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 */ 43 static 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 */ 84 static 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 96 int 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 } 128 129 void 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 } 135 136 void 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 } 147