[PATCH 4/5] drm/amd/display: Prevent PSR from being enabled if initialization fails

[Bhawanpreet Lakha]

From: Anthony Koo <Anthony.Koo at amd.com>

[Why]
PSR_SET command is sent to the microcontroller in order to initialize
parameters needed for PSR feature, such as telling the microcontroller
which pipe is driving the PSR supported panel. When this command is
skipped or fails, the microcontroller may program the wrong thing if
driver tries to enable PSR.

[How]
If PSR_SET fails, do not set psr_enable flag to indicate the feature is
not yet initialized.

Change-Id: If4cdcd73d408de5ccafa0dd5effebe1c4fd70f50
Signed-off-by: Anthony Koo <Anthony.Koo at amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr at amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
---
 drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c | 38 ++++++++++++++++-----------
 drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h  |  2 +-
 2 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
index 062a46543887..ca7989e4932b 100644
--- a/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
+++ b/drivers/gpu/drm/amd/display/dc/dce/dce_dmcu.c
@@ -150,7 +150,7 @@ static void dce_dmcu_set_psr_enable(struct dmcu *dmcu, bool enable, bool wait)
 	}
 }
 
-static void dce_dmcu_setup_psr(struct dmcu *dmcu,
+static bool dce_dmcu_setup_psr(struct dmcu *dmcu,
 		struct dc_link *link,
 		struct psr_context *psr_context)
 {
@@ -261,6 +261,8 @@ static void dce_dmcu_setup_psr(struct dmcu *dmcu,
 
 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);
+
+	return true;
 }
 
 static bool dce_is_dmcu_initialized(struct dmcu *dmcu)
@@ -545,24 +547,25 @@ static void dcn10_dmcu_set_psr_enable(struct dmcu *dmcu, bool enable, bool wait)
 	 *  least a few frames. Should never hit the max retry assert below.
 	 */
 	if (wait == true) {
-	for (retryCount = 0; retryCount <= 1000; retryCount++) {
-		dcn10_get_dmcu_psr_state(dmcu, &psr_state);
-		if (enable) {
-			if (psr_state != 0)
-				break;
-		} else {
-			if (psr_state == 0)
-				break;
+		for (retryCount = 0; retryCount <= 1000; retryCount++) {
+			dcn10_get_dmcu_psr_state(dmcu, &psr_state);
+			if (enable) {
+				if (psr_state != 0)
+					break;
+			} else {
+				if (psr_state == 0)
+					break;
+			}
+			udelay(500);
 		}
-		udelay(500);
-	}
 
-	/* assert if max retry hit */
-	ASSERT(retryCount <= 1000);
+		/* assert if max retry hit */
+		if (retryCount >= 1000)
+			ASSERT(0);
 	}
 }
 
-static void dcn10_dmcu_setup_psr(struct dmcu *dmcu,
+static bool dcn10_dmcu_setup_psr(struct dmcu *dmcu,
 		struct dc_link *link,
 		struct psr_context *psr_context)
 {
@@ -577,7 +580,7 @@ static void dcn10_dmcu_setup_psr(struct dmcu *dmcu,
 
 	/* If microcontroller is not running, do nothing */
 	if (dmcu->dmcu_state != DMCU_RUNNING)
-		return;
+		return false;
 
 	link->link_enc->funcs->psr_program_dp_dphy_fast_training(link->link_enc,
 			psr_context->psrExitLinkTrainingRequired);
@@ -677,6 +680,11 @@ static void dcn10_dmcu_setup_psr(struct dmcu *dmcu,
 
 	/* notifyDMCUMsg */
 	REG_UPDATE(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 1);
+
+	/* waitDMCUReadyForCmd */
+	REG_WAIT(MASTER_COMM_CNTL_REG, MASTER_COMM_INTERRUPT, 0, 1, 10000);
+
+	return true;
 }
 
 static void dcn10_psr_wait_loop(
diff --git a/drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h b/drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h
index de60f940030d..4550747fb61c 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/hw/dmcu.h
@@ -48,7 +48,7 @@ struct dmcu_funcs {
 			const char *src,
 			unsigned int bytes);
 	void (*set_psr_enable)(struct dmcu *dmcu, bool enable, bool wait);
-	void (*setup_psr)(struct dmcu *dmcu,
+	bool (*setup_psr)(struct dmcu *dmcu,
 			struct dc_link *link,
 			struct psr_context *psr_context);
 	void (*get_psr_state)(struct dmcu *dmcu, uint32_t *psr_state);
-- 
2.14.1