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 <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
  32 static 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
  43 static 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  */
  58 static 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_ERROR("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  */
  98 static 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
 111 int 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
 141 void 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
 147 void 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 }