kernel: fix an overlayfs deadlock on rmdir
[openwrt.git] / target / linux / cns21xx / patches-2.6.36 / 006-arm-add-fa-watchdog-driver.patch
1 --- a/drivers/watchdog/Kconfig
2 +++ b/drivers/watchdog/Kconfig
3 @@ -331,6 +331,13 @@ config IMX2_WDT
4 To compile this driver as a module, choose M here: the
5 module will be called imx2_wdt.
6
7 +config FA_WATCHDOG
8 + tristate "Faraday watchdog"
9 + depends on ARCH_GEMINI
10 + help
11 + Say Y here if you want support for the built-in watchdog timer
12 + found in some Faraday FA526 based SoCs.
13 +
14 # AVR32 Architecture
15
16 config AT32AP700X_WDT
17 --- a/drivers/watchdog/Makefile
18 +++ b/drivers/watchdog/Makefile
19 @@ -49,6 +49,7 @@ obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_
20 obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
21 obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
22 obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
23 +obj-$(CONFIG_FA_WATCHDOG) += fa_wdt.o
24
25 # AVR32 Architecture
26 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
27 --- /dev/null
28 +++ b/drivers/watchdog/fa_wdt.c
29 @@ -0,0 +1,411 @@
30 +/*
31 + * Watchdog driver for SoCs based on the Faraday FA526 core
32 + *
33 + * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
34 + * Copyright (C) 2010 Gabor Juhos <juhosg@openwrt.org>
35 + *
36 + * This program is free software; you can redistribute it and/or modify
37 + * it under the terms of the GNU General Public License version 2 as
38 + * published by the Free Software Foundation.
39 + */
40 +
41 +#include <linux/kernel.h>
42 +#include <linux/init.h>
43 +#include <linux/io.h>
44 +#include <linux/fs.h>
45 +#include <linux/notifier.h>
46 +#include <linux/reboot.h>
47 +#include <linux/uaccess.h>
48 +#include <linux/miscdevice.h>
49 +#include <linux/platform_device.h>
50 +#include <linux/watchdog.h>
51 +#include <linux/slab.h>
52 +#include <linux/fa_wdt.h>
53 +
54 +#define FA_WDCOUNTER 0x0
55 +#define FA_WDLOAD 0x4
56 +#define FA_WDRESTART 0x8
57 +
58 +#define WDRESTART_MAGIC 0x5AB9
59 +
60 +#define FA_WDCR 0xC
61 +
62 +#define WDCR_CLOCK_5MHZ (1 << 4)
63 +#define WDCR_SYS_RST (1 << 1)
64 +#define WDCR_ENABLE (1 << 0)
65 +
66 +#define WDT_DEFAULT_TIMEOUT 13
67 +
68 +/* status bits */
69 +#define WDT_ACTIVE 0
70 +#define WDT_OK_TO_CLOSE 1
71 +
72 +static unsigned int timeout = WDT_DEFAULT_TIMEOUT;
73 +static int nowayout = WATCHDOG_NOWAYOUT;
74 +
75 +static DEFINE_SPINLOCK(fa_wdt_lock);
76 +
77 +static struct platform_device *fa_wdt_dev;
78 +
79 +struct fa_wdt_struct {
80 + struct resource *res;
81 + struct device *dev;
82 + void __iomem *base;
83 + unsigned long status;
84 + unsigned int clock;
85 + unsigned int max_timeout;
86 +};
87 +
88 +static const struct watchdog_info fa_wdt_info = {
89 + .identity = "Faraday watchdog",
90 + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
91 + WDIOF_SETTIMEOUT,
92 +};
93 +
94 +/* Disable the watchdog. */
95 +static void fa_wdt_stop(struct fa_wdt_struct *fa_wdt)
96 +{
97 + spin_lock(&fa_wdt_lock);
98 +
99 + __raw_writel(0, fa_wdt->base + FA_WDCR);
100 +
101 + clear_bit(WDT_ACTIVE, &fa_wdt->status);
102 +
103 + spin_unlock(&fa_wdt_lock);
104 +}
105 +
106 +/* Service the watchdog */
107 +static void fa_wdt_service(struct fa_wdt_struct *fa_wdt)
108 +{
109 + __raw_writel(WDRESTART_MAGIC, fa_wdt->base + FA_WDRESTART);
110 +}
111 +
112 +/* Enable and reset the watchdog. */
113 +static void fa_wdt_start(struct fa_wdt_struct *fa_wdt)
114 +{
115 + spin_lock(&fa_wdt_lock);
116 +
117 + __raw_writel(timeout * fa_wdt->clock,
118 + fa_wdt->base + FA_WDLOAD);
119 +
120 + fa_wdt_service(fa_wdt);
121 +
122 + /* set clock before enabling */
123 + __raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,
124 + fa_wdt->base + FA_WDCR);
125 +
126 + __raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,
127 + fa_wdt->base + FA_WDCR);
128 +
129 + set_bit(WDT_ACTIVE, &fa_wdt->status);
130 +
131 + spin_unlock(&fa_wdt_lock);
132 +}
133 +
134 +/* Watchdog device is opened, and watchdog starts running. */
135 +static int fa_wdt_open(struct inode *inode, struct file *file)
136 +{
137 + struct fa_wdt_struct *fa_wdt = platform_get_drvdata(fa_wdt_dev);
138 +
139 + if (test_bit(WDT_ACTIVE, &fa_wdt->status))
140 + return -EBUSY;
141 +
142 + file->private_data = fa_wdt;
143 +
144 + fa_wdt_start(fa_wdt);
145 +
146 + return nonseekable_open(inode, file);
147 +}
148 +
149 +/* Close the watchdog device. */
150 +static int fa_wdt_close(struct inode *inode, struct file *file)
151 +{
152 + struct fa_wdt_struct *fa_wdt = file->private_data;
153 +
154 + /* Disable the watchdog if possible */
155 + if (test_bit(WDT_OK_TO_CLOSE, &fa_wdt->status))
156 + fa_wdt_stop(fa_wdt);
157 + else
158 + dev_warn(fa_wdt->dev, "Device closed unexpectedly - timer will not stop\n");
159 +
160 + return 0;
161 +}
162 +
163 +/* Handle commands from user-space. */
164 +static long fa_wdt_ioctl(struct file *file, unsigned int cmd,
165 + unsigned long arg)
166 +{
167 + struct fa_wdt_struct *fa_wdt = file->private_data;
168 +
169 + int value;
170 +
171 + switch (cmd) {
172 + case WDIOC_KEEPALIVE:
173 + fa_wdt_service(fa_wdt);
174 + return 0;
175 +
176 + case WDIOC_GETSUPPORT:
177 + return copy_to_user((struct watchdog_info *)arg, &fa_wdt_info,
178 + sizeof(fa_wdt_info)) ? -EFAULT : 0;
179 +
180 + case WDIOC_SETTIMEOUT:
181 + if (get_user(value, (int *)arg))
182 + return -EFAULT;
183 +
184 + if ((value < 1) || (value > fa_wdt->max_timeout))
185 + return -EINVAL;
186 +
187 + timeout = value;
188 +
189 + /* restart wdt to use new timeout */
190 + fa_wdt_stop(fa_wdt);
191 + fa_wdt_start(fa_wdt);
192 +
193 + /* Fall through */
194 + case WDIOC_GETTIMEOUT:
195 + return put_user(timeout, (int *)arg);
196 +
197 + case WDIOC_GETTIMELEFT:
198 + value = __raw_readl(fa_wdt->base + FA_WDCOUNTER);
199 + return put_user(value / fa_wdt->clock, (int *)arg);
200 +
201 + default:
202 + return -ENOTTY;
203 + }
204 +}
205 +
206 +/* Refresh the watchdog whenever device is written to. */
207 +static ssize_t fa_wdt_write(struct file *file, const char *data,
208 + size_t len, loff_t *ppos)
209 +{
210 + struct fa_wdt_struct *fa_wdt = file->private_data;
211 +
212 + if (len) {
213 + if (!nowayout) {
214 + size_t i;
215 +
216 + clear_bit(WDT_OK_TO_CLOSE, &fa_wdt->status);
217 + for (i = 0; i != len; i++) {
218 + char c;
219 +
220 + if (get_user(c, data + i))
221 + return -EFAULT;
222 + if (c == 'V')
223 + set_bit(WDT_OK_TO_CLOSE,
224 + &fa_wdt->status);
225 + }
226 + }
227 + fa_wdt_service(fa_wdt);
228 + }
229 +
230 + return len;
231 +}
232 +
233 +static int fa_wdt_notify_sys(struct notifier_block *this,
234 + unsigned long code, void *unused)
235 +{
236 + struct fa_wdt_struct *fa_wdt = platform_get_drvdata(fa_wdt_dev);
237 +
238 + if (code == SYS_DOWN || code == SYS_HALT)
239 + fa_wdt_stop(fa_wdt);
240 +
241 + return NOTIFY_DONE;
242 +}
243 +
244 +static struct notifier_block fa_wdt_notifier = {
245 + .notifier_call = fa_wdt_notify_sys,
246 +};
247 +
248 +static const struct file_operations fa_wdt_fops = {
249 + .owner = THIS_MODULE,
250 + .llseek = no_llseek,
251 + .unlocked_ioctl = fa_wdt_ioctl,
252 + .open = fa_wdt_open,
253 + .release = fa_wdt_close,
254 + .write = fa_wdt_write,
255 +};
256 +
257 +static struct miscdevice fa_wdt_miscdev = {
258 + .minor = WATCHDOG_MINOR,
259 + .name = "watchdog",
260 + .fops = &fa_wdt_fops,
261 +};
262 +
263 +static void fa_wdt_shutdown(struct platform_device *pdev)
264 +{
265 + struct fa_wdt_struct *fa_wdt = platform_get_drvdata(pdev);
266 +
267 + fa_wdt_stop(fa_wdt);
268 +}
269 +
270 +static int __devinit fa_wdt_probe(struct platform_device *pdev)
271 +{
272 + int ret;
273 + int res_size;
274 + struct resource *res;
275 + void __iomem *base;
276 + struct fa_wdt_struct *fa_wdt;
277 + struct fa_wdt_platform_data *pdata;
278 +
279 + pdata = pdev->dev.platform_data;
280 + if (!pdata) {
281 + dev_err(&pdev->dev, "no platform data specified\n");
282 + return -EINVAL;
283 + }
284 +
285 + if (!pdata->clock) {
286 + dev_err(&pdev->dev, "invalid clock value\n");
287 + return -EINVAL;
288 + }
289 +
290 + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
291 + if (!res) {
292 + dev_err(&pdev->dev, "can't get device resources\n");
293 + return -ENODEV;
294 + }
295 +
296 + res_size = resource_size(res);
297 + if (!request_mem_region(res->start, res_size, res->name)) {
298 + dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n",
299 + res_size, res->start);
300 + return -ENOMEM;
301 + }
302 +
303 + base = ioremap(res->start, res_size);
304 + if (!base) {
305 + dev_err(&pdev->dev, "ioremap failed\n");
306 + ret = -EIO;
307 + goto fail0;
308 + }
309 +
310 + fa_wdt = kzalloc(sizeof(struct fa_wdt_struct), GFP_KERNEL);
311 + if (!fa_wdt) {
312 + dev_err(&pdev->dev, "can't allocate interface\n");
313 + ret = -ENOMEM;
314 + goto fail1;
315 + }
316 +
317 + /* Setup fa_wdt driver structure */
318 + fa_wdt->base = base;
319 + fa_wdt->res = res;
320 + fa_wdt->dev = &pdev->dev;
321 + fa_wdt->clock = pdata->clock;
322 + fa_wdt->max_timeout = 0xffffffffU / pdata->clock;
323 +
324 + /* Set up platform driver data */
325 + platform_set_drvdata(pdev, fa_wdt);
326 + fa_wdt_dev = pdev;
327 +
328 + if (fa_wdt_miscdev.parent) {
329 + ret = -EBUSY;
330 + goto fail2;
331 + }
332 +
333 + ret = register_reboot_notifier(&fa_wdt_notifier);
334 + if (ret)
335 + goto fail2;
336 +
337 + fa_wdt_miscdev.parent = &pdev->dev;
338 +
339 + ret = misc_register(&fa_wdt_miscdev);
340 + if (ret)
341 + goto fail3;
342 +
343 + return 0;
344 +
345 +fail3:
346 + unregister_reboot_notifier(&fa_wdt_notifier);
347 +fail2:
348 + platform_set_drvdata(pdev, NULL);
349 + kfree(fa_wdt);
350 +fail1:
351 + iounmap(base);
352 +fail0:
353 + release_mem_region(res->start, res_size);
354 +
355 + return ret;
356 +}
357 +
358 +static int __devexit fa_wdt_remove(struct platform_device *pdev)
359 +{
360 + struct fa_wdt_struct *fa_wdt = platform_get_drvdata(pdev);
361 +
362 + platform_set_drvdata(pdev, NULL);
363 + misc_deregister(&fa_wdt_miscdev);
364 + unregister_reboot_notifier(&fa_wdt_notifier);
365 + fa_wdt_dev = NULL;
366 + iounmap(fa_wdt->base);
367 + release_mem_region(fa_wdt->res->start, resource_size(fa_wdt->res));
368 +
369 + kfree(fa_wdt);
370 +
371 + return 0;
372 +}
373 +
374 +#ifdef CONFIG_PM
375 +static int fa_wdt_suspend(struct platform_device *pdev, pm_message_t message)
376 +{
377 + struct fa_wdt_struct *fa_wdt = platform_get_drvdata(pdev);
378 + unsigned int reg;
379 +
380 + reg = __raw_readw(fa_wdt->base + FA_WDCR);
381 + reg &= ~(WDCR_WDENABLE);
382 + __raw_writel(reg, fa_wdt->base + FA_WDCR);
383 +
384 + return 0;
385 +}
386 +
387 +static int fa_wdt_resume(struct platform_device *pdev)
388 +{
389 + struct fa_wdt_struct *fa_wdt = platform_get_drvdata(pdev);
390 + unsigned int reg;
391 +
392 + if (fa_wdt->status) {
393 + reg = __raw_readw(fa_wdt->base + FA_WDCR);
394 + reg |= WDCR_WDENABLE;
395 + __raw_writel(reg, fa_wdt->base + FA_WDCR);
396 + }
397 +
398 + return 0;
399 +}
400 +#else
401 +#define fa_wdt_suspend NULL
402 +#define fa_wdt_resume NULL
403 +#endif
404 +
405 +static struct platform_driver fa_wdt_driver = {
406 + .probe = fa_wdt_probe,
407 + .remove = __devexit_p(fa_wdt_remove),
408 + .shutdown = fa_wdt_shutdown,
409 + .suspend = fa_wdt_suspend,
410 + .resume = fa_wdt_resume,
411 + .driver = {
412 + .name = "fa-wdt",
413 + .owner = THIS_MODULE,
414 + },
415 +};
416 +
417 +static int __init fa_wdt_init(void)
418 +{
419 + return platform_driver_probe(&fa_wdt_driver, fa_wdt_probe);
420 +}
421 +
422 +static void __exit fa_wdt_exit(void)
423 +{
424 + platform_driver_unregister(&fa_wdt_driver);
425 +}
426 +
427 +module_init(fa_wdt_init);
428 +module_exit(fa_wdt_exit);
429 +
430 +module_param(timeout, uint, 0);
431 +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
432 +
433 +module_param(nowayout, int, 0);
434 +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
435 +
436 +MODULE_AUTHOR("Paulius Zaleckas");
437 +MODULE_DESCRIPTION("Watchdog driver for Faraday FA526 based SoCs");
438 +MODULE_LICENSE("GPL v2");
439 +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
440 +MODULE_ALIAS("platform:fa-wdt");
441 --- /dev/null
442 +++ b/include/linux/fa_wdt.h
443 @@ -0,0 +1,13 @@
444 +/*
445 + * Platform data definition for the Faraday watchdog driver
446 + */
447 +
448 +#ifndef _FA_WDT_H
449 +#define _FA_WDT_H
450 +
451 +struct fa_wdt_platform_data {
452 + unsigned int clock;
453 +};
454 +
455 +#endif /* _FA_WDT_H */
456 +
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