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 #include <linux/kref.h>
  18
  19 #include <asm/dma-iommu.h>
  20
  21 #include "exynos_drm_drv.h"
  22 #include "exynos_drm_iommu.h"
  23
  24 /*
  25  * drm_create_iommu_mapping - create a mapping structure
  26  *
  27  * @drm_dev: DRM device
  28  */
  29 int drm_create_iommu_mapping(struct drm_device *drm_dev)
  30 {
  31         struct dma_iommu_mapping *mapping = NULL;
  32         struct exynos_drm_private *priv = drm_dev->dev_private;
  33
  34         if (!priv->da_start)
  35                 priv->da_start = EXYNOS_DEV_ADDR_START;
  36         if (!priv->da_space_size)
  37                 priv->da_space_size = EXYNOS_DEV_ADDR_SIZE;
  38
  39         mapping = arm_iommu_create_mapping(&platform_bus_type, priv->da_start,
  40                                                 priv->da_space_size);
  41
  42         if (IS_ERR(mapping))
  43                 return PTR_ERR(mapping);
  44
  45         priv->mapping = mapping;
  46
  47         return 0;
  48 }
  49
  50 /*
  51  * drm_release_iommu_mapping - release iommu mapping structure
  52  *
  53  * @drm_dev: DRM device
  54  *
  55  * if mapping->kref becomes 0 then all things related to iommu mapping
  56  * will be released
  57  */
  58 void drm_release_iommu_mapping(struct drm_device *drm_dev)
  59 {
  60         struct exynos_drm_private *priv = drm_dev->dev_private;
  61
  62         arm_iommu_release_mapping(priv->mapping);
  63 }
  64
  65 /*
  66  * drm_iommu_attach_device- attach device to iommu mapping
  67  *
  68  * @drm_dev: DRM device
  69  * @subdrv_dev: device to be attach
  70  *
  71  * This function should be called by sub drivers to attach it to iommu
  72  * mapping.
  73  */
  74 int drm_iommu_attach_device(struct drm_device *drm_dev,
  75                                 struct device *subdrv_dev)
  76 {
  77         struct exynos_drm_private *priv = drm_dev->dev_private;
  78         int ret;
  79
  80         if (!priv->mapping)
  81                 return 0;
  82
  83         subdrv_dev->dma_parms = devm_kzalloc(subdrv_dev,
  84                                         sizeof(*subdrv_dev->dma_parms),
  85                                         GFP_KERNEL);
  86         if (!subdrv_dev->dma_parms)
  87                 return -ENOMEM;
  88
  89         dma_set_max_seg_size(subdrv_dev, 0xffffffffu);
  90
  91         if (subdrv_dev->archdata.mapping)
  92                 arm_iommu_detach_device(subdrv_dev);
  93
  94         ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
  95         if (ret < 0) {
  96                 DRM_DEBUG_KMS("failed iommu attach.\n");
  97                 return ret;
  98         }
  99
 100         return 0;
 101 }
 102
 103 /*
 104  * drm_iommu_detach_device -detach device address space mapping from device
 105  *
 106  * @drm_dev: DRM device
 107  * @subdrv_dev: device to be detached
 108  *
 109  * This function should be called by sub drivers to detach it from iommu
 110  * mapping
 111  */
 112 void drm_iommu_detach_device(struct drm_device *drm_dev,
 113                                 struct device *subdrv_dev)
 114 {
 115         struct exynos_drm_private *priv = drm_dev->dev_private;
 116         struct dma_iommu_mapping *mapping = priv->mapping;
 117
 118         if (!mapping || !mapping->domain)
 119                 return;
 120
 121         arm_iommu_detach_device(subdrv_dev);
 122 }