From: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
The request API allows bundling media device parameters with request
objects and applying them atomically, either synchronously or
asynchronously.
Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ai...@linux.intel.com>
---
drivers/media/media-device.c | 366 ++++++++++++++++++++++++++++++++++++++++++-
include/media/media-device.h | 71 ++++++++-
include/uapi/linux/media.h | 10 ++
3 files changed, 441 insertions(+), 6 deletions(-)
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index da63da1..41ec5ac 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -19,11 +19,13 @@
/* We need to access legacy defines from linux/media.h */
#define __NEED_MEDIA_LEGACY_API
+#include <linux/anon_inodes.h>
#include <linux/compat.h>
#include <linux/export.h>
-#include <linux/idr.h>
+#include <linux/file.h>
#include <linux/ioctl.h>
#include <linux/media.h>
+#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/pci.h>
@@ -35,6 +37,349 @@
#ifdef CONFIG_MEDIA_CONTROLLER
+static const char *__request_state[] = {
+ "IDLE",
+ "QUEUED",
+ "COMPLETED",
+};
+
+const char *
+media_device_request_state_str(enum media_device_request_state state)
+{
+ if (state < ARRAY_SIZE(__request_state))
+ return __request_state[state];
+
+ return "UNKNOWN";
+}
+
+/*
-----------------------------------------------------------------------------
+ * Requests
+ */
+
+void media_device_request_get(struct media_device_request *req)
+{
+ kref_get(&req->kref);
+}
+EXPORT_SYMBOL_GPL(media_device_request_get);
+
+static void media_device_request_release(struct kref *kref)
+{
+ struct media_device_request *req =
+ container_of(kref, struct media_device_request, kref);
+ struct media_device *mdev = req->mdev;
+ unsigned long flags;
+
+ dev_dbg(mdev->dev, "request: release %s\n", req->debug_str);
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ list_del(&req->list);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ mdev->ops->req_free(mdev, req);
+}
+
+void media_device_request_put(struct media_device_request *req)
+{
+ kref_put(&req->kref, media_device_request_release);
+}
+EXPORT_SYMBOL_GPL(media_device_request_put);
+
+static int media_device_request_close(struct inode *inode, struct file *filp)
+{
+ struct media_device_request *req = filp->private_data;
+
+ media_device_request_put(req);
+
+ return 0;
+}
+
+static const struct file_operations request_fops = {
+ .owner = THIS_MODULE,
+ .release = media_device_request_close,
+};
+
+/**
+ * media_device_request_find - Find a request based on the file descriptor
+ * @mdev: The media device
+ * @request: The request file handle
+ *
+ * Find and return the request associated with the given file descriptor, or
+ * an error if no such request exists.
+ *
+ * When the function returns a request it increases its reference count. The
+ * caller is responsible for releasing the reference by calling
+ * media_device_request_put() on the request.
+ */
+struct media_device_request *
+media_device_request_find(struct media_device *mdev, int request)
+{
+ struct file *filp;
+ struct media_device_request *req;
+
+ filp = fget(request);
+ if (!filp)
+ return ERR_PTR(-ENOENT);
+
+ if (filp->f_op != &request_fops)
+ goto err_fput;
+ req = filp->private_data;
+ media_device_request_get(req);
+
+ if (req->mdev != mdev)
+ goto err_kref_put;
+
+ fput(filp);
+
+ return req;
+
+err_kref_put:
+ media_device_request_put(req);
+
+err_fput:
+ fput(filp);
+
+ return ERR_PTR(-EBADF);
+}
+EXPORT_SYMBOL_GPL(media_device_request_find);
+
+static int media_device_request_alloc(struct media_device *mdev,
+ struct file *filp,
+ struct media_request_cmd *cmd)
+{
+ struct media_device_request *req;
+#ifdef CONFIG_DYNAMIC_DEBUG
+ char comm[TASK_COMM_LEN];
+#endif
+ unsigned long flags;
+ int fd;
+ int ret;
+
+ 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;
+ }
+
+ req = mdev->ops->req_alloc(mdev);
+ if (!req) {
+ ret = -ENOMEM;
+ goto err_fput;
+ }
+
+ filp->private_data = req;
+ req->mdev = mdev;
+ req->state = MEDIA_DEVICE_REQUEST_STATE_IDLE;
+ kref_init(&req->kref);
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ list_add_tail(&req->req_list, &mdev->req_idle);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ cmd->request = fd;
+
+#ifdef CONFIG_DYNAMIC_DEBUG
+ get_task_comm(comm, current);
+ snprintf(req->debug_str, sizeof(req->debug_str), "%s:%d",
+ comm, fd);
+#endif
+
+ 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;
+}
+
+void media_device_request_complete(struct media_device *mdev,
+ struct media_device_request *req)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+
+ if (req->state == MEDIA_DEVICE_REQUEST_STATE_IDLE) {
+ dev_dbg(mdev->dev,
+ "request: not completing an idle request %s\n",
+ req->debug_str);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+ return;
+ }
+
+ if (WARN_ON(req->state != MEDIA_DEVICE_REQUEST_STATE_QUEUED)) {
+ dev_dbg(mdev->dev, "request: can't delete %s, state %s\n",
+ req->debug_str,
+ media_device_request_state_str(req->state));
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+ return;
+ }
+
+ req->state = MEDIA_DEVICE_REQUEST_STATE_COMPLETE;
+
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ media_device_request_put(req);
+}
+EXPORT_SYMBOL_GPL(media_device_request_complete);
+
+static int media_device_request_queue(
+ struct media_device *mdev, struct media_device_request *req, bool try)
+{
+ char *str = try ? "try" : "queue";
+ unsigned long flags;
+ int ret = 0;
+
+ dev_dbg(mdev->dev, "request: %s %s\n", str, req->debug_str);
+
+ /*
+ * Ensure the request that was just validated is the one that gets
+ * queued next.
+ */
+ mutex_lock(&mdev->req_queue_mutex);
+
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ if (req->state != MEDIA_DEVICE_REQUEST_STATE_IDLE) {
+ ret = -EINVAL;
+ dev_dbg(mdev->dev,
+ "request: unable to %s %s, request in state %s\n",
+ str, req->debug_str,
+ media_device_request_state_str(req->state));
+ } else {
+ req->state = MEDIA_DEVICE_REQUEST_STATE_QUEUED;
+ }
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ if (ret)
+ goto err_unlock;
+
+ ret = mdev->ops->req_validate(mdev, req);
+ if (ret || try) {
+ if (ret)
+ dev_dbg(mdev->dev,
+ "request: %s failed validation (%d)\n",
+ req->debug_str, ret);
+ goto err_set_idle;
+ }
+
+ /*
+ * Obtain a reference to the request, release once complete (or there's
+ * an error).
+ */
+ media_device_request_get(req);
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ list_move(&req->list, &mdev->req_queued);
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+ ret = mdev->ops->req_queue(mdev, req);
+ if (ret) {
+ dev_dbg(mdev->dev, "request: can't queue %s (%d)\n",
+ req->debug_str, ret);
+ goto err_put;
+ }
+
+ mutex_unlock(&mdev->req_queue_mutex);
+
+ return 0;
+
+err_put:
+ media_device_request_put(req);
+
+err_set_idle:
+ spin_lock_irqsave(&mdev->req_lock, flags);
+ req->state = MEDIA_DEVICE_REQUEST_STATE_IDLE;
+ spin_unlock_irqrestore(&mdev->req_lock, flags);
+
+err_unlock:
+ mutex_unlock(&mdev->req_queue_mutex);
+
+ return ret;
+
+}
+
+static long media_device_request_cmd(struct media_device *mdev,
+ struct file *filp,
+ struct media_request_cmd *cmd)
+{
+ struct media_device_request *req = NULL;
+ int ret;
+
+ if (!mdev->ops || !mdev->ops->req_alloc || !mdev->ops->req_free ||
+ !mdev->ops->req_validate || !mdev->ops->req_queue)
+ return -ENOTTY;
+
+ if (cmd->cmd != MEDIA_REQ_CMD_ALLOC) {
+ req = media_device_request_find(mdev, cmd->request);
+ if (!req)
+ return -EINVAL;
+ }
+
+ switch (cmd->cmd) {
+ case MEDIA_REQ_CMD_ALLOC:
+ ret = media_device_request_alloc(mdev, filp, cmd);
+ break;
+
+ case MEDIA_REQ_CMD_QUEUE:
+ ret = media_device_request_queue(mdev, req, false);
+ break;
+
+ case MEDIA_REQ_CMD_TRY:
+ ret = media_device_request_queue(mdev, req, true);
+ break;
+
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ if (req)
+ media_device_request_put(req);
+
+ return ret < 0 ? ret : 0;
+}
+
+/**
+ * media_device_request_alloc_simple - Callback to allocate memory for media
+ * request
+ *
+ * @mdev: The media device for which the request is to be allocated
+ *
+ * Allocate memory for a media request. Drivers are free to implement their own
+ * callbacks if more than just the size of the @struct media_device_request
+ * itself is needed. Driver's own data comes after @struct
media_device_request.
+ */
+struct media_device_request *
+media_device_request_alloc_simple(struct media_device *mdev)
+{
+ return kzalloc(sizeof(struct media_device_request), GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(media_device_request_alloc_simple);
+
+/**
+ * media_device_request_alloc_free - Callback to release media request memory
+ *
+ * @mdev: The media device
+ * @req: The request which is to be released
+ *
+ * Release the media request memory. If more than this is needed to clean up a
+ * media request, drivers are free to implement their own callbacks.
+ */
+void media_device_request_free_simple(struct media_device *mdev,
+ struct media_device_request *req)
+{
+ kfree(req);
+}
+EXPORT_SYMBOL_GPL(media_device_request_free_simple);
+
/*
-----------------------------------------------------------------------------
* Userspace API
*/
@@ -55,6 +400,7 @@ static int media_device_close(struct file *filp)
}
static int media_device_get_info(struct media_device *dev,
+ struct file *filp,
struct media_device_info *info)
{
memset(info, 0, sizeof(*info));
@@ -94,6 +440,7 @@ static struct media_entity *find_entity(struct media_device
*mdev, u32 id)
}
static long media_device_enum_entities(struct media_device *mdev,
+ struct file *filp,
struct media_entity_desc *entd)
{
struct media_entity *ent;
@@ -147,6 +494,7 @@ static void media_device_kpad_to_upad(const struct
media_pad *kpad,
}
static long media_device_enum_links(struct media_device *mdev,
+ struct file *filp,
struct media_links_enum *links)
{
struct media_entity *entity;
@@ -196,6 +544,7 @@ static long media_device_enum_links(struct media_device
*mdev,
}
static long media_device_setup_link(struct media_device *mdev,
+ struct file *filp,
struct media_link_desc *linkd)
{
struct media_link *link = NULL;
@@ -226,6 +575,7 @@ static long media_device_setup_link(struct media_device
*mdev,
}
static long media_device_get_topology(struct media_device *mdev,
+ struct file *filp,
struct media_v2_topology *topo)
{
struct media_entity *entity;
@@ -390,7 +740,8 @@ static long copy_arg_to_user(void __user *uarg, void *karg,
unsigned int cmd)
#define MEDIA_IOC_SZ_ARG(__cmd, func, fl, alt_sz, from_user, to_user) \
[_IOC_NR(MEDIA_IOC_##__cmd)] = { \
.cmd = MEDIA_IOC_##__cmd, \
- .fn = (long (*)(struct media_device *, void *))func, \
+ .fn = (long (*)(struct media_device *, \
+ struct file *, void *))func, \
.flags = fl, \
.alt_arg_sizes = alt_sz, \
.arg_from_user = from_user, \
@@ -417,7 +768,7 @@ struct media_ioctl_info {
* pointer is NULL.
*/
const unsigned short *alt_arg_sizes;
- long (*fn)(struct media_device *dev, void *arg);
+ long (*fn)(struct media_device *dev, struct file *file, void *arg);
long (*arg_from_user)(void *karg, void __user *uarg, unsigned int cmd);
long (*arg_to_user)(void __user *uarg, void *karg, unsigned int cmd);
};
@@ -428,6 +779,7 @@ static const struct media_ioctl_info ioctl_info[] = {
MEDIA_IOC(ENUM_LINKS, media_device_enum_links,
MEDIA_IOC_FL_GRAPH_MUTEX),
MEDIA_IOC(SETUP_LINK, media_device_setup_link,
MEDIA_IOC_FL_GRAPH_MUTEX),
MEDIA_IOC(G_TOPOLOGY, media_device_get_topology,
MEDIA_IOC_FL_GRAPH_MUTEX),
+ MEDIA_IOC(REQUEST_CMD, media_device_request_cmd, 0),
};
#define MASK_IOC_SIZE(cmd) \
@@ -500,7 +852,7 @@ static long media_device_ioctl(struct file *filp, unsigned
int cmd,
if (info->flags & MEDIA_IOC_FL_GRAPH_MUTEX)
mutex_lock(&dev->graph_mutex);
- ret = info->fn(dev, karg);
+ ret = info->fn(dev, filp, karg);
if (info->flags & MEDIA_IOC_FL_GRAPH_MUTEX)
mutex_unlock(&dev->graph_mutex);
@@ -540,7 +892,7 @@ static long media_device_enum_links32(struct media_device
*mdev,
links.pads = compat_ptr(pads_ptr);
links.links = compat_ptr(links_ptr);
- return media_device_enum_links(mdev, &links);
+ return media_device_enum_links(mdev, NULL, &links);
}
#define MEDIA_IOC_ENUM_LINKS32 _IOWR('|', 0x02, struct
media_links_enum32)
@@ -765,6 +1117,10 @@ int __must_check __media_device_register(struct
media_device *mdev,
if (!devnode)
return -ENOMEM;
+ spin_lock_init(&mdev->req_lock);
+ INIT_LIST_HEAD(&mdev->req_idle);
+ INIT_LIST_HEAD(&mdev->req_queued);
+
/* Register the device node. */
mdev->devnode = devnode;
devnode->fops = &media_device_fops;
diff --git a/include/media/media-device.h b/include/media/media-device.h
index bcc6ec4..0f32ceb 100644
--- a/include/media/media-device.h
+++ b/include/media/media-device.h
@@ -19,14 +19,51 @@
#ifndef _MEDIA_DEVICE_H
#define _MEDIA_DEVICE_H
+#include <linux/kref.h>
+#include <linux/idr.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <media/media-devnode.h>
#include <media/media-entity.h>
-struct ida;
struct device;
+struct ida;
+struct media_device;
+
+enum media_device_request_state {
+ MEDIA_DEVICE_REQUEST_STATE_IDLE,
+ MEDIA_DEVICE_REQUEST_STATE_QUEUED,
+ MEDIA_DEVICE_REQUEST_STATE_COMPLETE,
+};
+
+/**
+ * media_device_request_state_str - Convert media request state to a string
+ *
+ * @state: The state of the media request
+ *
+ * Returns the string corresponding to a media request state.
+ */
+const char *
+media_device_request_state_str(enum media_device_request_state state);
+
+/**
+ * struct media_device_request - Media device request
+ * @mdev: Media device this request belongs to
+ * @kref: Reference count
+ * @list: List entry in the media device requests list
+ * @debug_prefix: Prefix for debug messages (process name:fd)
+ * @state: The state of the request
+ */
+struct media_device_request {
+ struct media_device *mdev;
+ struct kref kref;
+ struct list_head list;
+#ifdef CONFIG_DYNAMIC_DEBUG
+ char debug_str[TASK_COMM_LEN + 6];
+#endif
+ enum media_device_request_state state;
+};
/**
* struct media_entity_notify - Media Entity Notify
@@ -50,10 +87,21 @@ struct media_entity_notify {
* struct media_device_ops - Media device operations
* @link_notify: Link state change notification callback. This callback is
* called with the graph_mutex held.
+ * @req_alloc: Allocate a request
+ * @req_free: Free a request
+ * @req_validate: Validate a request
+ * @req_queue: Queue a request
*/
struct media_device_ops {
int (*link_notify)(struct media_link *link, u32 flags,
unsigned int notification);
+ struct media_device_request *(*req_alloc)(struct media_device *mdev);
+ void (*req_free)(struct media_device *mdev,
+ struct media_device_request *req);
+ int (*req_validate)(struct media_device *mdev,
+ struct media_device_request *req);
+ int (*req_queue)(struct media_device *mdev,
+ struct media_device_request *req);
};
/**
@@ -88,6 +136,11 @@ struct media_device_ops {
* @disable_source: Disable Source Handler function pointer
*
* @ops: Operation handler callbacks
+ * @req_lock: Serialise access to @requests
+ * @req_queue_mutex: Serialise validating and queueing requests
+ * @req_idle: List of idle requests (@struct media_request.list)
+ * @req_queued: List of queued (and completed) requests (@struct
+ * media_request.list)
*
* This structure represents an abstract high-level media device. It allows
easy
* access to entities and provides basic media device-level support. The
@@ -158,6 +211,11 @@ struct media_device {
void (*disable_source)(struct media_entity *entity);
const struct media_device_ops *ops;
+
+ spinlock_t req_lock;
+ struct mutex req_queue_mutex;
+ struct list_head req_queued;
+ struct list_head req_idle;
};
/* We don't need to include pci.h or usb.h here */
@@ -475,4 +533,15 @@ static inline void __media_device_usb_init(struct
media_device *mdev,
#define media_device_usb_init(mdev, udev, name) \
__media_device_usb_init(mdev, udev, name, KBUILD_MODNAME)
+struct media_device_request *
+media_device_request_find(struct media_device *mdev, int request);
+void media_device_request_get(struct media_device_request *req);
+void media_device_request_put(struct media_device_request *req);
+void media_device_request_complete(struct media_device *mdev,
+ struct media_device_request *req);
+
+struct media_device_request *
+media_device_request_alloc_simple(struct media_device *mdev);
+void media_device_request_free_simple(struct media_device *mdev,
+ struct media_device_request *req);
#endif
diff --git a/include/uapi/linux/media.h b/include/uapi/linux/media.h
index c7e9a5c..9bc397b 100644
--- a/include/uapi/linux/media.h
+++ b/include/uapi/linux/media.h
@@ -342,11 +342,21 @@ struct media_v2_topology {
/* ioctls */
+#define MEDIA_REQ_CMD_ALLOC 0
+#define MEDIA_REQ_CMD_TRY 1
+#define MEDIA_REQ_CMD_QUEUE 2
+
+struct __attribute__ ((packed)) media_request_cmd {
+ __u32 cmd;
+ __s32 request;
+};
+
#define MEDIA_IOC_DEVICE_INFO _IOWR('|', 0x00, struct media_device_info)
#define MEDIA_IOC_ENUM_ENTITIES _IOWR('|', 0x01, struct
media_entity_desc)
#define MEDIA_IOC_ENUM_LINKS _IOWR('|', 0x02, struct media_links_enum)
#define MEDIA_IOC_SETUP_LINK _IOWR('|', 0x03, struct media_link_desc)
#define MEDIA_IOC_G_TOPOLOGY _IOWR('|', 0x04, struct media_v2_topology)
+#define MEDIA_IOC_REQUEST_CMD _IOWR('|', 0x05, struct media_request_cmd)
#if !defined(__KERNEL__) || defined(__NEED_MEDIA_LEGACY_API)
--
2.7.4
