drivers/gpu/drm/exynos/exynos_drm_iommu.c

   1 /* exynos_drm_iommu.c
   2  *
   3  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   4  * Author: Inki Dae <inki.dae@samsung.com>
   5  *
   6  * This program is free software; you can redistribute  it and/or modify it
   7  * under  the terms of  the GNU General  Public License as published by the
   8  * Free Software Foundation;  either version 2 of the  License, or (at your
   9  * option) any later version.
  10  */
  11
  12 #include <drm/drmP.h>
  13 #include <drm/exynos_drm.h>
  14
  15 #include <linux/dma-mapping.h>
  16 #include <linux/iommu.h>
  17
  18 #include "exynos_drm_drv.h"
  19 #include "exynos_drm_iommu.h"
  20
  21 static inline int configure_dma_max_seg_size(struct device *dev)
  22 {
  23         if (!dev->dma_parms)
  24                 dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL);
  25         if (!dev->dma_parms)
  26                 return -ENOMEM;
  27
  28         dma_set_max_seg_size(dev, DMA_BIT_MASK(32));
  29         return 0;
  30 }
  31
  32 static inline void clear_dma_max_seg_size(struct device *dev)
  33 {
  34         kfree(dev->dma_parms);
  35         dev->dma_parms = NULL;
  36 }
  37
  38 /*
  39  * drm_create_iommu_mapping - create a mapping structure
  40  *
  41  * @drm_dev: DRM device
  42  */
  43 int drm_create_iommu_mapping(struct drm_device *drm_dev)
  44 {
  45         struct exynos_drm_private *priv = drm_dev->dev_private;
  46
  47         return __exynos_iommu_create_mapping(priv, EXYNOS_DEV_ADDR_START,
  48                                              EXYNOS_DEV_ADDR_SIZE);
  49 }
  50
  51 /*
  52  * drm_release_iommu_mapping - release iommu mapping structure
  53  *
  54  * @drm_dev: DRM device
  55  */
  56 void drm_release_iommu_mapping(struct drm_device *drm_dev)
  57 {
  58         struct exynos_drm_private *priv = drm_dev->dev_private;
  59
  60         __exynos_iommu_release_mapping(priv);
  61 }
  62
  63 /*
  64  * drm_iommu_attach_device- attach device to iommu mapping
  65  *
  66  * @drm_dev: DRM device
  67  * @subdrv_dev: device to be attach
  68  *
  69  * This function should be called by sub drivers to attach it to iommu
  70  * mapping.
  71  */
  72 int drm_iommu_attach_device(struct drm_device *drm_dev,
  73                                 struct device *subdrv_dev)
  74 {
  75         struct exynos_drm_private *priv = drm_dev->dev_private;
  76         int ret;
  77
  78         if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) {
  79                 DRM_ERROR("Device %s lacks support for IOMMU\n",
  80                           dev_name(subdrv_dev));
  81                 return -EINVAL;
  82         }
  83
  84         ret = configure_dma_max_seg_size(subdrv_dev);
  85         if (ret)
  86                 return ret;
  87
  88         ret = __exynos_iommu_attach(priv, subdrv_dev);
  89         if (ret)
  90                 clear_dma_max_seg_size(subdrv_dev);
  91
  92         return 0;
  93 }
  94
  95 /*
  96  * drm_iommu_detach_device -detach device address space mapping from device
  97  *
  98  * @drm_dev: DRM device
  99  * @subdrv_dev: device to be detached
 100  *
 101  * This function should be called by sub drivers to detach it from iommu
 102  * mapping
 103  */
 104 void drm_iommu_detach_device(struct drm_device *drm_dev,
 105                                 struct device *subdrv_dev)
 106 {
 107         struct exynos_drm_private *priv = drm_dev->dev_private;
 108
 109         __exynos_iommu_detach(priv, subdrv_dev);
 110         clear_dma_max_seg_size(subdrv_dev);
 111 }