[PATCH v4 04/25] drm/dp: DRM DP helper/macros to get DP sink DSC parameters

[Singh, Gaurav K]

On 9/12/2018 6:25 AM, Manasi Navare wrote:
> This patch adds inline functions and helpers for obtaining
> DP sink's supported DSC parameters like DSC sink support,
> eDP compressed BPP supported, maximum slice count supported
> by the sink devices, DSC line buffer bit depth supported on DP sink,
> DSC sink maximum color depth by parsing corresponding DPCD registers.
>
> v4:
> * Add helper to give line buf bit depth (Manasi)
> * Correct the bit masking in color depth helper (manasi)
> v3:
> * Use SLICE_CAP_2 for DP (Anusha)
> v2:
> * Add DSC sink support macro (Jani N)
>
> Cc: Gaurav K Singh <gaurav.k.singh at intel.com>
> Cc: dri-devel at lists.freedesktop.org
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> Reviewed-by: Anusha Srivatsa <anusha.srivatsa at intel.com>

This patch looks good to me.

Reviewed-by: Gaurav K Singh <gaurav.k.singh at intel.com>

> ---
>   drivers/gpu/drm/drm_dp_helper.c | 90 +++++++++++++++++++++++++++++++++
>   include/drm/drm_dp_helper.h     | 30 +++++++++++
>   2 files changed, 120 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> index 8c6b9fd89f8a..5d5879f115ce 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -1337,3 +1337,93 @@ int drm_dp_read_desc(struct drm_dp_aux *aux, struct drm_dp_desc *desc,
>   	return 0;
>   }
>   EXPORT_SYMBOL(drm_dp_read_desc);
> +
> +/**
> + * DRM DP Helpers for DSC
> + */
> +u8 drm_dp_dsc_sink_max_slice_count(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE],
> +				   bool is_edp)
> +{
> +	u8 slice_cap1 = dsc_dpcd[DP_DSC_SLICE_CAP_1 - DP_DSC_SUPPORT];
> +
> +	if (is_edp) {
> +		/* For eDP, register DSC_SLICE_CAPABILITIES_1 gives slice count */
> +		if (slice_cap1 & DP_DSC_4_PER_DP_DSC_SINK)
> +			return 4;
> +		if (slice_cap1 & DP_DSC_2_PER_DP_DSC_SINK)
> +			return 2;
> +		if (slice_cap1 & DP_DSC_1_PER_DP_DSC_SINK)
> +			return 1;
> +	} else {
> +		/* For DP, use values from DSC_SLICE_CAP_1 and DSC_SLICE_CAP2 */
> +		u8 slice_cap2 = dsc_dpcd[DP_DSC_SLICE_CAP_2 - DP_DSC_SUPPORT];
> +
> +		if (slice_cap2 & DP_DSC_24_PER_DP_DSC_SINK)
> +			return 24;
> +		if (slice_cap2 & DP_DSC_20_PER_DP_DSC_SINK)
> +			return 20;
> +		if (slice_cap2 & DP_DSC_16_PER_DP_DSC_SINK)
> +			return 16;
> +		if (slice_cap1 & DP_DSC_12_PER_DP_DSC_SINK)
> +			return 12;
> +		if (slice_cap1 & DP_DSC_10_PER_DP_DSC_SINK)
> +			return 10;
> +		if (slice_cap1 & DP_DSC_8_PER_DP_DSC_SINK)
> +			return 8;
> +		if (slice_cap1 & DP_DSC_6_PER_DP_DSC_SINK)
> +			return 6;
> +		if (slice_cap1 & DP_DSC_4_PER_DP_DSC_SINK)
> +			return 4;
> +		if (slice_cap1 & DP_DSC_2_PER_DP_DSC_SINK)
> +			return 2;
> +		if (slice_cap1 & DP_DSC_1_PER_DP_DSC_SINK)
> +			return 1;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_dsc_sink_max_slice_count);
> +
> +u8 drm_dp_dsc_sink_line_buf_depth(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
> +{
> +	u8 line_buf_depth = dsc_dpcd[DP_DSC_LINE_BUF_BIT_DEPTH - DP_DSC_SUPPORT];
> +
> +	switch (line_buf_depth & DP_DSC_LINE_BUF_BIT_DEPTH_MASK) {
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_9:
> +		return 9;
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_10:
> +		return 10;
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_11:
> +		return 11;
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_12:
> +		return 12;
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_13:
> +		return 13;
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_14:
> +		return 14;
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_15:
> +		return 15;
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_16:
> +		return 16;
> +	case DP_DSC_LINE_BUF_BIT_DEPTH_8:
> +		return 8;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_dsc_sink_line_buf_depth);
> +
> +u8 drm_dp_dsc_sink_max_color_depth(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
> +{
> +	u8 color_depth = dsc_dpcd[DP_DSC_DEC_COLOR_DEPTH_CAP - DP_DSC_SUPPORT];
> +
> +	if (color_depth & DP_DSC_12_BPC)
> +		return 12;
> +	if (color_depth & DP_DSC_10_BPC)
> +		return 10;
> +	if (color_depth & DP_DSC_8_BPC)
> +		return 8;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_dp_dsc_sink_max_color_depth);
> diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> index 7f6237cad10d..ce6297908fd6 100644
> --- a/include/drm/drm_dp_helper.h
> +++ b/include/drm/drm_dp_helper.h
> @@ -1065,6 +1065,36 @@ drm_dp_is_branch(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
>   	return dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT;
>   }
>   
> +/* DP/eDP DSC support */
> +u8 drm_dp_dsc_sink_max_slice_count(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE],
> +				   bool is_edp);
> +u8 drm_dp_dsc_sink_line_buf_depth(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE]);
> +u8 drm_dp_dsc_sink_max_color_depth(const u8 dsc_dpc[DP_DSC_RECEIVER_CAP_SIZE]);
> +
> +static inline bool
> +drm_dp_sink_supports_dsc(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
> +{
> +	return dsc_dpcd[DP_DSC_SUPPORT - DP_DSC_SUPPORT] &
> +		DP_DSC_DECOMPRESSION_IS_SUPPORTED;
> +}
> +
> +static inline u16
> +drm_edp_dsc_sink_output_bpp(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
> +{
> +	return dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_LOW - DP_DSC_SUPPORT] |
> +		(dsc_dpcd[DP_DSC_MAX_BITS_PER_PIXEL_HI - DP_DSC_SUPPORT] &
> +		 DP_DSC_MAX_BITS_PER_PIXEL_HI_MASK <<
> +		 DP_DSC_MAX_BITS_PER_PIXEL_HI_SHIFT);
> +}
> +
> +static inline u32
> +drm_dp_dsc_sink_max_slice_width(const u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])
> +{
> +	/* Max Slicewidth = Number of Pixels * 320 */
> +	return dsc_dpcd[DP_DSC_MAX_SLICE_WIDTH - DP_DSC_SUPPORT] *
> +		DP_DSC_SLICE_WIDTH_MULTIPLIER;
> +}
> +
>   /*
>    * DisplayPort AUX channel
>    */