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
 21static 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
 32static 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 */
 43int 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 */
 56void 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 */
 72int 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 */
104void 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}