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