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-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  */
  43 static 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  */
  84 static 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
  96 int 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
 127 void 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
 134 void 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 }