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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/notifier.h>
 25 #include <linux/of.h>
 26 #include <linux/of_device.h>
 27 #include <linux/platform_device.h>
 28 #include <linux/reboot.h>
 29 #include <linux/types.h>
 30 #include <linux/watchdog.h>
 31 
 32 #define WDT_MAX_TIMEOUT         16
 33 #define WDT_MIN_TIMEOUT         1
 34 #define WDT_TIMEOUT_MASK        0x0F
 35 
 36 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
 37 
 38 #define WDT_MODE_EN             (1 << 0)
 39 
 40 #define DRV_NAME                "sunxi-wdt"
 41 #define DRV_VERSION             "1.0"
 42 
 43 static bool nowayout = WATCHDOG_NOWAYOUT;
 44 static unsigned int timeout = WDT_MAX_TIMEOUT;
 45 
 46 /*
 47  * This structure stores the register offsets for different variants
 48  * of Allwinner's watchdog hardware.
 49  */
 50 struct sunxi_wdt_reg {
 51         u8 wdt_ctrl;
 52         u8 wdt_cfg;
 53         u8 wdt_mode;
 54         u8 wdt_timeout_shift;
 55         u8 wdt_reset_mask;
 56         u8 wdt_reset_val;
 57 };
 58 
 59 struct sunxi_wdt_dev {
 60         struct watchdog_device wdt_dev;
 61         void __iomem *wdt_base;
 62         const struct sunxi_wdt_reg *wdt_regs;
 63         struct notifier_block restart_handler;
 64 };
 65 
 66 /*
 67  * wdt_timeout_map maps the watchdog timer interval value in seconds to
 68  * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3
 69  *
 70  * [timeout seconds] = register value
 71  *
 72  */
 73 
 74 static const int wdt_timeout_map[] = {
 75         [1] = 0x1,  /* 1s  */
 76         [2] = 0x2,  /* 2s  */
 77         [3] = 0x3,  /* 3s  */
 78         [4] = 0x4,  /* 4s  */
 79         [5] = 0x5,  /* 5s  */
 80         [6] = 0x6,  /* 6s  */
 81         [8] = 0x7,  /* 8s  */
 82         [10] = 0x8, /* 10s */
 83         [12] = 0x9, /* 12s */
 84         [14] = 0xA, /* 14s */
 85         [16] = 0xB, /* 16s */
 86 };
 87 
 88 
 89 static int sunxi_restart_handle(struct notifier_block *this, unsigned long mode,
 90                                 void *cmd)
 91 {
 92         struct sunxi_wdt_dev *sunxi_wdt = container_of(this,
 93                                                        struct sunxi_wdt_dev,
 94                                                        restart_handler);
 95         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 96         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 97         u32 val;
 98 
 99         /* Set system reset function */
100         val = readl(wdt_base + regs->wdt_cfg);
101         val &= ~(regs->wdt_reset_mask);
102         val |= regs->wdt_reset_val;
103         writel(val, wdt_base + regs->wdt_cfg);
104 
105         /* Set lowest timeout and enable watchdog */
106         val = readl(wdt_base + regs->wdt_mode);
107         val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
108         val |= WDT_MODE_EN;
109         writel(val, wdt_base + regs->wdt_mode);
110 
111         /*
112          * Restart the watchdog. The default (and lowest) interval
113          * value for the watchdog is 0.5s.
114          */
115         writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
116 
117         while (1) {
118                 mdelay(5);
119                 val = readl(wdt_base + regs->wdt_mode);
120                 val |= WDT_MODE_EN;
121                 writel(val, wdt_base + regs->wdt_mode);
122         }
123         return NOTIFY_DONE;
124 }
125 
126 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
127 {
128         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
129         void __iomem *wdt_base = sunxi_wdt->wdt_base;
130         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
131 
132         writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
133 
134         return 0;
135 }
136 
137 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
138                 unsigned int timeout)
139 {
140         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
141         void __iomem *wdt_base = sunxi_wdt->wdt_base;
142         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
143         u32 reg;
144 
145         if (wdt_timeout_map[timeout] == 0)
146                 timeout++;
147 
148         sunxi_wdt->wdt_dev.timeout = timeout;
149 
150         reg = readl(wdt_base + regs->wdt_mode);
151         reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
152         reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
153         writel(reg, wdt_base + regs->wdt_mode);
154 
155         sunxi_wdt_ping(wdt_dev);
156 
157         return 0;
158 }
159 
160 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
161 {
162         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
163         void __iomem *wdt_base = sunxi_wdt->wdt_base;
164         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
165 
166         writel(0, wdt_base + regs->wdt_mode);
167 
168         return 0;
169 }
170 
171 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
172 {
173         u32 reg;
174         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
175         void __iomem *wdt_base = sunxi_wdt->wdt_base;
176         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
177         int ret;
178 
179         ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
180                         sunxi_wdt->wdt_dev.timeout);
181         if (ret < 0)
182                 return ret;
183 
184         /* Set system reset function */
185         reg = readl(wdt_base + regs->wdt_cfg);
186         reg &= ~(regs->wdt_reset_mask);
187         reg |= ~(regs->wdt_reset_val);
188         writel(reg, wdt_base + regs->wdt_cfg);
189 
190         /* Enable watchdog */
191         reg = readl(wdt_base + regs->wdt_mode);
192         reg |= WDT_MODE_EN;
193         writel(reg, wdt_base + regs->wdt_mode);
194 
195         return 0;
196 }
197 
198 static const struct watchdog_info sunxi_wdt_info = {
199         .identity       = DRV_NAME,
200         .options        = WDIOF_SETTIMEOUT |
201                           WDIOF_KEEPALIVEPING |
202                           WDIOF_MAGICCLOSE,
203 };
204 
205 static const struct watchdog_ops sunxi_wdt_ops = {
206         .owner          = THIS_MODULE,
207         .start          = sunxi_wdt_start,
208         .stop           = sunxi_wdt_stop,
209         .ping           = sunxi_wdt_ping,
210         .set_timeout    = sunxi_wdt_set_timeout,
211 };
212 
213 static const struct sunxi_wdt_reg sun4i_wdt_reg = {
214         .wdt_ctrl = 0x00,
215         .wdt_cfg = 0x04,
216         .wdt_mode = 0x04,
217         .wdt_timeout_shift = 3,
218         .wdt_reset_mask = 0x02,
219         .wdt_reset_val = 0x02,
220 };
221 
222 static const struct sunxi_wdt_reg sun6i_wdt_reg = {
223         .wdt_ctrl = 0x10,
224         .wdt_cfg = 0x14,
225         .wdt_mode = 0x18,
226         .wdt_timeout_shift = 4,
227         .wdt_reset_mask = 0x03,
228         .wdt_reset_val = 0x01,
229 };
230 
231 static const struct of_device_id sunxi_wdt_dt_ids[] = {
232         { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg },
233         { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg },
234         { /* sentinel */ }
235 };
236 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
237 
238 static int sunxi_wdt_probe(struct platform_device *pdev)
239 {
240         struct sunxi_wdt_dev *sunxi_wdt;
241         const struct of_device_id *device;
242         struct resource *res;
243         int err;
244 
245         sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
246         if (!sunxi_wdt)
247                 return -EINVAL;
248 
249         platform_set_drvdata(pdev, sunxi_wdt);
250 
251         device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev);
252         if (!device)
253                 return -ENODEV;
254 
255         sunxi_wdt->wdt_regs = device->data;
256 
257         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
258         sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
259         if (IS_ERR(sunxi_wdt->wdt_base))
260                 return PTR_ERR(sunxi_wdt->wdt_base);
261 
262         sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
263         sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
264         sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
265         sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
266         sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
267         sunxi_wdt->wdt_dev.parent = &pdev->dev;
268 
269         watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
270         watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
271 
272         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
273 
274         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
275 
276         err = watchdog_register_device(&sunxi_wdt->wdt_dev);
277         if (unlikely(err))
278                 return err;
279 
280         sunxi_wdt->restart_handler.notifier_call = sunxi_restart_handle;
281         sunxi_wdt->restart_handler.priority = 128;
282         err = register_restart_handler(&sunxi_wdt->restart_handler);
283         if (err)
284                 dev_err(&pdev->dev,
285                         "cannot register restart handler (err=%d)\n", err);
286 
287         dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
288                         sunxi_wdt->wdt_dev.timeout, nowayout);
289 
290         return 0;
291 }
292 
293 static int sunxi_wdt_remove(struct platform_device *pdev)
294 {
295         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
296 
297         unregister_restart_handler(&sunxi_wdt->restart_handler);
298 
299         watchdog_unregister_device(&sunxi_wdt->wdt_dev);
300         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
301 
302         return 0;
303 }
304 
305 static void sunxi_wdt_shutdown(struct platform_device *pdev)
306 {
307         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
308 
309         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
310 }
311 
312 static struct platform_driver sunxi_wdt_driver = {
313         .probe          = sunxi_wdt_probe,
314         .remove         = sunxi_wdt_remove,
315         .shutdown       = sunxi_wdt_shutdown,
316         .driver         = {
317                 .owner          = THIS_MODULE,
318                 .name           = DRV_NAME,
319                 .of_match_table = sunxi_wdt_dt_ids,
320         },
321 };
322 
323 module_platform_driver(sunxi_wdt_driver);
324 
325 module_param(timeout, uint, 0);
326 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
327 
328 module_param(nowayout, bool, 0);
329 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
330                 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
331 
332 MODULE_LICENSE("GPL");
333 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
334 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
335 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
336 MODULE_VERSION(DRV_VERSION);
337 

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