[v9 12/13] video/hdmi: Add Unpack function for DRM infoframe

[Shankar, Uma]

>-----Original Message-----
>From: dri-devel [mailto:dri-devel-bounces at lists.freedesktop.org] On Behalf Of Ville
>Syrjälä
>Sent: Tuesday, May 14, 2019 1:20 AM
>To: Shankar, Uma <uma.shankar at intel.com>
>Cc: dcastagna at chromium.org; jonas at kwiboo.se; intel-gfx at lists.freedesktop.org;
>emil.l.velikov at gmail.com; dri-devel at lists.freedesktop.org;
>seanpaul at chromium.org; Syrjala, Ville <ville.syrjala at intel.com>; Lankhorst, Maarten
><maarten.lankhorst at intel.com>
>Subject: Re: [v9 12/13] video/hdmi: Add Unpack function for DRM infoframe
>
>On Thu, May 09, 2019 at 12:08:52AM +0530, Uma Shankar wrote:
>> Added unpack function for DRM infoframe for dynamic range and
>> mastering infoframe readout.
>>
>> Suggested-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>> Signed-off-by: Uma Shankar <uma.shankar at intel.com>
>> ---
>>  drivers/video/hdmi.c | 54
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/hdmi.h |  1 +
>>  2 files changed, 55 insertions(+)
>>
>> diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c index
>> 717ed7fb..110d405 100644
>> --- a/drivers/video/hdmi.c
>> +++ b/drivers/video/hdmi.c
>> @@ -1801,6 +1801,57 @@ static int hdmi_audio_infoframe_unpack(struct
>> hdmi_audio_infoframe *frame,  }
>>
>>  /**
>> + * hdmi_drm_infoframe_unpack() - unpack binary buffer to a HDMI DRM
>> +infoframe
>> + * @frame: HDMI DRM infoframe
>> + * @buffer: source buffer
>> + * @size: size of buffer
>> + *
>> + * Unpacks the information contained in binary @buffer into a
>> +structured
>> + * @frame of the HDMI Dynamic Range and Mastering (DRM) information frame.
>> + * Also verifies the checksum as required by section 5.3.5 of the
>> +HDMI 1.4
>> + * specification.
>> + *
>> + * Returns 0 on success or a negative error code on failure.
>> + */
>> +static int hdmi_drm_infoframe_unpack(struct hdmi_drm_infoframe *frame,
>> +				     const void *buffer, size_t size) {
>> +	const u8 *ptr = buffer;
>> +	int ret;
>> +
>> +	if (size < HDMI_INFOFRAME_SIZE(DRM))
>> +		return -EINVAL;
>> +
>> +	if (ptr[0] != HDMI_INFOFRAME_TYPE_DRM ||
>> +	    ptr[1] != 1 ||
>> +	    ptr[2] != HDMI_DRM_INFOFRAME_SIZE)
>> +		return -EINVAL;
>> +
>> +	if (hdmi_infoframe_checksum(buffer, HDMI_INFOFRAME_SIZE(DRM)) != 0)
>> +		return -EINVAL;
>> +
>> +	ret = hdmi_drm_infoframe_init(frame);
>> +	if (ret)
>> +		return ret;
>> +
>> +	frame->length = ptr[2];
>
>The length handling is inconsistnet between the compute and readout sides. I would
>suggest for now just put the length initialization into hdmi_drm_infoframe_init() (and
>remove it from the drm code), and check it in the check_only(). We can revisit it
>if/when other metadata formats become relevant.

Sure, will update this.

>> +	ptr += HDMI_INFOFRAME_HEADER_SIZE;
>> +
>> +	frame->eotf = ptr[0] & 0x7;
>> +	frame->metadata_type = ptr[1] & 0x7;
>> +
>> +	memcpy(&frame->display_primaries, &ptr[2], 12);
>> +	memcpy(&frame->white_point, &ptr[14], 4);
>
>Endianness fail.

Ok, will explicitly copy these.

>> +
>> +	frame->max_display_mastering_luminance = (ptr[19] << 8) | ptr[18];
>> +	frame->min_display_mastering_luminance = (ptr[21] << 8) | ptr[20];
>> +	frame->max_cll = (ptr[23] << 8) | ptr[22];
>> +	frame->max_fall = (ptr[25] << 8) | ptr[24];
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>>   * hdmi_infoframe_unpack() - unpack binary buffer to a HDMI infoframe
>>   * @frame: HDMI infoframe
>>   * @buffer: source buffer
>> @@ -1826,6 +1877,9 @@ int hdmi_infoframe_unpack(union hdmi_infoframe
>*frame,
>>  	case HDMI_INFOFRAME_TYPE_AVI:
>>  		ret = hdmi_avi_infoframe_unpack(&frame->avi, buffer, size);
>>  		break;
>> +	case HDMI_INFOFRAME_TYPE_DRM:
>> +		ret = hdmi_drm_infoframe_unpack(&frame->drm, buffer, size);
>> +		break;
>>  	case HDMI_INFOFRAME_TYPE_SPD:
>>  		ret = hdmi_spd_infoframe_unpack(&frame->spd, buffer, size);
>>  		break;
>> diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h index
>> 3d7f10f..ee55ba5 100644
>> --- a/include/linux/hdmi.h
>> +++ b/include/linux/hdmi.h
>> @@ -56,6 +56,7 @@ enum hdmi_infoframe_type {
>>  #define HDMI_AVI_INFOFRAME_SIZE    13
>>  #define HDMI_SPD_INFOFRAME_SIZE    25
>>  #define HDMI_AUDIO_INFOFRAME_SIZE  10
>> +#define HDMI_DRM_INFOFRAME_SIZE    26
>>
>>  #define HDMI_INFOFRAME_SIZE(type)	\
>>  	(HDMI_INFOFRAME_HEADER_SIZE + HDMI_ ## type ## _INFOFRAME_SIZE)
>> --
>> 1.9.1
>>
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>> dri-devel at lists.freedesktop.org
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>
>--
>Ville Syrjälä
>Intel
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