On Wed, 28 Aug 2024, Hans Verkuil <hverkuil-cisco@xxxxxxxxx> wrote:
> Add new helpers to export received or transmitted HDMI InfoFrames to
> debugfs.
>
> This complements similar code in drm where the transmitted HDMI infoframes
> are exported to debugfs.
>
> The same names have been used as in drm, so this is consistent.
>
> The exported infoframes can be parsed with the edid-decode utility.
>
> Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-dv-timings.c | 63 +++++++++++++++++++++++
> include/media/v4l2-dv-timings.h | 48 +++++++++++++++++
> 2 files changed, 111 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-dv-timings.c b/drivers/media/v4l2-core/v4l2-dv-timings.c
> index 942d0005c55e..86a8627f4bcc 100644
> --- a/drivers/media/v4l2-core/v4l2-dv-timings.c
> +++ b/drivers/media/v4l2-core/v4l2-dv-timings.c
> @@ -1154,3 +1154,66 @@ int v4l2_phys_addr_validate(u16 phys_addr, u16 *parent, u16 *port)
> return 0;
> }
> EXPORT_SYMBOL_GPL(v4l2_phys_addr_validate);
> +
> +#ifdef CONFIG_DEBUG_FS
> +
> +#define DEBUGFS_FOPS(type, flag) \
> +static ssize_t \
> +infoframe_read_##type(struct file *filp, \
> + char __user *ubuf, size_t count, loff_t *ppos) \
> +{ \
> + struct v4l2_debugfs_if *infoframes = filp->private_data; \
> + \
> + return infoframes->if_read((flag), infoframes->priv, filp, \
> + ubuf, count, ppos); \
> +} \
> + \
> +static const struct file_operations infoframe_##type##_fops = { \
> + .owner = THIS_MODULE, \
> + .open = simple_open, \
> + .read = infoframe_read_##type, \
> +}
> +
> +DEBUGFS_FOPS(avi, V4L2_DEBUGFS_IF_AVI);
> +DEBUGFS_FOPS(audio, V4L2_DEBUGFS_IF_AUDIO);
> +DEBUGFS_FOPS(spd, V4L2_DEBUGFS_IF_SPD);
> +DEBUGFS_FOPS(hdmi, V4L2_DEBUGFS_IF_HDMI);
> +
> +struct v4l2_debugfs_if *v4l2_debugfs_if_alloc(struct dentry *root, u32 if_types,
> + void *priv,
> + v4l2_debugfs_if_read_t if_read)
> +{
> + struct v4l2_debugfs_if *infoframes;
> +
> + if (IS_ERR_OR_NULL(root) || !if_types || !if_read)
> + return NULL;
> +
> + infoframes = kzalloc(sizeof(*infoframes), GFP_KERNEL);
> + if (!infoframes)
> + return NULL;
> +
> + infoframes->if_dir = debugfs_create_dir("infoframes", root);
> + infoframes->priv = priv;
> + infoframes->if_read = if_read;
> + if (if_types & V4L2_DEBUGFS_IF_AVI)
> + debugfs_create_file("avi", 0400, infoframes->if_dir, infoframes, &infoframe_avi_fops);
> + if (if_types & V4L2_DEBUGFS_IF_AUDIO)
> + debugfs_create_file("audio", 0400, infoframes->if_dir, infoframes, &infoframe_audio_fops);
> + if (if_types & V4L2_DEBUGFS_IF_SPD)
> + debugfs_create_file("spd", 0400, infoframes->if_dir, infoframes, &infoframe_spd_fops);
> + if (if_types & V4L2_DEBUGFS_IF_HDMI)
> + debugfs_create_file("hdmi", 0400, infoframes->if_dir, infoframes, &infoframe_hdmi_fops);
> + return infoframes;
> +}
> +EXPORT_SYMBOL_GPL(v4l2_debugfs_if_alloc);
> +
> +void v4l2_debugfs_if_free(struct v4l2_debugfs_if *infoframes)
> +{
> + if (infoframes) {
> + debugfs_remove_recursive(infoframes->if_dir);
> + kfree(infoframes);
> + }
> +}
> +EXPORT_SYMBOL_GPL(v4l2_debugfs_if_free);
> +
> +#endif
> diff --git a/include/media/v4l2-dv-timings.h b/include/media/v4l2-dv-timings.h
> index 8fa963326bf6..13830411bd6c 100644
> --- a/include/media/v4l2-dv-timings.h
> +++ b/include/media/v4l2-dv-timings.h
> @@ -8,6 +8,7 @@
> #ifndef __V4L2_DV_TIMINGS_H
> #define __V4L2_DV_TIMINGS_H
>
> +#include <linux/debugfs.h>
Please don't include headers from headers if you can get by with forward
declarations.
I recently discovered a lot of drm depending on getting seq_file.h and
debugfs.h via media/cec.h...
BR,
Jani.
> #include <linux/videodev2.h>
>
> /**
> @@ -251,4 +252,51 @@ void v4l2_set_edid_phys_addr(u8 *edid, unsigned int size, u16 phys_addr);
> u16 v4l2_phys_addr_for_input(u16 phys_addr, u8 input);
> int v4l2_phys_addr_validate(u16 phys_addr, u16 *parent, u16 *port);
>
> +/* Add support for exporting InfoFrames to debugfs */
> +
> +/*
> + * HDMI InfoFrames start with a 3 byte header, then a checksum,
> + * followed by the actual IF payload.
> + *
> + * The payload length is limited to 30 bytes according to the HDMI spec,
> + * but since the length is encoded in 5 bits, it can be 31 bytes theoretically.
> + * So set the max length as 31 + 3 (header) + 1 (checksum) = 35.
> + */
> +#define V4L2_DEBUGFS_IF_MAX_LEN (35)
> +
> +#define V4L2_DEBUGFS_IF_AVI BIT(0)
> +#define V4L2_DEBUGFS_IF_AUDIO BIT(1)
> +#define V4L2_DEBUGFS_IF_SPD BIT(2)
> +#define V4L2_DEBUGFS_IF_HDMI BIT(3)
> +
> +typedef ssize_t (*v4l2_debugfs_if_read_t)(u32 type, void *priv,
> + struct file *filp, char __user *ubuf,
> + size_t count, loff_t *ppos);
> +
> +struct v4l2_debugfs_if {
> + struct dentry *if_dir;
> + void *priv;
> +
> + v4l2_debugfs_if_read_t if_read;
> +};
> +
> +#ifdef CONFIG_DEBUG_FS
> +struct v4l2_debugfs_if *v4l2_debugfs_if_alloc(struct dentry *root, u32 if_types,
> + void *priv,
> + v4l2_debugfs_if_read_t if_read);
> +void v4l2_debugfs_if_free(struct v4l2_debugfs_if *infoframes);
> +#else
> +static inline
> +struct v4l2_debugfs_if *v4l2_debugfs_if_alloc(struct dentry *root, u32 if_types,
> + void *priv,
> + v4l2_debugfs_if_read_t if_read)
> +{
> + return NULL;
> +}
> +
> +static inline void v4l2_debugfs_if_free(struct v4l2_debugfs_if *infoframes)
> +{
> +}
> +#endif
> +
> #endif
--
Jani Nikula, Intel
