drm/amd/display: Add PSR-SU-RC support in DC

[Why]

PSR-SU Rate Control - or PSR-SU-RC - enables PSR-SU panels to work with
variable refresh rate to allow for more power savings. Lowering the
refresh rate can increase PSR residency by expanding the eDP main link
shut down duration. It can also lower panel power consumption.

There is a complication with PSR, since the eDP main link can be shut
down. Therefore, the timing controller (TCON) on the eDP sink nees to be
able to scan out its remote buffer independent of the main link. To
allow the eDP source to specify the sink's refresh rate while the link
is off, vendor-specific DPCD registers are used. This allows the eDP
source to then "Rate Control" the panel during PSR active.

[How]

Add DC support to communicate with PSR-SU-RC supported eDP sinks. The
sink will need to know the desired VTotal during PSR active.

This change only adds support to DC, support in amdgpu_dm is still
pending to enable this fully.

Signed-off-by: David Zhang <dingchen.zhang@amd.com>
Signed-off-by: Leo Li <sunpeng.li@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 25 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c b/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
index 9ca0cbb0af9b..0df06740ec39 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.c
@@ -250,6 +250,27 @@ static void dmub_psr_set_level(struct dmub_psr *dmub, uint16_t psr_level, uint8_
 	dc_dmub_srv_wait_idle(dc->dmub_srv);
 }
 
+/**
+ * Set PSR vtotal requirement for FreeSync PSR.
+ */
+static void dmub_psr_set_sink_vtotal_in_psr_active(struct dmub_psr *dmub,
+		uint16_t psr_vtotal_idle, uint16_t psr_vtotal_su)
+{
+	union dmub_rb_cmd cmd;
+	struct dc_context *dc = dmub->ctx;
+
+	memset(&cmd, 0, sizeof(cmd));
+	cmd.psr_set_vtotal.header.type = DMUB_CMD__PSR;
+	cmd.psr_set_vtotal.header.sub_type = DMUB_CMD__SET_SINK_VTOTAL_IN_PSR_ACTIVE;
+	cmd.psr_set_vtotal.header.payload_bytes = sizeof(struct dmub_cmd_psr_set_vtotal_data);
+	cmd.psr_set_vtotal.psr_set_vtotal_data.psr_vtotal_idle = psr_vtotal_idle;
+	cmd.psr_set_vtotal.psr_set_vtotal_data.psr_vtotal_su = psr_vtotal_su;
+
+	dc_dmub_srv_cmd_queue(dc->dmub_srv, &cmd);
+	dc_dmub_srv_cmd_execute(dc->dmub_srv);
+	dc_dmub_srv_wait_idle(dc->dmub_srv);
+}
+
 /*
  * Set PSR power optimization flags.
  */
@@ -358,6 +379,7 @@ static bool dmub_psr_copy_settings(struct dmub_psr *dmub,
 
 	copy_settings_data->line_capture_indication = 0;
 	copy_settings_data->line_time_in_us = psr_context->line_time_in_us;
+	copy_settings_data->rate_control_caps = psr_context->rate_control_caps;
 	copy_settings_data->fec_enable_status = (link->fec_state == dc_link_fec_enabled);
 	copy_settings_data->fec_enable_delay_in100us = link->dc->debug.fec_enable_delay_in100us;
 	copy_settings_data->cmd_version =  DMUB_CMD_PSR_CONTROL_VERSION_1;
@@ -435,6 +457,7 @@ static const struct dmub_psr_funcs psr_funcs = {
 	.psr_set_level			= dmub_psr_set_level,
 	.psr_force_static		= dmub_psr_force_static,
 	.psr_get_residency		= dmub_psr_get_residency,
+	.psr_set_sink_vtotal_in_psr_active	= dmub_psr_set_sink_vtotal_in_psr_active,
 	.psr_set_power_opt		= dmub_psr_set_power_opt,
 };
 
diff --git a/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.h b/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.h
index 01acc01cc191..74005b9d352a 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.h
+++ b/drivers/gpu/drm/amd/display/dc/dce/dmub_psr.h
@@ -46,6 +46,8 @@ struct dmub_psr_funcs {
 	void (*psr_force_static)(struct dmub_psr *dmub, uint8_t panel_inst);
 	void (*psr_get_residency)(struct dmub_psr *dmub, uint32_t *residency,
 	uint8_t panel_inst);
+	void (*psr_set_sink_vtotal_in_psr_active)(struct dmub_psr *dmub,
+	uint16_t psr_vtotal_idle, uint16_t psr_vtotal_su);
 	void (*psr_set_power_opt)(struct dmub_psr *dmub, unsigned int power_opt, uint8_t panel_inst);
 };