1 files changed, 503 insertions, 0 deletions
diff --git a/drivers/media/mc/mc-request.c b/drivers/media/mc/mc-request.c
new file mode 100644
index 000000000000..e3fca436c75b
--- /dev/null
+++ b/drivers/media/mc/mc-request.c
@@ -0,0 +1,503 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Media device request objects
+ *
+ * Copyright 2018 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ * Copyright (C) 2018 Intel Corporation
+ * Copyright (C) 2018 Google, Inc.
+ *
+ * Author: Hans Verkuil <hans.verkuil@cisco.com>
+ * Author: Sakari Ailus <sakari.ailus@linux.intel.com>
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/refcount.h>
+
+#include <media/media-device.h>
+#include <media/media-request.h>
+
+static const char * const request_state[] = {
+	[MEDIA_REQUEST_STATE_IDLE]	 = "idle",
+	[MEDIA_REQUEST_STATE_VALIDATING] = "validating",
+	[MEDIA_REQUEST_STATE_QUEUED]	 = "queued",
+	[MEDIA_REQUEST_STATE_COMPLETE]	 = "complete",
+	[MEDIA_REQUEST_STATE_CLEANING]	 = "cleaning",
+	[MEDIA_REQUEST_STATE_UPDATING]	 = "updating",
+};
+
+static const char *
+media_request_state_str(enum media_request_state state)
+{
+	BUILD_BUG_ON(ARRAY_SIZE(request_state) != NR_OF_MEDIA_REQUEST_STATE);
+
+	if (WARN_ON(state >= ARRAY_SIZE(request_state)))
+		return "invalid";
+	return request_state[state];
+}
+
+static void media_request_clean(struct media_request *req)
+{
+	struct media_request_object *obj, *obj_safe;
+
+	/* Just a sanity check. No other code path is allowed to change this. */
+	WARN_ON(req->state != MEDIA_REQUEST_STATE_CLEANING);
+	WARN_ON(req->updating_count);
+	WARN_ON(req->access_count);
+
+	list_for_each_entry_safe(obj, obj_safe, &req->objects, list) {
+		media_request_object_unbind(obj);
+		media_request_object_put(obj);
+	}
+
+	req->updating_count = 0;
+	req->access_count = 0;
+	WARN_ON(req->num_incomplete_objects);
+	req->num_incomplete_objects = 0;
+	wake_up_interruptible_all(&req->poll_wait);
+}
+
+static void media_request_release(struct kref *kref)
+{
+	struct media_request *req =
+		container_of(kref, struct media_request, kref);
+	struct media_device *mdev = req->mdev;
+
+	dev_dbg(mdev->dev, "request: release %s\n", req->debug_str);
+
+	/* No other users, no need for a spinlock */
+	req->state = MEDIA_REQUEST_STATE_CLEANING;
+
+	media_request_clean(req);
+
+	if (mdev->ops->req_free)
+		mdev->ops->req_free(req);
+	else
+		kfree(req);
+}
+
+void media_request_put(struct media_request *req)
+{
+	kref_put(&req->kref, media_request_release);
+}
+EXPORT_SYMBOL_GPL(media_request_put);
+
+static int media_request_close(struct inode *inode, struct file *filp)
+{
+	struct media_request *req = filp->private_data;
+
+	media_request_put(req);
+	return 0;
+}
+
+static __poll_t media_request_poll(struct file *filp,
+				   struct poll_table_struct *wait)
+{
+	struct media_request *req = filp->private_data;
+	unsigned long flags;
+	__poll_t ret = 0;
+
+	if (!(poll_requested_events(wait) & EPOLLPRI))
+		return 0;
+
+	poll_wait(filp, &req->poll_wait, wait);
+	spin_lock_irqsave(&req->lock, flags);
+	if (req->state == MEDIA_REQUEST_STATE_COMPLETE) {
+		ret = EPOLLPRI;
+		goto unlock;
+	}
+	if (req->state != MEDIA_REQUEST_STATE_QUEUED) {
+		ret = EPOLLERR;
+		goto unlock;
+	}
+
+unlock:
+	spin_unlock_irqrestore(&req->lock, flags);
+	return ret;
+}
+
+static long media_request_ioctl_queue(struct media_request *req)
+{
+	struct media_device *mdev = req->mdev;
+	enum media_request_state state;
+	unsigned long flags;
+	int ret;
+
+	dev_dbg(mdev->dev, "request: queue %s\n", req->debug_str);
+
+	/*
+	 * Ensure the request that is validated will be the one that gets queued
+	 * next by serialising the queueing process. This mutex is also used
+	 * to serialize with canceling a vb2 queue and with setting values such
+	 * as controls in a request.
+	 */
+	mutex_lock(&mdev->req_queue_mutex);
+
+	media_request_get(req);
+
+	spin_lock_irqsave(&req->lock, flags);
+	if (req->state == MEDIA_REQUEST_STATE_IDLE)
+		req->state = MEDIA_REQUEST_STATE_VALIDATING;
+	state = req->state;
+	spin_unlock_irqrestore(&req->lock, flags);
+	if (state != MEDIA_REQUEST_STATE_VALIDATING) {
+		dev_dbg(mdev->dev,
+			"request: unable to queue %s, request in state %s\n",
+			req->debug_str, media_request_state_str(state));
+		media_request_put(req);
+		mutex_unlock(&mdev->req_queue_mutex);
+		return -EBUSY;
+	}
+
+	ret = mdev->ops->req_validate(req);
+
+	/*
+	 * If the req_validate was successful, then we mark the state as QUEUED
+	 * and call req_queue. The reason we set the state first is that this
+	 * allows req_queue to unbind or complete the queued objects in case
+	 * they are immediately 'consumed'. State changes from QUEUED to another
+	 * state can only happen if either the driver changes the state or if
+	 * the user cancels the vb2 queue. The driver can only change the state
+	 * after each object is queued through the req_queue op (and note that
+	 * that op cannot fail), so setting the state to QUEUED up front is
+	 * safe.
+	 *
+	 * The other reason for changing the state is if the vb2 queue is
+	 * canceled, and that uses the req_queue_mutex which is still locked
+	 * while req_queue is called, so that's safe as well.
+	 */
+	spin_lock_irqsave(&req->lock, flags);
+	req->state = ret ? MEDIA_REQUEST_STATE_IDLE
+			 : MEDIA_REQUEST_STATE_QUEUED;
+	spin_unlock_irqrestore(&req->lock, flags);
+
+	if (!ret)
+		mdev->ops->req_queue(req);
+
+	mutex_unlock(&mdev->req_queue_mutex);
+
+	if (ret) {
+		dev_dbg(mdev->dev, "request: can't queue %s (%d)\n",
+			req->debug_str, ret);
+		media_request_put(req);
+	}
+
+	return ret;
+}
+
+static long media_request_ioctl_reinit(struct media_request *req)
+{
+	struct media_device *mdev = req->mdev;
+	unsigned long flags;
+
+	spin_lock_irqsave(&req->lock, flags);
+	if (req->state != MEDIA_REQUEST_STATE_IDLE &&
+	    req->state != MEDIA_REQUEST_STATE_COMPLETE) {
+		dev_dbg(mdev->dev,
+			"request: %s not in idle or complete state, cannot reinit\n",
+			req->debug_str);
+		spin_unlock_irqrestore(&req->lock, flags);
+		return -EBUSY;
+	}
+	if (req->access_count) {
+		dev_dbg(mdev->dev,
+			"request: %s is being accessed, cannot reinit\n",
+			req->debug_str);
+		spin_unlock_irqrestore(&req->lock, flags);
+		return -EBUSY;
+	}
+	req->state = MEDIA_REQUEST_STATE_CLEANING;
+	spin_unlock_irqrestore(&req->lock, flags);
+
+	media_request_clean(req);
+
+	spin_lock_irqsave(&req->lock, flags);
+	req->state = MEDIA_REQUEST_STATE_IDLE;
+	spin_unlock_irqrestore(&req->lock, flags);
+
+	return 0;
+}
+
+static long media_request_ioctl(struct file *filp, unsigned int cmd,
+				unsigned long arg)
+{
+	struct media_request *req = filp->private_data;
+
+	switch (cmd) {
+	case MEDIA_REQUEST_IOC_QUEUE:
+		return media_request_ioctl_queue(req);
+	case MEDIA_REQUEST_IOC_REINIT:
+		return media_request_ioctl_reinit(req);
+	default:
+		return -ENOIOCTLCMD;
+	}
+}
+
+static const struct file_operations request_fops = {
+	.owner = THIS_MODULE,
+	.poll = media_request_poll,
+	.unlocked_ioctl = media_request_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = media_request_ioctl,
+#endif /* CONFIG_COMPAT */
+	.release = media_request_close,
+};
+
+struct media_request *
+media_request_get_by_fd(struct media_device *mdev, int request_fd)
+{
+	struct fd f;
+	struct media_request *req;
+
+	if (!mdev || !mdev->ops ||
+	    !mdev->ops->req_validate || !mdev->ops->req_queue)
+		return ERR_PTR(-EBADR);
+
+	f = fdget(request_fd);
+	if (!f.file)
+		goto err_no_req_fd;
+
+	if (f.file->f_op != &request_fops)
+		goto err_fput;
+	req = f.file->private_data;
+	if (req->mdev != mdev)
+		goto err_fput;
+
+	/*
+	 * Note: as long as someone has an open filehandle of the request,
+	 * the request can never be released. The fdget() above ensures that
+	 * even if userspace closes the request filehandle, the release()
+	 * fop won't be called, so the media_request_get() always succeeds
+	 * and there is no race condition where the request was released
+	 * before media_request_get() is called.
+	 */
+	media_request_get(req);
+	fdput(f);
+
+	return req;
+
+err_fput:
+	fdput(f);
+
+err_no_req_fd:
+	dev_dbg(mdev->dev, "cannot find request_fd %d\n", request_fd);
+	return ERR_PTR(-EINVAL);
+}
+EXPORT_SYMBOL_GPL(media_request_get_by_fd);
+
+int media_request_alloc(struct media_device *mdev, int *alloc_fd)
+{
+	struct media_request *req;
+	struct file *filp;
+	int fd;
+	int ret;
+
+	/* Either both are NULL or both are non-NULL */
+	if (WARN_ON(!mdev->ops->req_alloc ^ !mdev->ops->req_free))
+		return -ENOMEM;
+
+	fd = get_unused_fd_flags(O_CLOEXEC);
+	if (fd < 0)
+		return fd;
+
+	filp = anon_inode_getfile("request", &request_fops, NULL, O_CLOEXEC);
+	if (IS_ERR(filp)) {
+		ret = PTR_ERR(filp);
+		goto err_put_fd;
+	}
+
+	if (mdev->ops->req_alloc)
+		req = mdev->ops->req_alloc(mdev);
+	else
+		req = kzalloc(sizeof(*req), GFP_KERNEL);
+	if (!req) {
+		ret = -ENOMEM;
+		goto err_fput;
+	}
+
+	filp->private_data = req;
+	req->mdev = mdev;
+	req->state = MEDIA_REQUEST_STATE_IDLE;
+	req->num_incomplete_objects = 0;
+	kref_init(&req->kref);
+	INIT_LIST_HEAD(&req->objects);
+	spin_lock_init(&req->lock);
+	init_waitqueue_head(&req->poll_wait);
+	req->updating_count = 0;
+	req->access_count = 0;
+
+	*alloc_fd = fd;
+
+	snprintf(req->debug_str, sizeof(req->debug_str), "%u:%d",
+		 atomic_inc_return(&mdev->request_id), fd);
+	dev_dbg(mdev->dev, "request: allocated %s\n", req->debug_str);
+
+	fd_install(fd, filp);
+
+	return 0;
+
+err_fput:
+	fput(filp);
+
+err_put_fd:
+	put_unused_fd(fd);
+
+	return ret;
+}
+
+static void media_request_object_release(struct kref *kref)
+{
+	struct media_request_object *obj =
+		container_of(kref, struct media_request_object, kref);
+	struct media_request *req = obj->req;
+
+	if (WARN_ON(req))
+		media_request_object_unbind(obj);
+	obj->ops->release(obj);
+}
+
+struct media_request_object *
+media_request_object_find(struct media_request *req,
+			  const struct media_request_object_ops *ops,
+			  void *priv)
+{
+	struct media_request_object *obj;
+	struct media_request_object *found = NULL;
+	unsigned long flags;
+
+	if (WARN_ON(!ops || !priv))
+		return NULL;
+
+	spin_lock_irqsave(&req->lock, flags);
+	list_for_each_entry(obj, &req->objects, list) {
+		if (obj->ops == ops && obj->priv == priv) {
+			media_request_object_get(obj);
+			found = obj;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&req->lock, flags);
+	return found;
+}
+EXPORT_SYMBOL_GPL(media_request_object_find);
+
+void media_request_object_put(struct media_request_object *obj)
+{
+	kref_put(&obj->kref, media_request_object_release);
+}
+EXPORT_SYMBOL_GPL(media_request_object_put);
+
+void media_request_object_init(struct media_request_object *obj)
+{
+	obj->ops = NULL;
+	obj->req = NULL;
+	obj->priv = NULL;
+	obj->completed = false;
+	INIT_LIST_HEAD(&obj->list);
+	kref_init(&obj->kref);
+}
+EXPORT_SYMBOL_GPL(media_request_object_init);
+
+int media_request_object_bind(struct media_request *req,
+			      const struct media_request_object_ops *ops,
+			      void *priv, bool is_buffer,
+			      struct media_request_object *obj)
+{
+	unsigned long flags;
+	int ret = -EBUSY;
+
+	if (WARN_ON(!ops->release))
+		return -EBADR;
+
+	spin_lock_irqsave(&req->lock, flags);
+
+	if (WARN_ON(req->state != MEDIA_REQUEST_STATE_UPDATING))
+		goto unlock;
+
+	obj->req = req;
+	obj->ops = ops;
+	obj->priv = priv;
+
+	if (is_buffer)
+		list_add_tail(&obj->list, &req->objects);
+	else
+		list_add(&obj->list, &req->objects);
+	req->num_incomplete_objects++;
+	ret = 0;
+
+unlock:
+	spin_unlock_irqrestore(&req->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(media_request_object_bind);
+
+void media_request_object_unbind(struct media_request_object *obj)
+{
+	struct media_request *req = obj->req;
+	unsigned long flags;
+	bool completed = false;
+
+	if (WARN_ON(!req))
+		return;
+
+	spin_lock_irqsave(&req->lock, flags);
+	list_del(&obj->list);
+	obj->req = NULL;
+
+	if (req->state == MEDIA_REQUEST_STATE_COMPLETE)
+		goto unlock;
+
+	if (WARN_ON(req->state == MEDIA_REQUEST_STATE_VALIDATING))
+		goto unlock;
+
+	if (req->state == MEDIA_REQUEST_STATE_CLEANING) {
+		if (!obj->completed)
+			req->num_incomplete_objects--;
+		goto unlock;
+	}
+
+	if (WARN_ON(!req->num_incomplete_objects))
+		goto unlock;
+
+	req->num_incomplete_objects--;
+	if (req->state == MEDIA_REQUEST_STATE_QUEUED &&
+	    !req->num_incomplete_objects) {
+		req->state = MEDIA_REQUEST_STATE_COMPLETE;
+		completed = true;
+		wake_up_interruptible_all(&req->poll_wait);
+	}
+
+unlock:
+	spin_unlock_irqrestore(&req->lock, flags);
+	if (obj->ops->unbind)
+		obj->ops->unbind(obj);
+	if (completed)
+		media_request_put(req);
+}
+EXPORT_SYMBOL_GPL(media_request_object_unbind);
+
+void media_request_object_complete(struct media_request_object *obj)
+{
+	struct media_request *req = obj->req;
+	unsigned long flags;
+	bool completed = false;
+
+	spin_lock_irqsave(&req->lock, flags);
+	if (obj->completed)
+		goto unlock;
+	obj->completed = true;
+	if (WARN_ON(!req->num_incomplete_objects) ||
+	    WARN_ON(req->state != MEDIA_REQUEST_STATE_QUEUED))
+		goto unlock;
+
+	if (!--req->num_incomplete_objects) {
+		req->state = MEDIA_REQUEST_STATE_COMPLETE;
+		wake_up_interruptible_all(&req->poll_wait);
+		completed = true;
+	}
+unlock:
+	spin_unlock_irqrestore(&req->lock, flags);
+	if (completed)
+		media_request_put(req);
+}
+EXPORT_SYMBOL_GPL(media_request_object_complete);