drm/exynos/iommu: merge IOMMU and DMA code

As DMA code is the only user of IOMMU code both files can be merged.
It allows to remove stub functions, after slight adjustment of
exynos_drm_register_dma. Since IOMMU functions are used locally they
can be marked static.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/Makefile

@@ -7,7 +7,6 @@ exynosdrm-y := exynos_drm_drv.o exynos_drm_crtc.o exynos_drm_fb.o \
 		exynos_drm_gem.o exynos_drm_plane.o exynos_drm_dma.o
 
 exynosdrm-$(CONFIG_DRM_FBDEV_EMULATION) += exynos_drm_fbdev.o
-exynosdrm-$(CONFIG_EXYNOS_IOMMU) += exynos_drm_iommu.o
 exynosdrm-$(CONFIG_DRM_EXYNOS_FIMD)	+= exynos_drm_fimd.o
 exynosdrm-$(CONFIG_DRM_EXYNOS5433_DECON)	+= exynos5433_drm_decon.o
 exynosdrm-$(CONFIG_DRM_EXYNOS7_DECON)	+= exynos7_drm_decon.o

drivers/gpu/drm/exynos/exynos_drm_dma.c

 // SPDX-License-Identifier: GPL-2.0
 //
 // Copyright (c) 2012 Samsung Electronics Co., Ltd.
+// Author: Inki Dae <inki.dae@samsung.com>
 // Author: Andrzej Hajda <a.hajda@samsung.com>
 
+#include <drm/drmP.h>
+#include <drm/exynos_drm.h>
+#include <linux/dma-iommu.h>
+#include <linux/dma-mapping.h>
+#include <linux/iommu.h>
+
 #include "exynos_drm_drv.h"
-#include "exynos_drm_iommu.h"
+
+#if defined(CONFIG_ARM_DMA_USE_IOMMU)
+#include <asm/dma-iommu.h>
+#else
+#define arm_iommu_create_mapping(...)	({ NULL; })
+#define arm_iommu_attach_device(...)	({ -ENODEV; })
+#define arm_iommu_release_mapping(...)	({ })
+#define arm_iommu_detach_device(...)	({ })
+#define to_dma_iommu_mapping(dev) NULL
+#endif
+
+#if !defined(CONFIG_IOMMU_DMA)
+#define iommu_dma_init_domain(...) ({ -EINVAL; })
+#endif
+
+#define EXYNOS_DEV_ADDR_START	0x20000000
+#define EXYNOS_DEV_ADDR_SIZE	0x40000000
+
+static inline int configure_dma_max_seg_size(struct device *dev)
+{
+	if (!dev->dma_parms)
+		dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL);
+	if (!dev->dma_parms)
+		return -ENOMEM;
+
+	dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
+	return 0;
+}
+
+static inline void clear_dma_max_seg_size(struct device *dev)
+{
+	kfree(dev->dma_parms);
+	dev->dma_parms = NULL;
+}
+
+/*
+ * drm_iommu_attach_device- attach device to iommu mapping
+ *
+ * @drm_dev: DRM device
+ * @subdrv_dev: device to be attach
+ *
+ * This function should be called by sub drivers to attach it to iommu
+ * mapping.
+ */
+static int drm_iommu_attach_device(struct drm_device *drm_dev,
+				struct device *subdrv_dev)
+{
+	struct exynos_drm_private *priv = drm_dev->dev_private;
+	int ret;
+
+	if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) {
+		DRM_ERROR("Device %s lacks support for IOMMU\n",
+			  dev_name(subdrv_dev));
+		return -EINVAL;
+	}
+
+	ret = configure_dma_max_seg_size(subdrv_dev);
+	if (ret)
+		return ret;
+
+	if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
+		if (to_dma_iommu_mapping(subdrv_dev))
+			arm_iommu_detach_device(subdrv_dev);
+
+		ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
+	} else if (IS_ENABLED(CONFIG_IOMMU_DMA)) {
+		ret = iommu_attach_device(priv->mapping, subdrv_dev);
+	}
+
+	if (ret)
+		clear_dma_max_seg_size(subdrv_dev);
+
+	return 0;
+}
+
+/*
+ * drm_iommu_detach_device -detach device address space mapping from device
+ *
+ * @drm_dev: DRM device
+ * @subdrv_dev: device to be detached
+ *
+ * This function should be called by sub drivers to detach it from iommu
+ * mapping
+ */
+static void drm_iommu_detach_device(struct drm_device *drm_dev,
+				struct device *subdrv_dev)
+{
+	struct exynos_drm_private *priv = drm_dev->dev_private;
+
+	if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
+		arm_iommu_detach_device(subdrv_dev);
+	else if (IS_ENABLED(CONFIG_IOMMU_DMA))
+		iommu_detach_device(priv->mapping, subdrv_dev);
+
+	clear_dma_max_seg_size(subdrv_dev);
+}
 
 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;
-		}
+	}
+
+	if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
+		return 0;
+
+	if (!priv->mapping) {
+		void *mapping;
+
+		if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
+			mapping = arm_iommu_create_mapping(&platform_bus_type,
+				EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE);
+		else if (IS_ENABLED(CONFIG_IOMMU_DMA))
+			mapping = iommu_get_domain_for_dev(priv->dma_dev);
+
+		if (IS_ERR(mapping))
+			return PTR_ERR(mapping);
+		priv->mapping = mapping;
 	}
 
 	return drm_iommu_attach_device(drm, dev);
@@ -35,6 +146,12 @@ void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev)
 
 void exynos_drm_cleanup_dma(struct drm_device *drm)
 {
-	if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
-		drm_release_iommu_mapping(drm);
+	struct exynos_drm_private *priv = drm->dev_private;
+
+	if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
+		return;
+
+	arm_iommu_release_mapping(priv->mapping);
+	priv->mapping = NULL;
+	priv->dma_dev = NULL;
 }

drivers/gpu/drm/exynos/exynos_drm_iommu.c

-/* exynos_drm_iommu.c
- *
- * Copyright (c) 2012 Samsung Electronics Co., Ltd.
- * Author: Inki Dae <inki.dae@samsung.com>
- *
- * This program is free software; you can redistribute  it and/or modify it
- * under  the terms of  the GNU General  Public License as published by the
- * Free Software Foundation;  either version 2 of the  License, or (at your
- * option) any later version.
- */
-
-#include <drm/drmP.h>
-#include <drm/exynos_drm.h>
-
-#include <linux/dma-iommu.h>
-#include <linux/dma-mapping.h>
-#include <linux/iommu.h>
-
-#include "exynos_drm_drv.h"
-#include "exynos_drm_iommu.h"
-
-#if defined(CONFIG_ARM_DMA_USE_IOMMU)
-#include <asm/dma-iommu.h>
-#else
-#define arm_iommu_create_mapping(...)	({ NULL; })
-#define arm_iommu_attach_device(...)	({ -ENODEV; })
-#define arm_iommu_release_mapping(...)	({ })
-#define arm_iommu_detach_device(...)	({ })
-#define to_dma_iommu_mapping(dev) NULL
-#endif
-
-#if !defined(CONFIG_IOMMU_DMA)
-#define iommu_dma_init_domain(...) ({ -EINVAL; })
-#endif
-
-#define EXYNOS_DEV_ADDR_START	0x20000000
-#define EXYNOS_DEV_ADDR_SIZE	0x40000000
-
-static inline int configure_dma_max_seg_size(struct device *dev)
-{
-	if (!dev->dma_parms)
-		dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL);
-	if (!dev->dma_parms)
-		return -ENOMEM;
-
-	dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
-	return 0;
-}
-
-static inline void clear_dma_max_seg_size(struct device *dev)
-{
-	kfree(dev->dma_parms);
-	dev->dma_parms = NULL;
-}
-
-/*
- * drm_create_iommu_mapping - create a mapping structure
- *
- * @drm_dev: DRM device
- */
-int drm_create_iommu_mapping(struct drm_device *drm_dev)
-{
-	struct exynos_drm_private *priv = drm_dev->dev_private;
-
-	if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
-		priv->mapping = arm_iommu_create_mapping(&platform_bus_type,
-			EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE);
-	else if (IS_ENABLED(CONFIG_IOMMU_DMA))
-		priv->mapping = iommu_get_domain_for_dev(priv->dma_dev);
-
-	return IS_ERR(priv->mapping);
-}
-
-/*
- * drm_release_iommu_mapping - release iommu mapping structure
- *
- * @drm_dev: DRM device
- */
-void drm_release_iommu_mapping(struct drm_device *drm_dev)
-{
-	struct exynos_drm_private *priv = drm_dev->dev_private;
-
-	arm_iommu_release_mapping(priv->mapping);
-	priv->mapping = NULL;
-}
-
-/*
- * drm_iommu_attach_device- attach device to iommu mapping
- *
- * @drm_dev: DRM device
- * @subdrv_dev: device to be attach
- *
- * This function should be called by sub drivers to attach it to iommu
- * mapping.
- */
-int drm_iommu_attach_device(struct drm_device *drm_dev,
-				struct device *subdrv_dev)
-{
-	struct exynos_drm_private *priv = drm_dev->dev_private;
-	int ret;
-
-	if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) {
-		DRM_ERROR("Device %s lacks support for IOMMU\n",
-			  dev_name(subdrv_dev));
-		return -EINVAL;
-	}
-
-	ret = configure_dma_max_seg_size(subdrv_dev);
-	if (ret)
-		return ret;
-
-	if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
-		if (to_dma_iommu_mapping(subdrv_dev))
-			arm_iommu_detach_device(subdrv_dev);
-
-		ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
-	} else if (IS_ENABLED(CONFIG_IOMMU_DMA)) {
-		ret = iommu_attach_device(priv->mapping, subdrv_dev);
-	}
-
-	if (ret)
-		clear_dma_max_seg_size(subdrv_dev);
-
-	return 0;
-}
-
-/*
- * drm_iommu_detach_device -detach device address space mapping from device
- *
- * @drm_dev: DRM device
- * @subdrv_dev: device to be detached
- *
- * This function should be called by sub drivers to detach it from iommu
- * mapping
- */
-void drm_iommu_detach_device(struct drm_device *drm_dev,
-				struct device *subdrv_dev)
-{
-	struct exynos_drm_private *priv = drm_dev->dev_private;
-
-	if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
-		arm_iommu_detach_device(subdrv_dev);
-	else if (IS_ENABLED(CONFIG_IOMMU_DMA))
-		iommu_detach_device(priv->mapping, subdrv_dev);
-
-	clear_dma_max_seg_size(subdrv_dev);
-}

drivers/gpu/drm/exynos/exynos_drm_iommu.h

-/* exynos_drm_iommu.h
- *
- * Copyright (c) 2012 Samsung Electronics Co., Ltd.
- * Authoer: Inki Dae <inki.dae@samsung.com>
- *
- * This program is free software; you can redistribute  it and/or modify it
- * under  the terms of  the GNU General  Public License as published by the
- * Free Software Foundation;  either version 2 of the  License, or (at your
- * option) any later version.
- */
-
-#ifndef _EXYNOS_DRM_IOMMU_H_
-#define _EXYNOS_DRM_IOMMU_H_
-
-#ifdef CONFIG_EXYNOS_IOMMU
-
-int drm_create_iommu_mapping(struct drm_device *drm_dev);
-
-void drm_release_iommu_mapping(struct drm_device *drm_dev);
-
-int drm_iommu_attach_device(struct drm_device *drm_dev,
-				struct device *subdrv_dev);
-
-void drm_iommu_detach_device(struct drm_device *dev_dev,
-				struct device *subdrv_dev);
-
-#else
-
-static inline int drm_create_iommu_mapping(struct drm_device *drm_dev)
-{
-	return 0;
-}
-
-static inline void drm_release_iommu_mapping(struct drm_device *drm_dev)
-{
-}
-
-static inline int drm_iommu_attach_device(struct drm_device *drm_dev,
-						struct device *subdrv_dev)
-{
-	return 0;
-}
-
-static inline void drm_iommu_detach_device(struct drm_device *drm_dev,
-						struct device *subdrv_dev)
-{
-}
-
-#endif
-#endif