cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

exynos_drm_dma.c (3959B)

      1// SPDX-License-Identifier: GPL-2.0
      2//
      3// Copyright (c) 2012 Samsung Electronics Co., Ltd.
      4// Author: Inki Dae <inki.dae@samsung.com>
      5// Author: Andrzej Hajda <a.hajda@samsung.com>
      6
      7#include <linux/dma-iommu.h>
      8#include <linux/dma-map-ops.h>
      9#include <linux/iommu.h>
     10#include <linux/platform_device.h>
     11
     12#include <drm/drm_print.h>
     13#include <drm/exynos_drm.h>
     14
     15#include "exynos_drm_drv.h"
     16
     17#if defined(CONFIG_ARM_DMA_USE_IOMMU)
     18#include <asm/dma-iommu.h>
     19#else
     20#define arm_iommu_create_mapping(...)	({ NULL; })
     21#define arm_iommu_attach_device(...)	({ -ENODEV; })
     22#define arm_iommu_release_mapping(...)	({ })
     23#define arm_iommu_detach_device(...)	({ })
     24#define to_dma_iommu_mapping(dev) NULL
     25#endif
     26
     27#if !defined(CONFIG_IOMMU_DMA)
     28#define iommu_dma_init_domain(...) ({ -EINVAL; })
     29#endif
     30
     31#define EXYNOS_DEV_ADDR_START	0x20000000
     32#define EXYNOS_DEV_ADDR_SIZE	0x40000000
     33
     34/*
     35 * drm_iommu_attach_device- attach device to iommu mapping
     36 *
     37 * @drm_dev: DRM device
     38 * @subdrv_dev: device to be attach
     39 *
     40 * This function should be called by sub drivers to attach it to iommu
     41 * mapping.
     42 */
     43static int drm_iommu_attach_device(struct drm_device *drm_dev,
     44				struct device *subdrv_dev, void **dma_priv)
     45{
     46	struct exynos_drm_private *priv = drm_dev->dev_private;
     47	int ret = 0;
     48
     49	if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) {
     50		DRM_DEV_ERROR(subdrv_dev, "Device %s lacks support for IOMMU\n",
     51			  dev_name(subdrv_dev));
     52		return -EINVAL;
     53	}
     54
     55	dma_set_max_seg_size(subdrv_dev, DMA_BIT_MASK(32));
     56	if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
     57		/*
     58		 * Keep the original DMA mapping of the sub-device and
     59		 * restore it on Exynos DRM detach, otherwise the DMA
     60		 * framework considers it as IOMMU-less during the next
     61		 * probe (in case of deferred probe or modular build)
     62		 */
     63		*dma_priv = to_dma_iommu_mapping(subdrv_dev);
     64		if (*dma_priv)
     65			arm_iommu_detach_device(subdrv_dev);
     66
     67		ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
     68	} else if (IS_ENABLED(CONFIG_IOMMU_DMA)) {
     69		ret = iommu_attach_device(priv->mapping, subdrv_dev);
     70	}
     71
     72	return ret;
     73}
     74
     75/*
     76 * drm_iommu_detach_device -detach device address space mapping from device
     77 *
     78 * @drm_dev: DRM device
     79 * @subdrv_dev: device to be detached
     80 *
     81 * This function should be called by sub drivers to detach it from iommu
     82 * mapping
     83 */
     84static void drm_iommu_detach_device(struct drm_device *drm_dev,
     85				    struct device *subdrv_dev, void **dma_priv)
     86{
     87	struct exynos_drm_private *priv = drm_dev->dev_private;
     88
     89	if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
     90		arm_iommu_detach_device(subdrv_dev);
     91		arm_iommu_attach_device(subdrv_dev, *dma_priv);
     92	} else if (IS_ENABLED(CONFIG_IOMMU_DMA))
     93		iommu_detach_device(priv->mapping, subdrv_dev);
     94}
     95
     96int exynos_drm_register_dma(struct drm_device *drm, struct device *dev,
     97			    void **dma_priv)
     98{
     99	struct exynos_drm_private *priv = drm->dev_private;
    100
    101	if (!priv->dma_dev) {
    102		priv->dma_dev = dev;
    103		DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",
    104			 dev_name(dev));
    105	}
    106
    107	if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
    108		return 0;
    109
    110	if (!priv->mapping) {
    111		void *mapping;
    112
    113		if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
    114			mapping = arm_iommu_create_mapping(&platform_bus_type,
    115				EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE);
    116		else if (IS_ENABLED(CONFIG_IOMMU_DMA))
    117			mapping = iommu_get_domain_for_dev(priv->dma_dev);
    118		else
    119			mapping = ERR_PTR(-ENODEV);
    120
    121		if (IS_ERR(mapping))
    122			return PTR_ERR(mapping);
    123		priv->mapping = mapping;
    124	}
    125
    126	return drm_iommu_attach_device(drm, dev, dma_priv);
    127}
    128
    129void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev,
    130			       void **dma_priv)
    131{
    132	if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
    133		drm_iommu_detach_device(drm, dev, dma_priv);
    134}
    135
    136void exynos_drm_cleanup_dma(struct drm_device *drm)
    137{
    138	struct exynos_drm_private *priv = drm->dev_private;
    139
    140	if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
    141		return;
    142
    143	arm_iommu_release_mapping(priv->mapping);
    144	priv->mapping = NULL;
    145	priv->dma_dev = NULL;
    146}