2 * sunxi Watchdog Driver
4 * Copyright (c) 2013 Carlo Caione
5 * 2012 Henrik Nordstrom
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.
13 * (c) Copyright 2010 Novell, Inc.
16 #include <linux/clk.h>
17 #include <linux/delay.h>
18 #include <linux/err.h>
19 #include <linux/init.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
25 #include <linux/of_device.h>
26 #include <linux/platform_device.h>
27 #include <linux/types.h>
28 #include <linux/watchdog.h>
30 #define WDT_MAX_TIMEOUT 16
31 #define WDT_MIN_TIMEOUT 1
32 #define WDT_TIMEOUT_MASK 0x0F
34 #define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1))
36 #define WDT_MODE_EN (1 << 0)
38 #define DRV_NAME "sunxi-wdt"
39 #define DRV_VERSION "1.0"
41 static bool nowayout = WATCHDOG_NOWAYOUT;
42 static unsigned int timeout = WDT_MAX_TIMEOUT;
45 * This structure stores the register offsets for different variants
46 * of Allwinner's watchdog hardware.
48 struct sunxi_wdt_reg {
57 struct sunxi_wdt_dev {
58 struct watchdog_device wdt_dev;
59 void __iomem *wdt_base;
60 const struct sunxi_wdt_reg *wdt_regs;
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
67 * [timeout seconds] = register value
71 static const int wdt_timeout_map[] = {
86 static int sunxi_wdt_restart(struct watchdog_device *wdt_dev)
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;
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);
99 /* Set lowest timeout and enable watchdog */
100 val = readl(wdt_base + regs->wdt_mode);
101 val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
103 writel(val, wdt_base + regs->wdt_mode);
106 * Restart the watchdog. The default (and lowest) interval
107 * value for the watchdog is 0.5s.
109 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
113 val = readl(wdt_base + regs->wdt_mode);
115 writel(val, wdt_base + regs->wdt_mode);
120 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev)
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;
126 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
131 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev,
132 unsigned int timeout)
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;
139 if (wdt_timeout_map[timeout] == 0)
142 sunxi_wdt->wdt_dev.timeout = timeout;
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);
149 sunxi_wdt_ping(wdt_dev);
154 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev)
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;
160 writel(0, wdt_base + regs->wdt_mode);
165 static int sunxi_wdt_start(struct watchdog_device *wdt_dev)
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;
173 ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
174 sunxi_wdt->wdt_dev.timeout);
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);
184 /* Enable watchdog */
185 reg = readl(wdt_base + regs->wdt_mode);
187 writel(reg, wdt_base + regs->wdt_mode);
192 static const struct watchdog_info sunxi_wdt_info = {
193 .identity = DRV_NAME,
194 .options = WDIOF_SETTIMEOUT |
195 WDIOF_KEEPALIVEPING |
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,
208 static const struct sunxi_wdt_reg sun4i_wdt_reg = {
212 .wdt_timeout_shift = 3,
213 .wdt_reset_mask = 0x02,
214 .wdt_reset_val = 0x02,
217 static const struct sunxi_wdt_reg sun6i_wdt_reg = {
221 .wdt_timeout_shift = 4,
222 .wdt_reset_mask = 0x03,
223 .wdt_reset_val = 0x01,
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 },
231 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
233 static int sunxi_wdt_probe(struct platform_device *pdev)
235 struct sunxi_wdt_dev *sunxi_wdt;
236 const struct of_device_id *device;
237 struct resource *res;
240 sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL);
244 platform_set_drvdata(pdev, sunxi_wdt);
246 device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev);
250 sunxi_wdt->wdt_regs = device->data;
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);
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;
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);
268 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt);
270 sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
272 err = watchdog_register_device(&sunxi_wdt->wdt_dev);
276 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",
277 sunxi_wdt->wdt_dev.timeout, nowayout);
282 static int sunxi_wdt_remove(struct platform_device *pdev)
284 struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
286 watchdog_unregister_device(&sunxi_wdt->wdt_dev);
287 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL);
292 static void sunxi_wdt_shutdown(struct platform_device *pdev)
294 struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev);
296 sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
299 static struct platform_driver sunxi_wdt_driver = {
300 .probe = sunxi_wdt_probe,
301 .remove = sunxi_wdt_remove,
302 .shutdown = sunxi_wdt_shutdown,
305 .of_match_table = sunxi_wdt_dt_ids,
309 module_platform_driver(sunxi_wdt_driver);
311 module_param(timeout, uint, 0);
312 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
314 module_param(nowayout, bool, 0);
315 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
316 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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);