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8cf18971 DP |
1 | #include <linux/init.h> |
2 | #include <linux/module.h> | |
3 | #include <linux/miscdevice.h> | |
4 | #include <linux/watchdog.h> | |
5 | #include <linux/io.h> | |
de81225a | 6 | #include <linux/spinlock.h> |
f26ef3dc AC |
7 | #include <linux/of_platform.h> |
8 | #include <linux/uaccess.h> | |
8cf18971 DP |
9 | #include <asm/mpc52xx.h> |
10 | ||
11 | ||
12 | #define GPT_MODE_WDT (1<<15) | |
13 | #define GPT_MODE_CE (1<<12) | |
14 | #define GPT_MODE_MS_TIMER (0x4) | |
15 | ||
16 | ||
17 | struct mpc5200_wdt { | |
18 | unsigned count; /* timer ticks before watchdog kicks in */ | |
19 | long ipb_freq; | |
20 | struct miscdevice miscdev; | |
21 | struct resource mem; | |
22 | struct mpc52xx_gpt __iomem *regs; | |
de81225a | 23 | spinlock_t io_lock; |
8cf18971 DP |
24 | }; |
25 | ||
de81225a WVS |
26 | /* is_active stores wether or not the /dev/watchdog device is opened */ |
27 | static unsigned long is_active; | |
8cf18971 DP |
28 | |
29 | /* misc devices don't provide a way, to get back to 'dev' or 'miscdev' from | |
30 | * file operations, which sucks. But there can be max 1 watchdog anyway, so... | |
31 | */ | |
32 | static struct mpc5200_wdt *wdt_global; | |
33 | ||
34 | ||
35 | /* helper to calculate timeout in timer counts */ | |
36 | static void mpc5200_wdt_set_timeout(struct mpc5200_wdt *wdt, int timeout) | |
37 | { | |
38 | /* use biggest prescaler of 64k */ | |
39 | wdt->count = (wdt->ipb_freq + 0xffff) / 0x10000 * timeout; | |
40 | ||
41 | if (wdt->count > 0xffff) | |
42 | wdt->count = 0xffff; | |
43 | } | |
44 | /* return timeout in seconds (calculated from timer count) */ | |
45 | static int mpc5200_wdt_get_timeout(struct mpc5200_wdt *wdt) | |
46 | { | |
47 | return wdt->count * 0x10000 / wdt->ipb_freq; | |
48 | } | |
49 | ||
50 | ||
51 | /* watchdog operations */ | |
52 | static int mpc5200_wdt_start(struct mpc5200_wdt *wdt) | |
53 | { | |
de81225a | 54 | spin_lock(&wdt->io_lock); |
8cf18971 DP |
55 | /* disable */ |
56 | out_be32(&wdt->regs->mode, 0); | |
57 | /* set timeout, with maximum prescaler */ | |
58 | out_be32(&wdt->regs->count, 0x0 | wdt->count); | |
59 | /* enable watchdog */ | |
f26ef3dc AC |
60 | out_be32(&wdt->regs->mode, GPT_MODE_CE | GPT_MODE_WDT | |
61 | GPT_MODE_MS_TIMER); | |
de81225a | 62 | spin_unlock(&wdt->io_lock); |
8cf18971 DP |
63 | |
64 | return 0; | |
65 | } | |
66 | static int mpc5200_wdt_ping(struct mpc5200_wdt *wdt) | |
67 | { | |
de81225a | 68 | spin_lock(&wdt->io_lock); |
8cf18971 | 69 | /* writing A5 to OCPW resets the watchdog */ |
f26ef3dc AC |
70 | out_be32(&wdt->regs->mode, 0xA5000000 | |
71 | (0xffffff & in_be32(&wdt->regs->mode))); | |
de81225a | 72 | spin_unlock(&wdt->io_lock); |
8cf18971 DP |
73 | return 0; |
74 | } | |
75 | static int mpc5200_wdt_stop(struct mpc5200_wdt *wdt) | |
76 | { | |
de81225a WVS |
77 | spin_lock(&wdt->io_lock); |
78 | /* disable */ | |
8cf18971 | 79 | out_be32(&wdt->regs->mode, 0); |
de81225a | 80 | spin_unlock(&wdt->io_lock); |
8cf18971 DP |
81 | return 0; |
82 | } | |
83 | ||
84 | ||
85 | /* file operations */ | |
a39f9d02 | 86 | static ssize_t mpc5200_wdt_write(struct file *file, const char __user *data, |
8cf18971 DP |
87 | size_t len, loff_t *ppos) |
88 | { | |
89 | struct mpc5200_wdt *wdt = file->private_data; | |
90 | mpc5200_wdt_ping(wdt); | |
91 | return 0; | |
92 | } | |
93 | static struct watchdog_info mpc5200_wdt_info = { | |
94 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, | |
95 | .identity = "mpc5200 watchdog on GPT0", | |
96 | }; | |
f26ef3dc AC |
97 | static long mpc5200_wdt_ioctl(struct file *file, unsigned int cmd, |
98 | unsigned long arg) | |
8cf18971 DP |
99 | { |
100 | struct mpc5200_wdt *wdt = file->private_data; | |
101 | int __user *data = (int __user *)arg; | |
102 | int timeout; | |
103 | int ret = 0; | |
104 | ||
105 | switch (cmd) { | |
106 | case WDIOC_GETSUPPORT: | |
de81225a | 107 | ret = copy_to_user(data, &mpc5200_wdt_info, |
f26ef3dc | 108 | sizeof(mpc5200_wdt_info)); |
8cf18971 DP |
109 | if (ret) |
110 | ret = -EFAULT; | |
111 | break; | |
112 | ||
de81225a WVS |
113 | case WDIOC_GETSTATUS: |
114 | case WDIOC_GETBOOTSTATUS: | |
115 | ret = put_user(0, data); | |
116 | break; | |
117 | ||
8cf18971 DP |
118 | case WDIOC_KEEPALIVE: |
119 | mpc5200_wdt_ping(wdt); | |
120 | break; | |
121 | ||
122 | case WDIOC_SETTIMEOUT: | |
123 | ret = get_user(timeout, data); | |
124 | if (ret) | |
125 | break; | |
126 | mpc5200_wdt_set_timeout(wdt, timeout); | |
127 | mpc5200_wdt_start(wdt); | |
128 | /* fall through and return the timeout */ | |
129 | ||
130 | case WDIOC_GETTIMEOUT: | |
131 | timeout = mpc5200_wdt_get_timeout(wdt); | |
132 | ret = put_user(timeout, data); | |
133 | break; | |
de81225a WVS |
134 | |
135 | default: | |
136 | ret = -ENOTTY; | |
8cf18971 DP |
137 | } |
138 | return ret; | |
139 | } | |
f26ef3dc | 140 | |
8cf18971 DP |
141 | static int mpc5200_wdt_open(struct inode *inode, struct file *file) |
142 | { | |
de81225a WVS |
143 | /* /dev/watchdog can only be opened once */ |
144 | if (test_and_set_bit(0, &is_active)) | |
145 | return -EBUSY; | |
146 | ||
147 | /* Set and activate the watchdog */ | |
8cf18971 DP |
148 | mpc5200_wdt_set_timeout(wdt_global, 30); |
149 | mpc5200_wdt_start(wdt_global); | |
150 | file->private_data = wdt_global; | |
de81225a | 151 | return nonseekable_open(inode, file); |
8cf18971 DP |
152 | } |
153 | static int mpc5200_wdt_release(struct inode *inode, struct file *file) | |
154 | { | |
155 | #if WATCHDOG_NOWAYOUT == 0 | |
156 | struct mpc5200_wdt *wdt = file->private_data; | |
157 | mpc5200_wdt_stop(wdt); | |
158 | wdt->count = 0; /* == disabled */ | |
159 | #endif | |
de81225a | 160 | clear_bit(0, &is_active); |
8cf18971 DP |
161 | return 0; |
162 | } | |
163 | ||
b47a166e | 164 | static const struct file_operations mpc5200_wdt_fops = { |
8cf18971 DP |
165 | .owner = THIS_MODULE, |
166 | .write = mpc5200_wdt_write, | |
7944d3a5 | 167 | .unlocked_ioctl = mpc5200_wdt_ioctl, |
8cf18971 DP |
168 | .open = mpc5200_wdt_open, |
169 | .release = mpc5200_wdt_release, | |
170 | }; | |
171 | ||
172 | /* module operations */ | |
f26ef3dc AC |
173 | static int mpc5200_wdt_probe(struct of_device *op, |
174 | const struct of_device_id *match) | |
8cf18971 DP |
175 | { |
176 | struct mpc5200_wdt *wdt; | |
177 | int err; | |
178 | const void *has_wdt; | |
179 | int size; | |
180 | ||
181 | has_wdt = of_get_property(op->node, "has-wdt", NULL); | |
d24bc314 MB |
182 | if (!has_wdt) |
183 | has_wdt = of_get_property(op->node, "fsl,has-wdt", NULL); | |
8cf18971 DP |
184 | if (!has_wdt) |
185 | return -ENODEV; | |
186 | ||
187 | wdt = kzalloc(sizeof(*wdt), GFP_KERNEL); | |
188 | if (!wdt) | |
189 | return -ENOMEM; | |
190 | ||
191 | wdt->ipb_freq = mpc52xx_find_ipb_freq(op->node); | |
192 | ||
193 | err = of_address_to_resource(op->node, 0, &wdt->mem); | |
194 | if (err) | |
195 | goto out_free; | |
196 | size = wdt->mem.end - wdt->mem.start + 1; | |
197 | if (!request_mem_region(wdt->mem.start, size, "mpc5200_wdt")) { | |
198 | err = -ENODEV; | |
199 | goto out_free; | |
200 | } | |
201 | wdt->regs = ioremap(wdt->mem.start, size); | |
202 | if (!wdt->regs) { | |
203 | err = -ENODEV; | |
204 | goto out_release; | |
205 | } | |
206 | ||
207 | dev_set_drvdata(&op->dev, wdt); | |
de81225a | 208 | spin_lock_init(&wdt->io_lock); |
8cf18971 DP |
209 | |
210 | wdt->miscdev = (struct miscdevice) { | |
211 | .minor = WATCHDOG_MINOR, | |
212 | .name = "watchdog", | |
213 | .fops = &mpc5200_wdt_fops, | |
214 | .parent = &op->dev, | |
215 | }; | |
216 | wdt_global = wdt; | |
217 | err = misc_register(&wdt->miscdev); | |
218 | if (!err) | |
219 | return 0; | |
220 | ||
221 | iounmap(wdt->regs); | |
7944d3a5 | 222 | out_release: |
8cf18971 | 223 | release_mem_region(wdt->mem.start, size); |
7944d3a5 | 224 | out_free: |
8cf18971 DP |
225 | kfree(wdt); |
226 | return err; | |
227 | } | |
228 | ||
229 | static int mpc5200_wdt_remove(struct of_device *op) | |
230 | { | |
231 | struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev); | |
232 | ||
233 | mpc5200_wdt_stop(wdt); | |
234 | misc_deregister(&wdt->miscdev); | |
235 | iounmap(wdt->regs); | |
236 | release_mem_region(wdt->mem.start, wdt->mem.end - wdt->mem.start + 1); | |
237 | kfree(wdt); | |
238 | ||
239 | return 0; | |
240 | } | |
241 | static int mpc5200_wdt_suspend(struct of_device *op, pm_message_t state) | |
242 | { | |
243 | struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev); | |
244 | mpc5200_wdt_stop(wdt); | |
245 | return 0; | |
246 | } | |
247 | static int mpc5200_wdt_resume(struct of_device *op) | |
248 | { | |
249 | struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev); | |
250 | if (wdt->count) | |
251 | mpc5200_wdt_start(wdt); | |
252 | return 0; | |
253 | } | |
254 | static int mpc5200_wdt_shutdown(struct of_device *op) | |
255 | { | |
256 | struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev); | |
257 | mpc5200_wdt_stop(wdt); | |
258 | return 0; | |
259 | } | |
260 | ||
261 | static struct of_device_id mpc5200_wdt_match[] = { | |
262 | { .compatible = "mpc5200-gpt", }, | |
d24bc314 | 263 | { .compatible = "fsl,mpc5200-gpt", }, |
8cf18971 DP |
264 | {}, |
265 | }; | |
266 | static struct of_platform_driver mpc5200_wdt_driver = { | |
267 | .owner = THIS_MODULE, | |
268 | .name = "mpc5200-gpt-wdt", | |
269 | .match_table = mpc5200_wdt_match, | |
270 | .probe = mpc5200_wdt_probe, | |
271 | .remove = mpc5200_wdt_remove, | |
272 | .suspend = mpc5200_wdt_suspend, | |
273 | .resume = mpc5200_wdt_resume, | |
274 | .shutdown = mpc5200_wdt_shutdown, | |
275 | }; | |
276 | ||
277 | ||
278 | static int __init mpc5200_wdt_init(void) | |
279 | { | |
280 | return of_register_platform_driver(&mpc5200_wdt_driver); | |
281 | } | |
282 | ||
283 | static void __exit mpc5200_wdt_exit(void) | |
284 | { | |
285 | of_unregister_platform_driver(&mpc5200_wdt_driver); | |
286 | } | |
287 | ||
288 | module_init(mpc5200_wdt_init); | |
289 | module_exit(mpc5200_wdt_exit); | |
290 | ||
291 | MODULE_AUTHOR("Domen Puncer <domen.puncer@telargo.com>"); | |
292 | MODULE_LICENSE("Dual BSD/GPL"); | |
de81225a | 293 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |