drm/exynos/exynos_drm_dma.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 //
0003 // Copyright (c) 2012 Samsung Electronics Co., Ltd.
0004 // Author: Inki Dae <inki.dae@samsung.com>
0005 // Author: Andrzej Hajda <a.hajda@samsung.com>
0006
0007 #include <linux/dma-iommu.h>
0008 #include <linux/dma-map-ops.h>
0009 #include <linux/iommu.h>
0010 #include <linux/platform_device.h>
0011
0012 #include <drm/drm_print.h>
0013 #include <drm/exynos_drm.h>
0014
0015 #include "exynos_drm_drv.h"
0016
0017 #if defined(CONFIG_ARM_DMA_USE_IOMMU)
0018 #include <asm/dma-iommu.h>
0019 #else
0020 #define arm_iommu_create_mapping(...)   ({ NULL; })
0021 #define arm_iommu_attach_device(...)    ({ -ENODEV; })
0022 #define arm_iommu_release_mapping(...)  ({ })
0023 #define arm_iommu_detach_device(...)    ({ })
0024 #define to_dma_iommu_mapping(dev) NULL
0025 #endif
0026
0027 #if !defined(CONFIG_IOMMU_DMA)
0028 #define iommu_dma_init_domain(...) ({ -EINVAL; })
0029 #endif
0030
0031 #define EXYNOS_DEV_ADDR_START   0x20000000
0032 #define EXYNOS_DEV_ADDR_SIZE    0x40000000
0033
0034 /*
0035  * drm_iommu_attach_device- attach device to iommu mapping
0036  *
0037  * @drm_dev: DRM device
0038  * @subdrv_dev: device to be attach
0039  *
0040  * This function should be called by sub drivers to attach it to iommu
0041  * mapping.
0042  */
0043 static int drm_iommu_attach_device(struct drm_device *drm_dev,
0044                 struct device *subdrv_dev, void **dma_priv)
0045 {
0046     struct exynos_drm_private *priv = drm_dev->dev_private;
0047     int ret = 0;
0048
0049     if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) {
0050         DRM_DEV_ERROR(subdrv_dev, "Device %s lacks support for IOMMU\n",
0051               dev_name(subdrv_dev));
0052         return -EINVAL;
0053     }
0054
0055     dma_set_max_seg_size(subdrv_dev, DMA_BIT_MASK(32));
0056     if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
0057         /*
0058          * Keep the original DMA mapping of the sub-device and
0059          * restore it on Exynos DRM detach, otherwise the DMA
0060          * framework considers it as IOMMU-less during the next
0061          * probe (in case of deferred probe or modular build)
0062          */
0063         *dma_priv = to_dma_iommu_mapping(subdrv_dev);
0064         if (*dma_priv)
0065             arm_iommu_detach_device(subdrv_dev);
0066
0067         ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
0068     } else if (IS_ENABLED(CONFIG_IOMMU_DMA)) {
0069         ret = iommu_attach_device(priv->mapping, subdrv_dev);
0070     }
0071
0072     return ret;
0073 }
0074
0075 /*
0076  * drm_iommu_detach_device -detach device address space mapping from device
0077  *
0078  * @drm_dev: DRM device
0079  * @subdrv_dev: device to be detached
0080  *
0081  * This function should be called by sub drivers to detach it from iommu
0082  * mapping
0083  */
0084 static void drm_iommu_detach_device(struct drm_device *drm_dev,
0085                     struct device *subdrv_dev, void **dma_priv)
0086 {
0087     struct exynos_drm_private *priv = drm_dev->dev_private;
0088
0089     if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
0090         arm_iommu_detach_device(subdrv_dev);
0091         arm_iommu_attach_device(subdrv_dev, *dma_priv);
0092     } else if (IS_ENABLED(CONFIG_IOMMU_DMA))
0093         iommu_detach_device(priv->mapping, subdrv_dev);
0094 }
0095
0096 int exynos_drm_register_dma(struct drm_device *drm, struct device *dev,
0097                 void **dma_priv)
0098 {
0099     struct exynos_drm_private *priv = drm->dev_private;
0100
0101     if (!priv->dma_dev) {
0102         priv->dma_dev = dev;
0103         DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n",
0104              dev_name(dev));
0105     }
0106
0107     if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
0108         return 0;
0109
0110     if (!priv->mapping) {
0111         void *mapping;
0112
0113         if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
0114             mapping = arm_iommu_create_mapping(&platform_bus_type,
0115                 EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE);
0116         else if (IS_ENABLED(CONFIG_IOMMU_DMA))
0117             mapping = iommu_get_domain_for_dev(priv->dma_dev);
0118         else
0119             mapping = ERR_PTR(-ENODEV);
0120
0121         if (IS_ERR(mapping))
0122             return PTR_ERR(mapping);
0123         priv->mapping = mapping;
0124     }
0125
0126     return drm_iommu_attach_device(drm, dev, dma_priv);
0127 }
0128
0129 void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev,
0130                    void **dma_priv)
0131 {
0132     if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
0133         drm_iommu_detach_device(drm, dev, dma_priv);
0134 }
0135
0136 void exynos_drm_cleanup_dma(struct drm_device *drm)
0137 {
0138     struct exynos_drm_private *priv = drm->dev_private;
0139
0140     if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
0141         return;
0142
0143     arm_iommu_release_mapping(priv->mapping);
0144     priv->mapping = NULL;
0145     priv->dma_dev = NULL;
0146 }