drm: vc4: dsi: enable video and then retry failed transfers

The DSI block appears to be able to come up stuck in a condition where it leaves the lanes in HS mode or just jabbering. This stops LP transfers from completing as there is no LP time available. This is signalled via the LP1 contention error. Enabling video briefly clears that condition, so if we detect the error condition, enable video mode and then retry. Signed-off-by: Dave Stevenson <[email protected]>
6by9 · Sep 20, 2024 · 44f0745 · 44f0745
1 parent a6891c8
commit 44f0745
Showing 1 changed file with 40 additions and 8 deletions.
diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
@@ -286,6 +286,8 @@
 					 DSI1_INT_PR_TO)
 
 #define DSI0_STAT		0x2c
+# define DSI0_STAT_ERR_CONT_LP1		BIT(6)
+# define DSI0_STAT_ERR_CONT_LP0		BIT(5)
 #define DSI0_HSTX_TO_CNT	0x30
 #define DSI0_LPRX_TO_CNT	0x34
 #define DSI0_TA_TO_CNT		0x38
@@ -1203,10 +1205,9 @@ static int vc4_dsi_bridge_attach(struct drm_bridge *bridge,
 				 &dsi->bridge, flags);
 }
 
-static ssize_t vc4_dsi_host_transfer(struct mipi_dsi_host *host,
-				     const struct mipi_dsi_msg *msg)
+static ssize_t vc4_dsi_transfer(struct vc4_dsi *dsi,
+				const struct mipi_dsi_msg *msg, bool log_error)
 {
-	struct vc4_dsi *dsi = host_to_dsi(host);
 	struct mipi_dsi_packet packet;
 	u32 pkth = 0, pktc = 0;
 	int i, ret;
@@ -1315,10 +1316,12 @@ static ssize_t vc4_dsi_host_transfer(struct mipi_dsi_host *host,
 	DSI_PORT_WRITE(TXPKT1C, pktc);
 
 	if (!wait_for_completion_timeout(&dsi->xfer_completion,
-					 msecs_to_jiffies(1000))) {
-		dev_err(&dsi->pdev->dev, "transfer interrupt wait timeout");
-		dev_err(&dsi->pdev->dev, "instat: 0x%08x\n",
-			DSI_PORT_READ(INT_STAT));
+					 msecs_to_jiffies(500))) {
+		if (log_error) {
+			dev_err(&dsi->pdev->dev, "transfer interrupt wait timeout");
+			dev_err(&dsi->pdev->dev, "instat: 0x%08x, stat: 0x%08x\n",
+				DSI_PORT_READ(INT_STAT), DSI_PORT_READ(INT_STAT));
+		}
 		ret = -ETIMEDOUT;
 	} else {
 		ret = dsi->xfer_result;
@@ -1361,7 +1364,8 @@ static ssize_t vc4_dsi_host_transfer(struct mipi_dsi_host *host,
 	return ret;
 
 reset_fifo_and_return:
-	DRM_ERROR("DSI transfer failed, resetting: %d\n", ret);
+	if (log_error)
+		DRM_ERROR("DSI transfer failed, resetting: %d\n", ret);
 
 	DSI_PORT_WRITE(TXPKT1C, DSI_PORT_READ(TXPKT1C) & ~DSI_TXPKT1C_CMD_EN);
 	udelay(1);
@@ -1374,6 +1378,34 @@ static ssize_t vc4_dsi_host_transfer(struct mipi_dsi_host *host,
 	return ret;
 }
 
+static ssize_t vc4_dsi_host_transfer(struct mipi_dsi_host *host,
+				     const struct mipi_dsi_msg *msg)
+{
+	struct vc4_dsi *dsi = host_to_dsi(host);
+	u32 stat, disp0_ctrl;
+	int ret;
+
+	ret = vc4_dsi_transfer(dsi, msg, false);
+
+	if (ret == -ETIMEDOUT) {
+		stat = DSI_PORT_READ(STAT);
+		if (stat & DSI_PORT_BIT(STAT_ERR_CONT_LP1)) {
+			DSI_PORT_WRITE(STAT, DSI_PORT_BIT(STAT_ERR_CONT_LP1));
+
+			disp0_ctrl = DSI_PORT_READ(DISP0_CTRL);
+			disp0_ctrl |= DSI_DISP0_ENABLE;
+			DSI_PORT_WRITE(DISP0_CTRL, disp0_ctrl);
+			msleep(30);
+			disp0_ctrl &= ~DSI_DISP0_ENABLE;
+			DSI_PORT_WRITE(DISP0_CTRL, disp0_ctrl);
+			msleep(30);
+
+			ret = vc4_dsi_transfer(dsi, msg, true);
+		}
+	}
+	return ret;
+}
+
 static const struct component_ops vc4_dsi_ops;
 static int vc4_dsi_host_attach(struct mipi_dsi_host *host,
 			       struct mipi_dsi_device *device)