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-mapping.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 static inline int configure_dma_max_seg_size(struct device *dev) 35 { 36 if (!dev->dma_parms) 37 dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL); 38 if (!dev->dma_parms) 39 return -ENOMEM; 40 41 dma_set_max_seg_size(dev, DMA_BIT_MASK(32)); 42 return 0; 43 } 44 45 static inline void clear_dma_max_seg_size(struct device *dev) 46 { 47 kfree(dev->dma_parms); 48 dev->dma_parms = NULL; 49 } 50 51 /* 52 * drm_iommu_attach_device- attach device to iommu mapping 53 * 54 * @drm_dev: DRM device 55 * @subdrv_dev: device to be attach 56 * 57 * This function should be called by sub drivers to attach it to iommu 58 * mapping. 59 */ 60 static int drm_iommu_attach_device(struct drm_device *drm_dev, 61 struct device *subdrv_dev) 62 { 63 struct exynos_drm_private *priv = drm_dev->dev_private; 64 int ret; 65 66 if (get_dma_ops(priv->dma_dev) != get_dma_ops(subdrv_dev)) { 67 DRM_DEV_ERROR(subdrv_dev, "Device %s lacks support for IOMMU\n", 68 dev_name(subdrv_dev)); 69 return -EINVAL; 70 } 71 72 ret = configure_dma_max_seg_size(subdrv_dev); 73 if (ret) 74 return ret; 75 76 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) { 77 if (to_dma_iommu_mapping(subdrv_dev)) 78 arm_iommu_detach_device(subdrv_dev); 79 80 ret = arm_iommu_attach_device(subdrv_dev, priv->mapping); 81 } else if (IS_ENABLED(CONFIG_IOMMU_DMA)) { 82 ret = iommu_attach_device(priv->mapping, subdrv_dev); 83 } 84 85 if (ret) 86 clear_dma_max_seg_size(subdrv_dev); 87 88 return 0; 89 } 90 91 /* 92 * drm_iommu_detach_device -detach device address space mapping from device 93 * 94 * @drm_dev: DRM device 95 * @subdrv_dev: device to be detached 96 * 97 * This function should be called by sub drivers to detach it from iommu 98 * mapping 99 */ 100 static void drm_iommu_detach_device(struct drm_device *drm_dev, 101 struct device *subdrv_dev) 102 { 103 struct exynos_drm_private *priv = drm_dev->dev_private; 104 105 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) 106 arm_iommu_detach_device(subdrv_dev); 107 else if (IS_ENABLED(CONFIG_IOMMU_DMA)) 108 iommu_detach_device(priv->mapping, subdrv_dev); 109 110 clear_dma_max_seg_size(subdrv_dev); 111 } 112 113 int exynos_drm_register_dma(struct drm_device *drm, struct device *dev) 114 { 115 struct exynos_drm_private *priv = drm->dev_private; 116 117 if (!priv->dma_dev) { 118 priv->dma_dev = dev; 119 DRM_INFO("Exynos DRM: using %s device for DMA mapping operations\n", 120 dev_name(dev)); 121 } 122 123 if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU)) 124 return 0; 125 126 if (!priv->mapping) { 127 void *mapping; 128 129 if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) 130 mapping = arm_iommu_create_mapping(&platform_bus_type, 131 EXYNOS_DEV_ADDR_START, EXYNOS_DEV_ADDR_SIZE); 132 else if (IS_ENABLED(CONFIG_IOMMU_DMA)) 133 mapping = iommu_get_domain_for_dev(priv->dma_dev); 134 135 if (IS_ERR(mapping)) 136 return PTR_ERR(mapping); 137 priv->mapping = mapping; 138 } 139 140 return drm_iommu_attach_device(drm, dev); 141 } 142 143 void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev) 144 { 145 if (IS_ENABLED(CONFIG_EXYNOS_IOMMU)) 146 drm_iommu_detach_device(drm, dev); 147 } 148 149 void exynos_drm_cleanup_dma(struct drm_device *drm) 150 { 151 struct exynos_drm_private *priv = drm->dev_private; 152 153 if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU)) 154 return; 155 156 arm_iommu_release_mapping(priv->mapping); 157 priv->mapping = NULL; 158 priv->dma_dev = NULL; 159 } 160