[v2] bus: mhi: Add Qcom WWAN control driver

Message ID	1615237167-19969-1-git-send-email-loic.poulain@linaro.org (mailing list archive)
State	Deferred
Delegated to:	Netdev Maintainers
Headers	show Return-Path: <netdev-owner@kernel.org> From: Loic Poulain <loic.poulain@linaro.org> To: manivannan.sadhasivam@linaro.org, hemantk@codeaurora.org, gregkh@linuxfoundation.org Cc: linux-arm-msm@vger.kernel.org, aleksander@aleksander.es, linux-kernel@vger.kernel.org, kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, bjorn.andersson@linaro.org, Loic Poulain <loic.poulain@linaro.org> Subject: [PATCH v2] bus: mhi: Add Qcom WWAN control driver Date: Mon, 8 Mar 2021 21:59:27 +0100 Message-Id: <1615237167-19969-1-git-send-email-loic.poulain@linaro.org> Precedence: bulk
Series	[v2] bus: mhi: Add Qcom WWAN control driver \| expand [v2] bus: mhi: Add Qcom WWAN control driver

Context	Check	Description
netdev/tree_selection	success	Not a local patch

diff --git a/drivers/bus/mhi/Kconfig b/drivers/bus/mhi/Kconfig index da5cd0c..3336ee5 100644 --- a/drivers/bus/mhi/Kconfig +++ b/drivers/bus/mhi/Kconfig @@ -29,3 +29,15 @@ config MHI_BUS_PCI_GENERIC This driver provides MHI PCI controller driver for devices such as Qualcomm SDX55 based PCIe modems. +config MHI_WWAN_CTRL + tristate "MHI WWAN control driver for QCOM based PCIe modems" + depends on MHI_BUS + help + MHI WWAN CTRL allow QCOM based PCIe modems to expose different modem + control protocols to userspace, including AT, MBIM, QMI, DIAG and + FIREHOSE. These protocols can be accessed directly from userspace + (e.g. AT commands) or via libraries/tools (e.g. libmbim, libqmi, + libqcdm...). + + To compile this driver as a module, choose M here: the module will be + called mhi_wwan_ctrl. diff --git a/drivers/bus/mhi/Makefile b/drivers/bus/mhi/Makefile index 0a2d778..ae25958 100644 --- a/drivers/bus/mhi/Makefile +++ b/drivers/bus/mhi/Makefile @@ -4,3 +4,6 @@ obj-y += core/ obj-$(CONFIG_MHI_BUS_PCI_GENERIC) += mhi_pci_generic.o mhi_pci_generic-y += pci_generic.o +# MHI client +mhi_wwan_ctrl-y := wwan_ctrl.o +obj-$(CONFIG_MHI_WWAN_CTRL) += mhi_wwan_ctrl.o diff --git a/drivers/bus/mhi/wwan_ctrl.c b/drivers/bus/mhi/wwan_ctrl.c new file mode 100644 index 0000000..4e3e993 --- /dev/null +++ b/drivers/bus/mhi/wwan_ctrl.c @@ -0,0 +1,559 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2018-2021, The Linux Foundation. All rights reserved.*/ + +#include <linux/kernel.h> +#include <linux/mhi.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/poll.h> + +#define MHI_WWAN_CTRL_DRIVER_NAME "mhi_wwan_ctrl" +#define MHI_WWAN_CTRL_MAX_MINORS 128 + +static DEFINE_IDR(mhi_wwan_ctrl_idr); +static DEFINE_MUTEX(mhi_wwan_ctrl_drv_lock); +static struct class *mhi_wwan_ctrl_class; +static int mhi_wwan_ctrl_major; + +/* WWAN interface Protocols used by user-space for controlling a modem */ +#define MHI_WWAN_CTRL_PROTO_AT "AT" /* AT command protocol */ +#define MHI_WWAN_CTRL_PROTO_MBIM "MBIM" /* Mobile Broadband Interface Model control protocol */ +#define MHI_WWAN_CTRL_PROTO_QMUX "QMI" /* Qcom modem/MSM interface for modem control */ +#define MHI_WWAN_CTRL_PROTO_QCDM "DIAG" /* Qcom Modem diagnostic interface */ +#define MHI_WWAN_CTRL_PROTO_FIREHOSE "FIREHOSE" /* XML based command protocol */ + +/* MHI wwan device flags */ +#define MHI_WWAN_DL_CAP BIT(0) +#define MHI_WWAN_UL_CAP BIT(1) +#define MHI_WWAN_CONNECTED BIT(2) + +struct mhi_wwan_buf { + struct list_head node; + void *data; + size_t len; + size_t consumed; +}; + +struct mhi_wwan_dev { + unsigned int minor; + size_t mtu; + + struct mhi_device *mhi_dev; + /* Protect against concurrent MHI device accesses (start, stop, open, close) */ + struct mutex mhi_dev_lock; + unsigned int mhi_dev_open_count; + + wait_queue_head_t ul_wq; + wait_queue_head_t dl_wq; + + /* Protect download buf queue against concurent update (read/xfer_cb) */ + spinlock_t dl_queue_lock; + struct list_head dl_queue; + + /* For serializing write/queueing to a same MHI channel */ + struct mutex write_lock; + + unsigned long flags; + + /* kref is used to safely track and release a mhi_wwan_dev instance, + * shared between mhi device probe/remove and user open/close. + */ + struct kref ref_count; +}; + +static void mhi_wwan_ctrl_dev_release(struct kref *ref) +{ + struct mhi_wwan_dev *wwandev = container_of(ref, struct mhi_wwan_dev, ref_count); + struct mhi_wwan_buf *buf_itr, *tmp; + + /* Release non consumed buffers */ + list_for_each_entry_safe(buf_itr, tmp, &wwandev->dl_queue, node) { + list_del(&buf_itr->node); + kfree(buf_itr->data); + } + + mutex_destroy(&wwandev->mhi_dev_lock); + mutex_destroy(&wwandev->write_lock); + + kfree(wwandev); +} + +static int mhi_wwan_ctrl_queue_inbound(struct mhi_wwan_dev *wwandev) +{ + struct mhi_device *mhi_dev = wwandev->mhi_dev; + struct device *dev = &mhi_dev->dev; + int nr_desc, i, ret = -EIO; + struct mhi_wwan_buf *ubuf; + void *buf; + + /* + * skip queuing without error if dl channel is not supported. This + * allows open to succeed for udev, supporting ul only channel. + */ + if (!wwandev->mhi_dev->dl_chan) + return 0; + + nr_desc = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE); + + for (i = 0; i < nr_desc; i++) { + buf = kmalloc(wwandev->mtu + sizeof(*ubuf), GFP_KERNEL); + if (!buf) + return -ENOMEM; + + /* save mhi_wwan_buf info at the end of buf */ + ubuf = buf + wwandev->mtu; + ubuf->data = buf; + + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, buf, wwandev->mtu, MHI_EOT); + if (ret) { + kfree(buf); + dev_err(dev, "Failed to queue buffer %d\n", i); + return ret; + } + } + + return ret; +} + +static int mhi_wwan_ctrl_open(struct inode *inode, struct file *filp) +{ + unsigned int minor = iminor(inode); + struct mhi_wwan_dev *wwandev = NULL; + int ret = 0; + + /* Retrieve corresponding mhi_wwan_dev and get a reference */ + mutex_lock(&mhi_wwan_ctrl_drv_lock); + wwandev = idr_find(&mhi_wwan_ctrl_idr, minor); + if (!wwandev) { + mutex_unlock(&mhi_wwan_ctrl_drv_lock); + return -ENODEV; + } + kref_get(&wwandev->ref_count); + mutex_unlock(&mhi_wwan_ctrl_drv_lock); + + /* Start MHI channel(s) if not yet started and fill RX queue */ + mutex_lock(&wwandev->mhi_dev_lock); + if (!wwandev->mhi_dev_open_count++) { + ret = mhi_prepare_for_transfer(wwandev->mhi_dev, 0); + if (!ret) + ret = mhi_wwan_ctrl_queue_inbound(wwandev); + if (ret) + wwandev->mhi_dev_open_count--; + } + mutex_unlock(&wwandev->mhi_dev_lock); + + if (ret) + return ret; + + filp->private_data = wwandev; + + /* stream-like non-seekable file descriptor */ + stream_open(inode, filp); + + return 0; +} + +static int mhi_wwan_ctrl_release(struct inode *inode, struct file *file) +{ + struct mhi_wwan_dev *wwandev = file->private_data; + + /* Stop the channels, if not already destroyed */ + mutex_lock(&wwandev->mhi_dev_lock); + if (!(--wwandev->mhi_dev_open_count) && wwandev->mhi_dev) + mhi_unprepare_from_transfer(wwandev->mhi_dev); + mutex_unlock(&wwandev->mhi_dev_lock); + + file->private_data = NULL; + + kref_put(&wwandev->ref_count, mhi_wwan_ctrl_dev_release); + + return 0; +} + +static __poll_t mhi_wwan_ctrl_poll(struct file *file, poll_table *wait) +{ + struct mhi_wwan_dev *wwandev = file->private_data; + __poll_t mask = 0; + + poll_wait(file, &wwandev->ul_wq, wait); + poll_wait(file, &wwandev->dl_wq, wait); + + /* Any buffer in the DL queue ? */ + spin_lock_bh(&wwandev->dl_queue_lock); + if (!list_empty(&wwandev->dl_queue)) + mask |= EPOLLIN | EPOLLRDNORM; + spin_unlock_bh(&wwandev->dl_queue_lock); + + /* If MHI queue is not full, write is possible */ + mutex_lock(&wwandev->mhi_dev_lock); + if (!wwandev->mhi_dev) + mask = EPOLLERR | EPOLLHUP; + else if (!mhi_queue_is_full(wwandev->mhi_dev, DMA_TO_DEVICE)) + mask |= EPOLLOUT | EPOLLWRNORM; + mutex_unlock(&wwandev->mhi_dev_lock); + + return mask; +} + +static ssize_t mhi_wwan_ctrl_write(struct file *file, const char __user *buf, + size_t count, loff_t *offp) +{ + struct mhi_wwan_dev *wwandev = file->private_data; + size_t bytes_xfered = 0; + void *kbuf = NULL; + int ret; + + if (!test_bit(MHI_WWAN_UL_CAP, &wwandev->flags)) + return -EOPNOTSUPP; + + if (!buf || !count) + return -EINVAL; + + /* Serialize MHI queueing */ + if (mutex_lock_interruptible(&wwandev->write_lock)) + return -EINTR; + + while (count) { + size_t xfer_size; + + /* Wait for available transfer descriptor */ + ret = wait_event_interruptible(wwandev->ul_wq, + !test_bit(MHI_WWAN_CONNECTED, &wwandev->flags) || + !mhi_queue_is_full(wwandev->mhi_dev, DMA_TO_DEVICE)); + if (ret) + break; + + if (!test_bit(MHI_WWAN_CONNECTED, &wwandev->flags)) { + ret = -EPIPE; + break; + } + + xfer_size = min_t(size_t, count, wwandev->mtu); + kbuf = kmalloc(xfer_size, GFP_KERNEL); + if (!kbuf) { + ret = -ENOMEM; + break; + } + + ret = copy_from_user(kbuf, buf, xfer_size); + if (ret) + break; + + /* Add buffer to MHI queue */ + ret = mhi_queue_buf(wwandev->mhi_dev, DMA_TO_DEVICE, kbuf, + xfer_size, MHI_EOT); + if (ret) + break; + + bytes_xfered += xfer_size; + count -= xfer_size; + buf += xfer_size; + kbuf = NULL; + } + + mutex_unlock(&wwandev->write_lock); + + kfree(kbuf); + + return ret ? ret : bytes_xfered; +} + +static int mhi_wwan_ctrl_recycle_ubuf(struct mhi_wwan_dev *wwandev, + struct mhi_wwan_buf *ubuf) +{ + int ret; + + mutex_lock(&wwandev->mhi_dev_lock); + + if (!wwandev->mhi_dev) { + ret = -ENODEV; + goto exit_unlock; + } + + ret = mhi_queue_buf(wwandev->mhi_dev, DMA_FROM_DEVICE, ubuf->data, + wwandev->mtu, MHI_EOT); + +exit_unlock: + mutex_unlock(&wwandev->mhi_dev_lock); + + return ret; +} + +static ssize_t mhi_wwan_ctrl_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct mhi_wwan_dev *wwandev = file->private_data; + bool recycle_buf = false; + struct mhi_wwan_buf *ubuf; + size_t copy_len; + char *copy_ptr; + int ret = 0; + + if (!test_bit(MHI_WWAN_DL_CAP, &wwandev->flags)) + return -EOPNOTSUPP; + + if (!buf) + return -EINVAL; + + spin_lock_irq(&wwandev->dl_queue_lock); + + /* Wait for at least one buffer in the dl queue (or device removal) */ + ret = wait_event_interruptible_lock_irq(wwandev->dl_wq, + !list_empty(&wwandev->dl_queue) || + !test_bit(MHI_WWAN_CONNECTED, &wwandev->flags), + wwandev->dl_queue_lock); + if (ret) { + goto err_unlock; + } else if (!test_bit(MHI_WWAN_CONNECTED, &wwandev->flags)) { + ret = -EPIPE; + goto err_unlock; + } + + ubuf = list_first_entry_or_null(&wwandev->dl_queue, struct mhi_wwan_buf, node); + if (!ubuf) { + ret = -EIO; + goto err_unlock; + } + + /* Consume the buffer */ + copy_len = min_t(size_t, count, ubuf->len - ubuf->consumed); + copy_ptr = ubuf->data + ubuf->consumed; + ubuf->consumed += copy_len; + + /* Remove buffer from the DL queue if entirely consumed */ + if (ubuf->consumed == ubuf->len) { + list_del(&ubuf->node); + recycle_buf = true; + } + + spin_unlock_irq(&wwandev->dl_queue_lock); + + ret = copy_to_user(buf, copy_ptr, copy_len); + if (ret) + return -EFAULT; + + if (recycle_buf) { + /* Give the buffer back to MHI queue */ + ret = mhi_wwan_ctrl_recycle_ubuf(wwandev, ubuf); + if (ret) /* unable to recycle, release */ + kfree(ubuf->data); + } + + return copy_len; + +err_unlock: + spin_unlock_irq(&wwandev->dl_queue_lock); + + return ret; +} + +static const struct file_operations mhidev_fops = { + .owner = THIS_MODULE, + .open = mhi_wwan_ctrl_open, + .release = mhi_wwan_ctrl_release, + .read = mhi_wwan_ctrl_read, + .write = mhi_wwan_ctrl_write, + .poll = mhi_wwan_ctrl_poll, +}; + +static void mhi_ul_xfer_cb(struct mhi_device *mhi_dev, + struct mhi_result *mhi_result) +{ + struct mhi_wwan_dev *wwandev = dev_get_drvdata(&mhi_dev->dev); + struct device *dev = &mhi_dev->dev; + + dev_dbg(dev, "%s: status: %d xfer_len: %zu\n", __func__, + mhi_result->transaction_status, mhi_result->bytes_xferd); + + kfree(mhi_result->buf_addr); + + /* Some space available in the 'upload' queue, advertise that */ + if (!mhi_result->transaction_status) + wake_up_interruptible(&wwandev->ul_wq); +} + +static void mhi_dl_xfer_cb(struct mhi_device *mhi_dev, + struct mhi_result *mhi_result) +{ + struct mhi_wwan_dev *wwandev = dev_get_drvdata(&mhi_dev->dev); + struct mhi_wwan_buf *ubuf; + + dev_dbg(&mhi_dev->dev, "%s: status: %d receive_len: %zu\n", __func__, + mhi_result->transaction_status, mhi_result->bytes_xferd); + + if (mhi_result->transaction_status && + mhi_result->transaction_status != -EOVERFLOW) { + kfree(mhi_result->buf_addr); + return; + } + + /* ubuf is placed at the end of the buffer (cf mhi_wwan_ctrl_queue_inbound) */ + ubuf = mhi_result->buf_addr + wwandev->mtu; + + /* paranoia, should never happen */ + if (WARN_ON(mhi_result->buf_addr != ubuf->data)) { + kfree(mhi_result->buf_addr); + return; + } + + ubuf->data = mhi_result->buf_addr; + ubuf->len = mhi_result->bytes_xferd; + ubuf->consumed = 0; + + spin_lock_bh(&wwandev->dl_queue_lock); + list_add_tail(&ubuf->node, &wwandev->dl_queue); + spin_unlock_bh(&wwandev->dl_queue_lock); + + wake_up_interruptible(&wwandev->dl_wq); +} + +static int mhi_wwan_ctrl_probe(struct mhi_device *mhi_dev, + const struct mhi_device_id *id) +{ + struct mhi_wwan_dev *wwandev; + struct device *dev; + int index, err; + + /* Create mhi_wwan data context */ + wwandev = kzalloc(sizeof(*wwandev), GFP_KERNEL); + if (!wwandev) + return -ENOMEM; + + /* Retrieve index */ + mutex_lock(&mhi_wwan_ctrl_drv_lock); + index = idr_alloc(&mhi_wwan_ctrl_idr, wwandev, 0, + MHI_WWAN_CTRL_MAX_MINORS, GFP_KERNEL); + mutex_unlock(&mhi_wwan_ctrl_drv_lock); + if (index < 0) { + err = index; + goto err_free_wwandev; + } + + /* Init mhi_wwan data */ + kref_init(&wwandev->ref_count); + mutex_init(&wwandev->mhi_dev_lock); + mutex_init(&wwandev->write_lock); + init_waitqueue_head(&wwandev->ul_wq); + init_waitqueue_head(&wwandev->dl_wq); + spin_lock_init(&wwandev->dl_queue_lock); + INIT_LIST_HEAD(&wwandev->dl_queue); + wwandev->mhi_dev = mhi_dev; + wwandev->minor = index; + wwandev->mtu = min_t(size_t, id->driver_data, MHI_MAX_MTU); + set_bit(MHI_WWAN_CONNECTED, &wwandev->flags); + + if (mhi_dev->dl_chan) + set_bit(MHI_WWAN_DL_CAP, &wwandev->flags); + if (mhi_dev->ul_chan) + set_bit(MHI_WWAN_UL_CAP, &wwandev->flags); + + dev_set_drvdata(&mhi_dev->dev, wwandev); + + /* Creates a new device and registers it with sysfs */ + dev = device_create(mhi_wwan_ctrl_class, &mhi_dev->dev, + MKDEV(mhi_wwan_ctrl_major, index), wwandev, + "wwan_%s", dev_name(&mhi_dev->dev)); + if (IS_ERR(dev)) { + err = PTR_ERR(dev); + goto err_free_idr; + } + + return 0; + +err_free_idr: + mutex_lock(&mhi_wwan_ctrl_drv_lock); + idr_remove(&mhi_wwan_ctrl_idr, wwandev->minor); + mutex_unlock(&mhi_wwan_ctrl_drv_lock); +err_free_wwandev: + kfree(wwandev); + dev_set_drvdata(&mhi_dev->dev, NULL); + + return err; +}; + +static void mhi_wwan_ctrl_remove(struct mhi_device *mhi_dev) +{ + struct mhi_wwan_dev *wwandev = dev_get_drvdata(&mhi_dev->dev); + + dev_set_drvdata(&mhi_dev->dev, NULL); + + mutex_lock(&mhi_wwan_ctrl_drv_lock); + idr_remove(&mhi_wwan_ctrl_idr, wwandev->minor); + mutex_unlock(&mhi_wwan_ctrl_drv_lock); + + clear_bit(MHI_WWAN_CONNECTED, &wwandev->flags); + device_destroy(mhi_wwan_ctrl_class, MKDEV(mhi_wwan_ctrl_major, wwandev->minor)); + + /* Unlink mhi_dev from mhi_wwan_dev */ + mutex_lock(&wwandev->mhi_dev_lock); + wwandev->mhi_dev = NULL; + mutex_unlock(&wwandev->mhi_dev_lock); + + /* wake up any blocked user */ + wake_up_interruptible(&wwandev->dl_wq); + wake_up_interruptible(&wwandev->ul_wq); + + kref_put(&wwandev->ref_count, mhi_wwan_ctrl_dev_release); +} + +/* .driver_data stores max mtu */ +static const struct mhi_device_id mhi_wwan_ctrl_match_table[] = { + { .chan = MHI_WWAN_CTRL_PROTO_AT, .driver_data = 4096 }, + { .chan = MHI_WWAN_CTRL_PROTO_MBIM, .driver_data = 4096 }, + { .chan = MHI_WWAN_CTRL_PROTO_QMUX, .driver_data = 4096 }, + { .chan = MHI_WWAN_CTRL_PROTO_QCDM, .driver_data = MHI_MAX_MTU }, + { .chan = MHI_WWAN_CTRL_PROTO_FIREHOSE, .driver_data = MHI_MAX_MTU }, + {}, +}; +MODULE_DEVICE_TABLE(mhi, mhi_wwan_ctrl_match_table); + +static struct mhi_driver mhi_wwan_ctrl_driver = { + .id_table = mhi_wwan_ctrl_match_table, + .remove = mhi_wwan_ctrl_remove, + .probe = mhi_wwan_ctrl_probe, + .ul_xfer_cb = mhi_ul_xfer_cb, + .dl_xfer_cb = mhi_dl_xfer_cb, + .driver = { + .name = MHI_WWAN_CTRL_DRIVER_NAME, + }, +}; + +static int __init mhi_wwan_ctrl_init(void) +{ + int ret; + + ret = register_chrdev(0, MHI_WWAN_CTRL_DRIVER_NAME, &mhidev_fops); + if (ret < 0) + return ret; + + mhi_wwan_ctrl_major = ret; + mhi_wwan_ctrl_class = class_create(THIS_MODULE, MHI_WWAN_CTRL_DRIVER_NAME); + if (IS_ERR(mhi_wwan_ctrl_class)) { + unregister_chrdev(mhi_wwan_ctrl_major, MHI_WWAN_CTRL_DRIVER_NAME); + return PTR_ERR(mhi_wwan_ctrl_class); + } + + ret = mhi_driver_register(&mhi_wwan_ctrl_driver); + if (ret) { + class_destroy(mhi_wwan_ctrl_class); + unregister_chrdev(mhi_wwan_ctrl_major, MHI_WWAN_CTRL_DRIVER_NAME); + } + + return ret; +} + +static void __exit mhi_wwan_ctrl_exit(void) +{ + mhi_driver_unregister(&mhi_wwan_ctrl_driver); + class_destroy(mhi_wwan_ctrl_class); + unregister_chrdev(mhi_wwan_ctrl_major, MHI_WWAN_CTRL_DRIVER_NAME); + idr_destroy(&mhi_wwan_ctrl_idr); +} + +module_init(mhi_wwan_ctrl_init); +module_exit(mhi_wwan_ctrl_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("MHI WWAN CTRL Driver"); +MODULE_AUTHOR("Hemant Kumar <hemantk@codeaurora.org>"); +MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");

[v2] bus: mhi: Add Qcom WWAN control driver

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