1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* intel-mid_wdt: generic Intel MID SCU watchdog driver
*
* Platforms supported so far:
* - Merrifield only
*
* Copyright (C) 2014 Intel Corporation. All rights reserved.
* Contact: David Cohen <david.a.cohen@linux.intel.com>
*/
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/nmi.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#include <linux/platform_data/intel-mid_wdt.h>
#include <asm/intel_scu_ipc.h>
#include <asm/intel-mid.h>
#define IPC_WATCHDOG 0xf8
#define MID_WDT_PRETIMEOUT 15
#define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT)
#define MID_WDT_TIMEOUT_MAX 170
#define MID_WDT_DEFAULT_TIMEOUT 90
/* SCU watchdog messages */
enum {
SCU_WATCHDOG_START = 0,
SCU_WATCHDOG_STOP,
SCU_WATCHDOG_KEEPALIVE,
};
struct mid_wdt {
struct watchdog_device wd;
struct device *dev;
struct intel_scu_ipc_dev *scu;
};
static inline int
wdt_command(struct mid_wdt *mid, int sub, const void *in, size_t inlen, size_t size)
{
struct intel_scu_ipc_dev *scu = mid->scu;
return intel_scu_ipc_dev_command_with_size(scu, IPC_WATCHDOG, sub, in,
inlen, size, NULL, 0);
}
static int wdt_start(struct watchdog_device *wd)
{
struct mid_wdt *mid = watchdog_get_drvdata(wd);
int ret, in_size;
int timeout = wd->timeout;
struct ipc_wd_start {
u32 pretimeout;
u32 timeout;
} ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout };
/*
* SCU expects the input size for watchdog IPC to be 2 which is the
* size of the structure in dwords. SCU IPC normally takes bytes
* but this is a special case where we specify size to be different
* than inlen.
*/
in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);
ret = wdt_command(mid, SCU_WATCHDOG_START, &ipc_wd_start,
sizeof(ipc_wd_start), in_size);
if (ret)
dev_crit(mid->dev, "error starting watchdog: %d\n", ret);
return ret;
}
static int wdt_ping(struct watchdog_device *wd)
{
struct mid_wdt *mid = watchdog_get_drvdata(wd);
int ret;
ret = wdt_command(mid, SCU_WATCHDOG_KEEPALIVE, NULL, 0, 0);
if (ret)
dev_crit(mid->dev, "Error executing keepalive: %d\n", ret);
return ret;
}
static int wdt_stop(struct watchdog_device *wd)
{
struct mid_wdt *mid = watchdog_get_drvdata(wd);
int ret;
ret = wdt_command(mid, SCU_WATCHDOG_STOP, NULL, 0, 0);
if (ret)
dev_crit(mid->dev, "Error stopping watchdog: %d\n", ret);
return ret;
}
static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
{
panic("Kernel Watchdog");
/* This code should not be reached */
return IRQ_HANDLED;
}
static const struct watchdog_info mid_wdt_info = {
.identity = "Intel MID SCU watchdog",
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops mid_wdt_ops = {
.owner = THIS_MODULE,
.start = wdt_start,
.stop = wdt_stop,
.ping = wdt_ping,
};
static int mid_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct watchdog_device *wdt_dev;
struct intel_mid_wdt_pdata *pdata = dev->platform_data;
struct mid_wdt *mid;
int ret;
if (!pdata) {
dev_err(dev, "missing platform data\n");
return -EINVAL;
}
if (pdata->probe) {
ret = pdata->probe(pdev);
if (ret)
return ret;
}
mid = devm_kzalloc(dev, sizeof(*mid), GFP_KERNEL);
if (!mid)
return -ENOMEM;
mid->dev = dev;
wdt_dev = &mid->wd;
wdt_dev->info = &mid_wdt_info;
wdt_dev->ops = &mid_wdt_ops;
wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN;
wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX;
wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT;
wdt_dev->parent = dev;
watchdog_set_nowayout(wdt_dev, WATCHDOG_NOWAYOUT);
watchdog_set_drvdata(wdt_dev, mid);
mid->scu = devm_intel_scu_ipc_dev_get(dev);
if (!mid->scu)
return -EPROBE_DEFER;
ret = devm_request_irq(dev, pdata->irq, mid_wdt_irq,
IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
wdt_dev);
if (ret) {
dev_err(dev, "error requesting warning irq %d\n", pdata->irq);
return ret;
}
/*
* The firmware followed by U-Boot leaves the watchdog running
* with the default threshold which may vary. When we get here
* we should make a decision to prevent any side effects before
* user space daemon will take care of it. The best option,
* taking into consideration that there is no way to read values
* back from hardware, is to enforce watchdog being run with
* deterministic values.
*/
ret = wdt_start(wdt_dev);
if (ret)
return ret;
/* Make sure the watchdog is serviced */
set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
ret = devm_watchdog_register_device(dev, wdt_dev);
if (ret)
return ret;
dev_info(dev, "Intel MID watchdog device probed\n");
return 0;
}
static struct platform_driver mid_wdt_driver = {
.probe = mid_wdt_probe,
.driver = {
.name = "intel_mid_wdt",
},
};
module_platform_driver(mid_wdt_driver);
MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>");
MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
MODULE_LICENSE("GPL");
|
