1 /* exynos_drm_iommu.c
2 *
3 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
4 * Author: Inki Dae <inki.dae@samsung.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 */
11
12 #include <drmP.h>
13 #include <drm/exynos_drm.h>
14
15 #include <linux/dma-mapping.h>
16 #include <linux/iommu.h>
17 #include <linux/kref.h>
18
19 #include <asm/dma-iommu.h>
20
21 #include "exynos_drm_drv.h"
22 #include "exynos_drm_iommu.h"
23
24 /*
25 * drm_create_iommu_mapping - create a mapping structure
26 *
27 * @drm_dev: DRM device
28 */
drm_create_iommu_mapping(struct drm_device * drm_dev)29 int drm_create_iommu_mapping(struct drm_device *drm_dev)
30 {
31 struct dma_iommu_mapping *mapping = NULL;
32 struct exynos_drm_private *priv = drm_dev->dev_private;
33 struct device *dev = drm_dev->dev;
34
35 if (!priv->da_start)
36 priv->da_start = EXYNOS_DEV_ADDR_START;
37 if (!priv->da_space_size)
38 priv->da_space_size = EXYNOS_DEV_ADDR_SIZE;
39
40 mapping = arm_iommu_create_mapping(&platform_bus_type, priv->da_start,
41 priv->da_space_size);
42
43 if (IS_ERR(mapping))
44 return PTR_ERR(mapping);
45
46 dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
47 GFP_KERNEL);
48 if (!dev->dma_parms)
49 goto error;
50
51 dma_set_max_seg_size(dev, 0xffffffffu);
52 dev->archdata.mapping = mapping;
53
54 return 0;
55 error:
56 arm_iommu_release_mapping(mapping);
57 return -ENOMEM;
58 }
59
60 /*
61 * drm_release_iommu_mapping - release iommu mapping structure
62 *
63 * @drm_dev: DRM device
64 *
65 * if mapping->kref becomes 0 then all things related to iommu mapping
66 * will be released
67 */
drm_release_iommu_mapping(struct drm_device * drm_dev)68 void drm_release_iommu_mapping(struct drm_device *drm_dev)
69 {
70 struct device *dev = drm_dev->dev;
71
72 arm_iommu_release_mapping(dev->archdata.mapping);
73 }
74
75 /*
76 * drm_iommu_attach_device- attach device to iommu mapping
77 *
78 * @drm_dev: DRM device
79 * @subdrv_dev: device to be attach
80 *
81 * This function should be called by sub drivers to attach it to iommu
82 * mapping.
83 */
drm_iommu_attach_device(struct drm_device * drm_dev,struct device * subdrv_dev)84 int drm_iommu_attach_device(struct drm_device *drm_dev,
85 struct device *subdrv_dev)
86 {
87 struct device *dev = drm_dev->dev;
88 int ret;
89
90 if (!dev->archdata.mapping)
91 return 0;
92
93 subdrv_dev->dma_parms = devm_kzalloc(subdrv_dev,
94 sizeof(*subdrv_dev->dma_parms),
95 GFP_KERNEL);
96 if (!subdrv_dev->dma_parms)
97 return -ENOMEM;
98
99 dma_set_max_seg_size(subdrv_dev, 0xffffffffu);
100
101 if (subdrv_dev->archdata.mapping)
102 arm_iommu_detach_device(subdrv_dev);
103
104 ret = arm_iommu_attach_device(subdrv_dev, dev->archdata.mapping);
105 if (ret < 0) {
106 DRM_DEBUG_KMS("failed iommu attach.\n");
107 return ret;
108 }
109
110 /*
111 * Set dma_ops to drm_device just one time.
112 *
113 * The dma mapping api needs device object and the api is used
114 * to allocate physial memory and map it with iommu table.
115 * If iommu attach succeeded, the sub driver would have dma_ops
116 * for iommu and also all sub drivers have same dma_ops.
117 */
118 if (get_dma_ops(dev) == get_dma_ops(NULL))
119 set_dma_ops(dev, get_dma_ops(subdrv_dev));
120
121 return 0;
122 }
123
124 /*
125 * drm_iommu_detach_device -detach device address space mapping from device
126 *
127 * @drm_dev: DRM device
128 * @subdrv_dev: device to be detached
129 *
130 * This function should be called by sub drivers to detach it from iommu
131 * mapping
132 */
drm_iommu_detach_device(struct drm_device * drm_dev,struct device * subdrv_dev)133 void drm_iommu_detach_device(struct drm_device *drm_dev,
134 struct device *subdrv_dev)
135 {
136 struct device *dev = drm_dev->dev;
137 struct dma_iommu_mapping *mapping = dev->archdata.mapping;
138
139 if (!mapping || !mapping->domain)
140 return;
141
142 arm_iommu_detach_device(subdrv_dev);
143 }
144