drm/amd/display: adjust MALL size available for DCN32 and DCN321

[Why]
MALL size available can vary for different SKUs.
Use num_chans read from VBIOS to determine the available MALL size we can use

[How]
Define max_chans for DCN32 and DCN321.
If num_chans is max_chans, then return max_chans as we can access the
 entire MALL space.
Otherwise, define avail_chans as the number of available channels we are
 allowed instead.
Return corresponding number of channels back and use this to calculate
 available MALL size.
Reviewed-by: Nevenko Stupar <Nevenko.Stupar@amd.com>
Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Samson Tam <Samson.Tam@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c

@@ -2150,13 +2150,19 @@ static bool dcn32_resource_construct(
 	dc->caps.max_cursor_size = 64;
 	dc->caps.min_horizontal_blanking_period = 80;
 	dc->caps.dmdata_alloc_size = 2048;
-	dc->caps.mall_size_per_mem_channel = 0;
+	dc->caps.mall_size_per_mem_channel = 4;
 	dc->caps.mall_size_total = 0;
 	dc->caps.cursor_cache_size = dc->caps.max_cursor_size * dc->caps.max_cursor_size * 8;
 
 	dc->caps.cache_line_size = 64;
 	dc->caps.cache_num_ways = 16;
-	dc->caps.max_cab_allocation_bytes = 67108864; // 64MB = 1024 * 1024 * 64
+
+	/* Calculate the available MALL space */
+	dc->caps.max_cab_allocation_bytes = dcn32_calc_num_avail_chans_for_mall(
+		dc, dc->ctx->dc_bios->vram_info.num_chans) *
+		dc->caps.mall_size_per_mem_channel * 1024 * 1024;
+	dc->caps.mall_size_total = dc->caps.max_cab_allocation_bytes;
+
 	dc->caps.subvp_fw_processing_delay_us = 15;
 	dc->caps.subvp_drr_max_vblank_margin_us = 40;
 	dc->caps.subvp_prefetch_end_to_mall_start_us = 15;
@@ -2593,3 +2599,55 @@ struct pipe_ctx *dcn32_acquire_idle_pipe_for_head_pipe_in_layer(
 
 	return idle_pipe;
 }
+
+unsigned int dcn32_calc_num_avail_chans_for_mall(struct dc *dc, int num_chans)
+{
+	/*
+	 * DCN32 and DCN321 SKUs may have different sizes for MALL
+	 *  but we may not be able to access all the MALL space.
+	 *  If the num_chans is power of 2, then we can access all
+	 *  of the available MALL space.  Otherwise, we can only
+	 *  access:
+	 *
+	 *  max_cab_size_in_bytes = total_cache_size_in_bytes *
+	 *    ((2^floor(log2(num_chans)))/num_chans)
+	 *
+	 * Calculating the MALL sizes for all available SKUs, we
+	 *  have come up with the follow simplified check.
+	 * - we have max_chans which provides the max MALL size.
+	 *  Each chans supports 4MB of MALL so:
+	 *
+	 *  total_cache_size_in_bytes = max_chans * 4 MB
+	 *
+	 * - we have avail_chans which shows the number of channels
+	 *  we can use if we can't access the entire MALL space.
+	 *  It is generally half of max_chans
+	 * - so we use the following checks:
+	 *
+	 *   if (num_chans == max_chans), return max_chans
+	 *   if (num_chans < max_chans), return avail_chans
+	 *
+	 * - exception is GC_11_0_0 where we can't access max_chans,
+	 *  so we define max_avail_chans as the maximum available
+	 *  MALL space
+	 *
+	 */
+	int gc_11_0_0_max_chans = 48;
+	int gc_11_0_0_max_avail_chans = 32;
+	int gc_11_0_0_avail_chans = 16;
+	int gc_11_0_3_max_chans = 16;
+	int gc_11_0_3_avail_chans = 8;
+	int gc_11_0_2_max_chans = 8;
+	int gc_11_0_2_avail_chans = 4;
+
+	if (ASICREV_IS_GC_11_0_0(dc->ctx->asic_id.hw_internal_rev)) {
+		return (num_chans == gc_11_0_0_max_chans) ?
+			gc_11_0_0_max_avail_chans : gc_11_0_0_avail_chans;
+	} else if (ASICREV_IS_GC_11_0_2(dc->ctx->asic_id.hw_internal_rev)) {
+		return (num_chans == gc_11_0_2_max_chans) ?
+			gc_11_0_2_max_chans : gc_11_0_2_avail_chans;
+	} else { // if (ASICREV_IS_GC_11_0_3(dc->ctx->asic_id.hw_internal_rev)) {
+		return (num_chans == gc_11_0_3_max_chans) ?
+			gc_11_0_3_max_chans : gc_11_0_3_avail_chans;
+	}
+}

drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.h

@@ -148,6 +148,8 @@ void dcn32_restore_mall_state(struct dc *dc,
 
 bool dcn32_allow_subvp_with_active_margin(struct pipe_ctx *pipe);
 
+unsigned int dcn32_calc_num_avail_chans_for_mall(struct dc *dc, int num_chans);
+
 /* definitions for run time init of reg offsets */
 
 /* CLK SRC */

drivers/gpu/drm/amd/display/dc/dcn321/dcn321_resource.c

@@ -1703,11 +1703,18 @@ static bool dcn321_resource_construct(
 	dc->caps.max_cursor_size = 64;
 	dc->caps.min_horizontal_blanking_period = 80;
 	dc->caps.dmdata_alloc_size = 2048;
-	dc->caps.mall_size_per_mem_channel = 0;
+	dc->caps.mall_size_per_mem_channel = 4;
 	dc->caps.mall_size_total = 0;
 	dc->caps.cursor_cache_size = dc->caps.max_cursor_size * dc->caps.max_cursor_size * 8;
 	dc->caps.cache_line_size = 64;
 	dc->caps.cache_num_ways = 16;
+
+	/* Calculate the available MALL space */
+	dc->caps.max_cab_allocation_bytes = dcn32_calc_num_avail_chans_for_mall(
+		dc, dc->ctx->dc_bios->vram_info.num_chans) *
+		dc->caps.mall_size_per_mem_channel * 1024 * 1024;
+	dc->caps.mall_size_total = dc->caps.max_cab_allocation_bytes;
+
 	dc->caps.max_cab_allocation_bytes = 33554432; // 32MB = 1024 * 1024 * 32
 	dc->caps.subvp_fw_processing_delay_us = 15;
 	dc->caps.subvp_drr_max_vblank_margin_us = 40;

drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c

@@ -2495,8 +2495,11 @@ void dcn32_update_bw_bounding_box_fpu(struct dc *dc, struct clk_bw_params *bw_pa
 		}
 
 		/* Override from VBIOS for num_chan */
-		if (dc->ctx->dc_bios->vram_info.num_chans)
+		if (dc->ctx->dc_bios->vram_info.num_chans) {
 			dcn3_2_soc.num_chans = dc->ctx->dc_bios->vram_info.num_chans;
+			dcn3_2_soc.mall_allocated_for_dcn_mbytes = (double)(dcn32_calc_num_avail_chans_for_mall(dc,
+				dc->ctx->dc_bios->vram_info.num_chans) * dc->caps.mall_size_per_mem_channel);
+		}
 
 		if (dc->ctx->dc_bios->vram_info.dram_channel_width_bytes)
 			dcn3_2_soc.dram_channel_width_bytes = dc->ctx->dc_bios->vram_info.dram_channel_width_bytes;

drivers/gpu/drm/amd/display/dc/dml/dcn321/dcn321_fpu.c

@@ -534,8 +534,11 @@ void dcn321_update_bw_bounding_box_fpu(struct dc *dc, struct clk_bw_params *bw_p
 		}
 
 		/* Override from VBIOS for num_chan */
-		if (dc->ctx->dc_bios->vram_info.num_chans)
+		if (dc->ctx->dc_bios->vram_info.num_chans) {
 			dcn3_21_soc.num_chans = dc->ctx->dc_bios->vram_info.num_chans;
+			dcn3_21_soc.mall_allocated_for_dcn_mbytes = (double)(dcn32_calc_num_avail_chans_for_mall(dc,
+				dc->ctx->dc_bios->vram_info.num_chans) * dc->caps.mall_size_per_mem_channel);
+		}
 
 		if (dc->ctx->dc_bios->vram_info.dram_channel_width_bytes)
 			dcn3_21_soc.dram_channel_width_bytes = dc->ctx->dc_bios->vram_info.dram_channel_width_bytes;