[PATCH 7/9] media: staging/imx: convert static vdev lists to list_head

From: Steve Longerbeam
Date: Sat Oct 28 2017 - 16:42:14 EST

Although not technically necessary because imx-media has only a
maximum of 8 video devices, and once setup the video device lists
are static, in anticipation of moving control ineritance to
v4l2-core, make the vdev lists more generic by converting to
dynamic list_head's.

After doing that, 'struct imx_media_pad' is now just a list_head
of video devices reachable from a pad. Allocate an array of list_head's,
one list_head for each pad, and attach that array to sd->host_priv.
An entry in the pad lists is of type 'struct imx_media_pad_vdev', and
points to a video device from the master list.

Signed-off-by: Steve Longerbeam <steve_longerbeam@xxxxxxxxxx>
---
drivers/staging/media/imx/imx-media-capture.c | 2 +
drivers/staging/media/imx/imx-media-dev.c | 77 +++++++++++++++------------
drivers/staging/media/imx/imx-media-utils.c | 16 +-----
drivers/staging/media/imx/imx-media.h | 39 +++++++-------
4 files changed, 68 insertions(+), 66 deletions(-)

diff --git a/drivers/staging/media/imx/imx-media-capture.c b/drivers/staging/media/imx/imx-media-capture.c
index ea145ba..def3df2 100644
--- a/drivers/staging/media/imx/imx-media-capture.c
+++ b/drivers/staging/media/imx/imx-media-capture.c
@@ -754,6 +754,8 @@ imx_media_capture_device_init(struct v4l2_subdev *src_sd, int pad)
vfd->queue = &priv->q;
priv->vdev.vfd = vfd;

+ INIT_LIST_HEAD(&priv->vdev.list);
+
video_set_drvdata(vfd, priv);

v4l2_ctrl_handler_init(&priv->ctrl_hdlr, 0);
diff --git a/drivers/staging/media/imx/imx-media-dev.c b/drivers/staging/media/imx/imx-media-dev.c
index 40c7cfd..b6acddb 100644
--- a/drivers/staging/media/imx/imx-media-dev.c
+++ b/drivers/staging/media/imx/imx-media-dev.c
@@ -229,10 +229,11 @@ static int imx_media_add_vdev_to_pad(struct imx_media_dev *imxmd,
struct media_pad *srcpad)
{
struct media_entity *entity = srcpad->entity;
- struct imx_media_pad *imxpad;
+ struct imx_media_pad_vdev *pad_vdev;
+ struct list_head *pad_vdev_list;
struct media_link *link;
struct v4l2_subdev *sd;
- int i, vdev_idx, ret;
+ int i, ret;

/* skip this entity if not a v4l2_subdev */
if (!is_media_entity_v4l2_subdev(entity))
@@ -240,8 +241,8 @@ static int imx_media_add_vdev_to_pad(struct imx_media_dev *imxmd,

sd = media_entity_to_v4l2_subdev(entity);

- imxpad = to_imx_media_pad(sd, srcpad->index);
- if (!imxpad) {
+ pad_vdev_list = to_pad_vdev_list(sd, srcpad->index);
+ if (!pad_vdev_list) {
v4l2_warn(&imxmd->v4l2_dev, "%s:%u has no vdev list!\n",
entity->name, srcpad->index);
/*
@@ -251,23 +252,22 @@ static int imx_media_add_vdev_to_pad(struct imx_media_dev *imxmd,
return 0;
}

- vdev_idx = imxpad->num_vdevs;
-
/* just return if we've been here before */
- for (i = 0; i < vdev_idx; i++)
- if (vdev == imxpad->vdev[i])
+ list_for_each_entry(pad_vdev, pad_vdev_list, list) {
+ if (pad_vdev->vdev == vdev)
return 0;
-
- if (vdev_idx >= IMX_MEDIA_MAX_VDEVS) {
- dev_err(imxmd->md.dev, "can't add %s to pad %s:%u\n",
- vdev->vfd->entity.name, entity->name, srcpad->index);
- return -ENOSPC;
}

dev_dbg(imxmd->md.dev, "adding %s to pad %s:%u\n",
vdev->vfd->entity.name, entity->name, srcpad->index);
- imxpad->vdev[vdev_idx] = vdev;
- imxpad->num_vdevs++;
+
+ pad_vdev = devm_kzalloc(imxmd->md.dev, sizeof(*pad_vdev), GFP_KERNEL);
+ if (!pad_vdev)
+ return -ENOMEM;
+
+ /* attach this vdev to this pad */
+ pad_vdev->vdev = vdev;
+ list_add_tail(&pad_vdev->list, pad_vdev_list);

/* move upstream from this entity's sink pads */
for (i = 0; i < entity->num_pads; i++) {
@@ -289,22 +289,32 @@ static int imx_media_add_vdev_to_pad(struct imx_media_dev *imxmd,
return 0;
}

+/*
+ * For every subdevice, allocate an array of list_head's, one list_head
+ * for each pad, to hold the list of video devices reachable from that
+ * pad.
+ */
static int imx_media_alloc_pad_vdev_lists(struct imx_media_dev *imxmd)
{
- struct imx_media_pad *imxpads;
+ struct list_head *vdev_lists;
struct media_entity *entity;
struct v4l2_subdev *sd;
+ int i;

list_for_each_entry(sd, &imxmd->v4l2_dev.subdevs, list) {
entity = &sd->entity;
- imxpads = devm_kzalloc(imxmd->md.dev,
- entity->num_pads * sizeof(*imxpads),
- GFP_KERNEL);
- if (!imxpads)
+ vdev_lists = devm_kzalloc(
+ imxmd->md.dev,
+ entity->num_pads * sizeof(*vdev_lists),
+ GFP_KERNEL);
+ if (!vdev_lists)
return -ENOMEM;

- /* attach imxpads to the subdev's host private pointer */
- sd->host_priv = imxpads;
+ /* attach to the subdev's host private pointer */
+ sd->host_priv = vdev_lists;
+
+ for (i = 0; i < entity->num_pads; i++)
+ INIT_LIST_HEAD(to_pad_vdev_list(sd, i));
}

return 0;
@@ -315,14 +325,13 @@ static int imx_media_create_pad_vdev_lists(struct imx_media_dev *imxmd)
{
struct imx_media_video_dev *vdev;
struct media_link *link;
- int i, ret;
+ int ret;

ret = imx_media_alloc_pad_vdev_lists(imxmd);
if (ret)
return ret;

- for (i = 0; i < imxmd->num_vdevs; i++) {
- vdev = imxmd->vdev[i];
+ list_for_each_entry(vdev, &imxmd->vdev_list, list) {
link = list_first_entry(&vdev->vfd->entity.links,
struct media_link, list);
ret = imx_media_add_vdev_to_pad(imxmd, vdev, link->source);
@@ -405,11 +414,12 @@ static int imx_media_link_notify(struct media_link *link, u32 flags,
unsigned int notification)
{
struct media_entity *source = link->source->entity;
- struct imx_media_pad *imxpad;
+ struct imx_media_pad_vdev *pad_vdev;
+ struct list_head *pad_vdev_list;
struct imx_media_dev *imxmd;
struct video_device *vfd;
struct v4l2_subdev *sd;
- int i, pad_idx, ret;
+ int pad_idx, ret;

ret = v4l2_pipeline_link_notify(link, flags, notification);
if (ret)
@@ -424,8 +434,8 @@ static int imx_media_link_notify(struct media_link *link, u32 flags,

imxmd = dev_get_drvdata(sd->v4l2_dev->dev);

- imxpad = to_imx_media_pad(sd, pad_idx);
- if (!imxpad) {
+ pad_vdev_list = to_pad_vdev_list(sd, pad_idx);
+ if (!pad_vdev_list) {
/* shouldn't happen, but no reason to fail link setup */
return 0;
}
@@ -439,8 +449,8 @@ static int imx_media_link_notify(struct media_link *link, u32 flags,
*/
if (notification == MEDIA_DEV_NOTIFY_PRE_LINK_CH &&
!(flags & MEDIA_LNK_FL_ENABLED)) {
- for (i = 0; i < imxpad->num_vdevs; i++) {
- vfd = imxpad->vdev[i]->vfd;
+ list_for_each_entry(pad_vdev, pad_vdev_list, list) {
+ vfd = pad_vdev->vdev->vfd;
dev_dbg(imxmd->md.dev,
"reset controls for %s\n",
vfd->entity.name);
@@ -449,8 +459,8 @@ static int imx_media_link_notify(struct media_link *link, u32 flags,
}
} else if (notification == MEDIA_DEV_NOTIFY_POST_LINK_CH &&
(link->flags & MEDIA_LNK_FL_ENABLED)) {
- for (i = 0; i < imxpad->num_vdevs; i++) {
- vfd = imxpad->vdev[i]->vfd;
+ list_for_each_entry(pad_vdev, pad_vdev_list, list) {
+ vfd = pad_vdev->vdev->vfd;
dev_dbg(imxmd->md.dev,
"refresh controls for %s\n",
vfd->entity.name);
@@ -505,6 +515,7 @@ static int imx_media_probe(struct platform_device *pdev)
dev_set_drvdata(imxmd->v4l2_dev.dev, imxmd);

INIT_LIST_HEAD(&imxmd->asd_list);
+ INIT_LIST_HEAD(&imxmd->vdev_list);

ret = imx_media_add_of_subdevs(imxmd, node);
if (ret) {
diff --git a/drivers/staging/media/imx/imx-media-utils.c b/drivers/staging/media/imx/imx-media-utils.c
index e143a88..13dafa7 100644
--- a/drivers/staging/media/imx/imx-media-utils.c
+++ b/drivers/staging/media/imx/imx-media-utils.c
@@ -705,24 +705,12 @@ EXPORT_SYMBOL_GPL(imx_media_find_subdev_by_devname);
int imx_media_add_video_device(struct imx_media_dev *imxmd,
struct imx_media_video_dev *vdev)
{
- int vdev_idx, ret = 0;
-
mutex_lock(&imxmd->mutex);

- vdev_idx = imxmd->num_vdevs;
- if (vdev_idx >= IMX_MEDIA_MAX_VDEVS) {
- dev_err(imxmd->md.dev,
- "%s: too many video devices! can't add %s\n",
- __func__, vdev->vfd->name);
- ret = -ENOSPC;
- goto out;
- }
+ list_add_tail(&vdev->list, &imxmd->vdev_list);

- imxmd->vdev[vdev_idx] = vdev;
- imxmd->num_vdevs++;
-out:
mutex_unlock(&imxmd->mutex);
- return ret;
+ return 0;
}
EXPORT_SYMBOL_GPL(imx_media_add_video_device);

diff --git a/drivers/staging/media/imx/imx-media.h b/drivers/staging/media/imx/imx-media.h
index 042de92..79d7958 100644
--- a/drivers/staging/media/imx/imx-media.h
+++ b/drivers/staging/media/imx/imx-media.h
@@ -19,9 +19,6 @@
#include <media/videobuf2-dma-contig.h>
#include <video/imx-ipu-v3.h>

-/* max video devices */
-#define IMX_MEDIA_MAX_VDEVS 8
-
/*
* Pad definitions for the subdevs with multiple source or
* sink pads
@@ -82,6 +79,9 @@ struct imx_media_video_dev {
/* the user format */
struct v4l2_format fmt;
const struct imx_media_pixfmt *cc;
+
+ /* links this vdev to master list */
+ struct list_head list;
};

static inline struct imx_media_buffer *to_imx_media_vb(struct vb2_buffer *vb)
@@ -91,24 +91,26 @@ static inline struct imx_media_buffer *to_imx_media_vb(struct vb2_buffer *vb)
return container_of(vbuf, struct imx_media_buffer, vbuf);
}

-/* to support control inheritance to video devices */
-struct imx_media_pad {
- /*
- * list of video devices that can be reached from this pad,
- * list is only valid for source pads.
- */
- struct imx_media_video_dev *vdev[IMX_MEDIA_MAX_VDEVS];
- int num_vdevs;
-};
-
-static inline struct imx_media_pad *
-to_imx_media_pad(struct v4l2_subdev *sd, int pad_index)
+/*
+ * to support control inheritance to video devices, this
+ * retrieves a pad's list_head of video devices that can
+ * be reached from the pad. Note that only the lists in
+ * source pads get populated, sink pads have empty lists.
+ */
+static inline struct list_head *
+to_pad_vdev_list(struct v4l2_subdev *sd, int pad_index)
{
- struct imx_media_pad *imxpads = sd->host_priv;
+ struct list_head *vdev_list = sd->host_priv;

- return imxpads ? &imxpads[pad_index] : NULL;
+ return vdev_list ? &vdev_list[pad_index] : NULL;
}

+/* an entry in a pad's video device list */
+struct imx_media_pad_vdev {
+ struct imx_media_video_dev *vdev;
+ struct list_head list;
+};
+
struct imx_media_internal_sd_platformdata {
char sd_name[V4L2_SUBDEV_NAME_SIZE];
u32 grp_id;
@@ -139,8 +141,7 @@ struct imx_media_dev {
struct mutex mutex; /* protect elements below */

/* master video device list */
- struct imx_media_video_dev *vdev[IMX_MEDIA_MAX_VDEVS];
- int num_vdevs;
+ struct list_head vdev_list;

/* IPUs this media driver control, valid after subdevs bound */
struct ipu_soc *ipu[2];
--
2.7.4