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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 | { | |
bb790362 | 46 | struct device *dev = watchdog_get_drvdata(wd); |
87a1ef80 DC |
47 | int ret, in_size; |
48 | int timeout = wd->timeout; | |
49 | struct ipc_wd_start { | |
50 | u32 pretimeout; | |
51 | u32 timeout; | |
52 | } ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout }; | |
53 | ||
54 | /* | |
55 | * SCU expects the input size for watchdog IPC to | |
56 | * be based on 4 bytes | |
57 | */ | |
58 | in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4); | |
59 | ||
60 | ret = wdt_command(SCU_WATCHDOG_START, (u32 *)&ipc_wd_start, in_size); | |
bb790362 | 61 | if (ret) |
87a1ef80 | 62 | dev_crit(dev, "error starting watchdog: %d\n", ret); |
87a1ef80 DC |
63 | |
64 | return ret; | |
65 | } | |
66 | ||
67 | static int wdt_ping(struct watchdog_device *wd) | |
68 | { | |
bb790362 | 69 | struct device *dev = watchdog_get_drvdata(wd); |
87a1ef80 DC |
70 | int ret; |
71 | ||
72 | ret = wdt_command(SCU_WATCHDOG_KEEPALIVE, NULL, 0); | |
bb790362 AS |
73 | if (ret) |
74 | dev_crit(dev, "Error executing keepalive: %d\n", ret); | |
87a1ef80 DC |
75 | |
76 | return ret; | |
77 | } | |
78 | ||
79 | static int wdt_stop(struct watchdog_device *wd) | |
80 | { | |
bb790362 | 81 | struct device *dev = watchdog_get_drvdata(wd); |
87a1ef80 DC |
82 | int ret; |
83 | ||
84 | ret = wdt_command(SCU_WATCHDOG_STOP, NULL, 0); | |
bb790362 AS |
85 | if (ret) |
86 | dev_crit(dev, "Error stopping watchdog: %d\n", ret); | |
87a1ef80 DC |
87 | |
88 | return ret; | |
89 | } | |
90 | ||
91 | static irqreturn_t mid_wdt_irq(int irq, void *dev_id) | |
92 | { | |
93 | panic("Kernel Watchdog"); | |
94 | ||
95 | /* This code should not be reached */ | |
96 | return IRQ_HANDLED; | |
97 | } | |
98 | ||
99 | static const struct watchdog_info mid_wdt_info = { | |
100 | .identity = "Intel MID SCU watchdog", | |
8cbb97ea | 101 | .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, |
87a1ef80 DC |
102 | }; |
103 | ||
104 | static const struct watchdog_ops mid_wdt_ops = { | |
105 | .owner = THIS_MODULE, | |
106 | .start = wdt_start, | |
107 | .stop = wdt_stop, | |
108 | .ping = wdt_ping, | |
109 | }; | |
110 | ||
111 | static int mid_wdt_probe(struct platform_device *pdev) | |
112 | { | |
113 | struct watchdog_device *wdt_dev; | |
114 | struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data; | |
115 | int ret; | |
116 | ||
117 | if (!pdata) { | |
118 | dev_err(&pdev->dev, "missing platform data\n"); | |
119 | return -EINVAL; | |
120 | } | |
121 | ||
122 | if (pdata->probe) { | |
123 | ret = pdata->probe(pdev); | |
124 | if (ret) | |
125 | return ret; | |
126 | } | |
127 | ||
128 | wdt_dev = devm_kzalloc(&pdev->dev, sizeof(*wdt_dev), GFP_KERNEL); | |
129 | if (!wdt_dev) | |
130 | return -ENOMEM; | |
131 | ||
132 | wdt_dev->info = &mid_wdt_info; | |
133 | wdt_dev->ops = &mid_wdt_ops; | |
134 | wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN; | |
135 | wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX; | |
136 | wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT; | |
6551881c | 137 | wdt_dev->parent = &pdev->dev; |
87a1ef80 DC |
138 | |
139 | watchdog_set_drvdata(wdt_dev, &pdev->dev); | |
87a1ef80 DC |
140 | |
141 | ret = devm_request_irq(&pdev->dev, pdata->irq, mid_wdt_irq, | |
142 | IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog", | |
143 | wdt_dev); | |
144 | if (ret) { | |
145 | dev_err(&pdev->dev, "error requesting warning irq %d\n", | |
146 | pdata->irq); | |
147 | return ret; | |
148 | } | |
149 | ||
954351e8 AS |
150 | /* |
151 | * The firmware followed by U-Boot leaves the watchdog running | |
152 | * with the default threshold which may vary. When we get here | |
153 | * we should make a decision to prevent any side effects before | |
154 | * user space daemon will take care of it. The best option, | |
155 | * taking into consideration that there is no way to read values | |
156 | * back from hardware, is to enforce watchdog being run with | |
157 | * deterministic values. | |
158 | */ | |
159 | ret = wdt_start(wdt_dev); | |
160 | if (ret) | |
161 | return ret; | |
162 | ||
163 | /* Make sure the watchdog is serviced */ | |
164 | set_bit(WDOG_HW_RUNNING, &wdt_dev->status); | |
31ecad65 | 165 | |
396164b7 | 166 | ret = devm_watchdog_register_device(&pdev->dev, wdt_dev); |
87a1ef80 DC |
167 | if (ret) { |
168 | dev_err(&pdev->dev, "error registering watchdog device\n"); | |
169 | return ret; | |
170 | } | |
171 | ||
172 | dev_info(&pdev->dev, "Intel MID watchdog device probed\n"); | |
173 | ||
174 | return 0; | |
175 | } | |
176 | ||
87a1ef80 DC |
177 | static struct platform_driver mid_wdt_driver = { |
178 | .probe = mid_wdt_probe, | |
87a1ef80 | 179 | .driver = { |
87a1ef80 DC |
180 | .name = "intel_mid_wdt", |
181 | }, | |
182 | }; | |
183 | ||
184 | module_platform_driver(mid_wdt_driver); | |
185 | ||
186 | MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>"); | |
187 | MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform"); | |
188 | MODULE_LICENSE("GPL"); |