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Linux/drivers/watchdog/sunxi_wdt.c

  1 /*
  2  *      sunxi Watchdog Driver
  3  *
  4  *      Copyright (c) 2013 Carlo Caione
  5  *                    2012 Henrik Nordstrom
  6  *
  7  *      This program is free software; you can redistribute it and/or
  8  *      modify it under the terms of the GNU General Public License
  9  *      as published by the Free Software Foundation; either version
 10  *      2 of the License, or (at your option) any later version.
 11  *
 12  *      Based on xen_wdt.c
 13  *      (c) Copyright 2010 Novell, Inc.
 14  */
 15 
 16 #include <linux/clk.h>
 17 #include <linux/delay.h>
 18 #include <linux/err.h>
 19 #include <linux/init.h>
 20 #include <linux/io.h>
 21 #include <linux/kernel.h>
 22 #include <linux/module.h>
 23 #include <linux/moduleparam.h>
 24 #include <linux/of.h>
 25 #include <linux/platform_device.h>
 26 #include <linux/reboot.h>
 27 #include <linux/types.h>
 28 #include <linux/watchdog.h>
 29 
 30 #include <asm/system_misc.h>
 31 
 32 #define WDT_MAX_TIMEOUT         16
 33 #define WDT_MIN_TIMEOUT         1
 34 #define WDT_MODE_TIMEOUT(n)     ((n) << 3)
 35 #define WDT_TIMEOUT_MASK        WDT_MODE_TIMEOUT(0x0F)
 36 
 37 #define WDT_CTRL                0x00
 38 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
 39 
 40 #define WDT_MODE                0x04
 41 #define WDT_MODE_EN             (1 << 0)
 42 #define WDT_MODE_RST_EN         (1 << 1)
 43 
 44 #define DRV_NAME                "sunxi-wdt"
 45 #define DRV_VERSION             "1.0"
 46 
 47 static bool nowayout = WATCHDOG_NOWAYOUT;
 48 static unsigned int timeout = WDT_MAX_TIMEOUT;
 49 
 50 struct sunxi_wdt_dev {
 51         struct watchdog_device wdt_dev;
 52         void __iomem *wdt_base;
 53 };
 54 
 55 /*
 56  * wdt_timeout_map maps the watchdog timer interval value in seconds to
 57  * the value of the register WDT_MODE bit 3:6
 58  *
 59  * [timeout seconds] = register value
 60  *
 61  */
 62 
 63 static const int wdt_timeout_map[] = {
 64         [1] = 0x1,  /* 1s  */
 65         [2] = 0x2,  /* 2s  */
 66         [3] = 0x3,  /* 3s  */
 67         [4] = 0x4,  /* 4s  */
 68         [5] = 0x5,  /* 5s  */
 69         [6] = 0x6,  /* 6s  */
 70         [8] = 0x7,  /* 8s  */
 71         [10] = 0x8, /* 10s */
 72         [12] = 0x9, /* 12s */
 73         [14] = 0xA, /* 14s */
 74         [16] = 0xB, /* 16s */
 75 };
 76 
 77 static void __iomem *reboot_wdt_base;
 78 
 79 static void sun4i_wdt_restart(enum reboot_mode mode, const char *cmd)
 80 {
 81         /* Enable timer and set reset bit in the watchdog */
 82         writel(WDT_MODE_EN | WDT_MODE_RST_EN, reboot_wdt_base + WDT_MODE);
 83 
 84         /*
 85          * Restart the watchdog. The default (and lowest) interval
 86          * value for the watchdog is 0.5s.
 87          */
 88         writel(WDT_CTRL_RELOAD, reboot_wdt_base + WDT_CTRL);
 89 
 90         while (1) {
 91                 mdelay(5);
 92                 writel(WDT_MODE_EN | WDT_MODE_RST_EN,
 93                        reboot_wdt_base + WDT_MODE);
 94         }
 95 }
 96 
 97 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
 98 {
 99         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
100         void __iomem *wdt_base = sunxi_wdt->wdt_base;
101 
102         iowrite32(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL);
103 
104         return 0;
105 }
106 
107 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
108                 unsigned int timeout)
109 {
110         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
111         void __iomem *wdt_base = sunxi_wdt->wdt_base;
112         u32 reg;
113 
114         if (wdt_timeout_map[timeout] == 0)
115                 timeout++;
116 
117         sunxi_wdt->wdt_dev.timeout = timeout;
118 
119         reg = ioread32(wdt_base + WDT_MODE);
120         reg &= ~WDT_TIMEOUT_MASK;
121         reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[timeout]);
122         iowrite32(reg, wdt_base + WDT_MODE);
123 
124         sunxi_wdt_ping(wdt_dev);
125 
126         return 0;
127 }
128 
129 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
130 {
131         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
132         void __iomem *wdt_base = sunxi_wdt->wdt_base;
133 
134         iowrite32(0, wdt_base + WDT_MODE);
135 
136         return 0;
137 }
138 
139 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
140 {
141         u32 reg;
142         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
143         void __iomem *wdt_base = sunxi_wdt->wdt_base;
144         int ret;
145 
146         ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
147                         sunxi_wdt->wdt_dev.timeout);
148         if (ret < 0)
149                 return ret;
150 
151         reg = ioread32(wdt_base + WDT_MODE);
152         reg |= (WDT_MODE_RST_EN | WDT_MODE_EN);
153         iowrite32(reg, wdt_base + WDT_MODE);
154 
155         return 0;
156 }
157 
158 static const struct watchdog_info sunxi_wdt_info = {
159         .identity       = DRV_NAME,
160         .options        = WDIOF_SETTIMEOUT |
161                           WDIOF_KEEPALIVEPING |
162                           WDIOF_MAGICCLOSE,
163 };
164 
165 static const struct watchdog_ops sunxi_wdt_ops = {
166         .owner          = THIS_MODULE,
167         .start          = sunxi_wdt_start,
168         .stop           = sunxi_wdt_stop,
169         .ping           = sunxi_wdt_ping,
170         .set_timeout    = sunxi_wdt_set_timeout,
171 };
172 
173 static int sunxi_wdt_probe(struct platform_device *pdev)
174 {
175         struct sunxi_wdt_dev *sunxi_wdt;
176         struct resource *res;
177         int err;
178 
179         sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
180         if (!sunxi_wdt)
181                 return -EINVAL;
182 
183         platform_set_drvdata(pdev, sunxi_wdt);
184 
185         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
186         sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
187         if (IS_ERR(sunxi_wdt->wdt_base))
188                 return PTR_ERR(sunxi_wdt->wdt_base);
189 
190         sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
191         sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
192         sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
193         sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
194         sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
195         sunxi_wdt->wdt_dev.parent = &pdev->dev;
196 
197         watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
198         watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
199 
200         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
201 
202         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
203 
204         err = watchdog_register_device(&sunxi_wdt->wdt_dev);
205         if (unlikely(err))
206                 return err;
207 
208         reboot_wdt_base = sunxi_wdt->wdt_base;
209         arm_pm_restart = sun4i_wdt_restart;
210 
211         dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
212                         sunxi_wdt->wdt_dev.timeout, nowayout);
213 
214         return 0;
215 }
216 
217 static int sunxi_wdt_remove(struct platform_device *pdev)
218 {
219         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
220 
221         arm_pm_restart = NULL;
222 
223         watchdog_unregister_device(&sunxi_wdt->wdt_dev);
224         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
225 
226         return 0;
227 }
228 
229 static void sunxi_wdt_shutdown(struct platform_device *pdev)
230 {
231         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
232 
233         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
234 }
235 
236 static const struct of_device_id sunxi_wdt_dt_ids[] = {
237         { .compatible = "allwinner,sun4i-a10-wdt" },
238         { /* sentinel */ }
239 };
240 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
241 
242 static struct platform_driver sunxi_wdt_driver = {
243         .probe          = sunxi_wdt_probe,
244         .remove         = sunxi_wdt_remove,
245         .shutdown       = sunxi_wdt_shutdown,
246         .driver         = {
247                 .owner          = THIS_MODULE,
248                 .name           = DRV_NAME,
249                 .of_match_table = sunxi_wdt_dt_ids,
250         },
251 };
252 
253 module_platform_driver(sunxi_wdt_driver);
254 
255 module_param(timeout, uint, 0);
256 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
257 
258 module_param(nowayout, bool, 0);
259 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
260                 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
261 
262 MODULE_LICENSE("GPL");
263 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
264 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
265 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
266 MODULE_VERSION(DRV_VERSION);
267 

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