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, void **dma_priv)
  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                 /*
  78                  * Keep the original DMA mapping of the sub-device and
  79                  * restore it on Exynos DRM detach, otherwise the DMA
  80                  * framework considers it as IOMMU-less during the next
  81                  * probe (in case of deferred probe or modular build)
  82                  */
  83                 *dma_priv = to_dma_iommu_mapping(subdrv_dev);
  84                 if (*dma_priv)
  85                         arm_iommu_detach_device(subdrv_dev);
  86
  87                 ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
  88         } else if (IS_ENABLED(CONFIG_IOMMU_DMA)) {
  89                 ret = iommu_attach_device(priv->mapping, subdrv_dev);
  90         }
  91
  92         if (ret)
  93                 clear_dma_max_seg_size(subdrv_dev);
  94
  95         return 0;
  96 }
  97
  98 /*
  99  * drm_iommu_detach_device -detach device address space mapping from device
 100  *
 101  * @drm_dev: DRM device
 102  * @subdrv_dev: device to be detached
 103  *
 104  * This function should be called by sub drivers to detach it from iommu
 105  * mapping
 106  */
 107 static void drm_iommu_detach_device(struct drm_device *drm_dev,
 108                                     struct device *subdrv_dev, void **dma_priv)
 109 {
 110         struct exynos_drm_private *priv = drm_dev->dev_private;
 111
 112         if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
 113                 arm_iommu_detach_device(subdrv_dev);
 114                 arm_iommu_attach_device(subdrv_dev, *dma_priv);
 115         } else if (IS_ENABLED(CONFIG_IOMMU_DMA))
 116                 iommu_detach_device(priv->mapping, subdrv_dev);
 117
 118         clear_dma_max_seg_size(subdrv_dev);
 119 }
 120
 121 int exynos_drm_register_dma(struct drm_device *drm, struct device *dev,
 122                             void **dma_priv)
 123 {
 124         struct exynos_drm_private *priv = drm->dev_private;
 125
 126         if (!priv->dma_dev) {
 127                 priv->dma_dev = dev;
 128                 DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",
 129                          dev_name(dev));
 130         }
 131
 132         if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 133                 return 0;
 134
 135         if (!priv->mapping) {
 136                 void *mapping;
 137
 138                 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
 139                         mapping = arm_iommu_create_mapping(&platform_bus_type,
 140                                 EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE);
 141                 else if (IS_ENABLED(CONFIG_IOMMU_DMA))
 142                         mapping = iommu_get_domain_for_dev(priv->dma_dev);
 143
 144                 if (IS_ERR(mapping))
 145                         return PTR_ERR(mapping);
 146                 priv->mapping = mapping;
 147         }
 148
 149         return drm_iommu_attach_device(drm, dev, dma_priv);
 150 }
 151
 152 void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev,
 153                                void **dma_priv)
 154 {
 155         if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 156                 drm_iommu_detach_device(drm, dev, dma_priv);
 157 }
 158
 159 void exynos_drm_cleanup_dma(struct drm_device *drm)
 160 {
 161         struct exynos_drm_private *priv = drm->dev_private;
 162
 163         if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
 164                 return;
 165
 166         arm_iommu_release_mapping(priv->mapping);
 167         priv->mapping = NULL;
 168         priv->dma_dev = NULL;
 169 }