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media: subdev: Split v4l2_subdev_get_frame_desc_passthrough() into locked and unlocked

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The recently added v4l2_subdev_get_frame_desc_passthrough() can be used
directly as an implementation for .get_frame_desc subdev op. However, in
some cases the drivers may want to add some customizations, while the
bulk of the work is still identical to what
v4l2_subdev_get_frame_desc_passthrough() does. Current locking scheme
makes this impossible to do properly.

Split v4l2_subdev_get_frame_desc_passthrough() into two functions:

__v4l2_subdev_get_frame_desc_passthrough(), which takes a locked subdev
state as a parameter, instead of locking and getting the active state
internally. Other than that, it does the same as
v4l2_subdev_get_frame_desc_passthrough() used to do.

v4l2_subdev_get_frame_desc_passthrough(), which locks the active state
and calls __v4l2_subdev_get_frame_desc_passthrough().

In other words, v4l2_subdev_get_frame_desc_passthrough() works as
before, but drivers can now alternatively add custom .get_frame_desc
code and call v4l2_subdev_get_frame_desc_passthrough().

An example use case is with DS90UB953 serializer: in normal use the
serializer passes through everything, but when test-pattern-generator
(TPG) is used, an internal TPG source is used. After this commit, the
UB953 get_frame_desc() can lock the state, look at the routing table to
see if we're in normal or TPG mode, then either call
__v4l2_subdev_get_frame_desc_passthrough() if in normal mode, or
construct a TPG frame desc if in TPG mode.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
[Sakari Ailus: Rebase on an earlier remote source pad error code fix.]
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
This commit is contained in:
Tomi Valkeinen 2026-03-17 14:09:42 +02:00 committed by Hans Verkuil
parent f40306e086
commit 64d712aa31
2 changed files with 61 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/media/v4l2-core/v4l2-subdev.c
View File

@ -2545,21 +2545,21 @@ int v4l2_subdev_s_stream_helper(struct v4l2_subdev *sd, int enable)
}
EXPORT_SYMBOL_GPL(v4l2_subdev_s_stream_helper);
int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
unsigned int pad,
struct v4l2_mbus_frame_desc *fd)
int __v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
struct v4l2_subdev_state *state,
unsigned int pad,
struct v4l2_mbus_frame_desc *fd)
{
struct media_pad *local_sink_pad;
struct v4l2_subdev_route *route;
struct v4l2_subdev_state *state;
struct device *dev = sd->dev;
int ret = 0;
lockdep_assert_held(state->lock);
if (WARN_ON(!(sd->entity.pads[pad].flags & MEDIA_PAD_FL_SOURCE)))
return -EINVAL;
state = v4l2_subdev_lock_and_get_active_state(sd);
/* Iterate over sink pads */
media_entity_for_each_pad(&sd->entity, local_sink_pad) {
struct v4l2_mbus_frame_desc source_fd;
@ -2586,15 +2586,12 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
if (IS_ERR(remote_source_pad)) {
dev_dbg(dev, "Failed to find remote pad for sink pad %u\n",
local_sink_pad->index);
ret = PTR_ERR(remote_source_pad);
goto out_unlock;
return PTR_ERR(remote_source_pad);
}
remote_sd = media_entity_to_v4l2_subdev(remote_source_pad->entity);
if (!remote_sd) {
ret = -EINVAL;
goto out_unlock;
}
if (!remote_sd)
return -EINVAL;
ret = v4l2_subdev_call(remote_sd, pad,
get_frame_desc,
@ -2604,7 +2601,7 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
dev_err(dev,
"Failed to get frame desc from remote subdev %s\n",
remote_sd->name);
goto out_unlock;
return ret;
}
have_source_fd = true;
@ -2615,8 +2612,7 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
dev_err(dev,
"Frame desc type mismatch: %u != %u\n",
fd->type, source_fd.type);
ret = -EPIPE;
goto out_unlock;
return -EPIPE;
}
}
@ -2631,14 +2627,12 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
dev_dbg(dev,
"Failed to find stream %u from source frame desc\n",
route->sink_stream);
ret = -EPIPE;
goto out_unlock;
return -EPIPE;
}
if (fd->num_entries >= V4L2_FRAME_DESC_ENTRY_MAX) {
dev_dbg(dev, "Frame desc entry limit reached\n");
ret = -ENOSPC;
goto out_unlock;
return -ENOSPC;
}
fd->entry[fd->num_entries] = *source_entry;
@ -2649,7 +2643,21 @@ int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
}
}
out_unlock:
return 0;
}
EXPORT_SYMBOL_GPL(__v4l2_subdev_get_frame_desc_passthrough);
int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
unsigned int pad,
struct v4l2_mbus_frame_desc *fd)
{
struct v4l2_subdev_state *state;
int ret;
state = v4l2_subdev_lock_and_get_active_state(sd);
ret = __v4l2_subdev_get_frame_desc_passthrough(sd, state, pad, fd);
v4l2_subdev_unlock_state(state);
return ret;

38
include/media/v4l2-subdev.h
View File

@ -1723,15 +1723,15 @@ int v4l2_subdev_disable_streams(struct v4l2_subdev *sd, u32 pad,
int v4l2_subdev_s_stream_helper(struct v4l2_subdev *sd, int enable);
/**
* v4l2_subdev_get_frame_desc_passthrough() - Helper to implement the subdev
* get_frame_desc operation in simple passthrough cases
* __v4l2_subdev_get_frame_desc_passthrough - Helper to implement the
* subdev get_frame_desc operation in simple passthrough cases
* @sd: The subdevice
* @state: The locked subdevice active state
* @pad: The source pad index
* @fd: The mbus frame desc
*
* This helper implements get_frame_desc operation for subdevices that pass
* streams through without modification. It can be assigned directly as the
* .get_frame_desc callback in &v4l2_subdev_pad_ops.
* This helper implements the get_frame_desc operation for subdevices that pass
* streams through without modification.
*
* The helper iterates over the subdevice's sink pads, calls get_frame_desc on
* the remote subdevice connected to each sink pad, and collects the frame desc
@ -1744,6 +1744,34 @@ int v4l2_subdev_s_stream_helper(struct v4l2_subdev *sd, int enable);
* sink pads are involved and the upstream sources report different frame desc
* types, -EPIPE is returned.
*
* The caller must hold the subdevice's active state lock. This variant is
* intended for drivers that need to perform additional work around the
* passthrough frame descriptor collection. Drivers that do not need any
* customization should use v4l2_subdev_get_frame_desc_passthrough() instead.
*
* Return: 0 on success, or a negative error code otherwise.
*/
int __v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,
struct v4l2_subdev_state *state,
unsigned int pad,
struct v4l2_mbus_frame_desc *fd);
/**
* v4l2_subdev_get_frame_desc_passthrough() - Helper to implement the subdev
* get_frame_desc operation in simple passthrough cases
* @sd: The subdevice
* @pad: The source pad index
* @fd: The mbus frame desc
*
* This function locks the subdevice's active state, calls
* __v4l2_subdev_get_frame_desc_passthrough(), and unlocks the state.
*
* This function can be assigned directly as the .get_frame_desc callback in
* &v4l2_subdev_pad_ops for subdevices that pass streams through without
* modification. Drivers that need to perform additional work should use
* __v4l2_subdev_get_frame_desc_passthrough() in their custom
* .get_frame_desc implementation instead.
*
* Return: 0 on success, or a negative error code otherwise.
*/
int v4l2_subdev_get_frame_desc_passthrough(struct v4l2_subdev *sd,