drivers: gpio: add virtio-gpio guest driver

Message ID	20210615174911.973-1-info@metux.net (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=FzV5=LJ=lists.infradead.org=linux-riscv-bounces+linux-riscv=archiver.kernel.org@kernel.org> DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B986610C8 From: "Enrico Weigelt, metux IT consult" <info@metux.net> To: linux-kernel@vger.kernel.org Cc: corbet@lwn.net, linus.walleij@linaro.org, bgolaszewski@baylibre.com, info@metux.net, mst@redhat.com, jasowang@redhat.com, keescook@chromium.org, anton@enomsg.org, ccross@android.com, tony.luck@intel.com, linux-doc@vger.kernel.org, linux-gpio@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-riscv@lists.infradead.org Subject: [PATCH] drivers: gpio: add virtio-gpio guest driver Date: Tue, 15 Jun 2021 19:49:11 +0200 Message-Id: <20210615174911.973-1-info@metux.net> MIME-Version: 1.0 Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" <linux-riscv-bounces@lists.infradead.org> Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org
Series	drivers: gpio: add virtio-gpio guest driver \| expand drivers: gpio: add virtio-gpio guest driver

diff --git a/Documentation/gpio/virtio-gpio.rst b/Documentation/gpio/virtio-gpio.rst new file mode 100644 index 000000000000..5fcc93f51174 --- /dev/null +++ b/Documentation/gpio/virtio-gpio.rst @@ -0,0 +1,195 @@ +=================== +Virtio-GPIO protocol specification +=================== +........... +Specification for virtio-based GPIO devices +........... + ++------------ ++Version_ 1.0 ++------------ + +General +=================== + +The virtio-gpio protocol provides access to general purpose IO devices via +virtio interfaces, used by many virtual machine monitors as well as hardware +fabrics. In VM setups, these GPIOs could be either provided by some simulator +(e.g. virtual HIL), routed to some external device or routed to real GPIOs on +the host (e.g. virtualized embedded applications). + +Instead of simulating some existing real GPIO chip within an VMM, this +protocol provides a hardware independent interface between CPU and device +that solely relies on an active virtio connection (no matter which transport +actually used), no other buses or additional platform driver logic required. + +At the same time, this protocol be implemented directly in virtio attached +hardware, FPGAs or tiny MCUs. + +Protocol layout +=================== + +Configuration space +---------------------- + ++--------+----------+-------------------------------+ +| Offset | Type | Description | ++========+==========+===============================+ +| 0x00 | u8 | version | ++--------+----------+-------------------------------+ +| 0x02 | u16 | number of GPIO lines | ++--------+----------+-------------------------------+ +| 0x04 | u32 | size of gpio name block | ++--------+----------+-------------------------------+ +| 0x20 | char[32] | device name (0-terminated) | ++--------+----------+-------------------------------+ +| 0x40 | char[] | line names block | ++--------+----------+-------------------------------+ + +- for version field currently only value 1 supported. +- the line names block holds a stream of zero-terminated strings, + containing the individual line names in ASCII. line names must unique. +- unspecified fields are reserved for future use and should be zero. + +Virtqueues and messages: +------------------------ + +- Queue #0: transmission from device to CPU +- Queue #1: transmission from CPU to device + +The queues transport messages of the struct virtio_gpio_msg: + +Message format: +~~~~~~~~~~~~~~~ + ++--------+----------+---------------+ +| Offset | Type | Description | ++========+==========+===============+ +| 0x00 | uint16 | message type | ++--------+----------+---------------+ +| 0x02 | uint16 | line id | ++--------+----------+---------------+ +| 0x04 | uint32 | value | ++--------+----------+---------------+ + +Message types: +~~~~~~~~~~~~~~ + ++---------+----------------------------------------+-----------------------------+ +| Code | Symbol | | ++=========+========================================+=============================+ +| 0x0001 | VIRTIO_GPIO_MSG_CPU_REQUEST | request gpio line | ++---------+----------------------------------------+-----------------------------+ +| 0x0002 | VIRTIO_GPIO_MSG_CPU_DIRECTION_INPUT | set direction to input | ++---------+----------------------------------------+-----------------------------+ +| 0x0003 | VIRTIO_GPIO_MSG_CPU_DIRECTION_OUTPUT | set direction to output | ++---------+----------------------------------------+-----------------------------+ +| 0x0004 | VIRTIO_GPIO_MSG_CPU_GET_DIRECTION | read current direction | ++---------+----------------------------------------+-----------------------------+ +| 0x0005 | VIRTIO_GPIO_MSG_CPU_GET_LEVEL | read current level | ++---------+----------------------------------------+-----------------------------+ +| 0x0006 | VIRTIO_GPIO_MSG_CPU_SET_LEVEL | set current (out) level | ++---------+----------------------------------------+-----------------------------+ +| 0x0011 | VIRTIO_GPIO_MSG_DEVICE_LEVEL | state changed (device->CPU) | ++---------+----------------------------------------+-----------------------------+ +| 0x8000 | VIRTIO_GPIO_MSG_REPLY | device reply mask | ++---------+----------------------------------------+-----------------------------+ + +Data flow: +---------------------- + +- all operations, except ``VIRTIO_GPIO_MSG_DEVICE_LEVEL``, are initiated by CPU +- device replies with the orinal ``type`` value OR'ed with ``VIRTIO_GPIO_MSG_REPLY`` +- ``VIRTIO_GPIO_MSG_DEVICE_LEVEL`` is only sent asynchronously from device to CPU +- in replies, a negative ``value`` field denotes an Unix-style / POSIX errno code +- valid direction values are: + * 0 = output + * 1 = input +- valid line state values are: + * 0 = inactive + * 1 = active + +VIRTIO_GPIO_MSG_CPU_REQUEST +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- notify the device that given line# is going to be used +- request: + * ``line`` field: line number + * ``value`` field: unused +- reply: + * ``value`` field: errno code (0 = success) + +VIRTIO_GPIO_MSG_CPU_DIRECTION_INPUT +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- set line line direction to input +- request: + * ``line`` field: line number + * ``value`` field: unused +- reply: value field holds errno + * ``value`` field: errno code (0 = success) + +VIRTIO_GPIO_MSG_CPU_DIRECTION_OUTPUT +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- set line direction to output and given line state +- request: + * ``line`` field: line number + * ``value`` field: output state (0=inactive, 1=active) +- reply: + * ``value`` field: holds errno + +VIRTIO_GPIO_MSG_CPU_GET_DIRECTION +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- retrieve line direction +- request: + * ``line`` field: line number + * ``value`` field: unused +- reply: + * ``value`` field: direction (0=output, 1=input) or errno code + +VIRTIO_GPIO_MSG_CPU_GET_LEVEL +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- retrieve line state value +- request: + * ``line`` field: line number + * ``value`` field: unused +- reply: + * ``value`` field: line state (0=inactive, 1=active) or errno code + +VIRTIO_GPIO_MSG_CPU_SET_LEVEL +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- set line state value (output only) +- request: + * ``line`` field: line number + * ``value`` field: line state (0=inactive, 1=active) +- reply: + * ``value`` field: new line state or errno code + +VIRTIO_GPIO_MSG_DEVICE_LEVEL +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +- async notification from device to CPU: line state changed +- ``line`` field: line number +- ``value`` field: new line state (0=inactive, 1=active) + +Request concurrency +=================== + +- CPU may send multiple request in serial, as long as the virtio queue + is not exceeded +- device replies must be sent in the same order than the CPU requests +- CPU should process asynchronous messages from device as soon as possible, + in order to avoid missing messages due to queue overrun + +Future versions +=================== + +- future versions must increment the ``version`` value +- the basic data structures (config space, message format) should remain + backwards compatible, but may increased in size or use reserved fields +- device needs to support commands in older versions +- CPU should not send commands of newer versions that the device doesn't support diff --git a/MAINTAINERS b/MAINTAINERS index bc0ceef87b73..1189ae5b442b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -19397,6 +19397,12 @@ F: Documentation/filesystems/virtiofs.rst F: fs/fuse/virtio_fs.c F: include/uapi/linux/virtio_fs.h +VIRTIO GPIO DRIVER +M: Enrico Weigelt, metux IT consult <info@metux.net> +S: Maintained +F: drivers/gpio/gpio-virtio.c +F: include/uapi/linux/virtio_gpio.h + VIRTIO GPU DRIVER M: David Airlie <airlied@linux.ie> M: Gerd Hoffmann <kraxel@redhat.com> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 1dd0ec6727fd..b9871e5b3c74 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -1655,6 +1655,13 @@ config GPIO_MOCKUP tools/testing/selftests/gpio/gpio-mockup.sh. Reference the usage in it. +config GPIO_VIRTIO + tristate "VirtIO GPIO support" + select VIRTIO + select GPIOLIB_IRQCHIP + help + Say Y here to enable guest support for virtio-based GPIOs. + endmenu endif diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index d7c81e1611a4..ba42e6549c87 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -162,6 +162,7 @@ obj-$(CONFIG_GPIO_TWL4030) += gpio-twl4030.o obj-$(CONFIG_GPIO_TWL6040) += gpio-twl6040.o obj-$(CONFIG_GPIO_UCB1400) += gpio-ucb1400.o obj-$(CONFIG_GPIO_UNIPHIER) += gpio-uniphier.o +obj-$(CONFIG_GPIO_VIRTIO) += gpio-virtio.o obj-$(CONFIG_GPIO_VF610) += gpio-vf610.o obj-$(CONFIG_GPIO_VIPERBOARD) += gpio-viperboard.o obj-$(CONFIG_GPIO_VISCONTI) += gpio-visconti.o diff --git a/drivers/gpio/gpio-virtio.c b/drivers/gpio/gpio-virtio.c new file mode 100644 index 000000000000..4938cd0350ff --- /dev/null +++ b/drivers/gpio/gpio-virtio.c @@ -0,0 +1,384 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/* + * GPIO driver for virtio-based virtual GPIOs + * + * Copyright (C) 2018 metux IT consult + * Author: Enrico Weigelt, metux IT consult <info@metux.net> + * + */ + +#include <linux/err.h> +#include <linux/gpio/driver.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/virtio_config.h> +#include <uapi/linux/virtio_ids.h> +#include <uapi/linux/virtio_gpio.h> + +#define CONFIG_VIRTIO_GPIO_MAX_IRQ 256 + +#define MSG_BUF_SZ (sizeof(struct virtio_gpio_msg)) + +struct virtio_gpio_priv { + struct gpio_chip gc; + spinlock_t vq_lock; + struct virtio_device *vdev; + int num_gpios; + char *name; + struct virtqueue *vq_rx; + struct virtqueue *vq_tx; + struct virtio_gpio_msg last; + wait_queue_head_t waitq; + unsigned long reply_wait; + struct irq_chip irq_chip; + DECLARE_BITMAP(irq_mask, CONFIG_VIRTIO_GPIO_MAX_IRQ); + unsigned int irq_parents; + struct mutex rpc_mutex; +}; + +static int virtio_gpio_prepare_inbuf(struct virtio_gpio_priv *priv) +{ + struct scatterlist rcv_sg; + struct virtio_gpio_msg *buf; + + buf = devm_kzalloc(&priv->vdev->dev, MSG_BUF_SZ, GFP_KERNEL); + if (!buf) { + dev_err(&priv->vdev->dev, "failed to allocate input buffer\n"); + return -ENOMEM; + } + + sg_init_one(&rcv_sg, buf, sizeof(struct virtio_gpio_priv)); + virtqueue_add_inbuf(priv->vq_rx, &rcv_sg, 1, buf, GFP_KERNEL); + virtqueue_kick(priv->vq_rx); + + return 0; +} + +static int virtio_gpio_xmit(struct virtio_gpio_priv *priv, int type, + int pin, int value, struct virtio_gpio_msg *ev) +{ + struct scatterlist xmit_sg; + int ret; + unsigned long flags; + + ev->type = cpu_to_le16(type); + ev->pin = cpu_to_le16(pin); + ev->value = cpu_to_le32(value); + + sg_init_one(&xmit_sg, ev, MSG_BUF_SZ); + spin_lock_irqsave(&priv->vq_lock, flags); + ret = virtqueue_add_outbuf(priv->vq_tx, &xmit_sg, 1, priv, GFP_KERNEL); + if (ret < 0) { + dev_err(&priv->vdev->dev, + "virtqueue_add_outbuf() failed: %d\n", ret); + goto out; + } + virtqueue_kick(priv->vq_tx); + +out: + spin_unlock_irqrestore(&priv->vq_lock, flags); + return ret; +} + +static inline void wakeup_event(struct virtio_gpio_priv *priv, int id) +{ + set_bit(id, &priv->reply_wait); +} + +static inline int check_event(struct virtio_gpio_priv *priv, int id) +{ + return test_bit(id, &priv->reply_wait); +} + +static inline void clear_event(struct virtio_gpio_priv *priv, int id) +{ + clear_bit(id, &priv->reply_wait); +} + +static int virtio_gpio_rpc(struct virtio_gpio_priv *priv, int type, + int pin, int value) +{ + int ret; + struct virtio_gpio_msg *buf = kzalloc(MSG_BUF_SZ, GFP_KERNEL); + + if (!buf) + return -ENOMEM; + + mutex_lock(&priv->rpc_mutex); + virtio_gpio_prepare_inbuf(priv); + clear_event(priv, type); + + ret = virtio_gpio_xmit(priv, type, pin, value, buf); + if (ret) + goto out; + + wait_event_interruptible(priv->waitq, check_event(priv, type)); + ret = priv->last.value; + +out: + mutex_unlock(&priv->rpc_mutex); + kfree(buf); + return ret; +} + +static int virtio_gpio_direction_input(struct gpio_chip *gc, + unsigned int pin) +{ + return virtio_gpio_rpc(gpiochip_get_data(gc), + VIRTIO_GPIO_MSG_CPU_DIRECTION_INPUT, + pin, 0); +} + +static int virtio_gpio_direction_output(struct gpio_chip *gc, + unsigned int pin, int value) +{ + return virtio_gpio_rpc(gpiochip_get_data(gc), + VIRTIO_GPIO_MSG_CPU_DIRECTION_OUTPUT, + pin, value); +} + +static int virtio_gpio_get_direction(struct gpio_chip *gc, unsigned int pin) +{ + return virtio_gpio_rpc(gpiochip_get_data(gc), + VIRTIO_GPIO_MSG_CPU_GET_DIRECTION, + pin, 0); +} + +static void virtio_gpio_set(struct gpio_chip *gc, + unsigned int pin, int value) +{ + virtio_gpio_rpc(gpiochip_get_data(gc), + VIRTIO_GPIO_MSG_CPU_SET_LEVEL, pin, value); +} + +static int virtio_gpio_get(struct gpio_chip *gc, + unsigned int pin) +{ + return virtio_gpio_rpc(gpiochip_get_data(gc), + VIRTIO_GPIO_MSG_CPU_GET_LEVEL, pin, 0); +} + +static int virtio_gpio_request(struct gpio_chip *gc, + unsigned int pin) +{ + return virtio_gpio_rpc(gpiochip_get_data(gc), + VIRTIO_GPIO_MSG_CPU_REQUEST, pin, 0); +} + +static void virtio_gpio_signal(struct virtio_gpio_priv *priv, int event, + int pin, int value) +{ + int mapped_irq = irq_find_mapping(priv->gc.irq.domain, pin); + + if ((pin < priv->num_gpios) && test_bit(pin, priv->irq_mask)) + generic_handle_irq(mapped_irq); +} + +static void virtio_gpio_data_rx(struct virtqueue *vq) +{ + struct virtio_gpio_priv *priv = vq->vdev->priv; + void *data; + unsigned int len; + struct virtio_gpio_msg *ev; + + data = virtqueue_get_buf(priv->vq_rx, &len); + if (!data || !len) { + dev_warn(&vq->vdev->dev, "RX received no data ! %d\n", len); + return; + } + + ev = data; + + memcpy(&priv->last, data, MSG_BUF_SZ); + + ev->type = le16_to_cpu(ev->type); + ev->pin = le16_to_cpu(ev->pin); + ev->value = le32_to_cpu(ev->value); + + switch (ev->type) { + case VIRTIO_GPIO_MSG_DEVICE_LEVEL: + virtio_gpio_prepare_inbuf(priv); + virtio_gpio_signal(priv, ev->type, ev->pin, ev->value); + break; + default: + wakeup_event(priv, ev->type & ~VIRTIO_GPIO_MSG_REPLY); + break; + } + + wake_up_all(&priv->waitq); + + devm_kfree(&priv->vdev->dev, data); +} + +static int virtio_gpio_alloc_vq(struct virtio_gpio_priv *priv) +{ + struct virtqueue *vqs[2]; + vq_callback_t *cbs[] = { + NULL, + virtio_gpio_data_rx, + }; + static const char * const names[] = { "in", "out", }; + int ret; + + ret = virtio_find_vqs(priv->vdev, 2, vqs, cbs, names, NULL); + if (ret) { + dev_err(&priv->vdev->dev, "failed to alloc vqs: %d\n", ret); + return ret; + } + + priv->vq_rx = vqs[0]; + priv->vq_tx = vqs[1]; + + ret = virtio_gpio_prepare_inbuf(priv); + if (ret) { + dev_err(&priv->vdev->dev, "preparing inbuf failed\n"); + return ret; + } + + virtqueue_enable_cb(priv->vq_rx); + virtio_device_ready(priv->vdev); + + return 0; +} + +static void virtio_gpio_irq_unmask(struct irq_data *irq) +{ + int hwirq = irqd_to_hwirq(irq); + struct virtio_gpio_priv *priv + = gpiochip_get_data(irq_data_get_irq_chip_data(irq)); + if (hwirq < CONFIG_VIRTIO_GPIO_MAX_IRQ) + set_bit(hwirq, priv->irq_mask); +} + +static void virtio_gpio_irq_mask(struct irq_data *irq) +{ + int hwirq = irqd_to_hwirq(irq); + struct virtio_gpio_priv *priv + = gpiochip_get_data(irq_data_get_irq_chip_data(irq)); + if (hwirq < CONFIG_VIRTIO_GPIO_MAX_IRQ) + clear_bit(hwirq, priv->irq_mask); +} + +static int virtio_gpio_probe(struct virtio_device *vdev) +{ + struct virtio_gpio_priv *priv; + struct virtio_gpio_config cf = {}; + char *name_buffer; + const char **gpio_names = NULL; + struct device *dev = &vdev->dev; + struct gpio_irq_chip *girq; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->name = devm_kzalloc(dev, sizeof(cf.name)+1, GFP_KERNEL); + if (!priv->name) + return -ENOMEM; + + spin_lock_init(&priv->vq_lock); + mutex_init(&priv->rpc_mutex); + + virtio_cread_le(vdev, struct virtio_gpio_config, version, &cf.version); + virtio_cread_le(vdev, struct virtio_gpio_config, num_gpios, + &cf.num_gpios); + virtio_cread_le(vdev, struct virtio_gpio_config, names_size, + &cf.names_size); + virtio_cread_bytes(vdev, offsetof(struct virtio_gpio_config, name), + priv->name, sizeof(cf.name)); + + if (cf.version != 1) { + dev_err(dev, "unsupported interface version %d\n", cf.version); + return -EINVAL; + } + + priv->num_gpios = cf.num_gpios; + + if (cf.names_size) { + char *bufwalk; + int idx = 0; + + name_buffer = devm_kzalloc(&vdev->dev, cf.names_size, + GFP_KERNEL)+1; + virtio_cread_bytes(vdev, sizeof(struct virtio_gpio_config), + name_buffer, cf.names_size); + name_buffer[cf.names_size] = 0; + + gpio_names = devm_kcalloc(dev, priv->num_gpios, sizeof(char *), + GFP_KERNEL); + bufwalk = name_buffer; + + while (idx < priv->num_gpios && + bufwalk < (name_buffer+cf.names_size)) { + gpio_names[idx] = (strlen(bufwalk) ? bufwalk : NULL); + bufwalk += strlen(bufwalk)+1; + idx++; + } + } + + priv->vdev = vdev; + vdev->priv = priv; + + priv->gc.owner = THIS_MODULE; + priv->gc.parent = dev; + priv->gc.label = (priv->name[0] ? priv->name + : dev_name(dev)); + priv->gc.ngpio = priv->num_gpios; + priv->gc.names = gpio_names; + priv->gc.base = -1; + priv->gc.request = virtio_gpio_request; + priv->gc.direction_input = virtio_gpio_direction_input; + priv->gc.direction_output = virtio_gpio_direction_output; + priv->gc.get_direction = virtio_gpio_get_direction; + priv->gc.get = virtio_gpio_get; + priv->gc.set = virtio_gpio_set; + priv->gc.can_sleep = true; + + priv->irq_chip.name = "virtio-gpio-irq"; + priv->irq_chip.irq_mask = virtio_gpio_irq_mask; + priv->irq_chip.irq_unmask = virtio_gpio_irq_unmask; + + girq = &priv->gc.irq; + + priv->gc.irq.chip = &priv->irq_chip; + priv->gc.irq.num_parents = 1; + priv->gc.irq.default_type = IRQ_TYPE_NONE; + priv->gc.irq.handler = handle_simple_irq; + priv->gc.irq.parents = &priv->irq_parents; + priv->irq_parents = 0; + + init_waitqueue_head(&priv->waitq); + + priv->reply_wait = 0; + + virtio_gpio_alloc_vq(priv); + + return devm_gpiochip_add_data(dev, &priv->gc, priv); +} + +static void virtio_gpio_remove(struct virtio_device *vdev) +{ + /* just dummy, virtio subsys can't cope w/ NULL vector */ +} + +static const struct virtio_device_id id_table[] = { + { VIRTIO_ID_GPIO, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static struct virtio_driver virtio_gpio_driver = { + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .id_table = id_table, + .probe = virtio_gpio_probe, + .remove = virtio_gpio_remove, +}; + +module_virtio_driver(virtio_gpio_driver); + +MODULE_AUTHOR("Enrico Weigelt, metux IT consult <info@metux.net>"); +MODULE_DESCRIPTION("VirtIO GPIO driver"); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/virtio_gpio.h b/include/uapi/linux/virtio_gpio.h new file mode 100644 index 000000000000..5b90acae6c85 --- /dev/null +++ b/include/uapi/linux/virtio_gpio.h @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ + +#ifndef _LINUX_VIRTIO_GPIO_H +#define _LINUX_VIRTIO_GPIO_H + +#include <linux/types.h> + +enum virtio_gpio_msg_type { + // requests from cpu to device + VIRTIO_GPIO_MSG_CPU_REQUEST = 0x01, + VIRTIO_GPIO_MSG_CPU_DIRECTION_INPUT = 0x02, + VIRTIO_GPIO_MSG_CPU_DIRECTION_OUTPUT = 0x03, + VIRTIO_GPIO_MSG_CPU_GET_DIRECTION = 0x04, + VIRTIO_GPIO_MSG_CPU_GET_LEVEL = 0x05, + VIRTIO_GPIO_MSG_CPU_SET_LEVEL = 0x06, + + // messages from host to guest + VIRTIO_GPIO_MSG_DEVICE_LEVEL = 0x11, // gpio state changed + + /* mask bit set on host->guest reply */ + VIRTIO_GPIO_MSG_REPLY = 0x8000, +}; + +struct virtio_gpio_config { + __u8 version; + __u8 reserved0; + __u16 num_gpios; + __u32 names_size; + __u8 reserved1[24]; + __u8 name[32]; +}; + +struct virtio_gpio_msg { + __le16 type; + __le16 pin; + __le32 value; +}; + +#endif /* _LINUX_VIRTIO_GPIO_H */ diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h index 4fe842c3a3a9..0c9bac389ce0 100644 --- a/include/uapi/linux/virtio_ids.h +++ b/include/uapi/linux/virtio_ids.h @@ -56,5 +56,6 @@ #define VIRTIO_ID_PMEM 27 /* virtio pmem */ #define VIRTIO_ID_MAC80211_HWSIM 29 /* virtio mac80211-hwsim */ #define VIRTIO_ID_BT 40 /* virtio bluetooth */ +#define VIRTIO_ID_GPIO 41 /* virtio GPIO */ #endif /* _LINUX_VIRTIO_IDS_H */

drivers: gpio: add virtio-gpio guest driver

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