disp: msm: dp: Implement dsc slice selection logic based on sink caps

The dp sink explicitly states the numbers of
slices it can support. When calculating the
number of slices for dsc configuration, ensure
that the sink supports the calculated number of
slices.

If the sink does not support the calculated
number of slices, keep rechecking sink support
for the subsequent slice increment, until we
reach the highest number of slices possible
according to the dp spec. If no compatible
sink slice support is found, do not enable dsc.

CRs-Fixed: 2325207
Change-Id: I485adacd258963cdec9cc52aa041373883ecadc7
Signed-off-by: Fuad Hossain <[email protected]>

msm/dp/dp_panel.c

@@ -1514,7 +1514,12 @@ struct dp_dsc_peak_throughput {
 	u32 peak_throughput;
 };
 
-struct dp_dsc_slices_per_line slice_per_line_tbl[] = {
+struct dp_dsc_slice_caps_bit_map {
+	u32 num_slices;
+	u32 bit_index;
+};
+
+const struct dp_dsc_slices_per_line slice_per_line_tbl[] = {
 	{0,     340,    1   },
 	{340,   680,    2   },
 	{680,   1360,   4   },
@@ -1543,13 +1548,54 @@ const struct dp_dsc_peak_throughput peak_throughput_mode_0_tbl[] = {
 	{14, 1000},
 };
 
+const struct dp_dsc_slice_caps_bit_map slice_caps_bit_map_tbl[] = {
+	{1, 0},
+	{2, 1},
+	{4, 3},
+	{6, 4},
+	{8, 5},
+	{10, 6},
+	{12, 7},
+	{16, 0},
+	{20, 1},
+	{24, 2},
+};
+
+static bool dp_panel_check_slice_support(u32 num_slices, u32 raw_data_1,
+		u32 raw_data_2)
+{
+	const struct dp_dsc_slice_caps_bit_map *bcap;
+	u32 raw_data;
+	int i;
+
+	if (num_slices <= 12)
+		raw_data = raw_data_1;
+	else
+		raw_data = raw_data_2;
+
+	for (i = 0; i < ARRAY_SIZE(slice_caps_bit_map_tbl); i++) {
+		bcap = &slice_caps_bit_map_tbl[i];
+
+		if (bcap->num_slices == num_slices) {
+			raw_data &= (1 << bcap->bit_index);
+
+			if (raw_data)
+				return true;
+			else
+				return false;
+		}
+	}
+
+	return false;
+}
+
 static int dp_panel_dsc_prepare_basic_params(
 		struct msm_compression_info *comp_info,
 		const struct dp_display_mode *dp_mode,
 		struct dp_panel *dp_panel)
 {
 	int i;
-	struct dp_dsc_slices_per_line *rec;
+	const struct dp_dsc_slices_per_line *rec;
 	const struct dp_dsc_peak_throughput *tput;
 	u32 slice_width;
 	u32 ppr = dp_mode->timing.pixel_clk_khz/1000;
@@ -1557,6 +1603,8 @@ static int dp_panel_dsc_prepare_basic_params(
 	u32 ppr_max_index;
 	u32 peak_throughput;
 	u32 ppr_per_slice;
+	u32 slice_caps_1;
+	u32 slice_caps_2;
 
 	comp_info->dsc_info.slice_per_pkt = 0;
 	for (i = 0; i < ARRAY_SIZE(slice_per_line_tbl); i++) {
@@ -1586,8 +1634,20 @@ static int dp_panel_dsc_prepare_basic_params(
 
 	ppr_per_slice = ppr/comp_info->dsc_info.slice_per_pkt;
 
+	slice_caps_1 = dp_panel->dsc_dpcd[4];
+	slice_caps_2 = dp_panel->dsc_dpcd[13] & 0x7;
+
+	/*
+	 * There are 3 conditions to check for sink support:
+	 * 1. The slice width cannot exceed the maximum.
+	 * 2. The ppr per slice cannot exceed the maximum.
+	 * 3. The number of slices must be explicitly supported.
+	 */
 	while (slice_width >= max_slice_width ||
-			ppr_per_slice > peak_throughput) {
+			ppr_per_slice > peak_throughput ||
+			!dp_panel_check_slice_support(
+			comp_info->dsc_info.slice_per_pkt, slice_caps_1,
+			slice_caps_2)) {
 		if (i == ARRAY_SIZE(slice_per_line_tbl))
 			return -EINVAL;