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-mapping.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 static inline int configure_dma_max_seg_size(struct device *dev)
  35 {
  36         if (!dev->dma_parms)
  37                 dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL);
  38         if (!dev->dma_parms)
  39                 return -ENOMEM;
  40
  41         dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
  42         return 0;
  43 }
  44
  45 static inline void clear_dma_max_seg_size(struct device *dev)
  46 {
  47         kfree(dev->dma_parms);
  48         dev->dma_parms = NULL;
  49 }
  50
  51 /*
  52  * drm_iommu_attach_device- attach device to iommu mapping
  53  *
  54  * @drm_dev: DRM device
  55  * @subdrv_dev: device to be attach
  56  *
  57  * This function should be called by sub drivers to attach it to iommu
  58  * mapping.
  59  */
  60 static int drm_iommu_attach_device(struct drm_device *drm_dev,
  61                                 struct device *subdrv_dev)
  62 {
  63         struct exynos_drm_private *priv = drm_dev->dev_private;
  64         int ret;
  65
  66         if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) {
  67                 DRM_DEV_ERROR(subdrv_dev, "Device %s lacks support for IOMMU\n",
  68                           dev_name(subdrv_dev));
  69                 return -EINVAL;
  70         }
  71
  72         ret = configure_dma_max_seg_size(subdrv_dev);
  73         if (ret)
  74                 return ret;
  75
  76         if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
  77                 if (to_dma_iommu_mapping(subdrv_dev))
  78                         arm_iommu_detach_device(subdrv_dev);
  79
  80                 ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
  81         } else if (IS_ENABLED(CONFIG_IOMMU_DMA)) {
  82                 ret = iommu_attach_device(priv->mapping, subdrv_dev);
  83         }
  84
  85         if (ret)
  86                 clear_dma_max_seg_size(subdrv_dev);
  87
  88         return 0;
  89 }
  90
  91 /*
  92  * drm_iommu_detach_device -detach device address space mapping from device
  93  *
  94  * @drm_dev: DRM device
  95  * @subdrv_dev: device to be detached
  96  *
  97  * This function should be called by sub drivers to detach it from iommu
  98  * mapping
  99  */
 100 static void drm_iommu_detach_device(struct drm_device *drm_dev,
 101                                 struct device *subdrv_dev)
 102 {
 103         struct exynos_drm_private *priv = drm_dev->dev_private;
 104
 105         if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
 106                 arm_iommu_detach_device(subdrv_dev);
 107         else if (IS_ENABLED(CONFIG_IOMMU_DMA))
 108                 iommu_detach_device(priv->mapping, subdrv_dev);
 109
 110         clear_dma_max_seg_size(subdrv_dev);
 111 }
 112
 113 int exynos_drm_register_dma(struct drm_device *drm, struct device *dev)
 114 {
 115         struct exynos_drm_private *priv = drm->dev_private;
 116
 117         if (!priv->dma_dev) {
 118                 priv->dma_dev = dev;
 119                 DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",
 120                          dev_name(dev));
 121         }
 122
 123         if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 124                 return 0;
 125
 126         if (!priv->mapping) {
 127                 void *mapping;
 128
 129                 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
 130                         mapping = arm_iommu_create_mapping(&platform_bus_type,
 131                                 EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE);
 132                 else if (IS_ENABLED(CONFIG_IOMMU_DMA))
 133                         mapping = iommu_get_domain_for_dev(priv->dma_dev);
 134
 135                 if (IS_ERR(mapping))
 136                         return PTR_ERR(mapping);
 137                 priv->mapping = mapping;
 138         }
 139
 140         return drm_iommu_attach_device(drm, dev);
 141 }
 142
 143 void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev)
 144 {
 145         if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 146                 drm_iommu_detach_device(drm, dev);
 147 }
 148
 149 void exynos_drm_cleanup_dma(struct drm_device *drm)
 150 {
 151         struct exynos_drm_private *priv = drm->dev_private;
 152
 153         if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 154                 return;
 155
 156         arm_iommu_release_mapping(priv->mapping);
 157         priv->mapping = NULL;
 158         priv->dma_dev = NULL;
 159 }