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1/*
2 * Simple heartbeat STM source driver
3 * Copyright (c) 2016, Intel Corporation.
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 * Heartbeat STM source will send repetitive messages over STM devices to a
15 * trace host.
16 */
17
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/hrtimer.h>
21#include <linux/slab.h>
22#include <linux/stm.h>
23
24#define STM_HEARTBEAT_MAX 32
25
26static int nr_devs = 4;
27static int interval_ms = 10;
28
29module_param(nr_devs, int, 0600);
30module_param(interval_ms, int, 0600);
31
32static struct stm_heartbeat {
33 struct stm_source_data data;
34 struct hrtimer hrtimer;
35 unsigned int active;
36} stm_heartbeat[STM_HEARTBEAT_MAX];
37
38static unsigned int nr_instances;
39
40static const char str[] = "heartbeat stm source driver is here to serve you";
41
42static enum hrtimer_restart stm_heartbeat_hrtimer_handler(struct hrtimer *hr)
43{
44 struct stm_heartbeat *heartbeat = container_of(hr, struct stm_heartbeat,
45 hrtimer);
46
47 stm_source_write(&heartbeat->data, 0, str, sizeof str);
48 if (heartbeat->active)
49 hrtimer_forward_now(hr, ms_to_ktime(interval_ms));
50
51 return heartbeat->active ? HRTIMER_RESTART : HRTIMER_NORESTART;
52}
53
54static int stm_heartbeat_link(struct stm_source_data *data)
55{
56 struct stm_heartbeat *heartbeat =
57 container_of(data, struct stm_heartbeat, data);
58
59 heartbeat->active = 1;
60 hrtimer_start(&heartbeat->hrtimer, ms_to_ktime(interval_ms),
61 HRTIMER_MODE_ABS);
62
63 return 0;
64}
65
66static void stm_heartbeat_unlink(struct stm_source_data *data)
67{
68 struct stm_heartbeat *heartbeat =
69 container_of(data, struct stm_heartbeat, data);
70
71 heartbeat->active = 0;
72 hrtimer_cancel(&heartbeat->hrtimer);
73}
74
75static int stm_heartbeat_init(void)
76{
77 int i, ret = -ENOMEM, __nr_instances = ACCESS_ONCE(nr_devs);
78
79 if (__nr_instances < 0 || __nr_instances > STM_HEARTBEAT_MAX)
80 return -EINVAL;
81
82 for (i = 0; i < __nr_instances; i++) {
83 stm_heartbeat[i].data.name =
84 kasprintf(GFP_KERNEL, "heartbeat.%d", i);
85 if (!stm_heartbeat[i].data.name)
86 goto fail_unregister;
87
88 stm_heartbeat[i].data.nr_chans = 1;
89 stm_heartbeat[i].data.link = stm_heartbeat_link;
90 stm_heartbeat[i].data.unlink = stm_heartbeat_unlink;
91 hrtimer_init(&stm_heartbeat[i].hrtimer, CLOCK_MONOTONIC,
92 HRTIMER_MODE_ABS);
93 stm_heartbeat[i].hrtimer.function =
94 stm_heartbeat_hrtimer_handler;
95
96 ret = stm_source_register_device(NULL, &stm_heartbeat[i].data);
97 if (ret)
98 goto fail_free;
99 }
100
101 nr_instances = __nr_instances;
102
103 return 0;
104
105fail_unregister:
106 for (i--; i >= 0; i--) {
107 stm_source_unregister_device(&stm_heartbeat[i].data);
108fail_free:
109 kfree(stm_heartbeat[i].data.name);
110 }
111
112 return ret;
113}
114
115static void stm_heartbeat_exit(void)
116{
117 int i;
118
119 for (i = 0; i < nr_instances; i++) {
120 stm_source_unregister_device(&stm_heartbeat[i].data);
121 kfree(stm_heartbeat[i].data.name);
122 }
123}
124
125module_init(stm_heartbeat_init);
126module_exit(stm_heartbeat_exit);
127
128MODULE_LICENSE("GPL v2");
129MODULE_DESCRIPTION("stm_heartbeat driver");
130MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Simple heartbeat STM source driver
4 * Copyright (c) 2016, Intel Corporation.
5 *
6 * Heartbeat STM source will send repetitive messages over STM devices to a
7 * trace host.
8 */
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/hrtimer.h>
13#include <linux/slab.h>
14#include <linux/stm.h>
15
16#define STM_HEARTBEAT_MAX 32
17
18static int nr_devs = 4;
19static int interval_ms = 10;
20
21module_param(nr_devs, int, 0400);
22module_param(interval_ms, int, 0600);
23
24static struct stm_heartbeat {
25 struct stm_source_data data;
26 struct hrtimer hrtimer;
27 unsigned int active;
28} stm_heartbeat[STM_HEARTBEAT_MAX];
29
30static const char str[] = "heartbeat stm source driver is here to serve you";
31
32static enum hrtimer_restart stm_heartbeat_hrtimer_handler(struct hrtimer *hr)
33{
34 struct stm_heartbeat *heartbeat = container_of(hr, struct stm_heartbeat,
35 hrtimer);
36
37 stm_source_write(&heartbeat->data, 0, str, sizeof str);
38 if (heartbeat->active)
39 hrtimer_forward_now(hr, ms_to_ktime(interval_ms));
40
41 return heartbeat->active ? HRTIMER_RESTART : HRTIMER_NORESTART;
42}
43
44static int stm_heartbeat_link(struct stm_source_data *data)
45{
46 struct stm_heartbeat *heartbeat =
47 container_of(data, struct stm_heartbeat, data);
48
49 heartbeat->active = 1;
50 hrtimer_start(&heartbeat->hrtimer, ms_to_ktime(interval_ms),
51 HRTIMER_MODE_ABS);
52
53 return 0;
54}
55
56static void stm_heartbeat_unlink(struct stm_source_data *data)
57{
58 struct stm_heartbeat *heartbeat =
59 container_of(data, struct stm_heartbeat, data);
60
61 heartbeat->active = 0;
62 hrtimer_cancel(&heartbeat->hrtimer);
63}
64
65static int stm_heartbeat_init(void)
66{
67 int i, ret;
68
69 if (nr_devs < 0 || nr_devs > STM_HEARTBEAT_MAX)
70 return -EINVAL;
71
72 for (i = 0; i < nr_devs; i++) {
73 stm_heartbeat[i].data.name =
74 kasprintf(GFP_KERNEL, "heartbeat.%d", i);
75 if (!stm_heartbeat[i].data.name) {
76 ret = -ENOMEM;
77 goto fail_unregister;
78 }
79
80 stm_heartbeat[i].data.nr_chans = 1;
81 stm_heartbeat[i].data.link = stm_heartbeat_link;
82 stm_heartbeat[i].data.unlink = stm_heartbeat_unlink;
83 hrtimer_init(&stm_heartbeat[i].hrtimer, CLOCK_MONOTONIC,
84 HRTIMER_MODE_ABS);
85 stm_heartbeat[i].hrtimer.function =
86 stm_heartbeat_hrtimer_handler;
87
88 ret = stm_source_register_device(NULL, &stm_heartbeat[i].data);
89 if (ret)
90 goto fail_free;
91 }
92
93 return 0;
94
95fail_unregister:
96 for (i--; i >= 0; i--) {
97 stm_source_unregister_device(&stm_heartbeat[i].data);
98fail_free:
99 kfree(stm_heartbeat[i].data.name);
100 }
101
102 return ret;
103}
104
105static void stm_heartbeat_exit(void)
106{
107 int i;
108
109 for (i = 0; i < nr_devs; i++) {
110 stm_source_unregister_device(&stm_heartbeat[i].data);
111 kfree(stm_heartbeat[i].data.name);
112 }
113}
114
115module_init(stm_heartbeat_init);
116module_exit(stm_heartbeat_exit);
117
118MODULE_LICENSE("GPL v2");
119MODULE_DESCRIPTION("stm_heartbeat driver");
120MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");