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

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