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/* exynos_drm_iommu.c
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* Author: Inki Dae <inki.dae@samsung.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <drmP.h>
#include <drm/exynos_drm.h>
#include <linux/dma-mapping.h>
#include <linux/iommu.h>
#include <linux/kref.h>
#include <asm/dma-iommu.h>
#include "exynos_drm_drv.h"
#include "exynos_drm_iommu.h"
/*
* drm_create_iommu_mapping - create a mapping structure
*
* @drm_dev: DRM device
*/
int drm_create_iommu_mapping(struct drm_device *drm_dev)
{
struct dma_iommu_mapping *mapping = NULL;
struct exynos_drm_private *priv = drm_dev->dev_private;
struct device *dev = drm_dev->dev;
if (!priv->da_start)
priv->da_start = EXYNOS_DEV_ADDR_START;
if (!priv->da_space_size)
priv->da_space_size = EXYNOS_DEV_ADDR_SIZE;
mapping = arm_iommu_create_mapping(&platform_bus_type, priv->da_start,
priv->da_space_size);
if (IS_ERR(mapping))
return PTR_ERR(mapping);
dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
GFP_KERNEL);
if (!dev->dma_parms)
goto error;
dma_set_max_seg_size(dev, 0xffffffffu);
dev->archdata.mapping = mapping;
return 0;
error:
arm_iommu_release_mapping(mapping);
return -ENOMEM;
}
/*
* drm_release_iommu_mapping - release iommu mapping structure
*
* @drm_dev: DRM device
*
* if mapping->kref becomes 0 then all things related to iommu mapping
* will be released
*/
void drm_release_iommu_mapping(struct drm_device *drm_dev)
{
struct device *dev = drm_dev->dev;
arm_iommu_release_mapping(dev->archdata.mapping);
}
/*
* drm_iommu_attach_device- attach device to iommu mapping
*
* @drm_dev: DRM device
* @subdrv_dev: device to be attach
*
* This function should be called by sub drivers to attach it to iommu
* mapping.
*/
int drm_iommu_attach_device(struct drm_device *drm_dev,
struct device *subdrv_dev)
{
struct device *dev = drm_dev->dev;
int ret;
if (!dev->archdata.mapping)
return 0;
subdrv_dev->dma_parms = devm_kzalloc(subdrv_dev,
sizeof(*subdrv_dev->dma_parms),
GFP_KERNEL);
if (!subdrv_dev->dma_parms)
return -ENOMEM;
dma_set_max_seg_size(subdrv_dev, 0xffffffffu);
if (subdrv_dev->archdata.mapping)
arm_iommu_detach_device(subdrv_dev);
ret = arm_iommu_attach_device(subdrv_dev, dev->archdata.mapping);
if (ret < 0) {
DRM_DEBUG_KMS("failed iommu attach.\n");
return ret;
}
/*
* Set dma_ops to drm_device just one time.
*
* The dma mapping api needs device object and the api is used
* to allocate physial memory and map it with iommu table.
* If iommu attach succeeded, the sub driver would have dma_ops
* for iommu and also all sub drivers have same dma_ops.
*/
if (get_dma_ops(dev) == get_dma_ops(NULL))
set_dma_ops(dev, get_dma_ops(subdrv_dev));
return 0;
}
/*
* drm_iommu_detach_device -detach device address space mapping from device
*
* @drm_dev: DRM device
* @subdrv_dev: device to be detached
*
* This function should be called by sub drivers to detach it from iommu
* mapping
*/
void drm_iommu_detach_device(struct drm_device *drm_dev,
struct device *subdrv_dev)
{
struct device *dev = drm_dev->dev;
struct dma_iommu_mapping *mapping = dev->archdata.mapping;
if (!mapping || !mapping->domain)
return;
iommu_detach_device(mapping->domain, subdrv_dev);
drm_release_iommu_mapping(drm_dev);
}
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