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68efd7d2fb
The 'order' parameter for IOMMU-aware dma-mapping implementation was introduced mainly as a hack to reduce size of the bitmap used for tracking IO virtual address space. Since now it is possible to dynamically resize the bitmap, this hack is not needed and can be removed without any impact on the client devices. This way the parameters for arm_iommu_create_mapping() becomes much easier to understand. 'size' parameter now means the maximum supported IO address space size. The code will allocate (resize) bitmap in chunks, ensuring that a single chunk is not larger than a single memory page to avoid unreliable allocations of size larger than PAGE_SIZE in atomic context. Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
144 lines
3.5 KiB
C
144 lines
3.5 KiB
C
/* exynos_drm_iommu.c
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*
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* Copyright (c) 2012 Samsung Electronics Co., Ltd.
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* Author: Inki Dae <inki.dae@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <drmP.h>
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#include <drm/exynos_drm.h>
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#include <linux/dma-mapping.h>
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#include <linux/iommu.h>
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#include <linux/kref.h>
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#include <asm/dma-iommu.h>
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#include "exynos_drm_drv.h"
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#include "exynos_drm_iommu.h"
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/*
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* drm_create_iommu_mapping - create a mapping structure
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*
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* @drm_dev: DRM device
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*/
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int drm_create_iommu_mapping(struct drm_device *drm_dev)
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{
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struct dma_iommu_mapping *mapping = NULL;
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struct exynos_drm_private *priv = drm_dev->dev_private;
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struct device *dev = drm_dev->dev;
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if (!priv->da_start)
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priv->da_start = EXYNOS_DEV_ADDR_START;
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if (!priv->da_space_size)
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priv->da_space_size = EXYNOS_DEV_ADDR_SIZE;
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mapping = arm_iommu_create_mapping(&platform_bus_type, priv->da_start,
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priv->da_space_size);
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if (IS_ERR(mapping))
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return PTR_ERR(mapping);
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dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
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GFP_KERNEL);
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if (!dev->dma_parms)
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goto error;
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dma_set_max_seg_size(dev, 0xffffffffu);
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dev->archdata.mapping = mapping;
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return 0;
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error:
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arm_iommu_release_mapping(mapping);
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return -ENOMEM;
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}
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/*
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* drm_release_iommu_mapping - release iommu mapping structure
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*
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* @drm_dev: DRM device
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*
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* if mapping->kref becomes 0 then all things related to iommu mapping
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* will be released
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*/
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void drm_release_iommu_mapping(struct drm_device *drm_dev)
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{
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struct device *dev = drm_dev->dev;
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arm_iommu_release_mapping(dev->archdata.mapping);
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}
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/*
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* drm_iommu_attach_device- attach device to iommu mapping
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*
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* @drm_dev: DRM device
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* @subdrv_dev: device to be attach
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*
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* This function should be called by sub drivers to attach it to iommu
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* mapping.
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*/
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int drm_iommu_attach_device(struct drm_device *drm_dev,
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struct device *subdrv_dev)
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{
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struct device *dev = drm_dev->dev;
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int ret;
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if (!dev->archdata.mapping) {
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DRM_ERROR("iommu_mapping is null.\n");
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return -EFAULT;
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}
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subdrv_dev->dma_parms = devm_kzalloc(subdrv_dev,
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sizeof(*subdrv_dev->dma_parms),
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GFP_KERNEL);
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if (!subdrv_dev->dma_parms)
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return -ENOMEM;
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dma_set_max_seg_size(subdrv_dev, 0xffffffffu);
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ret = arm_iommu_attach_device(subdrv_dev, dev->archdata.mapping);
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if (ret < 0) {
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DRM_DEBUG_KMS("failed iommu attach.\n");
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return ret;
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}
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/*
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* Set dma_ops to drm_device just one time.
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*
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* The dma mapping api needs device object and the api is used
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* to allocate physial memory and map it with iommu table.
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* If iommu attach succeeded, the sub driver would have dma_ops
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* for iommu and also all sub drivers have same dma_ops.
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*/
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if (!dev->archdata.dma_ops)
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dev->archdata.dma_ops = subdrv_dev->archdata.dma_ops;
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return 0;
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}
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/*
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* drm_iommu_detach_device -detach device address space mapping from device
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*
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* @drm_dev: DRM device
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* @subdrv_dev: device to be detached
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*
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* This function should be called by sub drivers to detach it from iommu
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* mapping
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*/
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void drm_iommu_detach_device(struct drm_device *drm_dev,
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struct device *subdrv_dev)
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{
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struct device *dev = drm_dev->dev;
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struct dma_iommu_mapping *mapping = dev->archdata.mapping;
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if (!mapping || !mapping->domain)
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return;
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iommu_detach_device(mapping->domain, subdrv_dev);
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drm_release_iommu_mapping(drm_dev);
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}
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