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