Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2021, NVIDIA Corporation.
4 */
5
6#include <linux/device.h>
7#include <linux/kref.h>
8#include <linux/of.h>
9#include <linux/of_platform.h>
10#include <linux/pid.h>
11#include <linux/slab.h>
12
13#include "context.h"
14#include "dev.h"
15
16static void host1x_memory_context_release(struct device *dev)
17{
18 /* context device is freed in host1x_memory_context_list_free() */
19}
20
21int host1x_memory_context_list_init(struct host1x *host1x)
22{
23 struct host1x_memory_context_list *cdl = &host1x->context_list;
24 struct device_node *node = host1x->dev->of_node;
25 struct host1x_memory_context *ctx;
26 unsigned int i;
27 int err;
28
29 cdl->devs = NULL;
30 cdl->len = 0;
31 mutex_init(&cdl->lock);
32
33 err = of_property_count_u32_elems(node, "iommu-map");
34 if (err < 0)
35 return 0;
36
37 cdl->devs = kcalloc(err, sizeof(*cdl->devs), GFP_KERNEL);
38 if (!cdl->devs)
39 return -ENOMEM;
40 cdl->len = err / 4;
41
42 for (i = 0; i < cdl->len; i++) {
43 ctx = &cdl->devs[i];
44
45 ctx->host = host1x;
46
47 device_initialize(&ctx->dev);
48
49 /*
50 * Due to an issue with T194 NVENC, only 38 bits can be used.
51 * Anyway, 256GiB of IOVA ought to be enough for anyone.
52 */
53 ctx->dma_mask = DMA_BIT_MASK(38);
54 ctx->dev.dma_mask = &ctx->dma_mask;
55 ctx->dev.coherent_dma_mask = ctx->dma_mask;
56 dev_set_name(&ctx->dev, "host1x-ctx.%d", i);
57 ctx->dev.bus = &host1x_context_device_bus_type;
58 ctx->dev.parent = host1x->dev;
59 ctx->dev.release = host1x_memory_context_release;
60
61 dma_set_max_seg_size(&ctx->dev, UINT_MAX);
62
63 err = device_add(&ctx->dev);
64 if (err) {
65 dev_err(host1x->dev, "could not add context device %d: %d\n", i, err);
66 put_device(&ctx->dev);
67 goto unreg_devices;
68 }
69
70 err = of_dma_configure_id(&ctx->dev, node, true, &i);
71 if (err) {
72 dev_err(host1x->dev, "IOMMU configuration failed for context device %d: %d\n",
73 i, err);
74 device_unregister(&ctx->dev);
75 goto unreg_devices;
76 }
77
78 if (!tegra_dev_iommu_get_stream_id(&ctx->dev, &ctx->stream_id) ||
79 !device_iommu_mapped(&ctx->dev)) {
80 dev_err(host1x->dev, "Context device %d has no IOMMU!\n", i);
81 device_unregister(&ctx->dev);
82 goto unreg_devices;
83 }
84 }
85
86 return 0;
87
88unreg_devices:
89 while (i--)
90 device_unregister(&cdl->devs[i].dev);
91
92 kfree(cdl->devs);
93 cdl->devs = NULL;
94 cdl->len = 0;
95
96 return err;
97}
98
99void host1x_memory_context_list_free(struct host1x_memory_context_list *cdl)
100{
101 unsigned int i;
102
103 for (i = 0; i < cdl->len; i++)
104 device_unregister(&cdl->devs[i].dev);
105
106 kfree(cdl->devs);
107 cdl->len = 0;
108}
109
110struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x,
111 struct device *dev,
112 struct pid *pid)
113{
114 struct host1x_memory_context_list *cdl = &host1x->context_list;
115 struct host1x_memory_context *free = NULL;
116 int i;
117
118 if (!cdl->len)
119 return ERR_PTR(-EOPNOTSUPP);
120
121 mutex_lock(&cdl->lock);
122
123 for (i = 0; i < cdl->len; i++) {
124 struct host1x_memory_context *cd = &cdl->devs[i];
125
126 if (cd->dev.iommu->iommu_dev != dev->iommu->iommu_dev)
127 continue;
128
129 if (cd->owner == pid) {
130 refcount_inc(&cd->ref);
131 mutex_unlock(&cdl->lock);
132 return cd;
133 } else if (!cd->owner && !free) {
134 free = cd;
135 }
136 }
137
138 if (!free) {
139 mutex_unlock(&cdl->lock);
140 return ERR_PTR(-EBUSY);
141 }
142
143 refcount_set(&free->ref, 1);
144 free->owner = get_pid(pid);
145
146 mutex_unlock(&cdl->lock);
147
148 return free;
149}
150EXPORT_SYMBOL_GPL(host1x_memory_context_alloc);
151
152void host1x_memory_context_get(struct host1x_memory_context *cd)
153{
154 refcount_inc(&cd->ref);
155}
156EXPORT_SYMBOL_GPL(host1x_memory_context_get);
157
158void host1x_memory_context_put(struct host1x_memory_context *cd)
159{
160 struct host1x_memory_context_list *cdl = &cd->host->context_list;
161
162 if (refcount_dec_and_mutex_lock(&cd->ref, &cdl->lock)) {
163 put_pid(cd->owner);
164 cd->owner = NULL;
165 mutex_unlock(&cdl->lock);
166 }
167}
168EXPORT_SYMBOL_GPL(host1x_memory_context_put);