Hi,
On Tue, Jul 18, 2017 at 4:20 AM, Chris Zhong <zyw@xxxxxxxxxxxxxx> wrote:
> The DP is using the same audio infoframe payload as hdmi, per DP 1.3
> spec, but it has a different header. Provide a new interface here,
> it just packs the payload.
>
> Signed-off-by: Chris Zhong <zyw@xxxxxxxxxxxxxx>
> ---
>
> Changes in v2: None
>
> drivers/video/hdmi.c | 66 ++++++++++++++++++++++++++++++++++++++--------------
> include/linux/hdmi.h | 3 ++-
> 2 files changed, 50 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
> index 1cf907e..e0b041e 100644
> --- a/drivers/video/hdmi.c
> +++ b/drivers/video/hdmi.c
> @@ -240,6 +240,49 @@ int hdmi_audio_infoframe_init(struct hdmi_audio_infoframe *frame)
> EXPORT_SYMBOL(hdmi_audio_infoframe_init);
>
> /**
> + * hdmi_audio_infoframe_pack_payload() - write HDMI audio infoframe payload to
> + * binary buffer
> + * @frame: HDMI audio infoframe
> + * @buffer: destination buffer
> + * @size: size of buffer
> + *
> + * Packs the information contained in the @frame structure into a binary
> + * representation that can be written into the corresponding controller
> + * registers.
> + *
> + * Returns 0 on success or a negative error code on failure.
> + */
> +ssize_t hdmi_audio_infoframe_pack_payload(struct hdmi_audio_infoframe *frame,
> + void *buffer, size_t size)
> +{
> + unsigned char channels;
> + u8 *ptr = buffer;
> +
> + if (size < frame->length)
You also need to return -ENOSPC if (size < 5). That's because below
you always write 5 elements into this array. I'll leave it to someone
with actual DRM experience to say whether they want a #define of some
sort here. Probably they do since someone made a #define for
"HDMI_INFOFRAME_HEADER_SIZE".
Also: you don't use frame->length anywhere in this function and it
doesn't seem to be related with packing the payload. Seems like you
shouldn't check it here.
> + return -ENOSPC;
> +
> + memset(buffer, 0, size);
I don't think the memset belongs here. It seems like all this
function is doing is setting up ptr[0] through ptr[4] and the memset()
doesn't belong with that, does it?
> @@ -256,22 +299,15 @@ EXPORT_SYMBOL(hdmi_audio_infoframe_init);
> ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
> void *buffer, size_t size)
> {
> - unsigned char channels;
> u8 *ptr = buffer;
> size_t length;
> + int ret;
>
> length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;
>
> if (size < length)
> return -ENOSPC;
>
> - memset(buffer, 0, size);
It seems like the memset() belongs here, logically. This function
deals with the whole buffer so it should be clearing it.
> -
> - if (frame->channels >= 2)
> - channels = frame->channels - 1;
> - else
> - channels = 0;
> -
> ptr[0] = frame->type;
> ptr[1] = frame->version;
> ptr[2] = frame->length;
> @@ -279,16 +315,10 @@ ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
>
> /* start infoframe payload */
> ptr += HDMI_INFOFRAME_HEADER_SIZE;
> -
> - ptr[0] = ((frame->coding_type & 0xf) << 4) | (channels & 0x7);
> - ptr[1] = ((frame->sample_frequency & 0x7) << 2) |
> - (frame->sample_size & 0x3);
> - ptr[2] = frame->coding_type_ext & 0x1f;
> - ptr[3] = frame->channel_allocation;
> - ptr[4] = (frame->level_shift_value & 0xf) << 3;
> -
> - if (frame->downmix_inhibit)
> - ptr[4] |= BIT(7);
> + ret = hdmi_audio_infoframe_pack_payload(frame, ptr,
> + size - HDMI_INFOFRAME_HEADER_SIZE);
> + if (ret)
> + return ret;
>
> hdmi_infoframe_set_checksum(buffer, length);
>
> diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h
> index d271ff2..d93c709 100644
> --- a/include/linux/hdmi.h
> +++ b/include/linux/hdmi.h
> @@ -272,7 +272,8 @@ struct hdmi_audio_infoframe {
> int hdmi_audio_infoframe_init(struct hdmi_audio_infoframe *frame);
> ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
> void *buffer, size_t size);
> -
> +ssize_t hdmi_audio_infoframe_pack_payload(struct hdmi_audio_infoframe *frame,
> + void *buffer, size_t size);
nit: seems like you're changing whitespace here (there used to be a
blank line before the enum).
> enum hdmi_3d_structure {
> HDMI_3D_STRUCTURE_INVALID = -1,
> HDMI_3D_STRUCTURE_FRAME_PACKING = 0,
> --
> 2.7.4
>
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