[PATCH v3 6/8] accel/qaic: Add mhi_qaic_cntl
Jeffrey Hugo
quic_jhugo at quicinc.com
Tue Mar 14 18:26:01 UTC 2023
On 3/14/2023 6:19 AM, Jacek Lawrynowicz wrote:
> Hi,
>
> On 06.03.2023 22:34, Jeffrey Hugo wrote:
>> From: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy at quicinc.com>
>>
>> Some of the MHI channels for an AIC100 device need to be routed to
>> userspace so that userspace can communicate directly with QSM. The MHI
>> bus does not support this, and while the WWAN subsystem does (for the same
>> reasons), AIC100 is not a WWAN device. Also, MHI is not something that
>> other accelerators are expected to share, thus an accel subsystem function
>> that meets this usecase is unlikely.
>>
>> Create a QAIC specific MHI userspace shim that exposes these channels.
>>
>> Start with QAIC_SAHARA which is required to boot AIC100 and is consumed by
>> the kickstart application as documented in aic100.rst
>>
>> Each AIC100 instance (currently, up to 16) in a system will create a
>> chardev for QAIC_SAHARA. This chardev will be found as
>> /dev/<mhi instance>_QAIC_SAHARA
>> For example - /dev/mhi0_QAIC_SAHARA
>>
>> Signed-off-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy at quicinc.com>
>> Signed-off-by: Jeffrey Hugo <quic_jhugo at quicinc.com>
>> Reviewed-by: Carl Vanderlip <quic_carlv at quicinc.com>
>> Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka at linux.intel.com>
>> ---
>> drivers/accel/qaic/mhi_qaic_ctrl.c | 581 +++++++++++++++++++++++++++++++++++++
>> drivers/accel/qaic/mhi_qaic_ctrl.h | 11 +
>> 2 files changed, 592 insertions(+)
>> create mode 100644 drivers/accel/qaic/mhi_qaic_ctrl.c
>> create mode 100644 drivers/accel/qaic/mhi_qaic_ctrl.h
>>
>> diff --git a/drivers/accel/qaic/mhi_qaic_ctrl.c b/drivers/accel/qaic/mhi_qaic_ctrl.c
>> new file mode 100644
>> index 0000000..f97279fd
>> --- /dev/null
>> +++ b/drivers/accel/qaic/mhi_qaic_ctrl.c
>> @@ -0,0 +1,581 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/* Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved. */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/mhi.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/module.h>
>> +#include <linux/poll.h>
>> +#include <linux/version.h>
>> +#include <linux/xarray.h>
>> +#include <uapi/linux/eventpoll.h>
>> +
>> +#include "mhi_qaic_ctrl.h"
>> +#include "qaic.h"
>> +
>> +#define MHI_QAIC_CTRL_DRIVER_NAME "mhi_qaic_ctrl"
>> +#define MHI_QAIC_CTRL_MAX_MINORS 128
>> +#define MHI_MAX_MTU 0xffff
>> +static DEFINE_XARRAY_ALLOC(mqc_xa);
>> +static struct class *mqc_dev_class;
>> +static int mqc_dev_major;
>> +
>> +/**
>> + * struct mqc_buf - Buffer structure used to receive data from device
>> + * @data: Address of data to read from
>> + * @odata: Original address returned from *alloc() API. Used to free this buf.
>> + * @len: Length of data in byte
>> + * @node: This buffer will be part of list managed in struct mqc_dev
>> + */
>> +struct mqc_buf {
>> + void *data;
>> + void *odata;
>> + size_t len;
>> + struct list_head node;
>> +};
>> +
>> +/**
>> + * struct mqc_dev - MHI QAIC Control Device
>> + * @minor: MQC device node minor number
>> + * @mhi_dev: Associated mhi device object
>> + * @mtu: Max TRE buffer length
>> + * @enabled: Flag to track the state of the MQC device
>> + * @lock: Mutex lock to serialize access to open_count
>> + * @read_lock: Mutex lock to serialize readers
>> + * @write_lock: Mutex lock to serialize writers
>> + * @ul_wq: Wait queue for writers
>> + * @dl_wq: Wait queue for readers
>> + * @dl_queue_lock: Spin lock to serialize access to download queue
>> + * @dl_queue: Queue of downloaded buffers
>> + * @open_count: Track open counts
>> + * @ref_count: Reference count for this structure
>> + */
>> +struct mqc_dev {
>> + uint32_t minor;
>> + struct mhi_device *mhi_dev;
>> + size_t mtu;
>> + bool enabled;
>
> Is enabled really needed. I would think that mhi_qaic_ctrl_remove() won't be called
> unless all open files are closed.
mhi_qaic_ctrl_remove() can be called at any time.
mhi_qaic_ctrl_remove() is part of the underlying pipe.
The user calls open(), has a valid open file. At some point, the device
crashes, which invalidates the user's connection to the device.
mhi_qaic_ctrl_remove() is called. We can't force the user to close the
file. All we can do is return an error.
>
>> + struct mutex lock;
>> + struct mutex read_lock;
>> + struct mutex write_lock;
>> + wait_queue_head_t ul_wq;
>> + wait_queue_head_t dl_wq;
>> + spinlock_t dl_queue_lock;
>> + struct list_head dl_queue;
>> + unsigned int open_count;
>> + struct kref ref_count;
>> +};
>> +
>> +static void mqc_dev_release(struct kref *ref)
>> +{
>> + struct mqc_dev *mqcdev = container_of(ref, struct mqc_dev, ref_count);
>> +
>> + mutex_destroy(&mqcdev->read_lock);
>> + mutex_destroy(&mqcdev->write_lock);
>> + mutex_destroy(&mqcdev->lock);
>> + kfree(mqcdev);
>> +}
>> +
>> +static int mhi_qaic_ctrl_fill_dl_queue(struct mqc_dev *mqcdev)
>> +{
>> + struct mhi_device *mhi_dev = mqcdev->mhi_dev;
>> + struct mqc_buf *ctrlbuf;
>> + int rx_budget;
>> + int ret = 0;
>> + void *data;
>> +
>> + rx_budget = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
>> + if (rx_budget < 0)
>> + return -EIO;
>> +
>> + while (rx_budget--) {
>> + data = kzalloc(mqcdev->mtu + sizeof(*ctrlbuf), GFP_KERNEL);
>> + if (!data)
>> + return -ENOMEM;
>> +
>> + ctrlbuf = data + mqcdev->mtu;
>> + ctrlbuf->odata = data;
>> +
>> + ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, data, mqcdev->mtu, MHI_EOT);
>> + if (ret) {
>> + kfree(data);
>> + dev_err(&mhi_dev->dev, "Failed to queue buffer\n");
>> + return ret;
>> + }
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static int mhi_qaic_ctrl_dev_start_chan(struct mqc_dev *mqcdev)
>> +{
>> + struct device *dev = &mqcdev->mhi_dev->dev;
>> + int ret = 0;
>> +
>> + ret = mutex_lock_interruptible(&mqcdev->lock);
>> + if (ret)
>> + return ret;
>> + if (!mqcdev->enabled) {
>
> How "enabled" can be 0 here? It is rather not possible to open the device after
> it was released.
Race condition. User called open() at roughly the same time
mhi_qaic_ctrl_remove() occured. You have two threads competing for the
same resource - one attempting to free it and one attempting to use it.
>
>> + ret = -ENODEV;
>> + goto release_dev_lock;
>> + }
>> + if (!mqcdev->open_count) {
>> + ret = mhi_prepare_for_transfer(mqcdev->mhi_dev);
>> + if (ret) {
>> + dev_err(dev, "Error starting transfer channels\n");
>> + goto release_dev_lock;
>> + }
>> +
>> + ret = mhi_qaic_ctrl_fill_dl_queue(mqcdev);
>> + if (ret) {
>> + dev_err(dev, "Error filling download queue.\n");
>> + goto mhi_unprepare;
>> + }
>> + }
>> + mqcdev->open_count++;
>> + mutex_unlock(&mqcdev->lock);
>> +
>> + return 0;
>> +
>> +mhi_unprepare:
>> + mhi_unprepare_from_transfer(mqcdev->mhi_dev);
>> +release_dev_lock:
>> + mutex_unlock(&mqcdev->lock);
>> + return ret;
>> +}
>> +
>> +static struct mqc_dev *mqc_dev_get_by_minor(unsigned int minor)
>> +{
>> + struct mqc_dev *mqcdev;
>> +
>> + xa_lock(&mqc_xa);
>> + mqcdev = xa_load(&mqc_xa, minor);
>> + if (mqcdev)
>> + kref_get(&mqcdev->ref_count);
>> + xa_unlock(&mqc_xa);
>> +
>> + return mqcdev;
>> +}
>> +
>> +static int mhi_qaic_ctrl_open(struct inode *inode, struct file *filp)
>> +{
>> + struct mqc_dev *mqcdev;
>> + int ret;
>> +
>> + mqcdev = mqc_dev_get_by_minor(iminor(inode));
>> + if (!mqcdev) {
>> + pr_debug("mqc: minor %d not found\n", iminor(inode));
>> + return -EINVAL;
>> + }
>> +
>> + ret = mhi_qaic_ctrl_dev_start_chan(mqcdev);
>> + if (ret) {
>> + kref_put(&mqcdev->ref_count, mqc_dev_release);
>> + return ret;
>> + }
>> +
>> + filp->private_data = mqcdev;
>> +
>> + return 0;
>> +}
>> +
>> +static void mhi_qaic_ctrl_buf_free(struct mqc_buf *ctrlbuf)
>> +{
>> + list_del(&ctrlbuf->node);
>> + kfree(ctrlbuf->odata);
>> +}
>> +
>> +static void __mhi_qaic_ctrl_release(struct mqc_dev *mqcdev)
>> +{
>> + struct mqc_buf *ctrlbuf, *tmp;
>> +
>> + mhi_unprepare_from_transfer(mqcdev->mhi_dev);
>> + wake_up_interruptible(&mqcdev->ul_wq);
>> + wake_up_interruptible(&mqcdev->dl_wq);
>> + /*
>> + * Free the dl_queue. As we have already unprepared mhi transfers, we
>> + * do not expect any callback functions that update dl_queue hence no need
>> + * to grab dl_queue lock.
>> + */
>> + mutex_lock(&mqcdev->read_lock);
>> + list_for_each_entry_safe(ctrlbuf, tmp, &mqcdev->dl_queue, node)
>> + mhi_qaic_ctrl_buf_free(ctrlbuf);
>> + mutex_unlock(&mqcdev->read_lock);
>> +}
>> +
>> +static int mhi_qaic_ctrl_release(struct inode *inode, struct file *file)
>> +{
>> + struct mqc_dev *mqcdev = file->private_data;
>> +
>> + mutex_lock(&mqcdev->lock);
>> + mqcdev->open_count--;
>> + if (!mqcdev->open_count && mqcdev->enabled)
>> + __mhi_qaic_ctrl_release(mqcdev);
>> + mutex_unlock(&mqcdev->lock);
>> +
>> + kref_put(&mqcdev->ref_count, mqc_dev_release);
>> +
>> + return 0;
>> +}
>> +
>> +static __poll_t mhi_qaic_ctrl_poll(struct file *file, poll_table *wait)
>> +{
>> + struct mqc_dev *mqcdev = file->private_data;
>> + struct mhi_device *mhi_dev;
>> + __poll_t mask = 0;
>> +
>> + mhi_dev = mqcdev->mhi_dev;
>> +
>> + poll_wait(file, &mqcdev->ul_wq, wait);
>> + poll_wait(file, &mqcdev->dl_wq, wait);
>> +
>> + mutex_lock(&mqcdev->lock);
>> + if (!mqcdev->enabled || !mqcdev->open_count) {
>> + mutex_unlock(&mqcdev->lock);
>> + return EPOLLERR;
>> + }
>> +
>> + spin_lock_bh(&mqcdev->dl_queue_lock);
>> + if (!list_empty(&mqcdev->dl_queue))
>> + mask |= EPOLLIN | EPOLLRDNORM;
>> + spin_unlock_bh(&mqcdev->dl_queue_lock);
>> +
>> + if (mutex_lock_interruptible(&mqcdev->write_lock)) {
>> + mutex_unlock(&mqcdev->lock);
>> + return EPOLLERR;
>> + }
>> + if (mhi_get_free_desc_count(mhi_dev, DMA_TO_DEVICE) > 0)
>> + mask |= EPOLLOUT | EPOLLWRNORM;
>> + mutex_unlock(&mqcdev->write_lock);
>> + mutex_unlock(&mqcdev->lock);
>> +
>> + dev_dbg(&mhi_dev->dev, "Client attempted to poll, returning mask 0x%x\n", mask);
>> +
>> + return mask;
>> +}
>> +
>> +static int mhi_qaic_ctrl_tx(struct mqc_dev *mqcdev)
>> +{
>> + int ret;
>> +
>> + ret = wait_event_interruptible(mqcdev->ul_wq,
>> + (!mqcdev->enabled || !mqcdev->open_count ||
>> + mhi_get_free_desc_count(mqcdev->mhi_dev,
>> + DMA_TO_DEVICE) > 0));
>> +
>> + if (!mqcdev->open_count)
>> + return -EPIPE;
>> + if (!mqcdev->enabled)
>> + return -ENODEV;
>
> I think that both "open_count" and "enabled" will never be 0 here.
> This function is called by read() and read() cannot be called without open
> file descriptor.
Looks like open_count should be removed here.
>
>> +
>> + return ret;
>> +}
>> +
>> +static ssize_t mhi_qaic_ctrl_write(struct file *file, const char __user *buf, size_t count,
>> + loff_t *offp)
>> +{
>> + struct mqc_dev *mqcdev = file->private_data;
>> + struct mhi_device *mhi_dev;
>> + size_t bytes_xfered = 0;
>> + struct device *dev;
>> + int ret, nr_desc;
>> +
>> + mhi_dev = mqcdev->mhi_dev;
>> + dev = &mhi_dev->dev;
>> +
>> + if (!mhi_dev->ul_chan)
>> + return -EOPNOTSUPP;
>> +
>> + if (!buf || !count)
>> + return -EINVAL;
>> +
>> + dev_dbg(dev, "Request to transfer %zu bytes\n", count);
>> +
>> + ret = mhi_qaic_ctrl_tx(mqcdev);
>> + if (ret) {
>> + dev_err(dev, "Failed to write %d\n", ret);
>> + return ret;
>> + }
>> +
>> + if (mutex_lock_interruptible(&mqcdev->write_lock))
>> + return -EINTR;
>> +
>> + nr_desc = mhi_get_free_desc_count(mhi_dev, DMA_TO_DEVICE);
>> + if (nr_desc * mqcdev->mtu < count) {
>> + ret = -EMSGSIZE;
>> + dev_dbg(dev, "Buffer too big to transfer\n");
>> + goto unlock_mutex;
>> + }
>> +
>> + while (count != bytes_xfered) {
>> + enum mhi_flags flags;
>> + size_t to_copy;
>> + void *kbuf;
>> +
>> + to_copy = min_t(size_t, count - bytes_xfered, mqcdev->mtu);
>> + kbuf = kmalloc(to_copy, GFP_KERNEL);
>> + if (!kbuf) {
>> + ret = -ENOMEM;
>> + goto unlock_mutex;
>> + }
>> +
>> + ret = copy_from_user(kbuf, buf + bytes_xfered, to_copy);
>> + if (ret) {
>> + kfree(kbuf);
>> + ret = -EFAULT;
>> + goto unlock_mutex;
>> + }
>> +
>> + if (bytes_xfered + to_copy == count)
>> + flags = MHI_EOT;
>> + else
>> + flags = MHI_CHAIN;
>> +
>> + ret = mhi_queue_buf(mhi_dev, DMA_TO_DEVICE, kbuf, to_copy, flags);
>> + if (ret) {
>> + kfree(kbuf);
>> + dev_err(dev, "Failed to queue buf of size %zu\n", to_copy);
>> + goto unlock_mutex;
>> + }
>> +
>> + bytes_xfered += to_copy;
>> + }
>> +
>> + mutex_unlock(&mqcdev->write_lock);
>> + dev_dbg(dev, "bytes xferred: %zu\n", bytes_xfered);
>> +
>> + return bytes_xfered;
>> +
>> +unlock_mutex:
>> + mutex_unlock(&mqcdev->write_lock);
>> + return ret;
>> +}
>> +
>> +static int mhi_qaic_ctrl_rx(struct mqc_dev *mqcdev)
>> +{
>> + int ret;
>> +
>> + ret = wait_event_interruptible(mqcdev->dl_wq, (!mqcdev->enabled || !mqcdev->open_count ||
>> + !list_empty(&mqcdev->dl_queue)));
>> +
>> + if (!mqcdev->open_count)
>> + return -EPERM;
>> + if (!mqcdev->enabled)
>> + return -ENODEV;
>> +
>> + return ret;
>> +}
>> +
>> +static ssize_t mhi_qaic_ctrl_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
>> +{
>> + struct mqc_dev *mqcdev = file->private_data;
>> + struct mqc_buf *ctrlbuf;
>> + size_t to_copy;
>> + int ret;
>> +
>> + if (!mqcdev->mhi_dev->dl_chan)
>> + return -EOPNOTSUPP;
>> +
>> + ret = mhi_qaic_ctrl_rx(mqcdev);
>> + if (ret) {
>> + dev_err(&mqcdev->mhi_dev->dev, "Failed to read %d\n", ret);
>> + return ret;
>> + }
>> +
>> + if (mutex_lock_interruptible(&mqcdev->read_lock))
>> + return -EINTR;
>> +
>> + ctrlbuf = list_first_entry_or_null(&mqcdev->dl_queue, struct mqc_buf, node);
>> + if (!ctrlbuf) {
>> + mutex_unlock(&mqcdev->read_lock);
>> + dev_dbg(&mqcdev->mhi_dev->dev, "Device has been released\n");
>
> I don't believe that the device can be released while in read() syscall.
> This error can only happen if read() from another thread processed the dl_queue first.
The list can be empty if mhi_qaic_ctrl_remove() occurs (pipe goes away).
>
>> + ret = -ENODEV;
>> + goto error_out;
>> + }
>> +
>> + to_copy = min_t(size_t, count, ctrlbuf->len);
>> + if (copy_to_user(buf, ctrlbuf->data, to_copy)) {
>> + mutex_unlock(&mqcdev->read_lock);
>> + dev_dbg(&mqcdev->mhi_dev->dev, "Failed to copy data to user buffer\n");
>> + ret = -EFAULT;
>> + goto error_out;
>> + }
>> +
>> + ctrlbuf->len -= to_copy;
>> + ctrlbuf->data += to_copy;
>> +
>> + if (!ctrlbuf->len) {
>> + spin_lock_bh(&mqcdev->dl_queue_lock);
>> + mhi_qaic_ctrl_buf_free(ctrlbuf);
>> + spin_unlock_bh(&mqcdev->dl_queue_lock);
>> + mhi_qaic_ctrl_fill_dl_queue(mqcdev);
>> + dev_dbg(&mqcdev->mhi_dev->dev, "Read buf freed\n");
>> + }
>> +
>> + mutex_unlock(&mqcdev->read_lock);
>> + return to_copy;
>> +
>> +error_out:
>> + mutex_unlock(&mqcdev->read_lock);
>> + return ret;
>> +}
>> +
>> +static const struct file_operations mhidev_fops = {
>> + .owner = THIS_MODULE,
>> + .open = mhi_qaic_ctrl_open,
>> + .release = mhi_qaic_ctrl_release,
>> + .read = mhi_qaic_ctrl_read,
>> + .write = mhi_qaic_ctrl_write,
>> + .poll = mhi_qaic_ctrl_poll,
>> +};
>> +
>> +static void mhi_qaic_ctrl_ul_xfer_cb(struct mhi_device *mhi_dev, struct mhi_result *mhi_result)
>> +{
>> + struct mqc_dev *mqcdev = dev_get_drvdata(&mhi_dev->dev);
>> +
>> + dev_dbg(&mhi_dev->dev, "%s: status: %d xfer_len: %zu\n", __func__,
>> + mhi_result->transaction_status, mhi_result->bytes_xferd);
>> +
>> + kfree(mhi_result->buf_addr);
>> +
>> + if (!mhi_result->transaction_status)
>> + wake_up_interruptible(&mqcdev->ul_wq);
>> +}
>> +
>> +static void mhi_qaic_ctrl_dl_xfer_cb(struct mhi_device *mhi_dev, struct mhi_result *mhi_result)
>> +{
>> + struct mqc_dev *mqcdev = dev_get_drvdata(&mhi_dev->dev);
>> + struct mqc_buf *ctrlbuf;
>> +
>> + 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;
>> + }
>> +
>> + ctrlbuf = mhi_result->buf_addr + mqcdev->mtu;
>> + ctrlbuf->data = mhi_result->buf_addr;
>> + ctrlbuf->len = mhi_result->bytes_xferd;
>> + spin_lock_bh(&mqcdev->dl_queue_lock);
>> + list_add_tail(&ctrlbuf->node, &mqcdev->dl_queue);
>> + spin_unlock_bh(&mqcdev->dl_queue_lock);
>> +
>> + wake_up_interruptible(&mqcdev->dl_wq);
>> +}
>> +
>> +static int mhi_qaic_ctrl_probe(struct mhi_device *mhi_dev, const struct mhi_device_id *id)
>> +{
>> + struct mqc_dev *mqcdev;
>> + struct device *dev;
>> + int ret;
>> +
>> + mqcdev = kzalloc(sizeof(*mqcdev), GFP_KERNEL);
>> + if (!mqcdev)
>> + return -ENOMEM;
>> +
>> + kref_init(&mqcdev->ref_count);
>> + mutex_init(&mqcdev->lock);
>> + mqcdev->mhi_dev = mhi_dev;
>> +
>> + ret = xa_alloc(&mqc_xa, &mqcdev->minor, mqcdev, XA_LIMIT(0, MHI_QAIC_CTRL_MAX_MINORS),
>> + GFP_KERNEL);
>> + if (ret) {
>> + kfree(mqcdev);
>> + return ret;
>> + }
>> +
>> + init_waitqueue_head(&mqcdev->ul_wq);
>> + init_waitqueue_head(&mqcdev->dl_wq);
>> + mutex_init(&mqcdev->read_lock);
>> + mutex_init(&mqcdev->write_lock);
>> + spin_lock_init(&mqcdev->dl_queue_lock);
>> + INIT_LIST_HEAD(&mqcdev->dl_queue);
>> + mqcdev->mtu = min_t(size_t, id->driver_data, MHI_MAX_MTU);
>> + mqcdev->enabled = true;
>> + mqcdev->open_count = 0;
>> + dev_set_drvdata(&mhi_dev->dev, mqcdev);
>> +
>> + dev = device_create(mqc_dev_class, &mhi_dev->dev, MKDEV(mqc_dev_major, mqcdev->minor),
>> + mqcdev, "%s", dev_name(&mhi_dev->dev));
>> + if (IS_ERR(dev)) {
>> + xa_erase(&mqc_xa, mqcdev->minor);
>> + dev_set_drvdata(&mhi_dev->dev, NULL);
>> + kfree(mqcdev);
>> + return PTR_ERR(dev);
>> + }
>> +
>> + return 0;
>> +};
>> +
>> +static void mhi_qaic_ctrl_remove(struct mhi_device *mhi_dev)
>> +{
>> + struct mqc_dev *mqcdev = dev_get_drvdata(&mhi_dev->dev);
>> +
>> + device_destroy(mqc_dev_class, MKDEV(mqc_dev_major, mqcdev->minor));
>> +
>> + mutex_lock(&mqcdev->lock);
>> + mqcdev->enabled = false;
>> + if (mqcdev->open_count)
>> + __mhi_qaic_ctrl_release(mqcdev);
>> + mutex_unlock(&mqcdev->lock);
>> +
>> + xa_erase(&mqc_xa, mqcdev->minor);
>> + kref_put(&mqcdev->ref_count, mqc_dev_release);
>> +}
>> +
>> +/* .driver_data stores max mtu */
>> +static const struct mhi_device_id mhi_qaic_ctrl_match_table[] = {
>> + { .chan = "QAIC_SAHARA", .driver_data = SZ_32K},
>> + {},
>> +};
>> +MODULE_DEVICE_TABLE(mhi, mhi_qaic_ctrl_match_table);
>> +
>> +static struct mhi_driver mhi_qaic_ctrl_driver = {
>> + .id_table = mhi_qaic_ctrl_match_table,
>> + .remove = mhi_qaic_ctrl_remove,
>> + .probe = mhi_qaic_ctrl_probe,
>> + .ul_xfer_cb = mhi_qaic_ctrl_ul_xfer_cb,
>> + .dl_xfer_cb = mhi_qaic_ctrl_dl_xfer_cb,
>> + .driver = {
>> + .name = MHI_QAIC_CTRL_DRIVER_NAME,
>> + },
>> +};
>> +
>> +int mhi_qaic_ctrl_init(void)
>> +{
>> + int ret;
>> +
>> + ret = register_chrdev(0, MHI_QAIC_CTRL_DRIVER_NAME, &mhidev_fops);
>> + if (ret < 0)
>> + return ret;
>> +
>> + mqc_dev_major = ret;
>> + mqc_dev_class = class_create(THIS_MODULE, MHI_QAIC_CTRL_DRIVER_NAME);
>> + if (IS_ERR(mqc_dev_class)) {
>> + ret = PTR_ERR(mqc_dev_class);
>> + goto unregister_chrdev;
>> + }
>> +
>> + ret = mhi_driver_register(&mhi_qaic_ctrl_driver);
>> + if (ret)
>> + goto destroy_class;
>> +
>> + return 0;
>> +
>> +destroy_class:
>> + class_destroy(mqc_dev_class);
>> +unregister_chrdev:
>> + unregister_chrdev(mqc_dev_major, MHI_QAIC_CTRL_DRIVER_NAME);
>> + return ret;
>> +}
>> +
>> +void mhi_qaic_ctrl_deinit(void)
>> +{
>> + mhi_driver_unregister(&mhi_qaic_ctrl_driver);
>> + class_destroy(mqc_dev_class);
>> + unregister_chrdev(mqc_dev_major, MHI_QAIC_CTRL_DRIVER_NAME);
>> + xa_destroy(&mqc_xa);
>> +}
>> diff --git a/drivers/accel/qaic/mhi_qaic_ctrl.h b/drivers/accel/qaic/mhi_qaic_ctrl.h
>> new file mode 100644
>> index 0000000..0545540
>> --- /dev/null
>> +++ b/drivers/accel/qaic/mhi_qaic_ctrl.h
>> @@ -0,0 +1,11 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only
>> + *
>> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
>> + */
>> +
>> +#ifndef __MHI_QAIC_CTRL_H__
>> +#define __MHI_QAIC_CTRL_H__
>> +
>> +int mhi_qaic_ctrl_init(void);
>> +void mhi_qaic_ctrl_deinit(void);
>
> Please add a new line here.
>
>> +#endif /* __MHI_QAIC_CTRL_H__ */
>
> Regards,
> Jacek
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