drm/exynos: simplify DMA mapping

Moving DMA mapping creation to drm_iommu_attach_device allows to avoid
looping through all components and maintaining DMA device flags.

v2: take care of configurations without IOMMU
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos5433_drm_decon.c

@@ -569,7 +569,7 @@ static int decon_bind(struct device *dev, struct device *master, void *data)
 
 	decon_clear_channels(ctx->crtc);
 
-	return drm_iommu_attach_device(drm_dev, dev);
+	return exynos_drm_register_dma(drm_dev, dev);
 }
 
 static void decon_unbind(struct device *dev, struct device *master, void *data)

drivers/gpu/drm/exynos/exynos7_drm_decon.c

@@ -133,7 +133,7 @@ static int decon_ctx_initialize(struct decon_context *ctx,
 
 	decon_clear_channels(ctx->crtc);
 
-	return drm_iommu_attach_device(drm_dev, ctx->dev);
+	return exynos_drm_register_dma(drm_dev, ctx->dev);
 }
 
 static void decon_ctx_remove(struct decon_context *ctx)

drivers/gpu/drm/exynos/exynos_drm_drv.c

@@ -45,6 +45,27 @@
 #define DRIVER_MAJOR	1
 #define DRIVER_MINOR	1
 
+int exynos_drm_register_dma(struct drm_device *drm, struct device *dev)
+{
+	struct exynos_drm_private *priv = drm->dev_private;
+	int ret;
+
+	if (!priv->dma_dev) {
+		priv->dma_dev = dev;
+		DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",
+			 dev_name(dev));
+		/* create common IOMMU mapping for all Exynos DRM devices */
+		ret = drm_create_iommu_mapping(drm);
+		if (ret < 0) {
+			priv->dma_dev = NULL;
+			DRM_ERROR("failed to create iommu mapping.\n");
+			return -EINVAL;
+		}
+	}
+
+	return drm_iommu_attach_device(drm, dev);
+}
+
 static int exynos_drm_open(struct drm_device *dev, struct drm_file *file)
 {
 	struct drm_exynos_file_private *file_priv;
@@ -175,8 +196,7 @@ struct exynos_drm_driver_info {
 
 #define DRM_COMPONENT_DRIVER	BIT(0)	/* supports component framework */
 #define DRM_VIRTUAL_DEVICE	BIT(1)	/* create virtual platform device */
-#define DRM_DMA_DEVICE		BIT(2)	/* can be used for dma allocations */
-#define DRM_FIMC_DEVICE		BIT(3)	/* devices shared with V4L2 subsystem */
+#define DRM_FIMC_DEVICE		BIT(2)	/* devices shared with V4L2 subsystem */
 
 #define DRV_PTR(drv, cond) (IS_ENABLED(cond) ? &drv : NULL)
 
@@ -187,16 +207,16 @@ struct exynos_drm_driver_info {
 static struct exynos_drm_driver_info exynos_drm_drivers[] = {
 	{
 		DRV_PTR(fimd_driver, CONFIG_DRM_EXYNOS_FIMD),
-		DRM_COMPONENT_DRIVER | DRM_DMA_DEVICE
+		DRM_COMPONENT_DRIVER
 	}, {
 		DRV_PTR(exynos5433_decon_driver, CONFIG_DRM_EXYNOS5433_DECON),
-		DRM_COMPONENT_DRIVER | DRM_DMA_DEVICE
+		DRM_COMPONENT_DRIVER
 	}, {
 		DRV_PTR(decon_driver, CONFIG_DRM_EXYNOS7_DECON),
-		DRM_COMPONENT_DRIVER | DRM_DMA_DEVICE
+		DRM_COMPONENT_DRIVER
 	}, {
 		DRV_PTR(mixer_driver, CONFIG_DRM_EXYNOS_MIXER),
-		DRM_COMPONENT_DRIVER | DRM_DMA_DEVICE
+		DRM_COMPONENT_DRIVER
 	}, {
 		DRV_PTR(mic_driver, CONFIG_DRM_EXYNOS_MIC),
 		DRM_COMPONENT_DRIVER
@@ -267,27 +287,6 @@ static struct component_match *exynos_drm_match_add(struct device *dev)
 	return match ?: ERR_PTR(-ENODEV);
 }
 
-static struct device *exynos_drm_get_dma_device(void)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(exynos_drm_drivers); ++i) {
-		struct exynos_drm_driver_info *info = &exynos_drm_drivers[i];
-		struct device *dev;
-
-		if (!info->driver || !(info->flags & DRM_DMA_DEVICE))
-			continue;
-
-		while ((dev = bus_find_device(&platform_bus_type, NULL,
-					    &info->driver->driver,
-					    (void *)platform_bus_type.match))) {
-			put_device(dev);
-			return dev;
-		}
-	}
-	return NULL;
-}
-
 static int exynos_drm_bind(struct device *dev)
 {
 	struct exynos_drm_private *private;
@@ -312,23 +311,6 @@ static int exynos_drm_bind(struct device *dev)
 	dev_set_drvdata(dev, drm);
 	drm->dev_private = (void *)private;
 
-	/* the first real CRTC device is used for all dma mapping operations */
-	private->dma_dev = exynos_drm_get_dma_device();
-	if (!private->dma_dev) {
-		DRM_ERROR("no device found for DMA mapping operations.\n");
-		ret = -ENODEV;
-		goto err_free_private;
-	}
-	DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",
-		 dev_name(private->dma_dev));
-
-	/* create common IOMMU mapping for all devices attached to Exynos DRM */
-	ret = drm_create_iommu_mapping(drm);
-	if (ret < 0) {
-		DRM_ERROR("failed to create iommu mapping.\n");
-		goto err_free_private;
-	}
-
 	drm_mode_config_init(drm);
 
 	exynos_drm_mode_config_init(drm);
@@ -386,7 +368,6 @@ static int exynos_drm_bind(struct device *dev)
 err_mode_config_cleanup:
 	drm_mode_config_cleanup(drm);
 	drm_release_iommu_mapping(drm);
-err_free_private:
 	kfree(private);
 err_free_drm:
 	drm_dev_put(drm);

drivers/gpu/drm/exynos/exynos_drm_drv.h

@@ -214,6 +214,8 @@ static inline struct device *to_dma_dev(struct drm_device *dev)
 	return priv->dma_dev;
 }
 
+int exynos_drm_register_dma(struct drm_device *drm, struct device *dev);
+
 #ifdef CONFIG_DRM_EXYNOS_DPI
 struct drm_encoder *exynos_dpi_probe(struct device *dev);
 int exynos_dpi_remove(struct drm_encoder *encoder);

drivers/gpu/drm/exynos/exynos_drm_fimc.c

@@ -1129,7 +1129,7 @@ static int fimc_bind(struct device *dev, struct device *master, void *data)
 	struct exynos_drm_ipp *ipp = &ctx->ipp;
 
 	ctx->drm_dev = drm_dev;
-	drm_iommu_attach_device(drm_dev, dev);
+	exynos_drm_register_dma(drm_dev, dev);
 
 	exynos_drm_ipp_register(drm_dev, ipp, &ipp_funcs,
 			DRM_EXYNOS_IPP_CAP_CROP | DRM_EXYNOS_IPP_CAP_ROTATE |

drivers/gpu/drm/exynos/exynos_drm_fimd.c

@@ -1011,7 +1011,7 @@ static int fimd_bind(struct device *dev, struct device *master, void *data)
 	if (is_drm_iommu_supported(drm_dev))
 		fimd_clear_channels(ctx->crtc);
 
-	return drm_iommu_attach_device(drm_dev, dev);
+	return exynos_drm_register_dma(drm_dev, dev);
 }
 
 static void fimd_unbind(struct device *dev, struct device *master,

drivers/gpu/drm/exynos/exynos_drm_g2d.c

@@ -1405,7 +1405,7 @@ static int g2d_bind(struct device *dev, struct device *master, void *data)
 		return ret;
 	}
 
-	ret = drm_iommu_attach_device(drm_dev, dev);
+	ret = exynos_drm_register_dma(drm_dev, dev);
 	if (ret < 0) {
 		dev_err(dev, "failed to enable iommu.\n");
 		g2d_fini_cmdlist(g2d);

drivers/gpu/drm/exynos/exynos_drm_gsc.c

@@ -1170,7 +1170,7 @@ static int gsc_bind(struct device *dev, struct device *master, void *data)
 	struct exynos_drm_ipp *ipp = &ctx->ipp;
 
 	ctx->drm_dev = drm_dev;
-	drm_iommu_attach_device(drm_dev, dev);
+	exynos_drm_register_dma(drm_dev, dev);
 
 	exynos_drm_ipp_register(drm_dev, ipp, &ipp_funcs,
 			DRM_EXYNOS_IPP_CAP_CROP | DRM_EXYNOS_IPP_CAP_ROTATE |

drivers/gpu/drm/exynos/exynos_drm_rotator.c

@@ -244,7 +244,7 @@ static int rotator_bind(struct device *dev, struct device *master, void *data)
 	struct exynos_drm_ipp *ipp = &rot->ipp;
 
 	rot->drm_dev = drm_dev;
-	drm_iommu_attach_device(drm_dev, dev);
+	exynos_drm_register_dma(drm_dev, dev);
 
 	exynos_drm_ipp_register(drm_dev, ipp, &ipp_funcs,
 			   DRM_EXYNOS_IPP_CAP_CROP | DRM_EXYNOS_IPP_CAP_ROTATE,

drivers/gpu/drm/exynos/exynos_drm_scaler.c

@@ -452,7 +452,7 @@ static int scaler_bind(struct device *dev, struct device *master, void *data)
 	struct exynos_drm_ipp *ipp = &scaler->ipp;
 
 	scaler->drm_dev = drm_dev;
-	drm_iommu_attach_device(drm_dev, dev);
+	exynos_drm_register_dma(drm_dev, dev);
 
 	exynos_drm_ipp_register(drm_dev, ipp, &ipp_funcs,
 			DRM_EXYNOS_IPP_CAP_CROP | DRM_EXYNOS_IPP_CAP_ROTATE |

drivers/gpu/drm/exynos/exynos_mixer.c

@@ -878,7 +878,7 @@ static int mixer_initialize(struct mixer_context *mixer_ctx,
 		}
 	}
 
-	return drm_iommu_attach_device(drm_dev, mixer_ctx->dev);
+	return exynos_drm_register_dma(drm_dev, mixer_ctx->dev);
 }
 
 static void mixer_ctx_remove(struct mixer_context *mixer_ctx)