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Linux/drivers/watchdog/ux500_wdt.c

  1 /*
  2  * Copyright (C) ST-Ericsson SA 2011-2013
  3  *
  4  * License Terms: GNU General Public License v2
  5  *
  6  * Author: Mathieu Poirier <mathieu.poirier@linaro.org> for ST-Ericsson
  7  * Author: Jonas Aaberg <jonas.aberg@stericsson.com> for ST-Ericsson
  8  */
  9 
 10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 11 
 12 #include <linux/module.h>
 13 #include <linux/kernel.h>
 14 #include <linux/moduleparam.h>
 15 #include <linux/err.h>
 16 #include <linux/uaccess.h>
 17 #include <linux/watchdog.h>
 18 #include <linux/platform_device.h>
 19 #include <linux/platform_data/ux500_wdt.h>
 20 
 21 #include <linux/mfd/dbx500-prcmu.h>
 22 
 23 #define WATCHDOG_TIMEOUT 600 /* 10 minutes */
 24 
 25 #define WATCHDOG_MIN    0
 26 #define WATCHDOG_MAX28  268435  /* 28 bit resolution in ms == 268435.455 s */
 27 #define WATCHDOG_MAX32  4294967 /* 32 bit resolution in ms == 4294967.295 s */
 28 
 29 static unsigned int timeout = WATCHDOG_TIMEOUT;
 30 module_param(timeout, uint, 0);
 31 MODULE_PARM_DESC(timeout,
 32         "Watchdog timeout in seconds. default="
 33                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
 34 
 35 static bool nowayout = WATCHDOG_NOWAYOUT;
 36 module_param(nowayout, bool, 0);
 37 MODULE_PARM_DESC(nowayout,
 38         "Watchdog cannot be stopped once started (default="
 39                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 40 
 41 static int ux500_wdt_start(struct watchdog_device *wdd)
 42 {
 43         return prcmu_enable_a9wdog(PRCMU_WDOG_ALL);
 44 }
 45 
 46 static int ux500_wdt_stop(struct watchdog_device *wdd)
 47 {
 48         return prcmu_disable_a9wdog(PRCMU_WDOG_ALL);
 49 }
 50 
 51 static int ux500_wdt_keepalive(struct watchdog_device *wdd)
 52 {
 53         return prcmu_kick_a9wdog(PRCMU_WDOG_ALL);
 54 }
 55 
 56 static int ux500_wdt_set_timeout(struct watchdog_device *wdd,
 57                                  unsigned int timeout)
 58 {
 59         ux500_wdt_stop(wdd);
 60         prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
 61         ux500_wdt_start(wdd);
 62 
 63         return 0;
 64 }
 65 
 66 static const struct watchdog_info ux500_wdt_info = {
 67         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 68         .identity = "Ux500 WDT",
 69         .firmware_version = 1,
 70 };
 71 
 72 static const struct watchdog_ops ux500_wdt_ops = {
 73         .owner = THIS_MODULE,
 74         .start = ux500_wdt_start,
 75         .stop  = ux500_wdt_stop,
 76         .ping  = ux500_wdt_keepalive,
 77         .set_timeout = ux500_wdt_set_timeout,
 78 };
 79 
 80 static struct watchdog_device ux500_wdt = {
 81         .info = &ux500_wdt_info,
 82         .ops = &ux500_wdt_ops,
 83         .min_timeout = WATCHDOG_MIN,
 84         .max_timeout = WATCHDOG_MAX32,
 85 };
 86 
 87 static int ux500_wdt_probe(struct platform_device *pdev)
 88 {
 89         int ret;
 90         struct ux500_wdt_data *pdata = dev_get_platdata(&pdev->dev);
 91 
 92         if (pdata) {
 93                 if (pdata->timeout > 0)
 94                         timeout = pdata->timeout;
 95                 if (pdata->has_28_bits_resolution)
 96                         ux500_wdt.max_timeout = WATCHDOG_MAX28;
 97         }
 98 
 99         watchdog_set_nowayout(&ux500_wdt, nowayout);
100 
101         /* disable auto off on sleep */
102         prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
103 
104         /* set HW initial value */
105         prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
106 
107         ret = watchdog_register_device(&ux500_wdt);
108         if (ret)
109                 return ret;
110 
111         dev_info(&pdev->dev, "initialized\n");
112 
113         return 0;
114 }
115 
116 static int ux500_wdt_remove(struct platform_device *dev)
117 {
118         watchdog_unregister_device(&ux500_wdt);
119 
120         return 0;
121 }
122 
123 #ifdef CONFIG_PM
124 static int ux500_wdt_suspend(struct platform_device *pdev,
125                              pm_message_t state)
126 {
127         if (watchdog_active(&ux500_wdt)) {
128                 ux500_wdt_stop(&ux500_wdt);
129                 prcmu_config_a9wdog(PRCMU_WDOG_CPU1, true);
130 
131                 prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
132                 ux500_wdt_start(&ux500_wdt);
133         }
134         return 0;
135 }
136 
137 static int ux500_wdt_resume(struct platform_device *pdev)
138 {
139         if (watchdog_active(&ux500_wdt)) {
140                 ux500_wdt_stop(&ux500_wdt);
141                 prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
142 
143                 prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
144                 ux500_wdt_start(&ux500_wdt);
145         }
146         return 0;
147 }
148 #else
149 #define ux500_wdt_suspend NULL
150 #define ux500_wdt_resume NULL
151 #endif
152 
153 static struct platform_driver ux500_wdt_driver = {
154         .probe          = ux500_wdt_probe,
155         .remove         = ux500_wdt_remove,
156         .suspend        = ux500_wdt_suspend,
157         .resume         = ux500_wdt_resume,
158         .driver         = {
159                 .owner  = THIS_MODULE,
160                 .name   = "ux500_wdt",
161         },
162 };
163 
164 module_platform_driver(ux500_wdt_driver);
165 
166 MODULE_AUTHOR("Jonas Aaberg <jonas.aberg@stericsson.com>");
167 MODULE_DESCRIPTION("Ux500 Watchdog Driver");
168 MODULE_LICENSE("GPL");
169 MODULE_ALIAS("platform:ux500_wdt");
170 

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