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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                              unsigned long action, void *data)
 88 {
 89         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 90         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 91         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
 92         u32 val;
 93 
 94         /* Set system reset function */
 95         val = readl(wdt_base + regs->wdt_cfg);
 96         val &= ~(regs->wdt_reset_mask);
 97         val |= regs->wdt_reset_val;
 98         writel(val, wdt_base + regs->wdt_cfg);
 99 
100         /* Set lowest timeout and enable watchdog */
101         val = readl(wdt_base + regs->wdt_mode);
102         val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
103         val |= WDT_MODE_EN;
104         writel(val, wdt_base + regs->wdt_mode);
105 
106         /*
107          * Restart the watchdog. The default (and lowest) interval
108          * value for the watchdog is 0.5s.
109          */
110         writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
111 
112         while (1) {
113                 mdelay(5);
114                 val = readl(wdt_base + regs->wdt_mode);
115                 val |= WDT_MODE_EN;
116                 writel(val, wdt_base + regs->wdt_mode);
117         }
118         return 0;
119 }
120 
121 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
122 {
123         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
124         void __iomem *wdt_base = sunxi_wdt->wdt_base;
125         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
126 
127         writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
128 
129         return 0;
130 }
131 
132 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
133                 unsigned int timeout)
134 {
135         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
136         void __iomem *wdt_base = sunxi_wdt->wdt_base;
137         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
138         u32 reg;
139 
140         if (wdt_timeout_map[timeout] == 0)
141                 timeout++;
142 
143         sunxi_wdt->wdt_dev.timeout = timeout;
144 
145         reg = readl(wdt_base + regs->wdt_mode);
146         reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
147         reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
148         writel(reg, wdt_base + regs->wdt_mode);
149 
150         sunxi_wdt_ping(wdt_dev);
151 
152         return 0;
153 }
154 
155 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
156 {
157         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
158         void __iomem *wdt_base = sunxi_wdt->wdt_base;
159         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
160 
161         writel(0, wdt_base + regs->wdt_mode);
162 
163         return 0;
164 }
165 
166 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
167 {
168         u32 reg;
169         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
170         void __iomem *wdt_base = sunxi_wdt->wdt_base;
171         const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
172         int ret;
173 
174         ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
175                         sunxi_wdt->wdt_dev.timeout);
176         if (ret < 0)
177                 return ret;
178 
179         /* Set system reset function */
180         reg = readl(wdt_base + regs->wdt_cfg);
181         reg &= ~(regs->wdt_reset_mask);
182         reg |= regs->wdt_reset_val;
183         writel(reg, wdt_base + regs->wdt_cfg);
184 
185         /* Enable watchdog */
186         reg = readl(wdt_base + regs->wdt_mode);
187         reg |= WDT_MODE_EN;
188         writel(reg, wdt_base + regs->wdt_mode);
189 
190         return 0;
191 }
192 
193 static const struct watchdog_info sunxi_wdt_info = {
194         .identity       = DRV_NAME,
195         .options        = WDIOF_SETTIMEOUT |
196                           WDIOF_KEEPALIVEPING |
197                           WDIOF_MAGICCLOSE,
198 };
199 
200 static const struct watchdog_ops sunxi_wdt_ops = {
201         .owner          = THIS_MODULE,
202         .start          = sunxi_wdt_start,
203         .stop           = sunxi_wdt_stop,
204         .ping           = sunxi_wdt_ping,
205         .set_timeout    = sunxi_wdt_set_timeout,
206         .restart        = sunxi_wdt_restart,
207 };
208 
209 static const struct sunxi_wdt_reg sun4i_wdt_reg = {
210         .wdt_ctrl = 0x00,
211         .wdt_cfg = 0x04,
212         .wdt_mode = 0x04,
213         .wdt_timeout_shift = 3,
214         .wdt_reset_mask = 0x02,
215         .wdt_reset_val = 0x02,
216 };
217 
218 static const struct sunxi_wdt_reg sun6i_wdt_reg = {
219         .wdt_ctrl = 0x10,
220         .wdt_cfg = 0x14,
221         .wdt_mode = 0x18,
222         .wdt_timeout_shift = 4,
223         .wdt_reset_mask = 0x03,
224         .wdt_reset_val = 0x01,
225 };
226 
227 static const struct of_device_id sunxi_wdt_dt_ids[] = {
228         { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg },
229         { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg },
230         { /* sentinel */ }
231 };
232 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
233 
234 static int sunxi_wdt_probe(struct platform_device *pdev)
235 {
236         struct sunxi_wdt_dev *sunxi_wdt;
237         const struct of_device_id *device;
238         struct resource *res;
239         int err;
240 
241         sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
242         if (!sunxi_wdt)
243                 return -EINVAL;
244 
245         platform_set_drvdata(pdev, sunxi_wdt);
246 
247         device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev);
248         if (!device)
249                 return -ENODEV;
250 
251         sunxi_wdt->wdt_regs = device->data;
252 
253         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
254         sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
255         if (IS_ERR(sunxi_wdt->wdt_base))
256                 return PTR_ERR(sunxi_wdt->wdt_base);
257 
258         sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
259         sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
260         sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
261         sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
262         sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
263         sunxi_wdt->wdt_dev.parent = &pdev->dev;
264 
265         watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
266         watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
267         watchdog_set_restart_priority(&sunxi_wdt->wdt_dev, 128);
268 
269         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
270 
271         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
272 
273         err = watchdog_register_device(&sunxi_wdt->wdt_dev);
274         if (unlikely(err))
275                 return err;
276 
277         dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
278                         sunxi_wdt->wdt_dev.timeout, nowayout);
279 
280         return 0;
281 }
282 
283 static int sunxi_wdt_remove(struct platform_device *pdev)
284 {
285         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
286 
287         watchdog_unregister_device(&sunxi_wdt->wdt_dev);
288         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
289 
290         return 0;
291 }
292 
293 static void sunxi_wdt_shutdown(struct platform_device *pdev)
294 {
295         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
296 
297         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
298 }
299 
300 static struct platform_driver sunxi_wdt_driver = {
301         .probe          = sunxi_wdt_probe,
302         .remove         = sunxi_wdt_remove,
303         .shutdown       = sunxi_wdt_shutdown,
304         .driver         = {
305                 .name           = DRV_NAME,
306                 .of_match_table = sunxi_wdt_dt_ids,
307         },
308 };
309 
310 module_platform_driver(sunxi_wdt_driver);
311 
312 module_param(timeout, uint, 0);
313 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
314 
315 module_param(nowayout, bool, 0);
316 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
317                 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
318 
319 MODULE_LICENSE("GPL");
320 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
321 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
322 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
323 MODULE_VERSION(DRV_VERSION);
324 

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