1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Simple kernel driver to link kernel Ftrace and an STM device
 4 * Copyright (c) 2016, Linaro Ltd.
 
 
 
 
 
 
 
 
 
 5 *
 6 * STM Ftrace will be registered as a trace_export.
 7 */
 8
 9#include <linux/module.h>
10#include <linux/stm.h>
11#include <linux/trace.h>
12
13#define STM_FTRACE_NR_CHANNELS 1
14#define STM_FTRACE_CHAN 0
15
16static int stm_ftrace_link(struct stm_source_data *data);
17static void stm_ftrace_unlink(struct stm_source_data *data);
18
19static struct stm_ftrace {
20	struct stm_source_data	data;
21	struct trace_export	ftrace;
22} stm_ftrace = {
23	.data	= {
24		.name		= "ftrace",
25		.nr_chans	= STM_FTRACE_NR_CHANNELS,
26		.link		= stm_ftrace_link,
27		.unlink		= stm_ftrace_unlink,
28	},
29};
30
31/**
32 * stm_ftrace_write() - write data to STM via 'stm_ftrace' source
33 * @buf:	buffer containing the data packet
34 * @len:	length of the data packet
35 */
36static void notrace
37stm_ftrace_write(struct trace_export *export, const void *buf, unsigned int len)
38{
39	struct stm_ftrace *stm = container_of(export, struct stm_ftrace, ftrace);
40
41	stm_source_write(&stm->data, STM_FTRACE_CHAN, buf, len);
42}
43
44static int stm_ftrace_link(struct stm_source_data *data)
45{
46	struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data);
47
48	sf->ftrace.write = stm_ftrace_write;
49
50	return register_ftrace_export(&sf->ftrace);
51}
52
53static void stm_ftrace_unlink(struct stm_source_data *data)
54{
55	struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data);
56
57	unregister_ftrace_export(&sf->ftrace);
58}
59
60static int __init stm_ftrace_init(void)
61{
62	int ret;
63
64	ret = stm_source_register_device(NULL, &stm_ftrace.data);
65	if (ret)
66		pr_err("Failed to register stm_source - ftrace.\n");
67
68	return ret;
69}
70
71static void __exit stm_ftrace_exit(void)
72{
73	stm_source_unregister_device(&stm_ftrace.data);
74}
75
76module_init(stm_ftrace_init);
77module_exit(stm_ftrace_exit);
78
79MODULE_LICENSE("GPL v2");
80MODULE_DESCRIPTION("stm_ftrace driver");
81MODULE_AUTHOR("Chunyan Zhang <zhang.chunyan@linaro.org>");

 
 1/*
 2 * Simple kernel driver to link kernel Ftrace and an STM device
 3 * Copyright (c) 2016, Linaro Ltd.
 4 *
 5 * This program is free software; you can redistribute it and/or modify it
 6 * under the terms and conditions of the GNU General Public License,
 7 * version 2, as published by the Free Software Foundation.
 8 *
 9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12 * more details.
13 *
14 * STM Ftrace will be registered as a trace_export.
15 */
16
17#include <linux/module.h>
18#include <linux/stm.h>
19#include <linux/trace.h>
20
21#define STM_FTRACE_NR_CHANNELS 1
22#define STM_FTRACE_CHAN 0
23
24static int stm_ftrace_link(struct stm_source_data *data);
25static void stm_ftrace_unlink(struct stm_source_data *data);
26
27static struct stm_ftrace {
28	struct stm_source_data	data;
29	struct trace_export	ftrace;
30} stm_ftrace = {
31	.data	= {
32		.name		= "ftrace",
33		.nr_chans	= STM_FTRACE_NR_CHANNELS,
34		.link		= stm_ftrace_link,
35		.unlink		= stm_ftrace_unlink,
36	},
37};
38
39/**
40 * stm_ftrace_write() - write data to STM via 'stm_ftrace' source
41 * @buf:	buffer containing the data packet
42 * @len:	length of the data packet
43 */
44static void notrace
45stm_ftrace_write(struct trace_export *export, const void *buf, unsigned int len)
46{
47	struct stm_ftrace *stm = container_of(export, struct stm_ftrace, ftrace);
48
49	stm_source_write(&stm->data, STM_FTRACE_CHAN, buf, len);
50}
51
52static int stm_ftrace_link(struct stm_source_data *data)
53{
54	struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data);
55
56	sf->ftrace.write = stm_ftrace_write;
57
58	return register_ftrace_export(&sf->ftrace);
59}
60
61static void stm_ftrace_unlink(struct stm_source_data *data)
62{
63	struct stm_ftrace *sf = container_of(data, struct stm_ftrace, data);
64
65	unregister_ftrace_export(&sf->ftrace);
66}
67
68static int __init stm_ftrace_init(void)
69{
70	int ret;
71
72	ret = stm_source_register_device(NULL, &stm_ftrace.data);
73	if (ret)
74		pr_err("Failed to register stm_source - ftrace.\n");
75
76	return ret;
77}
78
79static void __exit stm_ftrace_exit(void)
80{
81	stm_source_unregister_device(&stm_ftrace.data);
82}
83
84module_init(stm_ftrace_init);
85module_exit(stm_ftrace_exit);
86
87MODULE_LICENSE("GPL v2");
88MODULE_DESCRIPTION("stm_ftrace driver");
89MODULE_AUTHOR("Chunyan Zhang <zhang.chunyan@linaro.org>");