RE: [Intel-gfx] [PATCH v3 05/17] video/hdmi: Add Unpack only function for DRM infoframe

["Shankar, Uma" <uma.shankar@intel.com>]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Gwan-
> gyeong Mun
> Sent: Tuesday, February 4, 2020 4:50 AM
> To: intel-gfx@lists.freedesktop.org
> Cc: linux-fbdev@vger.kernel.org; dri-devel@lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH v3 05/17] video/hdmi: Add Unpack only function for DRM
> infoframe
> 
> It adds an unpack only function for DRM infoframe for dynamic range and mastering
> infoframe readout.
> It unpacks the information data block contained in the binary buffer into a structured
> frame of the HDMI Dynamic Range and Mastering (DRM) information frame.
> 
> In contrast to hdmi_drm_infoframe_unpack() function, it does not verify a
> checksum.
> 
> It can be used for unpacking a DP HDR Metadata Infoframe SDP case.
> DP HDR Metadata Infoframe SDP uses the same Dynamic Range and Mastering
> (DRM) information (CTA-861-G spec.) such as HDMI DRM infoframe.
> But DP SDP header and payload structure are different from HDMI DRM Infoframe.
> Therefore unpacking DRM infoframe for DP requires skipping of a verifying
> checksum.

Looks good to me.
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

> Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
> ---
>  drivers/video/hdmi.c | 58 +++++++++++++++++++++++++++++++-------------
>  include/linux/hdmi.h |  2 ++
>  2 files changed, 43 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c index
> 9c82e2a0a411..9818836d82b7 100644
> --- a/drivers/video/hdmi.c
> +++ b/drivers/video/hdmi.c
> @@ -1775,20 +1775,18 @@ hdmi_vendor_any_infoframe_unpack(union
> hdmi_vendor_any_infoframe *frame,  }
> 
>  /**
> - * hdmi_drm_infoframe_unpack() - unpack binary buffer to a HDMI DRM infoframe
> + * hdmi_drm_infoframe_unpack_only() - 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
> + * Unpacks the information data block 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)
> +int hdmi_drm_infoframe_unpack_only(struct hdmi_drm_infoframe *frame,
> +				   const void *buffer, size_t size)
>  {
>  	const u8 *ptr = buffer;
>  	const u8 *temp;
> @@ -1797,23 +1795,13 @@ static int hdmi_drm_infoframe_unpack(struct
> hdmi_drm_infoframe *frame,
>  	int ret;
>  	int i;
> 
> -	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)
> +	if (size < HDMI_DRM_INFOFRAME_SIZE)
>  		return -EINVAL;
> 
>  	ret = hdmi_drm_infoframe_init(frame);
>  	if (ret)
>  		return ret;
> 
> -	ptr += HDMI_INFOFRAME_HEADER_SIZE;
> -
>  	frame->eotf = ptr[0] & 0x7;
>  	frame->metadata_type = ptr[1] & 0x7;
> 
> @@ -1837,6 +1825,42 @@ static int hdmi_drm_infoframe_unpack(struct
> hdmi_drm_infoframe *frame,
> 
>  	return 0;
>  }
> +EXPORT_SYMBOL(hdmi_drm_infoframe_unpack_only);
> +
> +/**
> + * 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_unpack_only(frame, ptr +
> HDMI_INFOFRAME_HEADER_SIZE,
> +					     size - HDMI_INFOFRAME_HEADER_SIZE);
> +	return ret;
> +}
> 
>  /**
>   * hdmi_infoframe_unpack() - unpack binary buffer to a HDMI infoframe diff --git
> a/include/linux/hdmi.h b/include/linux/hdmi.h index 9918a6c910c5..afb43efc03e0
> 100644
> --- a/include/linux/hdmi.h
> +++ b/include/linux/hdmi.h
> @@ -219,6 +219,8 @@ ssize_t hdmi_drm_infoframe_pack(struct
> hdmi_drm_infoframe *frame, void *buffer,  ssize_t
> hdmi_drm_infoframe_pack_only(const struct hdmi_drm_infoframe *frame,
>  				     void *buffer, size_t size);
>  int hdmi_drm_infoframe_check(struct hdmi_drm_infoframe *frame);
> +int hdmi_drm_infoframe_unpack_only(struct hdmi_drm_infoframe *frame,
> +				   const void *buffer, size_t size);
> 
>  enum hdmi_spd_sdi {
>  	HDMI_SPD_SDI_UNKNOWN,
> --
> 2.24.1
> 
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