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1// SPDX-License-Identifier: GPL-2.02//3// Copyright (c) 2012 Samsung Electronics Co., Ltd.4// Author: Inki Dae <inki.dae@samsung.com>5// Author: Andrzej Hajda <a.hajda@samsung.com>6 7#include <linux/dma-map-ops.h>8#include <linux/iommu.h>9#include <linux/platform_device.h>10 11#include <drm/drm_print.h>12#include <drm/exynos_drm.h>13 14#include "exynos_drm_drv.h"15 16#if defined(CONFIG_ARM_DMA_USE_IOMMU)17#include <asm/dma-iommu.h>18#else19#define arm_iommu_create_mapping(...) ({ NULL; })20#define arm_iommu_attach_device(...) ({ -ENODEV; })21#define arm_iommu_release_mapping(...) ({ })22#define arm_iommu_detach_device(...) ({ })23#define to_dma_iommu_mapping(dev) NULL24#endif25 26#if !defined(CONFIG_IOMMU_DMA)27#define iommu_dma_init_domain(...) ({ -EINVAL; })28#endif29 30#define EXYNOS_DEV_ADDR_START 0x2000000031#define EXYNOS_DEV_ADDR_SIZE 0x4000000032 33/*34 * drm_iommu_attach_device- attach device to iommu mapping35 *36 * @drm_dev: DRM device37 * @subdrv_dev: device to be attach38 *39 * This function should be called by sub drivers to attach it to iommu40 * mapping.41 */42static int drm_iommu_attach_device(struct drm_device *drm_dev,43 struct device *subdrv_dev, void **dma_priv)44{45 struct exynos_drm_private *priv = drm_dev->dev_private;46 int ret = 0;47 48 if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) {49 DRM_DEV_ERROR(subdrv_dev, "Device %s lacks support for IOMMU\n",50 dev_name(subdrv_dev));51 return -EINVAL;52 }53 54 dma_set_max_seg_size(subdrv_dev, DMA_BIT_MASK(32));55 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {56 /*57 * Keep the original DMA mapping of the sub-device and58 * restore it on Exynos DRM detach, otherwise the DMA59 * framework considers it as IOMMU-less during the next60 * probe (in case of deferred probe or modular build)61 */62 *dma_priv = to_dma_iommu_mapping(subdrv_dev);63 if (*dma_priv)64 arm_iommu_detach_device(subdrv_dev);65 66 ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);67 } else if (IS_ENABLED(CONFIG_IOMMU_DMA)) {68 ret = iommu_attach_device(priv->mapping, subdrv_dev);69 }70 71 return ret;72}73 74/*75 * drm_iommu_detach_device -detach device address space mapping from device76 *77 * @drm_dev: DRM device78 * @subdrv_dev: device to be detached79 *80 * This function should be called by sub drivers to detach it from iommu81 * mapping82 */83static void drm_iommu_detach_device(struct drm_device *drm_dev,84 struct device *subdrv_dev, void **dma_priv)85{86 struct exynos_drm_private *priv = drm_dev->dev_private;87 88 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {89 arm_iommu_detach_device(subdrv_dev);90 arm_iommu_attach_device(subdrv_dev, *dma_priv);91 } else if (IS_ENABLED(CONFIG_IOMMU_DMA))92 iommu_detach_device(priv->mapping, subdrv_dev);93}94 95int exynos_drm_register_dma(struct drm_device *drm, struct device *dev,96 void **dma_priv)97{98 struct exynos_drm_private *priv = drm->dev_private;99 100 if (!priv->dma_dev) {101 priv->dma_dev = dev;102 DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",103 dev_name(dev));104 }105 106 if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))107 return 0;108 109 if (!priv->mapping) {110 void *mapping = NULL;111 112 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))113 mapping = arm_iommu_create_mapping(dev,114 EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE);115 else if (IS_ENABLED(CONFIG_IOMMU_DMA))116 mapping = iommu_get_domain_for_dev(priv->dma_dev);117 118 if (!mapping)119 return -ENODEV;120 priv->mapping = mapping;121 }122 123 return drm_iommu_attach_device(drm, dev, dma_priv);124}125 126void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev,127 void **dma_priv)128{129 if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))130 drm_iommu_detach_device(drm, dev, dma_priv);131}132 133void exynos_drm_cleanup_dma(struct drm_device *drm)134{135 struct exynos_drm_private *priv = drm->dev_private;136 137 if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))138 return;139 140 arm_iommu_release_mapping(priv->mapping);141 priv->mapping = NULL;142 priv->dma_dev = NULL;143}144