tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 */
29int 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 if (!priv->da_space_order)
40 priv->da_space_order = EXYNOS_DEV_ADDR_ORDER;
41
42 mapping = arm_iommu_create_mapping(&platform_bus_type, priv->da_start,
43 priv->da_space_size,
44 priv->da_space_order);
45 if (IS_ERR(mapping))
46 return PTR_ERR(mapping);
47
48 dev->dma_parms = devm_kzalloc(dev, sizeof(*dev->dma_parms),
49 GFP_KERNEL);
50 if (!dev->dma_parms)
51 goto error;
52
53 dma_set_max_seg_size(dev, 0xffffffffu);
54 dev->archdata.mapping = mapping;
55
56 return 0;
57error:
58 arm_iommu_release_mapping(mapping);
59 return -ENOMEM;
60}
61
62/*
63 * drm_release_iommu_mapping - release iommu mapping structure
64 *
65 * @drm_dev: DRM device
66 *
67 * if mapping->kref becomes 0 then all things related to iommu mapping
68 * will be released
69 */
70void drm_release_iommu_mapping(struct drm_device *drm_dev)
71{
72 struct device *dev = drm_dev->dev;
73
74 arm_iommu_release_mapping(dev->archdata.mapping);
75}
76
77/*
78 * drm_iommu_attach_device- attach device to iommu mapping
79 *
80 * @drm_dev: DRM device
81 * @subdrv_dev: device to be attach
82 *
83 * This function should be called by sub drivers to attach it to iommu
84 * mapping.
85 */
86int drm_iommu_attach_device(struct drm_device *drm_dev,
87 struct device *subdrv_dev)
88{
89 struct device *dev = drm_dev->dev;
90 int ret;
91
92 if (!dev->archdata.mapping) {
93 DRM_ERROR("iommu_mapping is null.\n");
94 return -EFAULT;
95 }
96
97 subdrv_dev->dma_parms = devm_kzalloc(subdrv_dev,
98 sizeof(*subdrv_dev->dma_parms),
99 GFP_KERNEL);
100 if (!subdrv_dev->dma_parms)
101 return -ENOMEM;
102
103 dma_set_max_seg_size(subdrv_dev, 0xffffffffu);
104
105 ret = arm_iommu_attach_device(subdrv_dev, dev->archdata.mapping);
106 if (ret < 0) {
107 DRM_DEBUG_KMS("failed iommu attach.\n");
108 return ret;
109 }
110
111 /*
112 * Set dma_ops to drm_device just one time.
113 *
114 * The dma mapping api needs device object and the api is used
115 * to allocate physial memory and map it with iommu table.
116 * If iommu attach succeeded, the sub driver would have dma_ops
117 * for iommu and also all sub drivers have same dma_ops.
118 */
119 if (!dev->archdata.dma_ops)
120 dev->archdata.dma_ops = subdrv_dev->archdata.dma_ops;
121
122 return 0;
123}
124
125/*
126 * drm_iommu_detach_device -detach device address space mapping from device
127 *
128 * @drm_dev: DRM device
129 * @subdrv_dev: device to be detached
130 *
131 * This function should be called by sub drivers to detach it from iommu
132 * mapping
133 */
134void drm_iommu_detach_device(struct drm_device *drm_dev,
135 struct device *subdrv_dev)
136{
137 struct device *dev = drm_dev->dev;
138 struct dma_iommu_mapping *mapping = dev->archdata.mapping;
139
140 if (!mapping || !mapping->domain)
141 return;
142
143 iommu_detach_device(mapping->domain, subdrv_dev);
144 drm_release_iommu_mapping(drm_dev);
145}