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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/err.h>
 18 #include <linux/init.h>
 19 #include <linux/io.h>
 20 #include <linux/kernel.h>
 21 #include <linux/module.h>
 22 #include <linux/moduleparam.h>
 23 #include <linux/of.h>
 24 #include <linux/platform_device.h>
 25 #include <linux/types.h>
 26 #include <linux/watchdog.h>
 27 
 28 #define WDT_MAX_TIMEOUT         16
 29 #define WDT_MIN_TIMEOUT         1
 30 #define WDT_MODE_TIMEOUT(n)     ((n) << 3)
 31 #define WDT_TIMEOUT_MASK        WDT_MODE_TIMEOUT(0x0F)
 32 
 33 #define WDT_CTRL                0x00
 34 #define WDT_CTRL_RELOAD         ((1 << 0) | (0x0a57 << 1))
 35 
 36 #define WDT_MODE                0x04
 37 #define WDT_MODE_EN             (1 << 0)
 38 #define WDT_MODE_RST_EN         (1 << 1)
 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 struct sunxi_wdt_dev {
 47         struct watchdog_device wdt_dev;
 48         void __iomem *wdt_base;
 49 };
 50 
 51 /*
 52  * wdt_timeout_map maps the watchdog timer interval value in seconds to
 53  * the value of the register WDT_MODE bit 3:6
 54  *
 55  * [timeout seconds] = register value
 56  *
 57  */
 58 
 59 static const int wdt_timeout_map[] = {
 60         [1] = 0x1,  /* 1s  */
 61         [2] = 0x2,  /* 2s  */
 62         [3] = 0x3,  /* 3s  */
 63         [4] = 0x4,  /* 4s  */
 64         [5] = 0x5,  /* 5s  */
 65         [6] = 0x6,  /* 6s  */
 66         [8] = 0x7,  /* 8s  */
 67         [10] = 0x8, /* 10s */
 68         [12] = 0x9, /* 12s */
 69         [14] = 0xA, /* 14s */
 70         [16] = 0xB, /* 16s */
 71 };
 72 
 73 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
 74 {
 75         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 76         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 77 
 78         iowrite32(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL);
 79 
 80         return 0;
 81 }
 82 
 83 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
 84                 unsigned int timeout)
 85 {
 86         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
 87         void __iomem *wdt_base = sunxi_wdt->wdt_base;
 88         u32 reg;
 89 
 90         if (wdt_timeout_map[timeout] == 0)
 91                 timeout++;
 92 
 93         sunxi_wdt->wdt_dev.timeout = timeout;
 94 
 95         reg = ioread32(wdt_base + WDT_MODE);
 96         reg &= ~WDT_TIMEOUT_MASK;
 97         reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[timeout]);
 98         iowrite32(reg, wdt_base + WDT_MODE);
 99 
100         sunxi_wdt_ping(wdt_dev);
101 
102         return 0;
103 }
104 
105 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
106 {
107         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
108         void __iomem *wdt_base = sunxi_wdt->wdt_base;
109 
110         iowrite32(0, wdt_base + WDT_MODE);
111 
112         return 0;
113 }
114 
115 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
116 {
117         u32 reg;
118         struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
119         void __iomem *wdt_base = sunxi_wdt->wdt_base;
120         int ret;
121 
122         ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
123                         sunxi_wdt->wdt_dev.timeout);
124         if (ret < 0)
125                 return ret;
126 
127         reg = ioread32(wdt_base + WDT_MODE);
128         reg |= (WDT_MODE_RST_EN | WDT_MODE_EN);
129         iowrite32(reg, wdt_base + WDT_MODE);
130 
131         return 0;
132 }
133 
134 static const struct watchdog_info sunxi_wdt_info = {
135         .identity       = DRV_NAME,
136         .options        = WDIOF_SETTIMEOUT |
137                           WDIOF_KEEPALIVEPING |
138                           WDIOF_MAGICCLOSE,
139 };
140 
141 static const struct watchdog_ops sunxi_wdt_ops = {
142         .owner          = THIS_MODULE,
143         .start          = sunxi_wdt_start,
144         .stop           = sunxi_wdt_stop,
145         .ping           = sunxi_wdt_ping,
146         .set_timeout    = sunxi_wdt_set_timeout,
147 };
148 
149 static int sunxi_wdt_probe(struct platform_device *pdev)
150 {
151         struct sunxi_wdt_dev *sunxi_wdt;
152         struct resource *res;
153         int err;
154 
155         sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
156         if (!sunxi_wdt)
157                 return -EINVAL;
158 
159         platform_set_drvdata(pdev, sunxi_wdt);
160 
161         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
162         sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
163         if (IS_ERR(sunxi_wdt->wdt_base))
164                 return PTR_ERR(sunxi_wdt->wdt_base);
165 
166         sunxi_wdt->wdt_dev.info = &sunxi_wdt_info;
167         sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops;
168         sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT;
169         sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT;
170         sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT;
171         sunxi_wdt->wdt_dev.parent = &pdev->dev;
172 
173         watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev);
174         watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout);
175 
176         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
177 
178         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
179 
180         err = watchdog_register_device(&sunxi_wdt->wdt_dev);
181         if (unlikely(err))
182                 return err;
183 
184         dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
185                         sunxi_wdt->wdt_dev.timeout, nowayout);
186 
187         return 0;
188 }
189 
190 static int sunxi_wdt_remove(struct platform_device *pdev)
191 {
192         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
193 
194         watchdog_unregister_device(&sunxi_wdt->wdt_dev);
195         watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
196 
197         return 0;
198 }
199 
200 static void sunxi_wdt_shutdown(struct platform_device *pdev)
201 {
202         struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
203 
204         sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
205 }
206 
207 static const struct of_device_id sunxi_wdt_dt_ids[] = {
208         { .compatible = "allwinner,sun4i-a10-wdt" },
209         { /* sentinel */ }
210 };
211 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
212 
213 static struct platform_driver sunxi_wdt_driver = {
214         .probe          = sunxi_wdt_probe,
215         .remove         = sunxi_wdt_remove,
216         .shutdown       = sunxi_wdt_shutdown,
217         .driver         = {
218                 .owner          = THIS_MODULE,
219                 .name           = DRV_NAME,
220                 .of_match_table = sunxi_wdt_dt_ids,
221         },
222 };
223 
224 module_platform_driver(sunxi_wdt_driver);
225 
226 module_param(timeout, uint, 0);
227 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
228 
229 module_param(nowayout, bool, 0);
230 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
231                 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
232 
233 MODULE_LICENSE("GPL");
234 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
235 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
236 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
237 MODULE_VERSION(DRV_VERSION);
238 

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