1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * RDC321x watchdog driver
4 *
5 * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
6 *
7 * This driver is highly inspired from the cpu5_wdt driver
8 */
9
10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/types.h>
13#include <linux/errno.h>
14#include <linux/miscdevice.h>
15#include <linux/fs.h>
16#include <linux/ioport.h>
17#include <linux/timer.h>
18#include <linux/completion.h>
19#include <linux/jiffies.h>
20#include <linux/platform_device.h>
21#include <linux/watchdog.h>
22#include <linux/io.h>
23#include <linux/uaccess.h>
24#include <linux/mfd/rdc321x.h>
25
26#define RDC_WDT_MASK	0x80000000 /* Mask */
27#define RDC_WDT_EN	0x00800000 /* Enable bit */
28#define RDC_WDT_WTI	0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
29#define RDC_WDT_RST	0x00100000 /* Reset bit */
30#define RDC_WDT_WIF	0x00040000 /* WDT IRQ Flag */
31#define RDC_WDT_IRT	0x00000100 /* IRQ Routing table */
32#define RDC_WDT_CNT	0x00000001 /* WDT count */
33
34#define RDC_CLS_TMR	0x80003844 /* Clear timer */
35
36#define RDC_WDT_INTERVAL	(HZ/10+1)
37
38static int ticks = 1000;
39
40/* some device data */
41
42static struct {
43	struct completion stop;
44	int running;
45	struct timer_list timer;
46	int queue;
47	int default_ticks;
48	unsigned long inuse;
49	spinlock_t lock;
50	struct pci_dev *sb_pdev;
51	int base_reg;
52} rdc321x_wdt_device;
53
54/* generic helper functions */
55
56static void rdc321x_wdt_trigger(struct timer_list *unused)
57{
58	unsigned long flags;
59	u32 val;
60
61	if (rdc321x_wdt_device.running)
62		ticks--;
63
64	/* keep watchdog alive */
65	spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
66	pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
67					rdc321x_wdt_device.base_reg, &val);
68	val |= RDC_WDT_EN;
69	pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
70					rdc321x_wdt_device.base_reg, val);
71	spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
72
73	/* requeue?? */
74	if (rdc321x_wdt_device.queue && ticks)
75		mod_timer(&rdc321x_wdt_device.timer,
76				jiffies + RDC_WDT_INTERVAL);
77	else {
78		/* ticks doesn't matter anyway */
79		complete(&rdc321x_wdt_device.stop);
80	}
81
82}
83
84static void rdc321x_wdt_reset(void)
85{
86	ticks = rdc321x_wdt_device.default_ticks;
87}
88
89static void rdc321x_wdt_start(void)
90{
91	unsigned long flags;
92
93	if (!rdc321x_wdt_device.queue) {
94		rdc321x_wdt_device.queue = 1;
95
96		/* Clear the timer */
97		spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
98		pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
99				rdc321x_wdt_device.base_reg, RDC_CLS_TMR);
100
101		/* Enable watchdog and set the timeout to 81.92 us */
102		pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
103					rdc321x_wdt_device.base_reg,
104					RDC_WDT_EN | RDC_WDT_CNT);
105		spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
106
107		mod_timer(&rdc321x_wdt_device.timer,
108				jiffies + RDC_WDT_INTERVAL);
109	}
110
111	/* if process dies, counter is not decremented */
112	rdc321x_wdt_device.running++;
113}
114
115static int rdc321x_wdt_stop(void)
116{
117	if (rdc321x_wdt_device.running)
118		rdc321x_wdt_device.running = 0;
119
120	ticks = rdc321x_wdt_device.default_ticks;
121
122	return -EIO;
123}
124
125/* filesystem operations */
126static int rdc321x_wdt_open(struct inode *inode, struct file *file)
127{
128	if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
129		return -EBUSY;
130
131	return stream_open(inode, file);
132}
133
134static int rdc321x_wdt_release(struct inode *inode, struct file *file)
135{
136	clear_bit(0, &rdc321x_wdt_device.inuse);
137	return 0;
138}
139
140static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
141				unsigned long arg)
142{
143	void __user *argp = (void __user *)arg;
144	u32 value;
145	static const struct watchdog_info ident = {
146		.options = WDIOF_CARDRESET,
147		.identity = "RDC321x WDT",
148	};
149	unsigned long flags;
150
151	switch (cmd) {
152	case WDIOC_KEEPALIVE:
153		rdc321x_wdt_reset();
154		break;
155	case WDIOC_GETSTATUS:
156		/* Read the value from the DATA register */
157		spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
158		pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
159					rdc321x_wdt_device.base_reg, &value);
160		spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
161		if (copy_to_user(argp, &value, sizeof(u32)))
162			return -EFAULT;
163		break;
164	case WDIOC_GETSUPPORT:
165		if (copy_to_user(argp, &ident, sizeof(ident)))
166			return -EFAULT;
167		break;
168	case WDIOC_SETOPTIONS:
169		if (copy_from_user(&value, argp, sizeof(int)))
170			return -EFAULT;
171		switch (value) {
172		case WDIOS_ENABLECARD:
173			rdc321x_wdt_start();
174			break;
175		case WDIOS_DISABLECARD:
176			return rdc321x_wdt_stop();
177		default:
178			return -EINVAL;
179		}
180		break;
181	default:
182		return -ENOTTY;
183	}
184	return 0;
185}
186
187static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
188				size_t count, loff_t *ppos)
189{
190	if (!count)
191		return -EIO;
192
193	rdc321x_wdt_reset();
194
195	return count;
196}
197
198static const struct file_operations rdc321x_wdt_fops = {
199	.owner		= THIS_MODULE,
200	.llseek		= no_llseek,
201	.unlocked_ioctl	= rdc321x_wdt_ioctl,
202	.compat_ioctl	= compat_ptr_ioctl,
203	.open		= rdc321x_wdt_open,
204	.write		= rdc321x_wdt_write,
205	.release	= rdc321x_wdt_release,
206};
207
208static struct miscdevice rdc321x_wdt_misc = {
209	.minor	= WATCHDOG_MINOR,
210	.name	= "watchdog",
211	.fops	= &rdc321x_wdt_fops,
212};
213
214static int rdc321x_wdt_probe(struct platform_device *pdev)
215{
216	int err;
217	struct resource *r;
218	struct rdc321x_wdt_pdata *pdata;
219
220	pdata = dev_get_platdata(&pdev->dev);
221	if (!pdata) {
222		dev_err(&pdev->dev, "no platform data supplied\n");
223		return -ENODEV;
224	}
225
226	r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
227	if (!r) {
228		dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
229		return -ENODEV;
230	}
231
232	rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
233	rdc321x_wdt_device.base_reg = r->start;
234	rdc321x_wdt_device.queue = 0;
235	rdc321x_wdt_device.default_ticks = ticks;
236
237	err = misc_register(&rdc321x_wdt_misc);
238	if (err < 0) {
239		dev_err(&pdev->dev, "misc_register failed\n");
240		return err;
241	}
242
243	spin_lock_init(&rdc321x_wdt_device.lock);
244
245	/* Reset the watchdog */
246	pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
247				rdc321x_wdt_device.base_reg, RDC_WDT_RST);
248
249	init_completion(&rdc321x_wdt_device.stop);
250
251	clear_bit(0, &rdc321x_wdt_device.inuse);
252
253	timer_setup(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
254
255	dev_info(&pdev->dev, "watchdog init success\n");
256
257	return 0;
258}
259
260static void rdc321x_wdt_remove(struct platform_device *pdev)
261{
262	if (rdc321x_wdt_device.queue) {
263		rdc321x_wdt_device.queue = 0;
264		wait_for_completion(&rdc321x_wdt_device.stop);
265	}
266
267	misc_deregister(&rdc321x_wdt_misc);
268}
269
270static struct platform_driver rdc321x_wdt_driver = {
271	.probe = rdc321x_wdt_probe,
272	.remove_new = rdc321x_wdt_remove,
273	.driver = {
274		.name = "rdc321x-wdt",
275	},
276};
277
278module_platform_driver(rdc321x_wdt_driver);
279
280MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
281MODULE_DESCRIPTION("RDC321x watchdog driver");
282MODULE_LICENSE("GPL");
283