> > +#include <linux/pci.h>
> > +#include <linux/intel-ish-client-if.h>
> > +
> > +/*
> > + * ISH TX/RX ring buffer pool size
> > + *
> > + * The AP->ISH messages and corresponding ISH->AP responses are
> > + * serialized. We need 1 TX and 1 RX buffer for these.
> > + *
> > + * The MKBP ISH->AP events are serialized. We need one additional RX
> > + * buffer for them.
> > + */
> > +#define CROS_ISH_CL_TX_RING_SIZE             8
> > +#define CROS_ISH_CL_RX_RING_SIZE             8
> > +
> > +/* ISH CrOS EC Host Commands */
> > +enum cros_ec_ish_channel {
> > +     CROS_EC_COMMAND = 1,                    /* AP->ISH message */
> > +     CROS_MKBP_EVENT = 2,                    /* ISH->AP events */
> > +};
> > +
> > +/*
> > + * ISH firmware timeout for 1 message send failure is 1Hz, and the
> > + * firmware will retry 2 times, so 3Hz is used for timeout.
> > + */
> > +#define ISHTP_SEND_TIMEOUT                   (3 * HZ)
> > +
> > +/* ISH Transport CrOS EC ISH client unique GUID */
> > +static const guid_t cros_ish_guid =
> > +     GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
> > +               0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6, 0xa0);
> > +
> > +struct header {
> > +     u8 channel;
> > +     u8 status;
> > +     u8 reserved[2];
> > +} __packed;
> > +
> > +struct cros_ish_out_msg {
> > +     struct header hdr;
> > +     struct ec_host_request ec_request;
> > +} __packed;
> > +
> > +struct cros_ish_in_msg {
> > +     struct header hdr;
> > +     struct ec_host_response ec_response;
> > +} __packed;
> > +
> > +#define IN_MSG_EC_RESPONSE_PREAMBLE                                  \
> > +     offsetof(struct cros_ish_in_msg, ec_response)
> > +
> > +#define OUT_MSG_EC_REQUEST_PREAMBLE                                  \
> > +     offsetof(struct cros_ish_out_msg, ec_request)
> > +
> > +#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
> > +
> > +/*
> > + * The Read-Write Semaphore is used to prevent message TX or RX while
> > + * the ishtp client is being initialized or undergoing reset.
> > + *
> > + * The readers are the kernel function calls responsible for IA->ISH
> > + * and ISH->AP messaging.
> > + *
> > + * The writers are .reset() and .probe() function.
> > + */
> > +DECLARE_RWSEM(init_lock);
> > +
> > +/**
> > + * struct response_info - Encapsulate firmware response related
> > + * information for passing between function ish_send() and
> > + * process_recv() callback.
> > + *
> > + * @data: Copy the data received from firmware here.
> > + * @max_size: Max size allocated for the @data buffer. If the received
> > + * data exceeds this value, we log an error.
> > + * @size: Actual size of data received from firmware.
> > + * @error: 0 for success, negative error code for a failure in process_recv().
> > + * @received: Set to true on receiving a valid firmware      response to host command
> > + * @wait_queue: Wait queue for host to wait for firmware response.
> > + */
> > +struct response_info {
> > +     void *data;
> > +     size_t max_size;
> > +     size_t size;
> > +     int error;
> > +     bool received;
> > +     wait_queue_head_t wait_queue;
> > +};
> > +
> > +/**
> > + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
> > + *
> > + * @cros_ish_cl: ISHTP firmware client instance.
> > + * @cl_device: ISHTP client device instance.
> > + * @response: Response info passing between ish_send() and process_recv().
> > + * @work_ishtp_reset: Work queue reset handling.
> > + * @work_ec_evt: Work queue for EC events.
> > + * @ec_dev: CrOS EC MFD device.
> > + *
> > + * This structure is used to store per client data.
> > + */
> > +struct ishtp_cl_data {
> > +     struct ishtp_cl *cros_ish_cl;
> > +     struct ishtp_cl_device *cl_device;
> > +
> > +     /*
> > +      * Used for passing firmware response information between
> > +      * ish_send() and process_recv() callback.
> > +      */
> > +     struct response_info response;
> > +
> > +     struct work_struct work_ishtp_reset;
> > +     struct work_struct work_ec_evt;
> > +     struct cros_ec_device *ec_dev;
> > +};
> > +
> > +/**
> > + * ish_evt_handler - ISH to AP event handler
> > + * @work: Work struct
> > + */
> > +static void ish_evt_handler(struct work_struct *work)
> > +{
> > +     struct ishtp_cl_data *client_data =
> > +             container_of(work, struct ishtp_cl_data, work_ec_evt);
> > +     struct cros_ec_device *ec_dev = client_data->ec_dev;
> > +
> > +     if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
> > +             blocking_notifier_call_chain(&ec_dev->event_notifier,
> > +                                          0, ec_dev);
> > +     }
> > +}
> > +
> > +/**
> > + * ish_send() - Send message from host to firmware
> > + *
> > + * @client_data: Client data instance
> > + * @out_msg: Message buffer to be sent to firmware
> > + * @out_size: Size of out going message
> > + * @in_msg: Message buffer where the incoming data is copied. This buffer
> > + * is allocated by calling
> > + * @in_size: Max size of incoming message
> > + *
> > + * Return: Number of bytes copied in the in_msg on success, negative
> > + * error code on failure.
> > + */
> > +static int ish_send(struct ishtp_cl_data *client_data,
> > +                 u8 *out_msg, size_t out_size,
> > +                 u8 *in_msg, size_t in_size)
> > +{
> > +     int rv;
> > +     struct header *out_hdr = (struct header *)out_msg;
> > +     struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
> > +
> > +     dev_dbg(cl_data_to_dev(client_data),
> > +             "%s: channel=%02u status=%02u\n",
> > +             __func__, out_hdr->channel, out_hdr->status);
> > +
> > +     /* Setup for incoming response */
> > +     client_data->response.data = in_msg;
> > +     client_data->response.max_size = in_size;
> > +     client_data->response.error = 0;
> > +     client_data->response.received = false;
> > +
> > +     rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
> > +     if (rv) {
> > +             dev_err(cl_data_to_dev(client_data),
> > +                     "ishtp_cl_send error %d\n", rv);
> > +             return rv;
> > +     }
> > +
> > +     wait_event_interruptible_timeout(client_data->response.wait_queue,
> > +                                      client_data->response.received,
> > +                                      ISHTP_SEND_TIMEOUT);
> > +     if (!client_data->response.received) {
> > +             dev_err(cl_data_to_dev(client_data),
> > +                     "Timed out for response to host message\n");
> > +             return -ETIMEDOUT;
> > +     }
> > +
> > +     if (client_data->response.error < 0)
> > +             return client_data->response.error;
> > +
> > +     return client_data->response.size;
> > +}
> > +
> > +/**
> > + * process_recv() - Received and parse incoming packet
> > + * @cros_ish_cl: Client instance to get stats
> > + * @rb_in_proc: Host interface message buffer
> > + *
> > + * Parse the incoming packet. If it is a response packet then it will
> > + * update per instance flags and wake up the caller waiting to for the
> > + * response. If it is an event packet then it will schedule event work.
> > + */
> > +static void process_recv(struct ishtp_cl *cros_ish_cl,
> > +                      struct ishtp_cl_rb *rb_in_proc)
> > +{
> > +     size_t data_len = rb_in_proc->buf_idx;
> > +     struct ishtp_cl_data *client_data =
> > +             ishtp_get_client_data(cros_ish_cl);
> > +     struct device *dev = cl_data_to_dev(client_data);
> > +     struct cros_ish_in_msg *in_msg =
> > +             (struct cros_ish_in_msg *)rb_in_proc->buffer.data;
> > +
> > +     /* Proceed only if reset or init is not in progress */
> > +     if (!down_read_trylock(&init_lock)) {
> > +             /* Free the buffer */
> > +             ishtp_cl_io_rb_recycle(rb_in_proc);
> > +             dev_warn(dev,
> > +                      "Host is not ready to receive incoming messages\n");
> > +             return;
> > +     }
> > +
> > +     /*
> > +      * All firmware messages contain a header. Check the buffer size
> > +      * before accessing elements inside.
> > +      */
> > +     if (!rb_in_proc->buffer.data) {
> > +             dev_warn(dev, "rb_in_proc->buffer.data returned null");
> > +             client_data->response.error = -EBADMSG;
> > +             goto end_error;
> > +     }
> > +
> > +     if (data_len < sizeof(struct header)) {
> > +             dev_err(dev, "data size %zu is less than header %zu\n",
> > +                     data_len, sizeof(struct header));
> > +             client_data->response.error = -EMSGSIZE;
> > +             goto end_error;
> > +     }
> > +
> > +     dev_dbg(dev, "channel=%02u status=%02u\n",
> > +             in_msg->hdr.channel, in_msg->hdr.status);
> > +
> > +     switch (in_msg->hdr.channel) {
> > +     case CROS_EC_COMMAND:
> > +             /* Sanity check */
> > +             if (!client_data->response.data) {
> > +                     dev_err(dev,
> > +                             "Receiving buffer is null. Should be allocated by calling function\n");
> > +                     client_data->response.error = -EINVAL;
> > +                     goto error_wake_up;
> > +             }
> > +
> > +             if (client_data->response.received) {
> > +                     dev_err(dev,
> > +                             "Previous firmware message not yet processed\n");
> > +                     client_data->response.error = -EINVAL;
> > +                     goto error_wake_up;
> > +             }
> > +
> > +             if (data_len > client_data->response.max_size) {
> > +                     dev_err(dev,
> > +                             "Received buffer size %zu is larger than allocated buffer %zu\n",
> > +                             data_len, client_data->response.max_size);
> > +                     client_data->response.error = -EMSGSIZE;
> > +                     goto error_wake_up;
> > +             }
> > +
> > +             if (in_msg->hdr.status) {
> > +                     dev_err(dev, "firmware returned status %d\n",
> > +                             in_msg->hdr.status);
> > +                     client_data->response.error = -EIO;
> > +                     goto error_wake_up;
> > +             }
> > +
> > +             /* Update the actual received buffer size */
> > +             client_data->response.size = data_len;
> > +
> > +             /*
> > +              * Copy the buffer received in firmware response for the
> > +              * calling thread.
> > +              */
> > +             memcpy(client_data->response.data,
> > +                    rb_in_proc->buffer.data, data_len);
> > +
> > +             /* Set flag before waking up the caller */
> > +             client_data->response.received = true;
> > +error_wake_up:
> > +             /* Wake the calling thread */
> > +             wake_up_interruptible(&client_data->response.wait_queue);
> > +
> > +             break;
> > +
> > +     case CROS_MKBP_EVENT:
> > +             /* The event system doesn't send any data in buffer */
> > +             schedule_work(&client_data->work_ec_evt);
> > +
> > +             break;
> > +
> > +     default:
> > +             dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
> > +     }
> > +
> > +end_error:
> > +     /* Free the buffer */
> > +     ishtp_cl_io_rb_recycle(rb_in_proc);
> > +
> > +     up_read(&init_lock);
> > +}
> > +
> > +/**
> > + * ish_event_cb() - bus driver callback for incoming message
> > + * @cl_device: ISHTP client device for which this message is targeted.
> > + *
> > + * Remove the packet from the list and process the message by calling
> > + * process_recv.
> > + */
> > +static void ish_event_cb(struct ishtp_cl_device *cl_device)
> > +{
> > +     struct ishtp_cl_rb *rb_in_proc;
> > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +
> > +     while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
> > +             /* Decide what to do with received data */
> > +             process_recv(cros_ish_cl, rb_in_proc);
> > +     }
> > +}
> > +
> > +/**
> > + * cros_ish_init() - Init function for ISHTP client
> > + * @cros_ish_cl: ISHTP client instance
> > + *
> > + * This function complete the initializtion of the client.
> > + *
> > + * Return: 0 for success, negative error code for failure.
> > + */
> > +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
> > +{
> > +     int rv;
> > +     struct ishtp_device *dev;
> > +     struct ishtp_fw_client *fw_client;
> > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > +
> > +     rv = ishtp_cl_link(cros_ish_cl);
> > +     if (rv) {
> > +             dev_err(cl_data_to_dev(client_data),
> > +                     "ishtp_cl_link failed\n");
> > +             return rv;
> > +     }
> > +
> > +     dev = ishtp_get_ishtp_device(cros_ish_cl);
> > +
> > +     /* Connect to firmware client */
> > +     ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
> > +     ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
> > +
> > +     fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
> > +     if (!fw_client) {
> > +             dev_err(cl_data_to_dev(client_data),
> > +                     "ish client uuid not found\n");
> > +             rv = -ENOENT;
> > +             goto err_cl_unlink;
> > +     }
> > +
> > +     ishtp_cl_set_fw_client_id(cros_ish_cl,
> > +                               ishtp_get_fw_client_id(fw_client));
> > +     ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
> > +
> > +     rv = ishtp_cl_connect(cros_ish_cl);
> > +     if (rv) {
> > +             dev_err(cl_data_to_dev(client_data),
> > +                     "client connect fail\n");
> > +             goto err_cl_unlink;
> > +     }
> > +
> > +     ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
> > +     return 0;
> > +
> > +err_cl_unlink:
> > +     ishtp_cl_unlink(cros_ish_cl);
> > +     return rv;
> > +}
> > +
> > +/**
> > + * cros_ish_deinit() - Deinit function for ISHTP client
> > + * @cros_ish_cl: ISHTP client instance
> > + *
> > + * Unlink and free cros_ec client
> > + */
> > +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
> > +{
> > +     ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> > +     ishtp_cl_disconnect(cros_ish_cl);
> > +     ishtp_cl_unlink(cros_ish_cl);
> > +     ishtp_cl_flush_queues(cros_ish_cl);
> > +
> > +     /* Disband and free all Tx and Rx client-level rings */
> > +     ishtp_cl_free(cros_ish_cl);
> > +}
> > +
> > +/**
> > + * prepare_cros_ec_rx() - Check & prepare receive buffer
> > + * @ec_dev: CrOS EC MFD device.
> > + * @in_msg: Incoming message buffer
> > + * @msg: cros_ec command used to send & receive data
> > + *
> > + * Return: 0 for success, negative error code for failure.
> > + *
> > + * Check the received buffer. Convert to cros_ec_command format.
> > + */
> > +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> > +                           const struct cros_ish_in_msg *in_msg,
> > +                           struct cros_ec_command *msg)
> > +{
> > +     u8 sum = 0;
> > +     int i, rv, offset;
> > +
> > +     /* Check response error code */
> > +     msg->result = in_msg->ec_response.result;
> > +     rv = cros_ec_check_result(ec_dev, msg);
> > +     if (rv < 0)
> > +             return rv;
> > +
> > +     if (in_msg->ec_response.data_len > msg->insize) {
> > +             dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
> > +                     in_msg->ec_response.data_len, msg->insize);
> > +             return -ENOSPC;
> > +     }
> > +
> > +     /* Copy response packet payload and compute checksum */
> > +     for (i = 0; i < sizeof(struct ec_host_response); i++)
> > +             sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
> > +
> > +     offset = sizeof(struct cros_ish_in_msg);
> > +     for (i = 0; i < in_msg->ec_response.data_len; i++)
> > +             sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
> > +
> > +     if (sum) {
> > +             dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
> > +             return -EBADMSG;
> > +     }
> > +
> > +     return 0;
> > +}
> > +
> > +static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
> > +                             struct cros_ec_command *msg)
> > +{
> > +     int rv;
> > +     struct ishtp_cl *cros_ish_cl = ec_dev->priv;
> > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > +     struct device *dev = cl_data_to_dev(client_data);
> > +     struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
> > +     struct cros_ish_out_msg *out_msg =
> > +             (struct cros_ish_out_msg *)ec_dev->dout;
> > +     size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
> > +     size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
> > +
> > +     /* Proceed only if reset-init is not in progress */
> > +     if (!down_read_trylock(&init_lock)) {
> > +             dev_warn(dev,
> > +                      "Host is not ready to send messages to ISH. Try again\n");
> > +             return -EAGAIN;
> > +     }
> > +
> > +     /* Sanity checks */
> > +     if (in_size > ec_dev->din_size) {
> > +             dev_err(dev,
> > +                     "Incoming payload size %zu is too large for ec_dev->din_size %d\n",
> > +                     in_size, ec_dev->din_size);
> > +             return -EMSGSIZE;
> > +     }
> > +
> > +     if (out_size > ec_dev->dout_size) {
> > +             dev_err(dev,
> > +                     "Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
> > +                     out_size, ec_dev->dout_size);
> > +             return -EMSGSIZE;
> > +     }
> > +
> > +     /* Prepare the package to be sent over ISH TP */
> > +     out_msg->hdr.channel = CROS_EC_COMMAND;
> > +     out_msg->hdr.status = 0;
> > +
> > +     ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
> > +     cros_ec_prepare_tx(ec_dev, msg);
> > +     ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
> > +
> > +     dev_dbg(dev,
> > +             "out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
> > +             out_msg->ec_request.struct_version,
> > +             out_msg->ec_request.checksum,
> > +             out_msg->ec_request.command,
> > +             out_msg->ec_request.command_version,
> > +             out_msg->ec_request.data_len);
> > +
> > +     /* Send command to ISH EC firmware and read response */
> > +     rv = ish_send(client_data,
> > +                   (u8 *)out_msg, out_size,
> > +                   (u8 *)in_msg, in_size);
> > +     if (rv < 0)
> > +             goto end_error;
> > +
> > +     rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
> > +     if (rv)
> > +             goto end_error;
> > +
> > +     rv = in_msg->ec_response.data_len;
> > +
> > +     dev_dbg(dev,
> > +             "in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
> > +             in_msg->ec_response.struct_version,
> > +             in_msg->ec_response.checksum,
> > +             in_msg->ec_response.result,
> > +             in_msg->ec_response.data_len);
> > +
> > +end_error:
> > +     if (msg->command == EC_CMD_REBOOT_EC)
> > +             msleep(EC_REBOOT_DELAY_MS);
> > +
> > +     up_read(&init_lock);
> > +
> > +     return rv;
> > +}
> > +
> > +static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
> > +{
> > +     struct cros_ec_device *ec_dev;
> > +     struct device *dev = cl_data_to_dev(client_data);
> > +
> > +     ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> > +     if (!ec_dev)
> > +             return -ENOMEM;
> > +
> > +     client_data->ec_dev = ec_dev;
> > +     dev->driver_data = ec_dev;
> > +
> > +     ec_dev->dev = dev;
> > +     ec_dev->priv = client_data->cros_ish_cl;
> > +     ec_dev->cmd_xfer = NULL;
> > +     ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
> > +     ec_dev->phys_name = dev_name(dev);
> > +     ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
> > +                        sizeof(struct ec_response_get_protocol_info);
> > +     ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
> > +
> > +     return cros_ec_register(ec_dev);
> > +}
> > +
> > +static void reset_handler(struct work_struct *work)
> > +{
> > +     int rv;
> > +     struct device *dev;
> > +     struct ishtp_cl *cros_ish_cl;
> > +     struct ishtp_cl_device *cl_device;
> > +     struct ishtp_cl_data *client_data =
> > +             container_of(work, struct ishtp_cl_data, work_ishtp_reset);
> > +
> > +     /* Lock for reset to complete */
> > +     down_write(&init_lock);
> > +
> > +     cros_ish_cl = client_data->cros_ish_cl;
> > +     cl_device = client_data->cl_device;
> > +
> > +     /* Unlink, flush queues & start again */
> > +     ishtp_cl_unlink(cros_ish_cl);
> > +     ishtp_cl_flush_queues(cros_ish_cl);
> > +     ishtp_cl_free(cros_ish_cl);
> > +
> > +     cros_ish_cl = ishtp_cl_allocate(cl_device);
> > +     if (!cros_ish_cl) {
> > +             up_write(&init_lock);
> > +             return;
> > +     }
> > +
> > +     ishtp_set_drvdata(cl_device, cros_ish_cl);
> > +     ishtp_set_client_data(cros_ish_cl, client_data);
> > +     client_data->cros_ish_cl = cros_ish_cl;
> > +
> > +     rv = cros_ish_init(cros_ish_cl);
> > +     if (rv) {
> > +             ishtp_cl_free(cros_ish_cl);
> > +             dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
> > +             up_write(&init_lock);
> > +             return;
> > +     }
> > +
> > +     /* Refresh ec_dev device pointers */
> > +     client_data->ec_dev->priv = client_data->cros_ish_cl;
> > +     dev = cl_data_to_dev(client_data);
> > +     dev->driver_data = client_data->ec_dev;
> > +
> > +     dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
> > +
> > +     up_write(&init_lock);
> > +}
> > +
> > +/**
> > + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
> > + * @cl_device: ISHTP client device instance
> > + *
> > + * Return: 0 for success, negative error code for failure.
> > + */
> > +static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
> > +{
> > +     int rv;
> > +     struct ishtp_cl *cros_ish_cl;
> > +     struct ishtp_cl_data *client_data =
> > +             devm_kzalloc(ishtp_device(cl_device),
> > +                          sizeof(*client_data), GFP_KERNEL);
> > +     if (!client_data)
> > +             return -ENOMEM;
> > +
> > +     /* Lock for initialization to complete */
> > +     down_write(&init_lock);
> > +
> > +     cros_ish_cl = ishtp_cl_allocate(cl_device);
> > +     if (!cros_ish_cl) {
> > +             rv = -ENOMEM;
> > +             goto end_ishtp_cl_alloc_error;
> > +     }
> > +
> > +     ishtp_set_drvdata(cl_device, cros_ish_cl);
> > +     ishtp_set_client_data(cros_ish_cl, client_data);
> > +     client_data->cros_ish_cl = cros_ish_cl;
> > +     client_data->cl_device = cl_device;
> > +
> > +     init_waitqueue_head(&client_data->response.wait_queue);
> > +
> > +     INIT_WORK(&client_data->work_ishtp_reset,
> > +               reset_handler);
> > +     INIT_WORK(&client_data->work_ec_evt,
> > +               ish_evt_handler);
> > +
> > +     rv = cros_ish_init(cros_ish_cl);
> > +     if (rv)
> > +             goto end_ishtp_cl_init_error;
> > +
> > +     ishtp_get_device(cl_device);
> > +
> > +     up_write(&init_lock);
> > +
> > +     /* Register croc_ec_dev mfd */
> > +     rv = cros_ec_dev_init(client_data);
> > +     if (rv)
> > +             goto end_cros_ec_dev_init_error;
> > +
> > +     return 0;
> > +
> > +end_cros_ec_dev_init_error:
> > +     ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> > +     ishtp_cl_disconnect(cros_ish_cl);
> > +     ishtp_cl_unlink(cros_ish_cl);
> > +     ishtp_cl_flush_queues(cros_ish_cl);
> > +     ishtp_put_device(cl_device);
> > +end_ishtp_cl_init_error:
> > +     ishtp_cl_free(cros_ish_cl);
> > +end_ishtp_cl_alloc_error:
> > +     up_write(&init_lock);
> > +     return rv;
> > +}
> > +
> > +/**
> > + * cros_ec_ishtp_remove() - ISHTP client driver remove callback
> > + * @cl_device: ISHTP client device instance
> > + *
> > + * Return: 0
> > + */
> > +static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
> > +{
> > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > +
> > +     cancel_work_sync(&client_data->work_ishtp_reset);
> > +     cancel_work_sync(&client_data->work_ec_evt);
> > +     cros_ish_deinit(cros_ish_cl);
> > +     ishtp_put_device(cl_device);
> > +
> > +     return 0;
> > +}
> > +
> > +/**
> > + * cros_ec_ishtp_reset() - ISHTP client driver reset callback
> > + * @cl_device: ISHTP client device instance
> > + *
> > + * Return: 0
> > + */
> > +static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
> > +{
> > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > +
> > +     schedule_work(&client_data->work_ishtp_reset);
> > +
> > +     return 0;
> > +}
> > +
> > +/**
> > + * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
> > + * @device: device instance
> > + *
> > + * Return: 0 for success, negative error code for failure.
> > + */
> > +static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
> > +{
> > +     struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > +
> > +     return cros_ec_suspend(client_data->ec_dev);
> > +}
> > +
> > +/**
> > + * cros_ec_ishtp_resume() - ISHTP client driver resume callback
> > + * @device: device instance
> > + *
> > + * Return: 0 for success, negative error code for failure.
> > + */
> > +static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
> > +{
> > +     struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > +
> > +     return cros_ec_resume(client_data->ec_dev);
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
> > +                      cros_ec_ishtp_resume);
> > +
> > +static struct ishtp_cl_driver        cros_ec_ishtp_driver = {
> > +     .name = "cros_ec_ishtp",
> > +     .guid = &cros_ish_guid,
> > +     .probe = cros_ec_ishtp_probe,
> > +     .remove = cros_ec_ishtp_remove,
> > +     .reset = cros_ec_ishtp_reset,
> > +     .driver = {
> > +             .pm = &cros_ec_ishtp_pm_ops,
> > +     },
> > +};
> > +
> > +static int __init cros_ec_ishtp_mod_init(void)
> > +{
> > +     return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
> > +}
> > +
> > +static void __exit cros_ec_ishtp_mod_exit(void)
> > +{
> > +     ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
> > +}
> > +
> > +module_init(cros_ec_ishtp_mod_init);
> > +module_exit(cros_ec_ishtp_mod_exit);
> > +
> > +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
> > +MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_ALIAS("ishtp:*");
> >
Rushikesh S Kadam May 16, 2019, 2:46 a.m. UTC | #3
Hi Enric

On Wed, May 15, 2019 at 11:23:13PM +0200, Enric Balletbo Serra wrote:
> Missatge de Enric Balletbo i Serra <enric.balletbo@collabora.com> del
> dia dc., 15 de maig 2019 a les 15:00:
> >
> > Hi,
> >
> > On 4/5/19 15:34, Rushikesh S Kadam wrote:
> > > This driver implements a slim layer to enable the ChromeOS
> > > EC kernel stack (cros_ec) to communicate with ChromeOS EC
> > > firmware running on the Intel Integrated Sensor Hub (ISH).
> > >
> > > The driver registers a ChromeOS EC MFD device to connect
> > > with cros_ec kernel stack (upper layer), and it registers a
> > > client with the ISH Transport Protocol bus (lower layer) to
> > > talk with the ISH firwmare. See description of the ISHTP
> > > protocol at Documentation/hid/intel-ish-hid.txt
> > >
> > > Signed-off-by: Rushikesh S Kadam <rushikesh.s.kadam@intel.com>
> > > Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> > > Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> > > Reviewed-by: Jett Rink <jettrink@chromium.org>
> > > Tested-by: Jett Rink <jettrink@chromium.org>
> > > ---
> >
> > The following patch is queued to the for-next branch for the autobuilders to
> > play with, if all goes well I'll add the patch for 5.3 when current merge window
> > closes.
> >
> 
> Actually, I reverted this patch and applied v6.
> 

Thanks for your help! sorry for the extra effort.

Regards
Rushikesh


> 
> > Thanks,
> >  Enric
> >
> > >
> > > Submitting the patch to linux-input@ per the discussion here
> > > https://lkml.org/lkml/2019/5/2/339
> > >
> > > The patch is baselined to hid git tree, branch for-5.2/ish
> > > https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git/log/?h=for-5.2/ish
> > >
> > > v5
> > >  - Submitting with all Acked-by & Tested-bys. No other changes.
> > >
> > > v4
> > >  - Coding style related changes. No functional changes. Addresses
> > >    review comments on v3.
> > >
> > > v3
> > >  - Made several changes to improve code readability. Replaced
> > >    multiple cl_data_to_dev(client_data) with dev variable. Use
> > >    reverse Xmas tree for variable defintion where it made sense.
> > >    Dropped few debug prints. Add docstring for function
> > >    prepare_cros_ec_rx().
> > >  - Fix code in function prepare_cros_ec_rx() under label
> > >    end_cros_ec_dev_init_error.
> > >  - Recycle buffer in process_recv() on failing to obtain the
> > >    semaphore.
> > >  - Increase ISHTP TX/RX ring buffer size to 8.
> > >  - Alphabetically ordered CROS_EC_ISHTP entries in Makefile and
> > >    Kconfig.
> > >  - Updated commit message.
> > >
> > > v2
> > >  - Dropped unused "reset" parameter in function cros_ec_init()
> > >  - Change driver name to cros_ec_ishtp to be consistent with other
> > >    references in the code.
> > >  - Fixed a few typos.
> > >
> > > v1
> > >  - Initial version
> > >
> > >  drivers/platform/chrome/Kconfig         |  13 +
> > >  drivers/platform/chrome/Makefile        |   1 +
> > >  drivers/platform/chrome/cros_ec_ishtp.c | 763 ++++++++++++++++++++++++++++++++
> > >  3 files changed, 777 insertions(+)
> > >  create mode 100644 drivers/platform/chrome/cros_ec_ishtp.c
> > >
> > > diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> > > index 16b1615..5848179 100644
> > > --- a/drivers/platform/chrome/Kconfig
> > > +++ b/drivers/platform/chrome/Kconfig
> > > @@ -62,6 +62,19 @@ config CROS_EC_I2C
> > >         a checksum. Failing accesses will be retried three times to
> > >         improve reliability.
> > >
> > > +config CROS_EC_ISHTP
> > > +     tristate "ChromeOS Embedded Controller (ISHTP)"
> > > +     depends on MFD_CROS_EC
> > > +     depends on INTEL_ISH_HID
> > > +     help
> > > +       If you say Y here, you get support for talking to the ChromeOS EC
> > > +       firmware running on Intel Integrated Sensor Hub (ISH), using the
> > > +       ISH Transport protocol (ISH-TP). This uses a simple byte-level
> > > +       protocol with a checksum.
> > > +
> > > +       To compile this driver as a module, choose M here: the
> > > +       module will be called cros_ec_ishtp.
> > > +
> > >  config CROS_EC_SPI
> > >       tristate "ChromeOS Embedded Controller (SPI)"
> > >       depends on MFD_CROS_EC && SPI
> > > diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> > > index cd591bf..4efe102 100644
> > > --- a/drivers/platform/chrome/Makefile
> > > +++ b/drivers/platform/chrome/Makefile
> > > @@ -7,6 +7,7 @@ cros_ec_ctl-objs                      := cros_ec_sysfs.o cros_ec_lightbar.o \
> > >                                          cros_ec_vbc.o cros_ec_debugfs.o
> > >  obj-$(CONFIG_CROS_EC_CTL)            += cros_ec_ctl.o
> > >  obj-$(CONFIG_CROS_EC_I2C)            += cros_ec_i2c.o
> > > +obj-$(CONFIG_CROS_EC_ISHTP)          += cros_ec_ishtp.o
> > >  obj-$(CONFIG_CROS_EC_SPI)            += cros_ec_spi.o
> > >  cros_ec_lpcs-objs                    := cros_ec_lpc.o cros_ec_lpc_reg.o
> > >  cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)       += cros_ec_lpc_mec.o
> > > diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
> > > new file mode 100644
> > > index 0000000..997503d
> > > --- /dev/null
> > > +++ b/drivers/platform/chrome/cros_ec_ishtp.c
> > > @@ -0,0 +1,763 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +// ISHTP interface for ChromeOS Embedded Controller
> > > +//
> > > +// Copyright (c) 2019, Intel Corporation.
> > > +//
> > > +// ISHTP client driver for talking to the Chrome OS EC firmware running
> > > +// on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
> > > +// (ISH-TP).
> > > +
> > > +#include <linux/delay.h>
> > > +#include <linux/mfd/core.h>
> > > +#include <linux/mfd/cros_ec.h>
> > > +#include <linux/mfd/cros_ec_commands.h>
> > > +#include <linux/module.h>
> > > +#include <linux/pci.h>
> > > +#include <linux/intel-ish-client-if.h>
> > > +
> > > +/*
> > > + * ISH TX/RX ring buffer pool size
> > > + *
> > > + * The AP->ISH messages and corresponding ISH->AP responses are
> > > + * serialized. We need 1 TX and 1 RX buffer for these.
> > > + *
> > > + * The MKBP ISH->AP events are serialized. We need one additional RX
> > > + * buffer for them.
> > > + */
> > > +#define CROS_ISH_CL_TX_RING_SIZE             8
> > > +#define CROS_ISH_CL_RX_RING_SIZE             8
> > > +
> > > +/* ISH CrOS EC Host Commands */
> > > +enum cros_ec_ish_channel {
> > > +     CROS_EC_COMMAND = 1,                    /* AP->ISH message */
> > > +     CROS_MKBP_EVENT = 2,                    /* ISH->AP events */
> > > +};
> > > +
> > > +/*
> > > + * ISH firmware timeout for 1 message send failure is 1Hz, and the
> > > + * firmware will retry 2 times, so 3Hz is used for timeout.
> > > + */
> > > +#define ISHTP_SEND_TIMEOUT                   (3 * HZ)
> > > +
> > > +/* ISH Transport CrOS EC ISH client unique GUID */
> > > +static const guid_t cros_ish_guid =
> > > +     GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
> > > +               0xb0, 0xd8, 0x9e, 0x7c, 0xda, 0xe0, 0xd6, 0xa0);
> > > +
> > > +struct header {
> > > +     u8 channel;
> > > +     u8 status;
> > > +     u8 reserved[2];
> > > +} __packed;
> > > +
> > > +struct cros_ish_out_msg {
> > > +     struct header hdr;
> > > +     struct ec_host_request ec_request;
> > > +} __packed;
> > > +
> > > +struct cros_ish_in_msg {
> > > +     struct header hdr;
> > > +     struct ec_host_response ec_response;
> > > +} __packed;
> > > +
> > > +#define IN_MSG_EC_RESPONSE_PREAMBLE                                  \
> > > +     offsetof(struct cros_ish_in_msg, ec_response)
> > > +
> > > +#define OUT_MSG_EC_REQUEST_PREAMBLE                                  \
> > > +     offsetof(struct cros_ish_out_msg, ec_request)
> > > +
> > > +#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
> > > +
> > > +/*
> > > + * The Read-Write Semaphore is used to prevent message TX or RX while
> > > + * the ishtp client is being initialized or undergoing reset.
> > > + *
> > > + * The readers are the kernel function calls responsible for IA->ISH
> > > + * and ISH->AP messaging.
> > > + *
> > > + * The writers are .reset() and .probe() function.
> > > + */
> > > +DECLARE_RWSEM(init_lock);
> > > +
> > > +/**
> > > + * struct response_info - Encapsulate firmware response related
> > > + * information for passing between function ish_send() and
> > > + * process_recv() callback.
> > > + *
> > > + * @data: Copy the data received from firmware here.
> > > + * @max_size: Max size allocated for the @data buffer. If the received
> > > + * data exceeds this value, we log an error.
> > > + * @size: Actual size of data received from firmware.
> > > + * @error: 0 for success, negative error code for a failure in process_recv().
> > > + * @received: Set to true on receiving a valid firmware      response to host command
> > > + * @wait_queue: Wait queue for host to wait for firmware response.
> > > + */
> > > +struct response_info {
> > > +     void *data;
> > > +     size_t max_size;
> > > +     size_t size;
> > > +     int error;
> > > +     bool received;
> > > +     wait_queue_head_t wait_queue;
> > > +};
> > > +
> > > +/**
> > > + * struct ishtp_cl_data - Encapsulate per ISH TP Client.
> > > + *
> > > + * @cros_ish_cl: ISHTP firmware client instance.
> > > + * @cl_device: ISHTP client device instance.
> > > + * @response: Response info passing between ish_send() and process_recv().
> > > + * @work_ishtp_reset: Work queue reset handling.
> > > + * @work_ec_evt: Work queue for EC events.
> > > + * @ec_dev: CrOS EC MFD device.
> > > + *
> > > + * This structure is used to store per client data.
> > > + */
> > > +struct ishtp_cl_data {
> > > +     struct ishtp_cl *cros_ish_cl;
> > > +     struct ishtp_cl_device *cl_device;
> > > +
> > > +     /*
> > > +      * Used for passing firmware response information between
> > > +      * ish_send() and process_recv() callback.
> > > +      */
> > > +     struct response_info response;
> > > +
> > > +     struct work_struct work_ishtp_reset;
> > > +     struct work_struct work_ec_evt;
> > > +     struct cros_ec_device *ec_dev;
> > > +};
> > > +
> > > +/**
> > > + * ish_evt_handler - ISH to AP event handler
> > > + * @work: Work struct
> > > + */
> > > +static void ish_evt_handler(struct work_struct *work)
> > > +{
> > > +     struct ishtp_cl_data *client_data =
> > > +             container_of(work, struct ishtp_cl_data, work_ec_evt);
> > > +     struct cros_ec_device *ec_dev = client_data->ec_dev;
> > > +
> > > +     if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
> > > +             blocking_notifier_call_chain(&ec_dev->event_notifier,
> > > +                                          0, ec_dev);
> > > +     }
> > > +}
> > > +
> > > +/**
> > > + * ish_send() - Send message from host to firmware
> > > + *
> > > + * @client_data: Client data instance
> > > + * @out_msg: Message buffer to be sent to firmware
> > > + * @out_size: Size of out going message
> > > + * @in_msg: Message buffer where the incoming data is copied. This buffer
> > > + * is allocated by calling
> > > + * @in_size: Max size of incoming message
> > > + *
> > > + * Return: Number of bytes copied in the in_msg on success, negative
> > > + * error code on failure.
> > > + */
> > > +static int ish_send(struct ishtp_cl_data *client_data,
> > > +                 u8 *out_msg, size_t out_size,
> > > +                 u8 *in_msg, size_t in_size)
> > > +{
> > > +     int rv;
> > > +     struct header *out_hdr = (struct header *)out_msg;
> > > +     struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
> > > +
> > > +     dev_dbg(cl_data_to_dev(client_data),
> > > +             "%s: channel=%02u status=%02u\n",
> > > +             __func__, out_hdr->channel, out_hdr->status);
> > > +
> > > +     /* Setup for incoming response */
> > > +     client_data->response.data = in_msg;
> > > +     client_data->response.max_size = in_size;
> > > +     client_data->response.error = 0;
> > > +     client_data->response.received = false;
> > > +
> > > +     rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
> > > +     if (rv) {
> > > +             dev_err(cl_data_to_dev(client_data),
> > > +                     "ishtp_cl_send error %d\n", rv);
> > > +             return rv;
> > > +     }
> > > +
> > > +     wait_event_interruptible_timeout(client_data->response.wait_queue,
> > > +                                      client_data->response.received,
> > > +                                      ISHTP_SEND_TIMEOUT);
> > > +     if (!client_data->response.received) {
> > > +             dev_err(cl_data_to_dev(client_data),
> > > +                     "Timed out for response to host message\n");
> > > +             return -ETIMEDOUT;
> > > +     }
> > > +
> > > +     if (client_data->response.error < 0)
> > > +             return client_data->response.error;
> > > +
> > > +     return client_data->response.size;
> > > +}
> > > +
> > > +/**
> > > + * process_recv() - Received and parse incoming packet
> > > + * @cros_ish_cl: Client instance to get stats
> > > + * @rb_in_proc: Host interface message buffer
> > > + *
> > > + * Parse the incoming packet. If it is a response packet then it will
> > > + * update per instance flags and wake up the caller waiting to for the
> > > + * response. If it is an event packet then it will schedule event work.
> > > + */
> > > +static void process_recv(struct ishtp_cl *cros_ish_cl,
> > > +                      struct ishtp_cl_rb *rb_in_proc)
> > > +{
> > > +     size_t data_len = rb_in_proc->buf_idx;
> > > +     struct ishtp_cl_data *client_data =
> > > +             ishtp_get_client_data(cros_ish_cl);
> > > +     struct device *dev = cl_data_to_dev(client_data);
> > > +     struct cros_ish_in_msg *in_msg =
> > > +             (struct cros_ish_in_msg *)rb_in_proc->buffer.data;
> > > +
> > > +     /* Proceed only if reset or init is not in progress */
> > > +     if (!down_read_trylock(&init_lock)) {
> > > +             /* Free the buffer */
> > > +             ishtp_cl_io_rb_recycle(rb_in_proc);
> > > +             dev_warn(dev,
> > > +                      "Host is not ready to receive incoming messages\n");
> > > +             return;
> > > +     }
> > > +
> > > +     /*
> > > +      * All firmware messages contain a header. Check the buffer size
> > > +      * before accessing elements inside.
> > > +      */
> > > +     if (!rb_in_proc->buffer.data) {
> > > +             dev_warn(dev, "rb_in_proc->buffer.data returned null");
> > > +             client_data->response.error = -EBADMSG;
> > > +             goto end_error;
> > > +     }
> > > +
> > > +     if (data_len < sizeof(struct header)) {
> > > +             dev_err(dev, "data size %zu is less than header %zu\n",
> > > +                     data_len, sizeof(struct header));
> > > +             client_data->response.error = -EMSGSIZE;
> > > +             goto end_error;
> > > +     }
> > > +
> > > +     dev_dbg(dev, "channel=%02u status=%02u\n",
> > > +             in_msg->hdr.channel, in_msg->hdr.status);
> > > +
> > > +     switch (in_msg->hdr.channel) {
> > > +     case CROS_EC_COMMAND:
> > > +             /* Sanity check */
> > > +             if (!client_data->response.data) {
> > > +                     dev_err(dev,
> > > +                             "Receiving buffer is null. Should be allocated by calling function\n");
> > > +                     client_data->response.error = -EINVAL;
> > > +                     goto error_wake_up;
> > > +             }
> > > +
> > > +             if (client_data->response.received) {
> > > +                     dev_err(dev,
> > > +                             "Previous firmware message not yet processed\n");
> > > +                     client_data->response.error = -EINVAL;
> > > +                     goto error_wake_up;
> > > +             }
> > > +
> > > +             if (data_len > client_data->response.max_size) {
> > > +                     dev_err(dev,
> > > +                             "Received buffer size %zu is larger than allocated buffer %zu\n",
> > > +                             data_len, client_data->response.max_size);
> > > +                     client_data->response.error = -EMSGSIZE;
> > > +                     goto error_wake_up;
> > > +             }
> > > +
> > > +             if (in_msg->hdr.status) {
> > > +                     dev_err(dev, "firmware returned status %d\n",
> > > +                             in_msg->hdr.status);
> > > +                     client_data->response.error = -EIO;
> > > +                     goto error_wake_up;
> > > +             }
> > > +
> > > +             /* Update the actual received buffer size */
> > > +             client_data->response.size = data_len;
> > > +
> > > +             /*
> > > +              * Copy the buffer received in firmware response for the
> > > +              * calling thread.
> > > +              */
> > > +             memcpy(client_data->response.data,
> > > +                    rb_in_proc->buffer.data, data_len);
> > > +
> > > +             /* Set flag before waking up the caller */
> > > +             client_data->response.received = true;
> > > +error_wake_up:
> > > +             /* Wake the calling thread */
> > > +             wake_up_interruptible(&client_data->response.wait_queue);
> > > +
> > > +             break;
> > > +
> > > +     case CROS_MKBP_EVENT:
> > > +             /* The event system doesn't send any data in buffer */
> > > +             schedule_work(&client_data->work_ec_evt);
> > > +
> > > +             break;
> > > +
> > > +     default:
> > > +             dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
> > > +     }
> > > +
> > > +end_error:
> > > +     /* Free the buffer */
> > > +     ishtp_cl_io_rb_recycle(rb_in_proc);
> > > +
> > > +     up_read(&init_lock);
> > > +}
> > > +
> > > +/**
> > > + * ish_event_cb() - bus driver callback for incoming message
> > > + * @cl_device: ISHTP client device for which this message is targeted.
> > > + *
> > > + * Remove the packet from the list and process the message by calling
> > > + * process_recv.
> > > + */
> > > +static void ish_event_cb(struct ishtp_cl_device *cl_device)
> > > +{
> > > +     struct ishtp_cl_rb *rb_in_proc;
> > > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > > +
> > > +     while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
> > > +             /* Decide what to do with received data */
> > > +             process_recv(cros_ish_cl, rb_in_proc);
> > > +     }
> > > +}
> > > +
> > > +/**
> > > + * cros_ish_init() - Init function for ISHTP client
> > > + * @cros_ish_cl: ISHTP client instance
> > > + *
> > > + * This function complete the initializtion of the client.
> > > + *
> > > + * Return: 0 for success, negative error code for failure.
> > > + */
> > > +static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
> > > +{
> > > +     int rv;
> > > +     struct ishtp_device *dev;
> > > +     struct ishtp_fw_client *fw_client;
> > > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > > +
> > > +     rv = ishtp_cl_link(cros_ish_cl);
> > > +     if (rv) {
> > > +             dev_err(cl_data_to_dev(client_data),
> > > +                     "ishtp_cl_link failed\n");
> > > +             return rv;
> > > +     }
> > > +
> > > +     dev = ishtp_get_ishtp_device(cros_ish_cl);
> > > +
> > > +     /* Connect to firmware client */
> > > +     ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
> > > +     ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
> > > +
> > > +     fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
> > > +     if (!fw_client) {
> > > +             dev_err(cl_data_to_dev(client_data),
> > > +                     "ish client uuid not found\n");
> > > +             rv = -ENOENT;
> > > +             goto err_cl_unlink;
> > > +     }
> > > +
> > > +     ishtp_cl_set_fw_client_id(cros_ish_cl,
> > > +                               ishtp_get_fw_client_id(fw_client));
> > > +     ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
> > > +
> > > +     rv = ishtp_cl_connect(cros_ish_cl);
> > > +     if (rv) {
> > > +             dev_err(cl_data_to_dev(client_data),
> > > +                     "client connect fail\n");
> > > +             goto err_cl_unlink;
> > > +     }
> > > +
> > > +     ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
> > > +     return 0;
> > > +
> > > +err_cl_unlink:
> > > +     ishtp_cl_unlink(cros_ish_cl);
> > > +     return rv;
> > > +}
> > > +
> > > +/**
> > > + * cros_ish_deinit() - Deinit function for ISHTP client
> > > + * @cros_ish_cl: ISHTP client instance
> > > + *
> > > + * Unlink and free cros_ec client
> > > + */
> > > +static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
> > > +{
> > > +     ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> > > +     ishtp_cl_disconnect(cros_ish_cl);
> > > +     ishtp_cl_unlink(cros_ish_cl);
> > > +     ishtp_cl_flush_queues(cros_ish_cl);
> > > +
> > > +     /* Disband and free all Tx and Rx client-level rings */
> > > +     ishtp_cl_free(cros_ish_cl);
> > > +}
> > > +
> > > +/**
> > > + * prepare_cros_ec_rx() - Check & prepare receive buffer
> > > + * @ec_dev: CrOS EC MFD device.
> > > + * @in_msg: Incoming message buffer
> > > + * @msg: cros_ec command used to send & receive data
> > > + *
> > > + * Return: 0 for success, negative error code for failure.
> > > + *
> > > + * Check the received buffer. Convert to cros_ec_command format.
> > > + */
> > > +static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
> > > +                           const struct cros_ish_in_msg *in_msg,
> > > +                           struct cros_ec_command *msg)
> > > +{
> > > +     u8 sum = 0;
> > > +     int i, rv, offset;
> > > +
> > > +     /* Check response error code */
> > > +     msg->result = in_msg->ec_response.result;
> > > +     rv = cros_ec_check_result(ec_dev, msg);
> > > +     if (rv < 0)
> > > +             return rv;
> > > +
> > > +     if (in_msg->ec_response.data_len > msg->insize) {
> > > +             dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
> > > +                     in_msg->ec_response.data_len, msg->insize);
> > > +             return -ENOSPC;
> > > +     }
> > > +
> > > +     /* Copy response packet payload and compute checksum */
> > > +     for (i = 0; i < sizeof(struct ec_host_response); i++)
> > > +             sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
> > > +
> > > +     offset = sizeof(struct cros_ish_in_msg);
> > > +     for (i = 0; i < in_msg->ec_response.data_len; i++)
> > > +             sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
> > > +
> > > +     if (sum) {
> > > +             dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
> > > +             return -EBADMSG;
> > > +     }
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
> > > +                             struct cros_ec_command *msg)
> > > +{
> > > +     int rv;
> > > +     struct ishtp_cl *cros_ish_cl = ec_dev->priv;
> > > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > > +     struct device *dev = cl_data_to_dev(client_data);
> > > +     struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
> > > +     struct cros_ish_out_msg *out_msg =
> > > +             (struct cros_ish_out_msg *)ec_dev->dout;
> > > +     size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
> > > +     size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
> > > +
> > > +     /* Proceed only if reset-init is not in progress */
> > > +     if (!down_read_trylock(&init_lock)) {
> > > +             dev_warn(dev,
> > > +                      "Host is not ready to send messages to ISH. Try again\n");
> > > +             return -EAGAIN;
> > > +     }
> > > +
> > > +     /* Sanity checks */
> > > +     if (in_size > ec_dev->din_size) {
> > > +             dev_err(dev,
> > > +                     "Incoming payload size %zu is too large for ec_dev->din_size %d\n",
> > > +                     in_size, ec_dev->din_size);
> > > +             return -EMSGSIZE;
> > > +     }
> > > +
> > > +     if (out_size > ec_dev->dout_size) {
> > > +             dev_err(dev,
> > > +                     "Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
> > > +                     out_size, ec_dev->dout_size);
> > > +             return -EMSGSIZE;
> > > +     }
> > > +
> > > +     /* Prepare the package to be sent over ISH TP */
> > > +     out_msg->hdr.channel = CROS_EC_COMMAND;
> > > +     out_msg->hdr.status = 0;
> > > +
> > > +     ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
> > > +     cros_ec_prepare_tx(ec_dev, msg);
> > > +     ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
> > > +
> > > +     dev_dbg(dev,
> > > +             "out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
> > > +             out_msg->ec_request.struct_version,
> > > +             out_msg->ec_request.checksum,
> > > +             out_msg->ec_request.command,
> > > +             out_msg->ec_request.command_version,
> > > +             out_msg->ec_request.data_len);
> > > +
> > > +     /* Send command to ISH EC firmware and read response */
> > > +     rv = ish_send(client_data,
> > > +                   (u8 *)out_msg, out_size,
> > > +                   (u8 *)in_msg, in_size);
> > > +     if (rv < 0)
> > > +             goto end_error;
> > > +
> > > +     rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
> > > +     if (rv)
> > > +             goto end_error;
> > > +
> > > +     rv = in_msg->ec_response.data_len;
> > > +
> > > +     dev_dbg(dev,
> > > +             "in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
> > > +             in_msg->ec_response.struct_version,
> > > +             in_msg->ec_response.checksum,
> > > +             in_msg->ec_response.result,
> > > +             in_msg->ec_response.data_len);
> > > +
> > > +end_error:
> > > +     if (msg->command == EC_CMD_REBOOT_EC)
> > > +             msleep(EC_REBOOT_DELAY_MS);
> > > +
> > > +     up_read(&init_lock);
> > > +
> > > +     return rv;
> > > +}
> > > +
> > > +static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
> > > +{
> > > +     struct cros_ec_device *ec_dev;
> > > +     struct device *dev = cl_data_to_dev(client_data);
> > > +
> > > +     ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> > > +     if (!ec_dev)
> > > +             return -ENOMEM;
> > > +
> > > +     client_data->ec_dev = ec_dev;
> > > +     dev->driver_data = ec_dev;
> > > +
> > > +     ec_dev->dev = dev;
> > > +     ec_dev->priv = client_data->cros_ish_cl;
> > > +     ec_dev->cmd_xfer = NULL;
> > > +     ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
> > > +     ec_dev->phys_name = dev_name(dev);
> > > +     ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
> > > +                        sizeof(struct ec_response_get_protocol_info);
> > > +     ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
> > > +
> > > +     return cros_ec_register(ec_dev);
> > > +}
> > > +
> > > +static void reset_handler(struct work_struct *work)
> > > +{
> > > +     int rv;
> > > +     struct device *dev;
> > > +     struct ishtp_cl *cros_ish_cl;
> > > +     struct ishtp_cl_device *cl_device;
> > > +     struct ishtp_cl_data *client_data =
> > > +             container_of(work, struct ishtp_cl_data, work_ishtp_reset);
> > > +
> > > +     /* Lock for reset to complete */
> > > +     down_write(&init_lock);
> > > +
> > > +     cros_ish_cl = client_data->cros_ish_cl;
> > > +     cl_device = client_data->cl_device;
> > > +
> > > +     /* Unlink, flush queues & start again */
> > > +     ishtp_cl_unlink(cros_ish_cl);
> > > +     ishtp_cl_flush_queues(cros_ish_cl);
> > > +     ishtp_cl_free(cros_ish_cl);
> > > +
> > > +     cros_ish_cl = ishtp_cl_allocate(cl_device);
> > > +     if (!cros_ish_cl) {
> > > +             up_write(&init_lock);
> > > +             return;
> > > +     }
> > > +
> > > +     ishtp_set_drvdata(cl_device, cros_ish_cl);
> > > +     ishtp_set_client_data(cros_ish_cl, client_data);
> > > +     client_data->cros_ish_cl = cros_ish_cl;
> > > +
> > > +     rv = cros_ish_init(cros_ish_cl);
> > > +     if (rv) {
> > > +             ishtp_cl_free(cros_ish_cl);
> > > +             dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
> > > +             up_write(&init_lock);
> > > +             return;
> > > +     }
> > > +
> > > +     /* Refresh ec_dev device pointers */
> > > +     client_data->ec_dev->priv = client_data->cros_ish_cl;
> > > +     dev = cl_data_to_dev(client_data);
> > > +     dev->driver_data = client_data->ec_dev;
> > > +
> > > +     dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
> > > +
> > > +     up_write(&init_lock);
> > > +}
> > > +
> > > +/**
> > > + * cros_ec_ishtp_probe() - ISHTP client driver probe callback
> > > + * @cl_device: ISHTP client device instance
> > > + *
> > > + * Return: 0 for success, negative error code for failure.
> > > + */
> > > +static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
> > > +{
> > > +     int rv;
> > > +     struct ishtp_cl *cros_ish_cl;
> > > +     struct ishtp_cl_data *client_data =
> > > +             devm_kzalloc(ishtp_device(cl_device),
> > > +                          sizeof(*client_data), GFP_KERNEL);
> > > +     if (!client_data)
> > > +             return -ENOMEM;
> > > +
> > > +     /* Lock for initialization to complete */
> > > +     down_write(&init_lock);
> > > +
> > > +     cros_ish_cl = ishtp_cl_allocate(cl_device);
> > > +     if (!cros_ish_cl) {
> > > +             rv = -ENOMEM;
> > > +             goto end_ishtp_cl_alloc_error;
> > > +     }
> > > +
> > > +     ishtp_set_drvdata(cl_device, cros_ish_cl);
> > > +     ishtp_set_client_data(cros_ish_cl, client_data);
> > > +     client_data->cros_ish_cl = cros_ish_cl;
> > > +     client_data->cl_device = cl_device;
> > > +
> > > +     init_waitqueue_head(&client_data->response.wait_queue);
> > > +
> > > +     INIT_WORK(&client_data->work_ishtp_reset,
> > > +               reset_handler);
> > > +     INIT_WORK(&client_data->work_ec_evt,
> > > +               ish_evt_handler);
> > > +
> > > +     rv = cros_ish_init(cros_ish_cl);
> > > +     if (rv)
> > > +             goto end_ishtp_cl_init_error;
> > > +
> > > +     ishtp_get_device(cl_device);
> > > +
> > > +     up_write(&init_lock);
> > > +
> > > +     /* Register croc_ec_dev mfd */
> > > +     rv = cros_ec_dev_init(client_data);
> > > +     if (rv)
> > > +             goto end_cros_ec_dev_init_error;
> > > +
> > > +     return 0;
> > > +
> > > +end_cros_ec_dev_init_error:
> > > +     ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
> > > +     ishtp_cl_disconnect(cros_ish_cl);
> > > +     ishtp_cl_unlink(cros_ish_cl);
> > > +     ishtp_cl_flush_queues(cros_ish_cl);
> > > +     ishtp_put_device(cl_device);
> > > +end_ishtp_cl_init_error:
> > > +     ishtp_cl_free(cros_ish_cl);
> > > +end_ishtp_cl_alloc_error:
> > > +     up_write(&init_lock);
> > > +     return rv;
> > > +}
> > > +
> > > +/**
> > > + * cros_ec_ishtp_remove() - ISHTP client driver remove callback
> > > + * @cl_device: ISHTP client device instance
> > > + *
> > > + * Return: 0
> > > + */
> > > +static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
> > > +{
> > > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > > +
> > > +     cancel_work_sync(&client_data->work_ishtp_reset);
> > > +     cancel_work_sync(&client_data->work_ec_evt);
> > > +     cros_ish_deinit(cros_ish_cl);
> > > +     ishtp_put_device(cl_device);
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +/**
> > > + * cros_ec_ishtp_reset() - ISHTP client driver reset callback
> > > + * @cl_device: ISHTP client device instance
> > > + *
> > > + * Return: 0
> > > + */
> > > +static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
> > > +{
> > > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > > +
> > > +     schedule_work(&client_data->work_ishtp_reset);
> > > +
> > > +     return 0;
> > > +}
> > > +
> > > +/**
> > > + * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
> > > + * @device: device instance
> > > + *
> > > + * Return: 0 for success, negative error code for failure.
> > > + */
> > > +static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
> > > +{
> > > +     struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> > > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > > +
> > > +     return cros_ec_suspend(client_data->ec_dev);
> > > +}
> > > +
> > > +/**
> > > + * cros_ec_ishtp_resume() - ISHTP client driver resume callback
> > > + * @device: device instance
> > > + *
> > > + * Return: 0 for success, negative error code for failure.
> > > + */
> > > +static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
> > > +{
> > > +     struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
> > > +     struct ishtp_cl *cros_ish_cl = ishtp_get_drvdata(cl_device);
> > > +     struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
> > > +
> > > +     return cros_ec_resume(client_data->ec_dev);
> > > +}
> > > +
> > > +static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
> > > +                      cros_ec_ishtp_resume);
> > > +
> > > +static struct ishtp_cl_driver        cros_ec_ishtp_driver = {
> > > +     .name = "cros_ec_ishtp",
> > > +     .guid = &cros_ish_guid,
> > > +     .probe = cros_ec_ishtp_probe,
> > > +     .remove = cros_ec_ishtp_remove,
> > > +     .reset = cros_ec_ishtp_reset,
> > > +     .driver = {
> > > +             .pm = &cros_ec_ishtp_pm_ops,
> > > +     },
> > > +};
> > > +
> > > +static int __init cros_ec_ishtp_mod_init(void)
> > > +{
> > > +     return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
> > > +}
> > > +
> > > +static void __exit cros_ec_ishtp_mod_exit(void)
> > > +{
> > > +     ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
> > > +}
> > > +
> > > +module_init(cros_ec_ishtp_mod_init);
> > > +module_exit(cros_ec_ishtp_mod_exit);
> > > +
> > > +MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
> > > +MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
> > > +
> > > +MODULE_LICENSE("GPL v2");
> > > +MODULE_ALIAS("ishtp:*");
> > >

--
diff mbox series

Patch

diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 16b1615..5848179 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -62,6 +62,19 @@  config CROS_EC_I2C
 	  a checksum. Failing accesses will be retried three times to
 	  improve reliability.
 
+config CROS_EC_ISHTP
+	tristate "ChromeOS Embedded Controller (ISHTP)"
+	depends on MFD_CROS_EC
+	depends on INTEL_ISH_HID
+	help
+	  If you say Y here, you get support for talking to the ChromeOS EC
+	  firmware running on Intel Integrated Sensor Hub (ISH), using the
+	  ISH Transport protocol (ISH-TP). This uses a simple byte-level
+	  protocol with a checksum.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cros_ec_ishtp.
+
 config CROS_EC_SPI
 	tristate "ChromeOS Embedded Controller (SPI)"
 	depends on MFD_CROS_EC && SPI
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index cd591bf..4efe102 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -7,6 +7,7 @@  cros_ec_ctl-objs			:= cros_ec_sysfs.o cros_ec_lightbar.o \
 					   cros_ec_vbc.o cros_ec_debugfs.o
 obj-$(CONFIG_CROS_EC_CTL)		+= cros_ec_ctl.o
 obj-$(CONFIG_CROS_EC_I2C)		+= cros_ec_i2c.o
+obj-$(CONFIG_CROS_EC_ISHTP)		+= cros_ec_ishtp.o
 obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
 cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_reg.o
 cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC)	+= cros_ec_lpc_mec.o
diff --git a/drivers/platform/chrome/cros_ec_ishtp.c b/drivers/platform/chrome/cros_ec_ishtp.c
new file mode 100644
index 0000000..997503d
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_ishtp.c
@@ -0,0 +1,763 @@ 
+// SPDX-License-Identifier: GPL-2.0
+// ISHTP interface for ChromeOS Embedded Controller
+//
+// Copyright (c) 2019, Intel Corporation.
+//
+// ISHTP client driver for talking to the Chrome OS EC firmware running
+// on Intel Integrated Sensor Hub (ISH) using the ISH Transport protocol
+// (ISH-TP).
+
+#include <linux/delay.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/intel-ish-client-if.h>
+
+/*
+ * ISH TX/RX ring buffer pool size
+ *
+ * The AP->ISH messages and corresponding ISH->AP responses are
+ * serialized. We need 1 TX and 1 RX buffer for these.
+ *
+ * The MKBP ISH->AP events are serialized. We need one additional RX
+ * buffer for them.
+ */
+#define CROS_ISH_CL_TX_RING_SIZE		8
+#define CROS_ISH_CL_RX_RING_SIZE		8
+
+/* ISH CrOS EC Host Commands */
+enum cros_ec_ish_channel {
+	CROS_EC_COMMAND = 1,			/* AP->ISH message */
+	CROS_MKBP_EVENT = 2,			/* ISH->AP events */
+};
+
+/*
+ * ISH firmware timeout for 1 message send failure is 1Hz, and the
+ * firmware will retry 2 times, so 3Hz is used for timeout.
+ */
+#define ISHTP_SEND_TIMEOUT			(3 * HZ)
+
+/* ISH Transport CrOS EC ISH client unique GUID */
+static const guid_t cros_ish_guid =
+	GUID_INIT(0x7b7154d0, 0x56f4, 0x4bdc,
+		  0xb0, 0xd8, 0x9e, 0x7c, 0xda,	0xe0, 0xd6, 0xa0);
+
+struct header {
+	u8 channel;
+	u8 status;
+	u8 reserved[2];
+} __packed;
+
+struct cros_ish_out_msg {
+	struct header hdr;
+	struct ec_host_request ec_request;
+} __packed;
+
+struct cros_ish_in_msg {
+	struct header hdr;
+	struct ec_host_response ec_response;
+} __packed;
+
+#define IN_MSG_EC_RESPONSE_PREAMBLE					\
+	offsetof(struct cros_ish_in_msg, ec_response)
+
+#define OUT_MSG_EC_REQUEST_PREAMBLE					\
+	offsetof(struct cros_ish_out_msg, ec_request)
+
+#define cl_data_to_dev(client_data) ishtp_device((client_data)->cl_device)
+
+/*
+ * The Read-Write Semaphore is used to prevent message TX or RX while
+ * the ishtp client is being initialized or undergoing reset.
+ *
+ * The readers are the kernel function calls responsible for IA->ISH
+ * and ISH->AP messaging.
+ *
+ * The writers are .reset() and .probe() function.
+ */
+DECLARE_RWSEM(init_lock);
+
+/**
+ * struct response_info - Encapsulate firmware response related
+ * information for passing between function ish_send() and
+ * process_recv() callback.
+ *
+ * @data: Copy the data received from firmware here.
+ * @max_size: Max size allocated for the @data buffer. If the received
+ * data exceeds this value, we log an error.
+ * @size: Actual size of data received from firmware.
+ * @error: 0 for success, negative error code for a failure in process_recv().
+ * @received: Set to true on receiving a valid firmware	response to host command
+ * @wait_queue: Wait queue for host to wait for firmware response.
+ */
+struct response_info {
+	void *data;
+	size_t max_size;
+	size_t size;
+	int error;
+	bool received;
+	wait_queue_head_t wait_queue;
+};
+
+/**
+ * struct ishtp_cl_data - Encapsulate per ISH TP Client.
+ *
+ * @cros_ish_cl: ISHTP firmware client instance.
+ * @cl_device: ISHTP client device instance.
+ * @response: Response info passing between ish_send() and process_recv().
+ * @work_ishtp_reset: Work queue reset handling.
+ * @work_ec_evt: Work queue for EC events.
+ * @ec_dev: CrOS EC MFD device.
+ *
+ * This structure is used to store per client data.
+ */
+struct ishtp_cl_data {
+	struct ishtp_cl *cros_ish_cl;
+	struct ishtp_cl_device *cl_device;
+
+	/*
+	 * Used for passing firmware response information between
+	 * ish_send() and process_recv() callback.
+	 */
+	struct response_info response;
+
+	struct work_struct work_ishtp_reset;
+	struct work_struct work_ec_evt;
+	struct cros_ec_device *ec_dev;
+};
+
+/**
+ * ish_evt_handler - ISH to AP event handler
+ * @work: Work struct
+ */
+static void ish_evt_handler(struct work_struct *work)
+{
+	struct ishtp_cl_data *client_data =
+		container_of(work, struct ishtp_cl_data, work_ec_evt);
+	struct cros_ec_device *ec_dev = client_data->ec_dev;
+
+	if (cros_ec_get_next_event(ec_dev, NULL) > 0) {
+		blocking_notifier_call_chain(&ec_dev->event_notifier,
+					     0, ec_dev);
+	}
+}
+
+/**
+ * ish_send() - Send message from host to firmware
+ *
+ * @client_data: Client data instance
+ * @out_msg: Message buffer to be sent to firmware
+ * @out_size: Size of out going message
+ * @in_msg: Message buffer where the incoming data is copied. This buffer
+ * is allocated by calling
+ * @in_size: Max size of incoming message
+ *
+ * Return: Number of bytes copied in the in_msg on success, negative
+ * error code on failure.
+ */
+static int ish_send(struct ishtp_cl_data *client_data,
+		    u8 *out_msg, size_t out_size,
+		    u8 *in_msg, size_t in_size)
+{
+	int rv;
+	struct header *out_hdr = (struct header *)out_msg;
+	struct ishtp_cl *cros_ish_cl = client_data->cros_ish_cl;
+
+	dev_dbg(cl_data_to_dev(client_data),
+		"%s: channel=%02u status=%02u\n",
+		__func__, out_hdr->channel, out_hdr->status);
+
+	/* Setup for incoming response */
+	client_data->response.data = in_msg;
+	client_data->response.max_size = in_size;
+	client_data->response.error = 0;
+	client_data->response.received = false;
+
+	rv = ishtp_cl_send(cros_ish_cl, out_msg, out_size);
+	if (rv) {
+		dev_err(cl_data_to_dev(client_data),
+			"ishtp_cl_send error %d\n", rv);
+		return rv;
+	}
+
+	wait_event_interruptible_timeout(client_data->response.wait_queue,
+					 client_data->response.received,
+					 ISHTP_SEND_TIMEOUT);
+	if (!client_data->response.received) {
+		dev_err(cl_data_to_dev(client_data),
+			"Timed out for response to host message\n");
+		return -ETIMEDOUT;
+	}
+
+	if (client_data->response.error < 0)
+		return client_data->response.error;
+
+	return client_data->response.size;
+}
+
+/**
+ * process_recv() - Received and parse incoming packet
+ * @cros_ish_cl: Client instance to get stats
+ * @rb_in_proc: Host interface message buffer
+ *
+ * Parse the incoming packet. If it is a response packet then it will
+ * update per instance flags and wake up the caller waiting to for the
+ * response. If it is an event packet then it will schedule event work.
+ */
+static void process_recv(struct ishtp_cl *cros_ish_cl,
+			 struct ishtp_cl_rb *rb_in_proc)
+{
+	size_t data_len = rb_in_proc->buf_idx;
+	struct ishtp_cl_data *client_data =
+		ishtp_get_client_data(cros_ish_cl);
+	struct device *dev = cl_data_to_dev(client_data);
+	struct cros_ish_in_msg *in_msg =
+		(struct cros_ish_in_msg *)rb_in_proc->buffer.data;
+
+	/* Proceed only if reset or init is not in progress */
+	if (!down_read_trylock(&init_lock)) {
+		/* Free the buffer */
+		ishtp_cl_io_rb_recycle(rb_in_proc);
+		dev_warn(dev,
+			 "Host is not ready to receive incoming messages\n");
+		return;
+	}
+
+	/*
+	 * All firmware messages contain a header. Check the buffer size
+	 * before accessing elements inside.
+	 */
+	if (!rb_in_proc->buffer.data) {
+		dev_warn(dev, "rb_in_proc->buffer.data returned null");
+		client_data->response.error = -EBADMSG;
+		goto end_error;
+	}
+
+	if (data_len < sizeof(struct header)) {
+		dev_err(dev, "data size %zu is less than header %zu\n",
+			data_len, sizeof(struct header));
+		client_data->response.error = -EMSGSIZE;
+		goto end_error;
+	}
+
+	dev_dbg(dev, "channel=%02u status=%02u\n",
+		in_msg->hdr.channel, in_msg->hdr.status);
+
+	switch (in_msg->hdr.channel) {
+	case CROS_EC_COMMAND:
+		/* Sanity check */
+		if (!client_data->response.data) {
+			dev_err(dev,
+				"Receiving buffer is null. Should be allocated by calling function\n");
+			client_data->response.error = -EINVAL;
+			goto error_wake_up;
+		}
+
+		if (client_data->response.received) {
+			dev_err(dev,
+				"Previous firmware message not yet processed\n");
+			client_data->response.error = -EINVAL;
+			goto error_wake_up;
+		}
+
+		if (data_len > client_data->response.max_size) {
+			dev_err(dev,
+				"Received buffer size %zu is larger than allocated buffer %zu\n",
+				data_len, client_data->response.max_size);
+			client_data->response.error = -EMSGSIZE;
+			goto error_wake_up;
+		}
+
+		if (in_msg->hdr.status) {
+			dev_err(dev, "firmware returned status %d\n",
+				in_msg->hdr.status);
+			client_data->response.error = -EIO;
+			goto error_wake_up;
+		}
+
+		/* Update the actual received buffer size */
+		client_data->response.size = data_len;
+
+		/*
+		 * Copy the buffer received in firmware response for the
+		 * calling thread.
+		 */
+		memcpy(client_data->response.data,
+		       rb_in_proc->buffer.data, data_len);
+
+		/* Set flag before waking up the caller */
+		client_data->response.received = true;
+error_wake_up:
+		/* Wake the calling thread */
+		wake_up_interruptible(&client_data->response.wait_queue);
+
+		break;
+
+	case CROS_MKBP_EVENT:
+		/* The event system doesn't send any data in buffer */
+		schedule_work(&client_data->work_ec_evt);
+
+		break;
+
+	default:
+		dev_err(dev, "Invalid channel=%02d\n", in_msg->hdr.channel);
+	}
+
+end_error:
+	/* Free the buffer */
+	ishtp_cl_io_rb_recycle(rb_in_proc);
+
+	up_read(&init_lock);
+}
+
+/**
+ * ish_event_cb() - bus driver callback for incoming message
+ * @cl_device: ISHTP client device for which this message is targeted.
+ *
+ * Remove the packet from the list and process the message by calling
+ * process_recv.
+ */
+static void ish_event_cb(struct ishtp_cl_device *cl_device)
+{
+	struct ishtp_cl_rb *rb_in_proc;
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+
+	while ((rb_in_proc = ishtp_cl_rx_get_rb(cros_ish_cl)) != NULL) {
+		/* Decide what to do with received data */
+		process_recv(cros_ish_cl, rb_in_proc);
+	}
+}
+
+/**
+ * cros_ish_init() - Init function for ISHTP client
+ * @cros_ish_cl: ISHTP client instance
+ *
+ * This function complete the initializtion of the client.
+ *
+ * Return: 0 for success, negative error code for failure.
+ */
+static int cros_ish_init(struct ishtp_cl *cros_ish_cl)
+{
+	int rv;
+	struct ishtp_device *dev;
+	struct ishtp_fw_client *fw_client;
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	rv = ishtp_cl_link(cros_ish_cl);
+	if (rv) {
+		dev_err(cl_data_to_dev(client_data),
+			"ishtp_cl_link failed\n");
+		return rv;
+	}
+
+	dev = ishtp_get_ishtp_device(cros_ish_cl);
+
+	/* Connect to firmware client */
+	ishtp_set_tx_ring_size(cros_ish_cl, CROS_ISH_CL_TX_RING_SIZE);
+	ishtp_set_rx_ring_size(cros_ish_cl, CROS_ISH_CL_RX_RING_SIZE);
+
+	fw_client = ishtp_fw_cl_get_client(dev, &cros_ish_guid);
+	if (!fw_client) {
+		dev_err(cl_data_to_dev(client_data),
+			"ish client uuid not found\n");
+		rv = -ENOENT;
+		goto err_cl_unlink;
+	}
+
+	ishtp_cl_set_fw_client_id(cros_ish_cl,
+				  ishtp_get_fw_client_id(fw_client));
+	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_CONNECTING);
+
+	rv = ishtp_cl_connect(cros_ish_cl);
+	if (rv) {
+		dev_err(cl_data_to_dev(client_data),
+			"client connect fail\n");
+		goto err_cl_unlink;
+	}
+
+	ishtp_register_event_cb(client_data->cl_device, ish_event_cb);
+	return 0;
+
+err_cl_unlink:
+	ishtp_cl_unlink(cros_ish_cl);
+	return rv;
+}
+
+/**
+ * cros_ish_deinit() - Deinit function for ISHTP client
+ * @cros_ish_cl: ISHTP client instance
+ *
+ * Unlink and free cros_ec client
+ */
+static void cros_ish_deinit(struct ishtp_cl *cros_ish_cl)
+{
+	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
+	ishtp_cl_disconnect(cros_ish_cl);
+	ishtp_cl_unlink(cros_ish_cl);
+	ishtp_cl_flush_queues(cros_ish_cl);
+
+	/* Disband and free all Tx and Rx client-level rings */
+	ishtp_cl_free(cros_ish_cl);
+}
+
+/**
+ * prepare_cros_ec_rx() - Check & prepare receive buffer
+ * @ec_dev: CrOS EC MFD device.
+ * @in_msg: Incoming message buffer
+ * @msg: cros_ec command used to send & receive data
+ *
+ * Return: 0 for success, negative error code for failure.
+ *
+ * Check the received buffer. Convert to cros_ec_command format.
+ */
+static int prepare_cros_ec_rx(struct cros_ec_device *ec_dev,
+			      const struct cros_ish_in_msg *in_msg,
+			      struct cros_ec_command *msg)
+{
+	u8 sum = 0;
+	int i, rv, offset;
+
+	/* Check response error code */
+	msg->result = in_msg->ec_response.result;
+	rv = cros_ec_check_result(ec_dev, msg);
+	if (rv < 0)
+		return rv;
+
+	if (in_msg->ec_response.data_len > msg->insize) {
+		dev_err(ec_dev->dev, "Packet too long (%d bytes, expected %d)",
+			in_msg->ec_response.data_len, msg->insize);
+		return -ENOSPC;
+	}
+
+	/* Copy response packet payload and compute checksum */
+	for (i = 0; i < sizeof(struct ec_host_response); i++)
+		sum += ((u8 *)in_msg)[IN_MSG_EC_RESPONSE_PREAMBLE + i];
+
+	offset = sizeof(struct cros_ish_in_msg);
+	for (i = 0; i < in_msg->ec_response.data_len; i++)
+		sum += msg->data[i] = ((u8 *)in_msg)[offset + i];
+
+	if (sum) {
+		dev_dbg(ec_dev->dev, "Bad received packet checksum %d\n", sum);
+		return -EBADMSG;
+	}
+
+	return 0;
+}
+
+static int cros_ec_pkt_xfer_ish(struct cros_ec_device *ec_dev,
+				struct cros_ec_command *msg)
+{
+	int rv;
+	struct ishtp_cl *cros_ish_cl = ec_dev->priv;
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+	struct device *dev = cl_data_to_dev(client_data);
+	struct cros_ish_in_msg *in_msg = (struct cros_ish_in_msg *)ec_dev->din;
+	struct cros_ish_out_msg *out_msg =
+		(struct cros_ish_out_msg *)ec_dev->dout;
+	size_t in_size = sizeof(struct cros_ish_in_msg) + msg->insize;
+	size_t out_size = sizeof(struct cros_ish_out_msg) + msg->outsize;
+
+	/* Proceed only if reset-init is not in progress */
+	if (!down_read_trylock(&init_lock)) {
+		dev_warn(dev,
+			 "Host is not ready to send messages to ISH. Try again\n");
+		return -EAGAIN;
+	}
+
+	/* Sanity checks */
+	if (in_size > ec_dev->din_size) {
+		dev_err(dev,
+			"Incoming payload size %zu is too large for ec_dev->din_size %d\n",
+			in_size, ec_dev->din_size);
+		return -EMSGSIZE;
+	}
+
+	if (out_size > ec_dev->dout_size) {
+		dev_err(dev,
+			"Outgoing payload size %zu is too large for ec_dev->dout_size %d\n",
+			out_size, ec_dev->dout_size);
+		return -EMSGSIZE;
+	}
+
+	/* Prepare the package to be sent over ISH TP */
+	out_msg->hdr.channel = CROS_EC_COMMAND;
+	out_msg->hdr.status = 0;
+
+	ec_dev->dout += OUT_MSG_EC_REQUEST_PREAMBLE;
+	cros_ec_prepare_tx(ec_dev, msg);
+	ec_dev->dout -= OUT_MSG_EC_REQUEST_PREAMBLE;
+
+	dev_dbg(dev,
+		"out_msg: struct_ver=0x%x checksum=0x%x command=0x%x command_ver=0x%x data_len=0x%x\n",
+		out_msg->ec_request.struct_version,
+		out_msg->ec_request.checksum,
+		out_msg->ec_request.command,
+		out_msg->ec_request.command_version,
+		out_msg->ec_request.data_len);
+
+	/* Send command to ISH EC firmware and read response */
+	rv = ish_send(client_data,
+		      (u8 *)out_msg, out_size,
+		      (u8 *)in_msg, in_size);
+	if (rv < 0)
+		goto end_error;
+
+	rv = prepare_cros_ec_rx(ec_dev, in_msg, msg);
+	if (rv)
+		goto end_error;
+
+	rv = in_msg->ec_response.data_len;
+
+	dev_dbg(dev,
+		"in_msg: struct_ver=0x%x checksum=0x%x result=0x%x data_len=0x%x\n",
+		in_msg->ec_response.struct_version,
+		in_msg->ec_response.checksum,
+		in_msg->ec_response.result,
+		in_msg->ec_response.data_len);
+
+end_error:
+	if (msg->command == EC_CMD_REBOOT_EC)
+		msleep(EC_REBOOT_DELAY_MS);
+
+	up_read(&init_lock);
+
+	return rv;
+}
+
+static int cros_ec_dev_init(struct ishtp_cl_data *client_data)
+{
+	struct cros_ec_device *ec_dev;
+	struct device *dev = cl_data_to_dev(client_data);
+
+	ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
+	if (!ec_dev)
+		return -ENOMEM;
+
+	client_data->ec_dev = ec_dev;
+	dev->driver_data = ec_dev;
+
+	ec_dev->dev = dev;
+	ec_dev->priv = client_data->cros_ish_cl;
+	ec_dev->cmd_xfer = NULL;
+	ec_dev->pkt_xfer = cros_ec_pkt_xfer_ish;
+	ec_dev->phys_name = dev_name(dev);
+	ec_dev->din_size = sizeof(struct cros_ish_in_msg) +
+			   sizeof(struct ec_response_get_protocol_info);
+	ec_dev->dout_size = sizeof(struct cros_ish_out_msg);
+
+	return cros_ec_register(ec_dev);
+}
+
+static void reset_handler(struct work_struct *work)
+{
+	int rv;
+	struct device *dev;
+	struct ishtp_cl *cros_ish_cl;
+	struct ishtp_cl_device *cl_device;
+	struct ishtp_cl_data *client_data =
+		container_of(work, struct ishtp_cl_data, work_ishtp_reset);
+
+	/* Lock for reset to complete */
+	down_write(&init_lock);
+
+	cros_ish_cl = client_data->cros_ish_cl;
+	cl_device = client_data->cl_device;
+
+	/* Unlink, flush queues & start again */
+	ishtp_cl_unlink(cros_ish_cl);
+	ishtp_cl_flush_queues(cros_ish_cl);
+	ishtp_cl_free(cros_ish_cl);
+
+	cros_ish_cl = ishtp_cl_allocate(cl_device);
+	if (!cros_ish_cl) {
+		up_write(&init_lock);
+		return;
+	}
+
+	ishtp_set_drvdata(cl_device, cros_ish_cl);
+	ishtp_set_client_data(cros_ish_cl, client_data);
+	client_data->cros_ish_cl = cros_ish_cl;
+
+	rv = cros_ish_init(cros_ish_cl);
+	if (rv) {
+		ishtp_cl_free(cros_ish_cl);
+		dev_err(cl_data_to_dev(client_data), "Reset Failed\n");
+		up_write(&init_lock);
+		return;
+	}
+
+	/* Refresh ec_dev device pointers */
+	client_data->ec_dev->priv = client_data->cros_ish_cl;
+	dev = cl_data_to_dev(client_data);
+	dev->driver_data = client_data->ec_dev;
+
+	dev_info(cl_data_to_dev(client_data), "Chrome EC ISH reset done\n");
+
+	up_write(&init_lock);
+}
+
+/**
+ * cros_ec_ishtp_probe() - ISHTP client driver probe callback
+ * @cl_device: ISHTP client device instance
+ *
+ * Return: 0 for success, negative error code for failure.
+ */
+static int cros_ec_ishtp_probe(struct ishtp_cl_device *cl_device)
+{
+	int rv;
+	struct ishtp_cl *cros_ish_cl;
+	struct ishtp_cl_data *client_data =
+		devm_kzalloc(ishtp_device(cl_device),
+			     sizeof(*client_data), GFP_KERNEL);
+	if (!client_data)
+		return -ENOMEM;
+
+	/* Lock for initialization to complete */
+	down_write(&init_lock);
+
+	cros_ish_cl = ishtp_cl_allocate(cl_device);
+	if (!cros_ish_cl) {
+		rv = -ENOMEM;
+		goto end_ishtp_cl_alloc_error;
+	}
+
+	ishtp_set_drvdata(cl_device, cros_ish_cl);
+	ishtp_set_client_data(cros_ish_cl, client_data);
+	client_data->cros_ish_cl = cros_ish_cl;
+	client_data->cl_device = cl_device;
+
+	init_waitqueue_head(&client_data->response.wait_queue);
+
+	INIT_WORK(&client_data->work_ishtp_reset,
+		  reset_handler);
+	INIT_WORK(&client_data->work_ec_evt,
+		  ish_evt_handler);
+
+	rv = cros_ish_init(cros_ish_cl);
+	if (rv)
+		goto end_ishtp_cl_init_error;
+
+	ishtp_get_device(cl_device);
+
+	up_write(&init_lock);
+
+	/* Register croc_ec_dev mfd */
+	rv = cros_ec_dev_init(client_data);
+	if (rv)
+		goto end_cros_ec_dev_init_error;
+
+	return 0;
+
+end_cros_ec_dev_init_error:
+	ishtp_set_connection_state(cros_ish_cl, ISHTP_CL_DISCONNECTING);
+	ishtp_cl_disconnect(cros_ish_cl);
+	ishtp_cl_unlink(cros_ish_cl);
+	ishtp_cl_flush_queues(cros_ish_cl);
+	ishtp_put_device(cl_device);
+end_ishtp_cl_init_error:
+	ishtp_cl_free(cros_ish_cl);
+end_ishtp_cl_alloc_error:
+	up_write(&init_lock);
+	return rv;
+}
+
+/**
+ * cros_ec_ishtp_remove() - ISHTP client driver remove callback
+ * @cl_device: ISHTP client device instance
+ *
+ * Return: 0
+ */
+static int cros_ec_ishtp_remove(struct ishtp_cl_device *cl_device)
+{
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	cancel_work_sync(&client_data->work_ishtp_reset);
+	cancel_work_sync(&client_data->work_ec_evt);
+	cros_ish_deinit(cros_ish_cl);
+	ishtp_put_device(cl_device);
+
+	return 0;
+}
+
+/**
+ * cros_ec_ishtp_reset() - ISHTP client driver reset callback
+ * @cl_device: ISHTP client device instance
+ *
+ * Return: 0
+ */
+static int cros_ec_ishtp_reset(struct ishtp_cl_device *cl_device)
+{
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	schedule_work(&client_data->work_ishtp_reset);
+
+	return 0;
+}
+
+/**
+ * cros_ec_ishtp_suspend() - ISHTP client driver suspend callback
+ * @device: device instance
+ *
+ * Return: 0 for success, negative error code for failure.
+ */
+static int __maybe_unused cros_ec_ishtp_suspend(struct device *device)
+{
+	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	return cros_ec_suspend(client_data->ec_dev);
+}
+
+/**
+ * cros_ec_ishtp_resume() - ISHTP client driver resume callback
+ * @device: device instance
+ *
+ * Return: 0 for success, negative error code for failure.
+ */
+static int __maybe_unused cros_ec_ishtp_resume(struct device *device)
+{
+	struct ishtp_cl_device *cl_device = dev_get_drvdata(device);
+	struct ishtp_cl	*cros_ish_cl = ishtp_get_drvdata(cl_device);
+	struct ishtp_cl_data *client_data = ishtp_get_client_data(cros_ish_cl);
+
+	return cros_ec_resume(client_data->ec_dev);
+}
+
+static SIMPLE_DEV_PM_OPS(cros_ec_ishtp_pm_ops, cros_ec_ishtp_suspend,
+			 cros_ec_ishtp_resume);
+
+static struct ishtp_cl_driver	cros_ec_ishtp_driver = {
+	.name = "cros_ec_ishtp",
+	.guid = &cros_ish_guid,
+	.probe = cros_ec_ishtp_probe,
+	.remove = cros_ec_ishtp_remove,
+	.reset = cros_ec_ishtp_reset,
+	.driver = {
+		.pm = &cros_ec_ishtp_pm_ops,
+	},
+};
+
+static int __init cros_ec_ishtp_mod_init(void)
+{
+	return ishtp_cl_driver_register(&cros_ec_ishtp_driver, THIS_MODULE);
+}
+
+static void __exit cros_ec_ishtp_mod_exit(void)
+{
+	ishtp_cl_driver_unregister(&cros_ec_ishtp_driver);
+}
+
+module_init(cros_ec_ishtp_mod_init);
+module_exit(cros_ec_ishtp_mod_exit);
+
+MODULE_DESCRIPTION("ChromeOS EC ISHTP Client Driver");
+MODULE_AUTHOR("Rushikesh S Kadam <rushikesh.s.kadam@intel.com>");
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("ishtp:*");