blob: ca66e8e746357ecc71fad77e2d565afdd087079b [file] [log] [blame]
David Cohen87a1ef82014-04-15 13:06:05 -07001/*
2 * intel-mid_wdt: generic Intel MID SCU watchdog driver
3 *
4 * Platforms supported so far:
5 * - Merrifield only
6 *
7 * Copyright (C) 2014 Intel Corporation. All rights reserved.
8 * Contact: David Cohen <david.a.cohen@linux.intel.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of version 2 of the GNU General
12 * Public License as published by the Free Software Foundation.
13 */
14
15#include <linux/interrupt.h>
16#include <linux/module.h>
17#include <linux/nmi.h>
18#include <linux/platform_device.h>
19#include <linux/watchdog.h>
20#include <linux/platform_data/intel-mid_wdt.h>
21
22#include <asm/intel_scu_ipc.h>
23#include <asm/intel-mid.h>
24
25#define IPC_WATCHDOG 0xf8
26
27#define MID_WDT_PRETIMEOUT 15
28#define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT)
29#define MID_WDT_TIMEOUT_MAX 170
30#define MID_WDT_DEFAULT_TIMEOUT 90
31
32/* SCU watchdog messages */
33enum {
34 SCU_WATCHDOG_START = 0,
35 SCU_WATCHDOG_STOP,
36 SCU_WATCHDOG_KEEPALIVE,
37};
38
39static inline int wdt_command(int sub, u32 *in, int inlen)
40{
41 return intel_scu_ipc_command(IPC_WATCHDOG, sub, in, inlen, NULL, 0);
42}
43
44static int wdt_start(struct watchdog_device *wd)
45{
46 int ret, in_size;
47 int timeout = wd->timeout;
48 struct ipc_wd_start {
49 u32 pretimeout;
50 u32 timeout;
51 } ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout };
52
53 /*
54 * SCU expects the input size for watchdog IPC to
55 * be based on 4 bytes
56 */
57 in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4);
58
59 ret = wdt_command(SCU_WATCHDOG_START, (u32 *)&ipc_wd_start, in_size);
60 if (ret) {
61 struct device *dev = watchdog_get_drvdata(wd);
62 dev_crit(dev, "error starting watchdog: %d\n", ret);
63 }
64
65 return ret;
66}
67
68static int wdt_ping(struct watchdog_device *wd)
69{
70 int ret;
71
72 ret = wdt_command(SCU_WATCHDOG_KEEPALIVE, NULL, 0);
73 if (ret) {
74 struct device *dev = watchdog_get_drvdata(wd);
75 dev_crit(dev, "Error executing keepalive: 0x%x\n", ret);
76 }
77
78 return ret;
79}
80
81static int wdt_stop(struct watchdog_device *wd)
82{
83 int ret;
84
85 ret = wdt_command(SCU_WATCHDOG_STOP, NULL, 0);
86 if (ret) {
87 struct device *dev = watchdog_get_drvdata(wd);
88 dev_crit(dev, "Error stopping watchdog: 0x%x\n", ret);
89 }
90
91 return ret;
92}
93
94static irqreturn_t mid_wdt_irq(int irq, void *dev_id)
95{
96 panic("Kernel Watchdog");
97
98 /* This code should not be reached */
99 return IRQ_HANDLED;
100}
101
102static const struct watchdog_info mid_wdt_info = {
103 .identity = "Intel MID SCU watchdog",
104 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
105};
106
107static const struct watchdog_ops mid_wdt_ops = {
108 .owner = THIS_MODULE,
109 .start = wdt_start,
110 .stop = wdt_stop,
111 .ping = wdt_ping,
112};
113
114static int mid_wdt_probe(struct platform_device *pdev)
115{
116 struct watchdog_device *wdt_dev;
117 struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data;
118 int ret;
119
120 if (!pdata) {
121 dev_err(&pdev->dev, "missing platform data\n");
122 return -EINVAL;
123 }
124
125 if (pdata->probe) {
126 ret = pdata->probe(pdev);
127 if (ret)
128 return ret;
129 }
130
131 wdt_dev = devm_kzalloc(&pdev->dev, sizeof(*wdt_dev), GFP_KERNEL);
132 if (!wdt_dev)
133 return -ENOMEM;
134
135 wdt_dev->info = &mid_wdt_info;
136 wdt_dev->ops = &mid_wdt_ops;
137 wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN;
138 wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX;
139 wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT;
140
141 watchdog_set_drvdata(wdt_dev, &pdev->dev);
142 platform_set_drvdata(pdev, wdt_dev);
143
144 ret = devm_request_irq(&pdev->dev, pdata->irq, mid_wdt_irq,
145 IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog",
146 wdt_dev);
147 if (ret) {
148 dev_err(&pdev->dev, "error requesting warning irq %d\n",
149 pdata->irq);
150 return ret;
151 }
152
153 ret = watchdog_register_device(wdt_dev);
154 if (ret) {
155 dev_err(&pdev->dev, "error registering watchdog device\n");
156 return ret;
157 }
158
159 dev_info(&pdev->dev, "Intel MID watchdog device probed\n");
160
161 return 0;
162}
163
164static int mid_wdt_remove(struct platform_device *pdev)
165{
166 struct watchdog_device *wd = platform_get_drvdata(pdev);
167 watchdog_unregister_device(wd);
168 return 0;
169}
170
171static struct platform_driver mid_wdt_driver = {
172 .probe = mid_wdt_probe,
173 .remove = mid_wdt_remove,
174 .driver = {
175 .owner = THIS_MODULE,
176 .name = "intel_mid_wdt",
177 },
178};
179
180module_platform_driver(mid_wdt_driver);
181
182MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>");
183MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform");
184MODULE_LICENSE("GPL");