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authorAlan Cox <alan@lxorguk.ukuu.org.uk>2008-08-04 12:54:46 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-08-04 20:12:07 -0400
commit41dc8b72e37c514f7332cbc3f3dd864910c2a1fa (patch)
treefbdb145a083f03a0e6c24a6fc527477b773c5099
parentd6547378df1c11bc6790b87abedb3526ded40ef9 (diff)
s3c2410_wdt watchdog driver: Locking and coding style
Kill off use of semaphores. Fix ioctl races and locking holes. From: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/watchdog/s3c2410_wdt.c148
1 files changed, 80 insertions, 68 deletions
diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index 98532c0e0689..97b4a2e8eb09 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -46,9 +46,8 @@
46#include <linux/platform_device.h> 46#include <linux/platform_device.h>
47#include <linux/interrupt.h> 47#include <linux/interrupt.h>
48#include <linux/clk.h> 48#include <linux/clk.h>
49 49#include <linux/uaccess.h>
50#include <asm/uaccess.h> 50#include <linux/io.h>
51#include <asm/io.h>
52 51
53#include <asm/arch/map.h> 52#include <asm/arch/map.h>
54 53
@@ -65,8 +64,8 @@
65static int nowayout = WATCHDOG_NOWAYOUT; 64static int nowayout = WATCHDOG_NOWAYOUT;
66static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME; 65static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
67static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT; 66static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
68static int soft_noboot = 0; 67static int soft_noboot;
69static int debug = 0; 68static int debug;
70 69
71module_param(tmr_margin, int, 0); 70module_param(tmr_margin, int, 0);
72module_param(tmr_atboot, int, 0); 71module_param(tmr_atboot, int, 0);
@@ -74,24 +73,23 @@ module_param(nowayout, int, 0);
74module_param(soft_noboot, int, 0); 73module_param(soft_noboot, int, 0);
75module_param(debug, int, 0); 74module_param(debug, int, 0);
76 75
77MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")"); 76MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default="
78 77 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
79MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT)); 78MODULE_PARM_DESC(tmr_atboot,
80 79 "Watchdog is started at boot time if set to 1, default="
81MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 80 __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
82 81MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
82 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
83MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)"); 83MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
84
85MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)"); 84MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
86 85
87 86
88typedef enum close_state { 87typedef enum close_state {
89 CLOSE_STATE_NOT, 88 CLOSE_STATE_NOT,
90 CLOSE_STATE_ALLOW=0x4021 89 CLOSE_STATE_ALLOW = 0x4021
91} close_state_t; 90} close_state_t;
92 91
93static DECLARE_MUTEX(open_lock); 92static unsigned long open_lock;
94
95static struct device *wdt_dev; /* platform device attached to */ 93static struct device *wdt_dev; /* platform device attached to */
96static struct resource *wdt_mem; 94static struct resource *wdt_mem;
97static struct resource *wdt_irq; 95static struct resource *wdt_irq;
@@ -99,38 +97,58 @@ static struct clk *wdt_clock;
99static void __iomem *wdt_base; 97static void __iomem *wdt_base;
100static unsigned int wdt_count; 98static unsigned int wdt_count;
101static close_state_t allow_close; 99static close_state_t allow_close;
100static DEFINE_SPINLOCK(wdt_lock);
102 101
103/* watchdog control routines */ 102/* watchdog control routines */
104 103
105#define DBG(msg...) do { \ 104#define DBG(msg...) do { \
106 if (debug) \ 105 if (debug) \
107 printk(KERN_INFO msg); \ 106 printk(KERN_INFO msg); \
108 } while(0) 107 } while (0)
109 108
110/* functions */ 109/* functions */
111 110
112static int s3c2410wdt_keepalive(void) 111static void s3c2410wdt_keepalive(void)
113{ 112{
113 spin_lock(&wdt_lock);
114 writel(wdt_count, wdt_base + S3C2410_WTCNT); 114 writel(wdt_count, wdt_base + S3C2410_WTCNT);
115 return 0; 115 spin_unlock(&wdt_lock);
116} 116}
117 117
118static int s3c2410wdt_stop(void) 118static void __s3c2410wdt_stop(void)
119{ 119{
120 unsigned long wtcon; 120 unsigned long wtcon;
121 121
122 spin_lock(&wdt_lock);
122 wtcon = readl(wdt_base + S3C2410_WTCON); 123 wtcon = readl(wdt_base + S3C2410_WTCON);
123 wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN); 124 wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
124 writel(wtcon, wdt_base + S3C2410_WTCON); 125 writel(wtcon, wdt_base + S3C2410_WTCON);
126 spin_unlock(&wdt_lock);
127}
125 128
126 return 0; 129static void __s3c2410wdt_stop(void)
130{
131 unsigned long wtcon;
132
133 wtcon = readl(wdt_base + S3C2410_WTCON);
134 wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
135 writel(wtcon, wdt_base + S3C2410_WTCON);
136}
137
138static void s3c2410wdt_stop(void)
139{
140 spin_lock(&wdt_lock);
141 __s3c2410wdt_stop();
142 spin_unlock(&wdt_lock);
127} 143}
128 144
129static int s3c2410wdt_start(void) 145static void s3c2410wdt_start(void)
130{ 146{
131 unsigned long wtcon; 147 unsigned long wtcon;
132 148
133 s3c2410wdt_stop(); 149 spin_lock(&wdt_lock);
150
151 __s3c2410wdt_stop();
134 152
135 wtcon = readl(wdt_base + S3C2410_WTCON); 153 wtcon = readl(wdt_base + S3C2410_WTCON);
136 wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128; 154 wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
@@ -149,6 +167,7 @@ static int s3c2410wdt_start(void)
149 writel(wdt_count, wdt_base + S3C2410_WTDAT); 167 writel(wdt_count, wdt_base + S3C2410_WTDAT);
150 writel(wdt_count, wdt_base + S3C2410_WTCNT); 168 writel(wdt_count, wdt_base + S3C2410_WTCNT);
151 writel(wtcon, wdt_base + S3C2410_WTCON); 169 writel(wtcon, wdt_base + S3C2410_WTCON);
170 spin_unlock(&wdt_lock);
152 171
153 return 0; 172 return 0;
154} 173}
@@ -211,7 +230,7 @@ static int s3c2410wdt_set_heartbeat(int timeout)
211 230
212static int s3c2410wdt_open(struct inode *inode, struct file *file) 231static int s3c2410wdt_open(struct inode *inode, struct file *file)
213{ 232{
214 if(down_trylock(&open_lock)) 233 if (test_and_set_bit(0, &open_lock))
215 return -EBUSY; 234 return -EBUSY;
216 235
217 if (nowayout) 236 if (nowayout)
@@ -231,15 +250,14 @@ static int s3c2410wdt_release(struct inode *inode, struct file *file)
231 * Lock it in if it's a module and we set nowayout 250 * Lock it in if it's a module and we set nowayout
232 */ 251 */
233 252
234 if (allow_close == CLOSE_STATE_ALLOW) { 253 if (allow_close == CLOSE_STATE_ALLOW)
235 s3c2410wdt_stop(); 254 s3c2410wdt_stop();
236 } else { 255 else {
237 dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n"); 256 dev_err(wdt_dev, "Unexpected close, not stopping watchdog\n");
238 s3c2410wdt_keepalive(); 257 s3c2410wdt_keepalive();
239 } 258 }
240
241 allow_close = CLOSE_STATE_NOT; 259 allow_close = CLOSE_STATE_NOT;
242 up(&open_lock); 260 clear_bit(0, &open_lock);
243 return 0; 261 return 0;
244} 262}
245 263
@@ -249,7 +267,7 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
249 /* 267 /*
250 * Refresh the timer. 268 * Refresh the timer.
251 */ 269 */
252 if(len) { 270 if (len) {
253 if (!nowayout) { 271 if (!nowayout) {
254 size_t i; 272 size_t i;
255 273
@@ -265,7 +283,6 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
265 allow_close = CLOSE_STATE_ALLOW; 283 allow_close = CLOSE_STATE_ALLOW;
266 } 284 }
267 } 285 }
268
269 s3c2410wdt_keepalive(); 286 s3c2410wdt_keepalive();
270 } 287 }
271 return len; 288 return len;
@@ -273,48 +290,41 @@ static ssize_t s3c2410wdt_write(struct file *file, const char __user *data,
273 290
274#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE 291#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
275 292
276static struct watchdog_info s3c2410_wdt_ident = { 293static const struct watchdog_info s3c2410_wdt_ident = {
277 .options = OPTIONS, 294 .options = OPTIONS,
278 .firmware_version = 0, 295 .firmware_version = 0,
279 .identity = "S3C2410 Watchdog", 296 .identity = "S3C2410 Watchdog",
280}; 297};
281 298
282 299
283static int s3c2410wdt_ioctl(struct inode *inode, struct file *file, 300static long s3c2410wdt_ioctl(struct file *file, unsigned int cmd,
284 unsigned int cmd, unsigned long arg) 301 unsigned long arg)
285{ 302{
286 void __user *argp = (void __user *)arg; 303 void __user *argp = (void __user *)arg;
287 int __user *p = argp; 304 int __user *p = argp;
288 int new_margin; 305 int new_margin;
289 306
290 switch (cmd) { 307 switch (cmd) {
291 default: 308 default:
292 return -ENOTTY; 309 return -ENOTTY;
293 310 case WDIOC_GETSUPPORT:
294 case WDIOC_GETSUPPORT: 311 return copy_to_user(argp, &s3c2410_wdt_ident,
295 return copy_to_user(argp, &s3c2410_wdt_ident, 312 sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0;
296 sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0; 313 case WDIOC_GETSTATUS:
297 314 case WDIOC_GETBOOTSTATUS:
298 case WDIOC_GETSTATUS: 315 return put_user(0, p);
299 case WDIOC_GETBOOTSTATUS: 316 case WDIOC_KEEPALIVE:
300 return put_user(0, p); 317 s3c2410wdt_keepalive();
301 318 return 0;
302 case WDIOC_KEEPALIVE: 319 case WDIOC_SETTIMEOUT:
303 s3c2410wdt_keepalive(); 320 if (get_user(new_margin, p))
304 return 0; 321 return -EFAULT;
305 322 if (s3c2410wdt_set_heartbeat(new_margin))
306 case WDIOC_SETTIMEOUT: 323 return -EINVAL;
307 if (get_user(new_margin, p)) 324 s3c2410wdt_keepalive();
308 return -EFAULT; 325 return put_user(tmr_margin, p);
309 326 case WDIOC_GETTIMEOUT:
310 if (s3c2410wdt_set_heartbeat(new_margin)) 327 return put_user(tmr_margin, p);
311 return -EINVAL;
312
313 s3c2410wdt_keepalive();
314 return put_user(tmr_margin, p);
315
316 case WDIOC_GETTIMEOUT:
317 return put_user(tmr_margin, p);
318 } 328 }
319} 329}
320 330
@@ -324,7 +334,7 @@ static const struct file_operations s3c2410wdt_fops = {
324 .owner = THIS_MODULE, 334 .owner = THIS_MODULE,
325 .llseek = no_llseek, 335 .llseek = no_llseek,
326 .write = s3c2410wdt_write, 336 .write = s3c2410wdt_write,
327 .ioctl = s3c2410wdt_ioctl, 337 .unlocked_ioctl = s3c2410wdt_ioctl,
328 .open = s3c2410wdt_open, 338 .open = s3c2410wdt_open,
329 .release = s3c2410wdt_release, 339 .release = s3c2410wdt_release,
330}; 340};
@@ -411,14 +421,15 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
411 * not, try the default value */ 421 * not, try the default value */
412 422
413 if (s3c2410wdt_set_heartbeat(tmr_margin)) { 423 if (s3c2410wdt_set_heartbeat(tmr_margin)) {
414 started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); 424 started = s3c2410wdt_set_heartbeat(
425 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
415 426
416 if (started == 0) { 427 if (started == 0)
417 dev_info(dev,"tmr_margin value out of range, default %d used\n", 428 dev_info(dev,
429 "tmr_margin value out of range, default %d used\n",
418 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); 430 CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
419 } else { 431 else
420 dev_info(dev, "default timer value is out of range, cannot start\n"); 432 dev_info(dev, "default timer value is out of range, cannot start\n");
421 }
422 } 433 }
423 434
424 ret = misc_register(&s3c2410wdt_miscdev); 435 ret = misc_register(&s3c2410wdt_miscdev);
@@ -447,7 +458,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
447 (wtcon & S3C2410_WTCON_ENABLE) ? "" : "in", 458 (wtcon & S3C2410_WTCON_ENABLE) ? "" : "in",
448 (wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis", 459 (wtcon & S3C2410_WTCON_RSTEN) ? "" : "dis",
449 (wtcon & S3C2410_WTCON_INTEN) ? "" : "en"); 460 (wtcon & S3C2410_WTCON_INTEN) ? "" : "en");
450 461
451 return 0; 462 return 0;
452 463
453 err_clk: 464 err_clk:
@@ -487,7 +498,7 @@ static int s3c2410wdt_remove(struct platform_device *dev)
487 498
488static void s3c2410wdt_shutdown(struct platform_device *dev) 499static void s3c2410wdt_shutdown(struct platform_device *dev)
489{ 500{
490 s3c2410wdt_stop(); 501 s3c2410wdt_stop();
491} 502}
492 503
493#ifdef CONFIG_PM 504#ifdef CONFIG_PM
@@ -540,7 +551,8 @@ static struct platform_driver s3c2410wdt_driver = {
540}; 551};
541 552
542 553
543static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n"; 554static char banner[] __initdata =
555 KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
544 556
545static int __init watchdog_init(void) 557static int __init watchdog_init(void)
546{ 558{