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87a1ef80 DC |
1 | /* |
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 */ | |
33 | enum { | |
34 | SCU_WATCHDOG_START = 0, | |
35 | SCU_WATCHDOG_STOP, | |
36 | SCU_WATCHDOG_KEEPALIVE, | |
37 | }; | |
38 | ||
39 | static 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 | ||
44 | static 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 | ||
68 | static 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 | ||
81 | static 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 | ||
94 | static 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 | ||
102 | static const struct watchdog_info mid_wdt_info = { | |
103 | .identity = "Intel MID SCU watchdog", | |
104 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, | |
105 | }; | |
106 | ||
107 | static 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 | ||
114 | static 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 | ||
164 | static 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 | ||
171 | static struct platform_driver mid_wdt_driver = { | |
172 | .probe = mid_wdt_probe, | |
173 | .remove = mid_wdt_remove, | |
174 | .driver = { | |
87a1ef80 DC |
175 | .name = "intel_mid_wdt", |
176 | }, | |
177 | }; | |
178 | ||
179 | module_platform_driver(mid_wdt_driver); | |
180 | ||
181 | MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>"); | |
182 | MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform"); | |
183 | MODULE_LICENSE("GPL"); |