1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * A dummy STM device for stm/stm_source class testing. |
4 | * Copyright (c) 2014, Intel Corporation. |
5 | * |
6 | * STM class implements generic infrastructure for System Trace Module devices |
7 | * as defined in MIPI STPv2 specification. |
8 | */ |
9 | |
10 | #undef DEBUG |
11 | #include <linux/kernel.h> |
12 | #include <linux/module.h> |
13 | #include <linux/slab.h> |
14 | #include <linux/stm.h> |
15 | #include <uapi/linux/stm.h> |
16 | |
17 | static ssize_t notrace |
18 | dummy_stm_packet(struct stm_data *stm_data, unsigned int master, |
19 | unsigned int channel, unsigned int packet, unsigned int flags, |
20 | unsigned int size, const unsigned char *payload) |
21 | { |
22 | #ifdef DEBUG |
23 | u64 pl = 0; |
24 | |
25 | if (payload) |
26 | pl = *(u64 *)payload; |
27 | |
28 | if (size < 8) |
29 | pl &= (1ull << (size * 8)) - 1; |
30 | trace_printk("[%u:%u] [pkt: %x/%x] (%llx)\n" , master, channel, |
31 | packet, size, pl); |
32 | #endif |
33 | return size; |
34 | } |
35 | |
36 | #define DUMMY_STM_MAX 32 |
37 | |
38 | static struct stm_data dummy_stm[DUMMY_STM_MAX]; |
39 | |
40 | static int nr_dummies = 4; |
41 | |
42 | module_param(nr_dummies, int, 0400); |
43 | |
44 | static unsigned int fail_mode; |
45 | |
46 | module_param(fail_mode, int, 0600); |
47 | |
48 | static unsigned int master_min; |
49 | |
50 | module_param(master_min, int, 0400); |
51 | |
52 | static unsigned int master_max = STP_MASTER_MAX; |
53 | |
54 | module_param(master_max, int, 0400); |
55 | |
56 | static unsigned int nr_channels = STP_CHANNEL_MAX; |
57 | |
58 | module_param(nr_channels, int, 0400); |
59 | |
60 | static int dummy_stm_link(struct stm_data *data, unsigned int master, |
61 | unsigned int channel) |
62 | { |
63 | if (fail_mode && (channel & fail_mode)) |
64 | return -EINVAL; |
65 | |
66 | return 0; |
67 | } |
68 | |
69 | static int dummy_stm_init(void) |
70 | { |
71 | int i, ret = -ENOMEM; |
72 | |
73 | if (nr_dummies < 0 || nr_dummies > DUMMY_STM_MAX) |
74 | return -EINVAL; |
75 | |
76 | if (master_min > master_max || |
77 | master_max > STP_MASTER_MAX || |
78 | nr_channels > STP_CHANNEL_MAX) |
79 | return -EINVAL; |
80 | |
81 | for (i = 0; i < nr_dummies; i++) { |
82 | dummy_stm[i].name = kasprintf(GFP_KERNEL, fmt: "dummy_stm.%d" , i); |
83 | if (!dummy_stm[i].name) |
84 | goto fail_unregister; |
85 | |
86 | dummy_stm[i].sw_start = master_min; |
87 | dummy_stm[i].sw_end = master_max; |
88 | dummy_stm[i].sw_nchannels = nr_channels; |
89 | dummy_stm[i].packet = dummy_stm_packet; |
90 | dummy_stm[i].link = dummy_stm_link; |
91 | |
92 | ret = stm_register_device(NULL, stm_data: &dummy_stm[i], THIS_MODULE); |
93 | if (ret) |
94 | goto fail_free; |
95 | } |
96 | |
97 | return 0; |
98 | |
99 | fail_unregister: |
100 | for (i--; i >= 0; i--) { |
101 | stm_unregister_device(stm_data: &dummy_stm[i]); |
102 | fail_free: |
103 | kfree(objp: dummy_stm[i].name); |
104 | } |
105 | |
106 | return ret; |
107 | |
108 | } |
109 | |
110 | static void dummy_stm_exit(void) |
111 | { |
112 | int i; |
113 | |
114 | for (i = 0; i < nr_dummies; i++) { |
115 | stm_unregister_device(stm_data: &dummy_stm[i]); |
116 | kfree(objp: dummy_stm[i].name); |
117 | } |
118 | } |
119 | |
120 | module_init(dummy_stm_init); |
121 | module_exit(dummy_stm_exit); |
122 | |
123 | MODULE_LICENSE("GPL v2" ); |
124 | MODULE_DESCRIPTION("dummy_stm device" ); |
125 | MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>" ); |
126 | |