new file mode 100644
@@ -0,0 +1,570 @@
+// 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/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;
+ 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) {
+ 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) {
+ 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 ||
+ mhi_get_free_desc_count(mqcdev->mhi_dev,
+ DMA_TO_DEVICE) > 0));
+
+ if (!mqcdev->enabled)
+ return -ENODEV;
+
+ 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)
+ 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 ||
+ !list_empty(&mqcdev->dl_queue)));
+
+ 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)
+ 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);
+ 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);
+}
new file mode 100644
@@ -0,0 +1,12 @@
+/* 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);
+
+#endif /* __MHI_QAIC_CTRL_H__ */