From: Tomi Valkeinen Date: Tue, 17 Mar 2026 12:09:42 +0000 (+0200) Subject: media: subdev: Split v4l2_subdev_get_frame_desc_passthrough() into locked and unlocked X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=64d712aa31f30a125291e7c47209ef7ebd3285a3;p=thirdparty%2Fkernel%2Fstable.git media: subdev: Split v4l2_subdev_get_frame_desc_passthrough() into locked and unlocked 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 [Sakari Ailus: Rebase on an earlier remote source pad error code fix.] Reviewed-by: Laurent Pinchart Signed-off-by: Sakari Ailus Signed-off-by: Hans Verkuil --- diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 998b500c5499..831c69c958b8 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -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; diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index 23c03ba7f84c..d256b7ec8f84 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -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,