2 files changed, 581 insertions, 0 deletions
diff --git a/drivers/accel/qaic/mhi_qaic_ctrl.c b/drivers/accel/qaic/mhi_qaic_ctrl.c
new file mode 100644
index 000000000000..0c7e571f1f12
--- /dev/null
+++ b/drivers/accel/qaic/mhi_qaic_ctrl.c
@@ -0,0 +1,569 @@
+// 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 {
+	u32 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);
+}
diff --git a/drivers/accel/qaic/mhi_qaic_ctrl.h b/drivers/accel/qaic/mhi_qaic_ctrl.h
new file mode 100644
index 000000000000..930b3ace1a59
--- /dev/null
+++ b/drivers/accel/qaic/mhi_qaic_ctrl.h
@@ -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__ */