[PATCH v3 3/3] drm/bridge: analogix_dp: detect Sink PSR state after configuring the PSR

[Yakir Yang]

Make sure the request PSR state takes effect in analogix_dp_send_psr_spd()
function, or print the sink PSR error state if we failed to apply the
requested PSR setting.

Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
---
Changes in v3:
- Update commit message
- Add DP_TIMEOUT_PSR_LOOP_MS marcos
- Correct the return values of analogix_dp_send_psr_spd()

Changes in v2:
- A bunch of good fixes from Sean

 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c |  6 ++----
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  5 +++--
 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c  | 25 ++++++++++++++++++++--
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 5fe3982..c0ce16a 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -116,8 +116,7 @@ int analogix_dp_enable_psr(struct device *dev)
 	psr_vsc.DB0 = 0;
 	psr_vsc.DB1 = EDP_VSC_PSR_STATE_ACTIVE | EDP_VSC_PSR_CRC_VALUES_VALID;
 
-	analogix_dp_send_psr_spd(dp, &psr_vsc);
-	return 0;
+	return analogix_dp_send_psr_spd(dp, &psr_vsc);
 }
 EXPORT_SYMBOL_GPL(analogix_dp_enable_psr);
 
@@ -139,8 +138,7 @@ int analogix_dp_disable_psr(struct device *dev)
 	psr_vsc.DB0 = 0;
 	psr_vsc.DB1 = 0;
 
-	analogix_dp_send_psr_spd(dp, &psr_vsc);
-	return 0;
+	return analogix_dp_send_psr_spd(dp, &psr_vsc);
 }
 EXPORT_SYMBOL_GPL(analogix_dp_disable_psr);
 
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
index d564e90..a27f1e3 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -20,6 +20,7 @@
 #define MAX_EQ_LOOP 5
 
 #define DP_TIMEOUT_LOOP_MS			msecs_to_jiffies(1)
+#define DP_TIMEOUT_PSR_LOOP_MS			msecs_to_jiffies(300)
 
 /* DP_MAX_LANE_COUNT */
 #define DPCD_ENHANCED_FRAME_CAP(x)		(((x) >> 7) & 0x1)
@@ -248,8 +249,8 @@ void analogix_dp_config_video_slave_mode(struct analogix_dp_device *dp);
 void analogix_dp_enable_scrambling(struct analogix_dp_device *dp);
 void analogix_dp_disable_scrambling(struct analogix_dp_device *dp);
 void analogix_dp_enable_psr_crc(struct analogix_dp_device *dp);
-void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
-			      struct edp_vsc_psr *vsc);
+int analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
+			     struct edp_vsc_psr *vsc);
 ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
 			     struct drm_dp_aux_msg *msg);
 #endif /* _ANALOGIX_DP_CORE_H */
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 15a4cf0..7fd4ed0 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1004,10 +1004,12 @@ void analogix_dp_enable_psr_crc(struct analogix_dp_device *dp)
 	writel(PSR_VID_CRC_ENABLE, dp->reg_base + ANALOGIX_DP_CRC_CON);
 }
 
-void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
-			      struct edp_vsc_psr *vsc)
+int analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
+			     struct edp_vsc_psr *vsc)
 {
+	unsigned long timeout;
 	unsigned int val;
+	u8 sink;
 
 	/* don't send info frame */
 	val = readl(dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
@@ -1048,6 +1050,25 @@ void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
 	val = readl(dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
 	val |= IF_EN;
 	writel(val, dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
+
+	timeout = jiffies + DP_TIMEOUT_PSR_LOOP_MS;
+	while (time_before(jiffies, timeout)) {
+		val = drm_dp_dpcd_readb(&dp->aux, DP_PSR_STATUS, &sink);
+		if (val != 1) {
+			dev_err(dp->dev, "PSR_STATUS read failed ret=%d", val);
+			return -EBUSY;
+		}
+
+		if ((vsc->DB1 && sink == DP_PSR_SINK_ACTIVE_RFB) ||
+		    (!vsc->DB1 && sink == DP_PSR_SINK_INACTIVE))
+			return 0;
+
+		usleep_range(1000, 1500);
+	}
+
+	dev_warn(dp->dev, "Failed to apply PSR, sink state was [%x]", sink);
+
+	return -ETIMEDOUT;
 }
 
 ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
-- 
1.9.1