drm/amd/display: add a func to disable accelerated mode

[Why]
When driver disabled, we driver force the YCbCr420 to RGB,
which means some register will be changed, such as
RDPCS_PHY_DP_MPLLB_TX_CLK_DIV changed from 1 to 0
When driver re-enabled, OS will Set Mode YCbCr420 again,
which means the register RDPCS_PHY_DP_MPLLB_TX_CLK_DIV
should to be 1 again, but dmub fw can’t update the
register to 1 due to the mpll is not off

[How]
Adds an interface to disable accelerated mode bit,
which allows DM to decide to call during driver
disable/unload scenarios.
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Yao Wang1 <Yao.Wang1@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Solomon Chiu <solomon.chiu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/bios/bios_parser_helper.c

@@ -64,9 +64,10 @@ bool bios_is_accelerated_mode(
 
 
 void bios_set_scratch_acc_mode_change(
-	struct dc_bios *bios)
+	struct dc_bios *bios,
+	uint32_t state)
 {
-	REG_UPDATE(BIOS_SCRATCH_6, S6_ACC_MODE, 1);
+	REG_UPDATE(BIOS_SCRATCH_6, S6_ACC_MODE, state);
 }
 
 

drivers/gpu/drm/amd/display/dc/bios/bios_parser_helper.h

@@ -32,7 +32,7 @@ uint8_t *bios_get_image(struct dc_bios *bp, uint32_t offset,
 	uint32_t size);
 
 bool bios_is_accelerated_mode(struct dc_bios *bios);
-void bios_set_scratch_acc_mode_change(struct dc_bios *bios);
+void bios_set_scratch_acc_mode_change(struct dc_bios *bios, uint32_t state);
 void bios_set_scratch_critical_state(struct dc_bios *bios, bool state);
 uint32_t bios_get_vga_enabled_displays(struct dc_bios *bios);
 

drivers/gpu/drm/amd/display/dc/core/dc.c

@@ -41,6 +41,7 @@
 #include "dc_bios_types.h"
 
 #include "bios_parser_interface.h"
+#include "bios/bios_parser_helper.h"
 #include "include/irq_service_interface.h"
 #include "transform.h"
 #include "dmcu.h"
@@ -3372,3 +3373,20 @@ bool dc_process_dmub_aux_transfer_async(struct dc *dc,
 
 	return true;
 }
+
+/**
+ *****************************************************************************
+ *  Function: dc_disable_accelerated_mode
+ *
+ *  @brief
+ *		disable accelerated mode
+ *
+ *  @param
+ *		[in] dc: dc structure
+ *
+ *****************************************************************************
+ */
+void dc_disable_accelerated_mode(struct dc *dc)
+{
+	bios_set_scratch_acc_mode_change(dc->ctx->dc_bios, 0);
+}

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

@@ -1313,4 +1313,10 @@ bool dc_process_dmub_aux_transfer_async(struct dc *dc,
  * DSC Interfaces
  ******************************************************************************/
 #include "dc_dsc.h"
+
+/*******************************************************************************
+ * Disable acc mode Interfaces
+ ******************************************************************************/
+void dc_disable_accelerated_mode(struct dc *dc);
+
 #endif /* DC_INTERFACE_H_ */

drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c

@@ -1750,7 +1750,7 @@ void dce110_enable_accelerated_mode(struct dc *dc, struct dc_state *context)
 		if (edp_link_with_sink && !keep_edp_vdd_on)
 			dc->hwss.edp_power_control(edp_link_with_sink, false);
 	}
-	bios_set_scratch_acc_mode_change(dc->ctx->dc_bios);
+	bios_set_scratch_acc_mode_change(dc->ctx->dc_bios, 1);
 }
 
 static uint32_t compute_pstate_blackout_duration(