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
43static bool nowayout = WATCHDOG_NOWAYOUT;
44static 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 */
50struct 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
59struct 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
74static 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
89static 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
126static 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
137static 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
160static 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
171static 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
198static const struct watchdog_info sunxi_wdt_info = {
199	.identity	= DRV_NAME,
200	.options	= WDIOF_SETTIMEOUT |
201			  WDIOF_KEEPALIVEPING |
202			  WDIOF_MAGICCLOSE,
203};
204
205static 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
213static 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
222static 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
231static 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};
236MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
237
238static 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
293static 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
305static 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
312static struct platform_driver sunxi_wdt_driver = {
313	.probe		= sunxi_wdt_probe,
314	.remove		= sunxi_wdt_remove,
315	.shutdown	= sunxi_wdt_shutdown,
316	.driver		= {
317		.name		= DRV_NAME,
318		.of_match_table	= sunxi_wdt_dt_ids,
319	},
320};
321
322module_platform_driver(sunxi_wdt_driver);
323
324module_param(timeout, uint, 0);
325MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");
326
327module_param(nowayout, bool, 0);
328MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
329		"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
330
331MODULE_LICENSE("GPL");
332MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>");
333MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>");
334MODULE_DESCRIPTION("sunxi WatchDog Timer Driver");
335MODULE_VERSION(DRV_VERSION);
336