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20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/fs.h>
23#include <linux/init.h>
24#include <linux/kernel.h>
25#include <linux/timer.h>
26#include <linux/miscdevice.h>
27#include <linux/of_address.h>
28#include <linux/of_platform.h>
29#include <linux/module.h>
30#include <linux/watchdog.h>
31#include <linux/io.h>
32#include <linux/uaccess.h>
33#include <sysdev/fsl_soc.h>
34
35struct mpc8xxx_wdt {
36 __be32 res0;
37 __be32 swcrr;
38#define SWCRR_SWTC 0xFFFF0000
39#define SWCRR_SWEN 0x00000004
40#define SWCRR_SWRI 0x00000002
41#define SWCRR_SWPR 0x00000001
42 __be32 swcnr;
43 u8 res1[2];
44 __be16 swsrr;
45 u8 res2[0xF0];
46};
47
48struct mpc8xxx_wdt_type {
49 int prescaler;
50 bool hw_enabled;
51};
52
53static struct mpc8xxx_wdt __iomem *wd_base;
54static int mpc8xxx_wdt_init_late(void);
55
56static u16 timeout = 0xffff;
57module_param(timeout, ushort, 0);
58MODULE_PARM_DESC(timeout,
59 "Watchdog timeout in ticks. (0<timeout<65536, default=65535)");
60
61static bool reset = 1;
62module_param(reset, bool, 0);
63MODULE_PARM_DESC(reset,
64 "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
65
66static bool nowayout = WATCHDOG_NOWAYOUT;
67module_param(nowayout, bool, 0);
68MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
69 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
70
71
72
73
74
75static int prescale = 1;
76
77static DEFINE_SPINLOCK(wdt_spinlock);
78
79static void mpc8xxx_wdt_keepalive(void)
80{
81
82 spin_lock(&wdt_spinlock);
83 out_be16(&wd_base->swsrr, 0x556c);
84 out_be16(&wd_base->swsrr, 0xaa39);
85 spin_unlock(&wdt_spinlock);
86}
87
88static struct watchdog_device mpc8xxx_wdt_dev;
89static void mpc8xxx_wdt_timer_ping(unsigned long arg);
90static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0,
91 (unsigned long)&mpc8xxx_wdt_dev);
92
93static void mpc8xxx_wdt_timer_ping(unsigned long arg)
94{
95 struct watchdog_device *w = (struct watchdog_device *)arg;
96
97 mpc8xxx_wdt_keepalive();
98
99 mod_timer(&wdt_timer, jiffies + HZ * w->timeout / 2);
100}
101
102static int mpc8xxx_wdt_start(struct watchdog_device *w)
103{
104 u32 tmp = SWCRR_SWEN;
105
106
107 if (prescale)
108 tmp |= SWCRR_SWPR;
109 if (reset)
110 tmp |= SWCRR_SWRI;
111
112 tmp |= timeout << 16;
113
114 out_be32(&wd_base->swcrr, tmp);
115
116 del_timer_sync(&wdt_timer);
117
118 return 0;
119}
120
121static int mpc8xxx_wdt_ping(struct watchdog_device *w)
122{
123 mpc8xxx_wdt_keepalive();
124 return 0;
125}
126
127static int mpc8xxx_wdt_stop(struct watchdog_device *w)
128{
129 mod_timer(&wdt_timer, jiffies);
130 return 0;
131}
132
133static struct watchdog_info mpc8xxx_wdt_info = {
134 .options = WDIOF_KEEPALIVEPING,
135 .firmware_version = 1,
136 .identity = "MPC8xxx",
137};
138
139static struct watchdog_ops mpc8xxx_wdt_ops = {
140 .owner = THIS_MODULE,
141 .start = mpc8xxx_wdt_start,
142 .ping = mpc8xxx_wdt_ping,
143 .stop = mpc8xxx_wdt_stop,
144};
145
146static struct watchdog_device mpc8xxx_wdt_dev = {
147 .info = &mpc8xxx_wdt_info,
148 .ops = &mpc8xxx_wdt_ops,
149};
150
151static const struct of_device_id mpc8xxx_wdt_match[];
152static int mpc8xxx_wdt_probe(struct platform_device *ofdev)
153{
154 int ret;
155 const struct of_device_id *match;
156 struct device_node *np = ofdev->dev.of_node;
157 const struct mpc8xxx_wdt_type *wdt_type;
158 u32 freq = fsl_get_sys_freq();
159 bool enabled;
160 unsigned int timeout_sec;
161
162 match = of_match_device(mpc8xxx_wdt_match, &ofdev->dev);
163 if (!match)
164 return -EINVAL;
165 wdt_type = match->data;
166
167 if (!freq || freq == -1)
168 return -EINVAL;
169
170 wd_base = of_iomap(np, 0);
171 if (!wd_base)
172 return -ENOMEM;
173
174 enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
175 if (!enabled && wdt_type->hw_enabled) {
176 pr_info("could not be enabled in software\n");
177 ret = -ENOSYS;
178 goto err_unmap;
179 }
180
181
182 if (prescale)
183 timeout_sec = (timeout * wdt_type->prescaler) / freq;
184 else
185 timeout_sec = timeout / freq;
186
187 mpc8xxx_wdt_dev.timeout = timeout_sec;
188#ifdef MODULE
189 ret = mpc8xxx_wdt_init_late();
190 if (ret)
191 goto err_unmap;
192#endif
193
194 pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n",
195 reset ? "reset" : "interrupt", timeout, timeout_sec);
196
197
198
199
200
201
202 if (enabled)
203 mod_timer(&wdt_timer, jiffies);
204 return 0;
205err_unmap:
206 iounmap(wd_base);
207 wd_base = NULL;
208 return ret;
209}
210
211static int mpc8xxx_wdt_remove(struct platform_device *ofdev)
212{
213 pr_crit("Watchdog removed, expect the %s soon!\n",
214 reset ? "reset" : "machine check exception");
215 del_timer_sync(&wdt_timer);
216 watchdog_unregister_device(&mpc8xxx_wdt_dev);
217 iounmap(wd_base);
218
219 return 0;
220}
221
222static const struct of_device_id mpc8xxx_wdt_match[] = {
223 {
224 .compatible = "mpc83xx_wdt",
225 .data = &(struct mpc8xxx_wdt_type) {
226 .prescaler = 0x10000,
227 },
228 },
229 {
230 .compatible = "fsl,mpc8610-wdt",
231 .data = &(struct mpc8xxx_wdt_type) {
232 .prescaler = 0x10000,
233 .hw_enabled = true,
234 },
235 },
236 {
237 .compatible = "fsl,mpc823-wdt",
238 .data = &(struct mpc8xxx_wdt_type) {
239 .prescaler = 0x800,
240 .hw_enabled = true,
241 },
242 },
243 {},
244};
245MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
246
247static struct platform_driver mpc8xxx_wdt_driver = {
248 .probe = mpc8xxx_wdt_probe,
249 .remove = mpc8xxx_wdt_remove,
250 .driver = {
251 .name = "mpc8xxx_wdt",
252 .of_match_table = mpc8xxx_wdt_match,
253 },
254};
255
256
257
258
259
260
261static int mpc8xxx_wdt_init_late(void)
262{
263 int ret;
264
265 if (!wd_base)
266 return -ENODEV;
267
268 watchdog_set_nowayout(&mpc8xxx_wdt_dev, nowayout);
269
270 ret = watchdog_register_device(&mpc8xxx_wdt_dev);
271 if (ret) {
272 pr_err("cannot register watchdog device (err=%d)\n", ret);
273 return ret;
274 }
275 return 0;
276}
277#ifndef MODULE
278module_init(mpc8xxx_wdt_init_late);
279#endif
280
281static int __init mpc8xxx_wdt_init(void)
282{
283 return platform_driver_register(&mpc8xxx_wdt_driver);
284}
285arch_initcall(mpc8xxx_wdt_init);
286
287static void __exit mpc8xxx_wdt_exit(void)
288{
289 platform_driver_unregister(&mpc8xxx_wdt_driver);
290}
291module_exit(mpc8xxx_wdt_exit);
292
293MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
294MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
295 "uProcessors");
296MODULE_LICENSE("GPL");
297
