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 */
 29int 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 */
 58void 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 */
 74int 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 */
112void 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}