[PATCH v2 6/9] drm/i915/psr/bdw+: Enable CRC check in the static frame on the sink side

["José Roberto de Souza" <jose.souza@intel.com>]

Sink can be configured to calculate the CRC over the static frame and
compare with the CRC calculated and transmited in the VSC SDP by
source, if there is a mismatch sink will do a short pulse in HPD
and set DP_PSR_LINK_CRC_ERROR on DP_PSR_ERROR_STATUS.

Also spec recommends to disable MAX_SLEEP as a trigger to exit PSR when
CRC check is enabled to improve power savings.

Spec: 7723

Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
---

Changes from v1:
- printing a debug message when sink assert a error

 drivers/gpu/drm/i915/i915_reg.h  |  1 +
 drivers/gpu/drm/i915/intel_psr.c | 24 +++++++++++++++++-------
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index fb106026a1f4..d3efbd654889 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4016,6 +4016,7 @@ enum {
 #define   EDP_PSR_SKIP_AUX_EXIT			(1<<12)
 #define   EDP_PSR_TP1_TP2_SEL			(0<<11)
 #define   EDP_PSR_TP1_TP3_SEL			(1<<11)
+#define   EDP_PSR_CRC_ENABLE			(1<<10) /* BDW+ */
 #define   EDP_PSR_TP2_TP3_TIME_500us		(0<<8)
 #define   EDP_PSR_TP2_TP3_TIME_100us		(1<<8)
 #define   EDP_PSR_TP2_TP3_TIME_2500us		(2<<8)
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 558b08a43f9e..1920e7d03e06 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -290,6 +290,8 @@ static void hsw_psr_enable_sink(struct intel_dp *intel_dp)
 		dpcd_val |= DP_PSR_ENABLE_PSR2;
 	if (dev_priv->psr.link_standby)
 		dpcd_val |= DP_PSR_MAIN_LINK_ACTIVE;
+	if (!dev_priv->psr.psr2_enabled && INTEL_GEN(dev_priv) >= 8)
+		dpcd_val |= DP_PSR_CRC_VERIFICATION;
 	drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, dpcd_val);
 
 	drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER, DP_SET_POWER_D0);
@@ -377,6 +379,9 @@ static void hsw_activate_psr1(struct intel_dp *intel_dp)
 	else
 		val |= EDP_PSR_TP1_TP2_SEL;
 
+	if (INTEL_GEN(dev_priv) >= 8)
+		val |= EDP_PSR_CRC_ENABLE;
+
 	val |= I915_READ(EDP_PSR_CTL) & EDP_PSR_RESTORE_PSR_ACTIVE_CTX_MASK;
 	I915_WRITE(EDP_PSR_CTL, val);
 }
@@ -602,10 +607,12 @@ static void hsw_psr_enable_source(struct intel_dp *intel_dp,
 		 * preventing  other hw tracking issues now we can rely
 		 * on frontbuffer tracking.
 		 */
-		I915_WRITE(EDP_PSR_DEBUG,
-			   EDP_PSR_DEBUG_MASK_MEMUP |
-			   EDP_PSR_DEBUG_MASK_HPD |
-			   EDP_PSR_DEBUG_MASK_LPSP);
+		u32 val = EDP_PSR_DEBUG_MASK_MEMUP | EDP_PSR_DEBUG_MASK_HPD
+			  | EDP_PSR_DEBUG_MASK_LPSP;
+
+		if (INTEL_GEN(dev_priv) >= 8)
+			val |= EDP_PSR_DEBUG_MASK_MAX_SLEEP;
+		I915_WRITE(EDP_PSR_DEBUG, val);
 	}
 }
 
@@ -1161,14 +1168,17 @@ void intel_psr_hpd_short_pulse_handle(struct intel_dp *intel_dp)
 		goto dpcd_error;
 	}
 
-	if (val & DP_PSR_RFB_STORAGE_ERROR) {
-		DRM_DEBUG_KMS("PSR RFB storage error, exiting PSR\n");
+	if (val & (DP_PSR_RFB_STORAGE_ERROR | DP_PSR_LINK_CRC_ERROR)) {
+		if (val & DP_PSR_RFB_STORAGE_ERROR)
+			DRM_DEBUG_KMS("PSR RFB storage error, exiting PSR\n");
+		if (val & DP_PSR_LINK_CRC_ERROR)
+			DRM_DEBUG_KMS("PSR Link CRC error, exiting PSR\n");
 		intel_psr_exit(dev_priv);
 	}
 	/* clear status register */
 	drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_ERROR_STATUS, val);
 
-	/* TODO: handle other PSR/PSR2 errors */
+	/* TODO: handle PSR2 errors */
 dpcd_error:
 	intel_psr_schedule_activate_work(dev_priv);
 not_enabled:
-- 
2.17.0

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