LXR linux/drivers/gpu/drm/exynos/exynos_drm

   1// SPDX-License-Identifier: GPL-2.0
   2//
   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 <drm/drmP.h>
   8#include <drm/exynos_drm.h>
   9#include <linux/dma-iommu.h>
  10#include <linux/dma-mapping.h>
  11#include <linux/iommu.h>
  12
  13#include "exynos_drm_drv.h"
  14
  15#if defined(CONFIG_ARM_DMA_USE_IOMMU)
  16#include <asm/dma-iommu.h>
  17#else
  18#define arm_iommu_create_mapping(...)   ({ NULL; })
  19#define arm_iommu_attach_device(...)    ({ -ENODEV; })
  20#define arm_iommu_release_mapping(...)  ({ })
  21#define arm_iommu_detach_device(...)    ({ })
  22#define to_dma_iommu_mapping(dev) NULL
  23#endif
  24
  25#if !defined(CONFIG_IOMMU_DMA)
  26#define iommu_dma_init_domain(...) ({ -EINVAL; })
  27#endif
  28
  29#define EXYNOS_DEV_ADDR_START   0x20000000
  30#define EXYNOS_DEV_ADDR_SIZE    0x40000000
  31
  32static inline int configure_dma_max_seg_size(struct device *dev)
  33{
  34        if (!dev->dma_parms)
  35                dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL);
  36        if (!dev->dma_parms)
  37                return -ENOMEM;
  38
  39        dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
  40        return 0;
  41}
  42
  43static inline void clear_dma_max_seg_size(struct device *dev)
  44{
  45        kfree(dev->dma_parms);
  46        dev->dma_parms = NULL;
  47}
  48
  49/*
  50 * drm_iommu_attach_device- attach device to iommu mapping
  51 *
  52 * @drm_dev: DRM device
  53 * @subdrv_dev: device to be attach
  54 *
  55 * This function should be called by sub drivers to attach it to iommu
  56 * mapping.
  57 */
  58static int drm_iommu_attach_device(struct drm_device *drm_dev,
  59                                struct device *subdrv_dev)
  60{
  61        struct exynos_drm_private *priv = drm_dev->dev_private;
  62        int ret;
  63
  64        if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) {
  65                DRM_DEV_ERROR(subdrv_dev, "Device %s lacks support for IOMMU\n",
  66                          dev_name(subdrv_dev));
  67                return -EINVAL;
  68        }
  69
  70        ret = configure_dma_max_seg_size(subdrv_dev);
  71        if (ret)
  72                return ret;
  73
  74        if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
  75                if (to_dma_iommu_mapping(subdrv_dev))
  76                        arm_iommu_detach_device(subdrv_dev);
  77
  78                ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
  79        } else if (IS_ENABLED(CONFIG_IOMMU_DMA)) {
  80                ret = iommu_attach_device(priv->mapping, subdrv_dev);
  81        }
  82
  83        if (ret)
  84                clear_dma_max_seg_size(subdrv_dev);
  85
  86        return 0;
  87}
  88
  89/*
  90 * drm_iommu_detach_device -detach device address space mapping from device
  91 *
  92 * @drm_dev: DRM device
  93 * @subdrv_dev: device to be detached
  94 *
  95 * This function should be called by sub drivers to detach it from iommu
  96 * mapping
  97 */
  98static void drm_iommu_detach_device(struct drm_device *drm_dev,
  99                                struct device *subdrv_dev)
 100{
 101        struct exynos_drm_private *priv = drm_dev->dev_private;
 102
 103        if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
 104                arm_iommu_detach_device(subdrv_dev);
 105        else if (IS_ENABLED(CONFIG_IOMMU_DMA))
 106                iommu_detach_device(priv->mapping, subdrv_dev);
 107
 108        clear_dma_max_seg_size(subdrv_dev);
 109}
 110
 111int exynos_drm_register_dma(struct drm_device *drm, struct device *dev)
 112{
 113        struct exynos_drm_private *priv = drm->dev_private;
 114
 115        if (!priv->dma_dev) {
 116                priv->dma_dev = dev;
 117                DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",
 118                         dev_name(dev));
 119        }
 120
 121        if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 122                return 0;
 123
 124        if (!priv->mapping) {
 125                void *mapping;
 126
 127                if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
 128                        mapping = arm_iommu_create_mapping(&platform_bus_type,
 129                                EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE);
 130                else if (IS_ENABLED(CONFIG_IOMMU_DMA))
 131                        mapping = iommu_get_domain_for_dev(priv->dma_dev);
 132
 133                if (IS_ERR(mapping))
 134                        return PTR_ERR(mapping);
 135                priv->mapping = mapping;
 136        }
 137
 138        return drm_iommu_attach_device(drm, dev);
 139}
 140
 141void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev)
 142{
 143        if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 144                drm_iommu_detach_device(drm, dev);
 145}
 146
 147void exynos_drm_cleanup_dma(struct drm_device *drm)
 148{
 149        struct exynos_drm_private *priv = drm->dev_private;
 150
 151        if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 152                return;
 153
 154        arm_iommu_release_mapping(priv->mapping);
 155        priv->mapping = NULL;
 156        priv->dma_dev = NULL;
 157}
 158