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 */
drm_iommu_attach_device(struct drm_device * drm_dev,struct device * subdrv_dev,void ** dma_priv)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 */
drm_iommu_detach_device(struct drm_device * drm_dev,struct device * subdrv_dev,void ** dma_priv)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
exynos_drm_register_dma(struct drm_device * drm,struct device * dev,void ** dma_priv)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 = NULL;
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
119 if (!mapping)
120 return -ENODEV;
121 priv->mapping = mapping;
122 }
123
124 return drm_iommu_attach_device(drm, dev, dma_priv);
125 }
126
exynos_drm_unregister_dma(struct drm_device * drm,struct device * dev,void ** dma_priv)127 void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev,
128 void **dma_priv)
129 {
130 if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
131 drm_iommu_detach_device(drm, dev, dma_priv);
132 }
133
exynos_drm_cleanup_dma(struct drm_device * drm)134 void exynos_drm_cleanup_dma(struct drm_device *drm)
135 {
136 struct exynos_drm_private *priv = drm->dev_private;
137
138 if (!IS_ENABLED(CONFIG_EXYNOS_IOMMU))
139 return;
140
141 arm_iommu_release_mapping(priv->mapping);
142 priv->mapping = NULL;
143 priv->dma_dev = NULL;
144 }
145