drm/amd/display: Add DMUB service function check if hw initialized

[Why]
We want to avoid reprogramming the cache window when possible.

We don't need to worry about it for S3 but we *do* need to worry about
it for S4 resume.

DM can check whether hardware should be reinitialized or store software
state when going to S4 to know whether we need to reprogram hardware.

[How]
Add helpers to the DMUB service to check hardware initialization state.

DM will hook it up later.
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -252,6 +252,8 @@ struct dmub_srv_hw_funcs {
 
 	bool (*is_supported)(struct dmub_srv *dmub);
 
+	bool (*is_hw_init)(struct dmub_srv *dmub);
+
 	bool (*is_phy_init)(struct dmub_srv *dmub);
 
 	bool (*is_auto_load_done)(struct dmub_srv *dmub);
@@ -380,6 +382,15 @@ enum dmub_status dmub_srv_calc_fb_info(struct dmub_srv *dmub,
 enum dmub_status dmub_srv_has_hw_support(struct dmub_srv *dmub,
 					 bool *is_supported);
 
+/**
+ * dmub_srv_is_hw_init() - returns hardware init state
+ *
+ * Return:
+ *   DMUB_STATUS_OK - success
+ *   DMUB_STATUS_INVALID - unspecified error
+ */
+enum dmub_status dmub_srv_is_hw_init(struct dmub_srv *dmub, bool *is_hw_init);
+
 /**
  * dmub_srv_hw_init() - initializes the underlying DMUB hardware
  * @dmub: the dmub service

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

@@ -122,6 +122,11 @@ void dmub_dcn20_set_inbox1_wptr(struct dmub_srv *dmub, uint32_t wptr_offset)
 	REG_WRITE(DMCUB_INBOX1_WPTR, wptr_offset);
 }
 
+bool dmub_dcn20_is_hw_init(struct dmub_srv *dmub)
+{
+	return REG_READ(DMCUB_REGION3_CW2_BASE_ADDRESS) != 0;
+}
+
 bool dmub_dcn20_is_supported(struct dmub_srv *dmub)
 {
 	uint32_t supported = 0;

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

@@ -55,6 +55,8 @@ uint32_t dmub_dcn20_get_inbox1_rptr(struct dmub_srv *dmub);
 
 void dmub_dcn20_set_inbox1_wptr(struct dmub_srv *dmub, uint32_t wptr_offset);
 
+bool dmub_dcn20_is_hw_init(struct dmub_srv *dmub);
+
 bool dmub_dcn20_is_supported(struct dmub_srv *dmub);
 
 bool dmub_dcn20_is_phy_init(struct dmub_srv *dmub);

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

@@ -76,6 +76,7 @@ static bool dmub_srv_hw_setup(struct dmub_srv *dmub, enum dmub_asic asic)
 		funcs->set_inbox1_wptr = dmub_dcn20_set_inbox1_wptr;
 		funcs->is_supported = dmub_dcn20_is_supported;
 		funcs->is_phy_init = dmub_dcn20_is_phy_init;
+		funcs->is_hw_init = dmub_dcn20_is_hw_init;
 
 		if (asic == DMUB_ASIC_DCN21) {
 			funcs->backdoor_load = dmub_dcn21_backdoor_load;
@@ -234,6 +235,19 @@ enum dmub_status dmub_srv_has_hw_support(struct dmub_srv *dmub,
 	return DMUB_STATUS_OK;
 }
 
+enum dmub_status dmub_srv_is_hw_init(struct dmub_srv *dmub, bool *is_hw_init)
+{
+	*is_hw_init = false;
+
+	if (!dmub->sw_init)
+		return DMUB_STATUS_INVALID;
+
+	if (dmub->hw_funcs.is_hw_init)
+		*is_hw_init = dmub->hw_funcs.is_hw_init(dmub);
+
+	return DMUB_STATUS_OK;
+}
+
 enum dmub_status dmub_srv_hw_init(struct dmub_srv *dmub,
 				  const struct dmub_srv_hw_params *params)
 {