drm/amd/display: Make DMCUB bss/data firmware blob optional

[Why]
By moving everything out of .data into the other regions we can drop
the requirement for the second blob and unify it all into the inst/const
blob.

[How]
We need to still support the blob being there and not being there for
backwards compatibility.

Look for the DMCUB metadata section in the end of the inst/const blob
instead of bss/data is missing.

Clear CW2 if we don't have the data blob so we don't hang when
transitioning between data blob/blobless firmwares.

Don't memcpy the blob into CW2 region if it doesn't exist.

Signed-off-by: Nicholas Kazlauskas <[e-mail]>
Reviewed-by: Tony Cheng <[e-mail]>
Acked-by: Rodrigo Siqueira <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

···
 				fw_inst_const_size);
 	}
 
-	memcpy(fb_info->fb[DMUB_WINDOW_2_BSS_DATA].cpu_addr, fw_bss_data,
-	       fw_bss_data_size);
+	if (fw_bss_data_size)
+		memcpy(fb_info->fb[DMUB_WINDOW_2_BSS_DATA].cpu_addr,
+		       fw_bss_data, fw_bss_data_size);
 
 	/* Copy firmware bios info into FB memory. */
 	memcpy(fb_info->fb[DMUB_WINDOW_3_VBIOS].cpu_addr, adev->bios,
···
 		adev->dm.dmub_fw->data +
 		le32_to_cpu(hdr->header.ucode_array_offset_bytes) +
 		le32_to_cpu(hdr->inst_const_bytes);
+	region_params.fw_inst_const =
+		adev->dm.dmub_fw->data +
+		le32_to_cpu(hdr->header.ucode_array_offset_bytes) +
+		PSP_HEADER_BYTES;
 
 	status = dmub_srv_calc_region_info(dmub_srv, &region_params,
 					   &region_info);

drivers/gpu/drm/amd/display/dmub/inc/dmub_srv.h

···
 	uint32_t inst_const_size;
 	uint32_t bss_data_size;
 	uint32_t vbios_size;
+	const uint8_t *fw_inst_const;
 	const uint8_t *fw_bss_data;
 };
 

drivers/gpu/drm/amd/display/dmub/src/dmub_dcn20.c

···
 
 	dmub_dcn20_get_fb_base_offset(dmub, &fb_base, &fb_offset);
 
-	dmub_dcn20_translate_addr(&cw2->offset, fb_base, fb_offset, &offset);
+	if (cw2->region.base != cw2->region.top) {
+		dmub_dcn20_translate_addr(&cw2->offset, fb_base, fb_offset,
+					  &offset);
 
-	REG_WRITE(DMCUB_REGION3_CW2_OFFSET, offset.u.low_part);
-	REG_WRITE(DMCUB_REGION3_CW2_OFFSET_HIGH, offset.u.high_part);
-	REG_WRITE(DMCUB_REGION3_CW2_BASE_ADDRESS, cw2->region.base);
-	REG_SET_2(DMCUB_REGION3_CW2_TOP_ADDRESS, 0,
-		  DMCUB_REGION3_CW2_TOP_ADDRESS, cw2->region.top,
-		  DMCUB_REGION3_CW2_ENABLE, 1);
+		REG_WRITE(DMCUB_REGION3_CW2_OFFSET, offset.u.low_part);
+		REG_WRITE(DMCUB_REGION3_CW2_OFFSET_HIGH, offset.u.high_part);
+		REG_WRITE(DMCUB_REGION3_CW2_BASE_ADDRESS, cw2->region.base);
+		REG_SET_2(DMCUB_REGION3_CW2_TOP_ADDRESS, 0,
+			  DMCUB_REGION3_CW2_TOP_ADDRESS, cw2->region.top,
+			  DMCUB_REGION3_CW2_ENABLE, 1);
+	} else {
+		REG_WRITE(DMCUB_REGION3_CW2_OFFSET, 0);
+		REG_WRITE(DMCUB_REGION3_CW2_OFFSET_HIGH, 0);
+		REG_WRITE(DMCUB_REGION3_CW2_BASE_ADDRESS, 0);
+		REG_WRITE(DMCUB_REGION3_CW2_TOP_ADDRESS, 0);
+	}
 
 	dmub_dcn20_translate_addr(&cw3->offset, fb_base, fb_offset, &offset);
 

drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c

···
 }
 
 static const struct dmub_fw_meta_info *
-dmub_get_fw_meta_info(const uint8_t *fw_bss_data, uint32_t fw_bss_data_size)
+dmub_get_fw_meta_info(const struct dmub_srv_region_params *params)
 {
 	const union dmub_fw_meta *meta;
+	const uint8_t *blob = NULL;
+	uint32_t blob_size = 0;
 
-	if (fw_bss_data == NULL)
+	if (params->fw_bss_data) {
+		/* Legacy metadata region. */
+		blob = params->fw_bss_data;
+		blob_size = params->bss_data_size;
+	} else if (params->fw_inst_const) {
+		/* Combined metadata region. */
+		blob = params->fw_inst_const;
+		blob_size = params->inst_const_size;
+	}
+
+	if (!blob || !blob_size)
 		return NULL;
 
-	if (fw_bss_data_size < sizeof(union dmub_fw_meta) + DMUB_FW_META_OFFSET)
+	if (blob_size < sizeof(union dmub_fw_meta) + DMUB_FW_META_OFFSET)
 		return NULL;
 
-	meta = (const union dmub_fw_meta *)(fw_bss_data + fw_bss_data_size -
+	meta = (const union dmub_fw_meta *)(blob + blob_size -
 					    DMUB_FW_META_OFFSET -
 					    sizeof(union dmub_fw_meta));
 
···
 	mail->base = dmub_align(bios->top, 256);
 	mail->top = mail->base + DMUB_MAILBOX_SIZE;
 
-	fw_info = dmub_get_fw_meta_info(params->fw_bss_data,
-					params->bss_data_size);
+	fw_info = dmub_get_fw_meta_info(params);
 
 	if (fw_info) {
 		fw_state_size = fw_info->fw_region_size;