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f220df66 AS |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * An example software sink buffer for Intel TH MSU. | |
4 | * | |
5 | * Copyright (C) 2019 Intel Corporation. | |
6 | */ | |
7 | ||
8 | #include <linux/intel_th.h> | |
9 | #include <linux/module.h> | |
10 | #include <linux/slab.h> | |
11 | #include <linux/device.h> | |
12 | #include <linux/dma-mapping.h> | |
13 | ||
14 | #define MAX_SGTS 16 | |
15 | ||
16 | struct msu_sink_private { | |
17 | struct device *dev; | |
18 | struct sg_table **sgts; | |
19 | unsigned int nr_sgts; | |
20 | }; | |
21 | ||
22 | static void *msu_sink_assign(struct device *dev, int *mode) | |
23 | { | |
24 | struct msu_sink_private *priv; | |
25 | ||
26 | priv = kzalloc(sizeof(*priv), GFP_KERNEL); | |
27 | if (!priv) | |
28 | return NULL; | |
29 | ||
30 | priv->sgts = kcalloc(MAX_SGTS, sizeof(void *), GFP_KERNEL); | |
31 | if (!priv->sgts) { | |
32 | kfree(priv); | |
33 | return NULL; | |
34 | } | |
35 | ||
36 | priv->dev = dev; | |
37 | *mode = MSC_MODE_MULTI; | |
38 | ||
39 | return priv; | |
40 | } | |
41 | ||
42 | static void msu_sink_unassign(void *data) | |
43 | { | |
44 | struct msu_sink_private *priv = data; | |
45 | ||
46 | kfree(priv->sgts); | |
47 | kfree(priv); | |
48 | } | |
49 | ||
50 | /* See also: msc.c: __msc_buffer_win_alloc() */ | |
51 | static int msu_sink_alloc_window(void *data, struct sg_table **sgt, size_t size) | |
52 | { | |
53 | struct msu_sink_private *priv = data; | |
54 | unsigned int nents; | |
55 | struct scatterlist *sg_ptr; | |
56 | void *block; | |
57 | int ret, i; | |
58 | ||
59 | if (priv->nr_sgts == MAX_SGTS) | |
60 | return -ENOMEM; | |
61 | ||
62 | nents = DIV_ROUND_UP(size, PAGE_SIZE); | |
63 | ||
64 | ret = sg_alloc_table(*sgt, nents, GFP_KERNEL); | |
65 | if (ret) | |
66 | return -ENOMEM; | |
67 | ||
68 | priv->sgts[priv->nr_sgts++] = *sgt; | |
69 | ||
70 | for_each_sg((*sgt)->sgl, sg_ptr, nents, i) { | |
71 | block = dma_alloc_coherent(priv->dev->parent->parent, | |
72 | PAGE_SIZE, &sg_dma_address(sg_ptr), | |
73 | GFP_KERNEL); | |
74 | sg_set_buf(sg_ptr, block, PAGE_SIZE); | |
75 | } | |
76 | ||
77 | return nents; | |
78 | } | |
79 | ||
80 | /* See also: msc.c: __msc_buffer_win_free() */ | |
81 | static void msu_sink_free_window(void *data, struct sg_table *sgt) | |
82 | { | |
83 | struct msu_sink_private *priv = data; | |
84 | struct scatterlist *sg_ptr; | |
85 | int i; | |
86 | ||
87 | for_each_sg(sgt->sgl, sg_ptr, sgt->nents, i) { | |
88 | dma_free_coherent(priv->dev->parent->parent, PAGE_SIZE, | |
89 | sg_virt(sg_ptr), sg_dma_address(sg_ptr)); | |
90 | } | |
91 | ||
92 | sg_free_table(sgt); | |
93 | priv->nr_sgts--; | |
94 | } | |
95 | ||
96 | static int msu_sink_ready(void *data, struct sg_table *sgt, size_t bytes) | |
97 | { | |
98 | struct msu_sink_private *priv = data; | |
99 | ||
100 | intel_th_msc_window_unlock(priv->dev, sgt); | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
105 | static const struct msu_buffer sink_mbuf = { | |
106 | .name = "sink", | |
107 | .assign = msu_sink_assign, | |
108 | .unassign = msu_sink_unassign, | |
109 | .alloc_window = msu_sink_alloc_window, | |
110 | .free_window = msu_sink_free_window, | |
111 | .ready = msu_sink_ready, | |
112 | }; | |
113 | ||
114 | module_intel_th_msu_buffer(sink_mbuf); | |
115 | ||
116 | MODULE_LICENSE("GPL v2"); |