openwrt/target/linux/bcm27xx/patches-5.15/950-0476-drm-vc4-Release-workaround-buffer-and-DMA-in-error-p.patch

From 51f5523151d8de2b1476482e575bb5989e55ba16 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Tue, 6 Jul 2021 18:53:28 +0100
Subject: [PATCH] drm/vc4: Release workaround buffer and DMA in error
 paths and unbind

On Pi0-3 the driver allocates a buffer and requests a DMA channel
because the ARM can't write to DSI1's registers directly.
However unbind and the error paths in bind don't release the buffer or
the DMA channel.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/gpu/drm/vc4/vc4_dsi.c | 51 ++++++++++++++++++++++++++---------
 1 file changed, 39 insertions(+), 12 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_dsi.c
+++ b/drivers/gpu/drm/vc4/vc4_dsi.c
@@ -1612,7 +1612,7 @@ static int vc4_dsi_bind(struct device *d
 			if (ret != -EPROBE_DEFER)
 				DRM_ERROR("Failed to get DMA channel: %d\n",
 					  ret);
-			return ret;
+			goto err_free_dma_mem;
 		}
 
 		/* Get the physical address of the device's registers.  The
@@ -1641,7 +1641,7 @@ static int vc4_dsi_bind(struct device *d
 	if (ret) {
 		if (ret != -EPROBE_DEFER)
 			dev_err(dev, "Failed to get interrupt: %d\n", ret);
-		return ret;
+		goto err_free_dma;
 	}
 
 	dsi->escape_clock = devm_clk_get(dev, "escape");
@@ -1649,7 +1649,7 @@ static int vc4_dsi_bind(struct device *d
 		ret = PTR_ERR(dsi->escape_clock);
 		if (ret != -EPROBE_DEFER)
 			dev_err(dev, "Failed to get escape clock: %d\n", ret);
-		return ret;
+		goto err_free_dma;
 	}
 
 	dsi->pll_phy_clock = devm_clk_get(dev, "phy");
@@ -1657,7 +1657,7 @@ static int vc4_dsi_bind(struct device *d
 		ret = PTR_ERR(dsi->pll_phy_clock);
 		if (ret != -EPROBE_DEFER)
 			dev_err(dev, "Failed to get phy clock: %d\n", ret);
-		return ret;
+		goto err_free_dma;
 	}
 
 	dsi->pixel_clock = devm_clk_get(dev, "pixel");
@@ -1665,7 +1665,7 @@ static int vc4_dsi_bind(struct device *d
 		ret = PTR_ERR(dsi->pixel_clock);
 		if (ret != -EPROBE_DEFER)
 			dev_err(dev, "Failed to get pixel clock: %d\n", ret);
-		return ret;
+		goto err_free_dma;
 	}
 
 	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
@@ -1680,33 +1680,37 @@ static int vc4_dsi_bind(struct device *d
 		if (ret == -ENODEV)
 			return 0;
 
-		return ret;
+		goto err_free_dma;
 	}
 
 	if (panel) {
 		dsi->bridge = devm_drm_panel_bridge_add_typed(dev, panel,
 							      DRM_MODE_CONNECTOR_DSI);
-		if (IS_ERR(dsi->bridge))
-			return PTR_ERR(dsi->bridge);
+		if (IS_ERR(dsi->bridge)) {
+			ret = PTR_ERR(dsi->bridge);
+			goto err_free_dma;
+		}
 	}
 
 	/* The esc clock rate is supposed to always be 100Mhz. */
 	ret = clk_set_rate(dsi->escape_clock, 100 * 1000000);
 	if (ret) {
 		dev_err(dev, "Failed to set esc clock: %d\n", ret);
-		return ret;
+		goto err_free_dma;
 	}
 
 	ret = vc4_dsi_init_phy_clocks(dsi);
 	if (ret)
-		return ret;
+		goto err_free_dma;
 
 	drm_simple_encoder_init(drm, dsi->encoder, DRM_MODE_ENCODER_DSI);
 	drm_encoder_helper_add(dsi->encoder, &vc4_dsi_encoder_helper_funcs);
 
 	ret = drm_bridge_attach(dsi->encoder, dsi->bridge, NULL, 0);
-	if (ret)
-		return ret;
+	if (ret) {
+		dev_err(dev, "bridge attach failed: %d\n", ret);
+		goto err_free_dma;
+	}
 	/* Disable the atomic helper calls into the bridge.  We
 	 * manually call the bridge pre_enable / enable / etc. calls
 	 * from our driver, since we need to sequence them within the
@@ -1719,6 +1723,19 @@ static int vc4_dsi_bind(struct device *d
 	pm_runtime_enable(dev);
 
 	return 0;
+
+err_free_dma:
+	if (dsi->reg_dma_chan) {
+		dma_release_channel(dsi->reg_dma_chan);
+		dsi->reg_dma_chan = NULL;
+	}
+err_free_dma_mem:
+	if (dsi->reg_dma_mem) {
+		dma_free_coherent(dev, 4, dsi->reg_dma_mem, dsi->reg_dma_paddr);
+		dsi->reg_dma_mem = NULL;
+	}
+
+	return ret;
 }
 
 static void vc4_dsi_unbind(struct device *dev, struct device *master,
@@ -1735,6 +1752,16 @@ static void vc4_dsi_unbind(struct device
 	 */
 	list_splice_init(&dsi->bridge_chain, &dsi->encoder->bridge_chain);
 	drm_encoder_cleanup(dsi->encoder);
+
+	if (dsi->reg_dma_chan) {
+		dma_release_channel(dsi->reg_dma_chan);
+		dsi->reg_dma_chan = NULL;
+	}
+
+	if (dsi->reg_dma_mem) {
+		dma_free_coherent(dev, 4, dsi->reg_dma_mem, dsi->reg_dma_paddr);
+		dsi->reg_dma_mem = NULL;
+	}
 }
 
 static const struct component_ops vc4_dsi_ops = {