drivers/gpu/drm/exynos/exynos_drm_dma.c

   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-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 #else
  19 #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) NULL
  24 #endif
  25
  26 #if !defined(CONFIG_IOMMU_DMA)
  27 #define iommu_dma_init_domain(...) ({ -EINVAL; })
  28 #endif
  29
  30 #define EXYNOS_DEV_ADDR_START   0x20000000
  31 #define EXYNOS_DEV_ADDR_SIZE    0x40000000
  32
  33 /*
  34  * drm_iommu_attach_device- attach device to iommu mapping
  35  *
  36  * @drm_dev: DRM device
  37  * @subdrv_dev: device to be attach
  38  *
  39  * This function should be called by sub drivers to attach it to iommu
  40  * mapping.
  41  */
  42 static 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 and
  58                  * restore it on Exynos DRM detach, otherwise the DMA
  59                  * framework considers it as IOMMU-less during the next
  60                  * 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 device
  76  *
  77  * @drm_dev: DRM device
  78  * @subdrv_dev: device to be detached
  79  *
  80  * This function should be called by sub drivers to detach it from iommu
  81  * mapping
  82  */
  83 static 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
  95 int 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;
 111
 112                 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
 113                         mapping = arm_iommu_create_mapping(&platform_bus_type,
 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                 else
 118                         mapping = ERR_PTR(-ENODEV);
 119
 120                 if (IS_ERR(mapping))
 121                         return PTR_ERR(mapping);
 122                 priv->mapping = mapping;
 123         }
 124
 125         return drm_iommu_attach_device(drm, dev, dma_priv);
 126 }
 127
 128 void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev,
 129                                void **dma_priv)
 130 {
 131         if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 132                 drm_iommu_detach_device(drm, dev, dma_priv);
 133 }
 134
 135 void exynos_drm_cleanup_dma(struct drm_device *drm)
 136 {
 137         struct exynos_drm_private *priv = drm->dev_private;
 138
 139         if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 140                 return;
 141
 142         arm_iommu_release_mapping(priv->mapping);
 143         priv->mapping = NULL;
 144         priv->dma_dev = NULL;
 145 }