diff options
Diffstat (limited to 'drivers/char/watchdog/shwdt.c')
| -rw-r--r-- | drivers/char/watchdog/shwdt.c | 110 |
1 files changed, 75 insertions, 35 deletions
diff --git a/drivers/char/watchdog/shwdt.c b/drivers/char/watchdog/shwdt.c index 1355038f1044..e5b8c64f1d65 100644 --- a/drivers/char/watchdog/shwdt.c +++ b/drivers/char/watchdog/shwdt.c @@ -27,7 +27,7 @@ #include <linux/notifier.h> #include <linux/ioport.h> #include <linux/fs.h> - +#include <linux/mm.h> #include <asm/io.h> #include <asm/uaccess.h> #include <asm/watchdog.h> @@ -125,7 +125,6 @@ static void sh_wdt_start(void) /** * sh_wdt_stop - Stop the Watchdog - * * Stops the watchdog. */ static void sh_wdt_stop(void) @@ -141,22 +140,20 @@ static void sh_wdt_stop(void) /** * sh_wdt_keepalive - Keep the Userspace Watchdog Alive - * * The Userspace watchdog got a KeepAlive: schedule the next heartbeat. */ -static void sh_wdt_keepalive(void) +static inline void sh_wdt_keepalive(void) { next_heartbeat = jiffies + (heartbeat * HZ); } /** * sh_wdt_set_heartbeat - Set the Userspace Watchdog heartbeat - * * Set the Userspace Watchdog heartbeat */ static int sh_wdt_set_heartbeat(int t) { - if ((t < 1) || (t > 3600)) /* arbitrary upper limit */ + if (unlikely((t < 1) || (t > 3600))) /* arbitrary upper limit */ return -EINVAL; heartbeat = t; @@ -165,7 +162,6 @@ static int sh_wdt_set_heartbeat(int t) /** * sh_wdt_ping - Ping the Watchdog - * * @data: Unused * * Clears overflow bit, resets timer counter. @@ -182,14 +178,13 @@ static void sh_wdt_ping(unsigned long data) sh_wdt_write_cnt(0); mod_timer(&timer, next_ping_period(clock_division_ratio)); - } else { - printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n"); - } + } else + printk(KERN_WARNING PFX "Heartbeat lost! Will not ping " + "the watchdog\n"); } /** * sh_wdt_open - Open the Device - * * @inode: inode of device * @file: file handle of device * @@ -209,7 +204,6 @@ static int sh_wdt_open(struct inode *inode, struct file *file) /** * sh_wdt_close - Close the Device - * * @inode: inode of device * @file: file handle of device * @@ -220,7 +214,8 @@ static int sh_wdt_close(struct inode *inode, struct file *file) if (shwdt_expect_close == 42) { sh_wdt_stop(); } else { - printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); + printk(KERN_CRIT PFX "Unexpected close, not " + "stopping watchdog!\n"); sh_wdt_keepalive(); } @@ -232,7 +227,6 @@ static int sh_wdt_close(struct inode *inode, struct file *file) /** * sh_wdt_write - Write to Device - * * @file: file handle of device * @buf: buffer to write * @count: length of buffer @@ -264,8 +258,56 @@ static ssize_t sh_wdt_write(struct file *file, const char *buf, } /** - * sh_wdt_ioctl - Query Device + * sh_wdt_mmap - map WDT/CPG registers into userspace + * @file: file structure for the device + * @vma: VMA to map the registers into + * + * A simple mmap() implementation for the corner cases where the counter + * needs to be mapped in userspace directly. Due to the relatively small + * size of the area, neighbouring registers not necessarily tied to the + * CPG will also be accessible through the register page, so this remains + * configurable for users that really know what they're doing. * + * Additionaly, the register page maps in the CPG register base relative + * to the nearest page-aligned boundary, which requires that userspace do + * the appropriate CPU subtype math for calculating the page offset for + * the counter value. + */ +static int sh_wdt_mmap(struct file *file, struct vm_area_struct *vma) +{ + int ret = -ENOSYS; + +#ifdef CONFIG_SH_WDT_MMAP + unsigned long addr; + + /* Only support the simple cases where we map in a register page. */ + if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff) + return -EINVAL; + + /* + * Pick WTCNT as the start, it's usually the first register after the + * FRQCR, and neither one are generally page-aligned out of the box. + */ + addr = WTCNT & ~(PAGE_SIZE - 1); + + vma->vm_flags |= VM_IO; + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + + if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT, + PAGE_SIZE, vma->vm_page_prot)) { + printk(KERN_ERR PFX "%s: io_remap_pfn_range failed\n", + __FUNCTION__); + return -EAGAIN; + } + + ret = 0; +#endif + + return ret; +} + +/** + * sh_wdt_ioctl - Query Device * @inode: inode of device * @file: file handle of device * @cmd: watchdog command @@ -326,7 +368,6 @@ static int sh_wdt_ioctl(struct inode *inode, struct file *file, /** * sh_wdt_notify_sys - Notifier Handler - * * @this: notifier block * @code: notifier event * @unused: unused @@ -337,9 +378,8 @@ static int sh_wdt_ioctl(struct inode *inode, struct file *file, static int sh_wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused) { - if (code == SYS_DOWN || code == SYS_HALT) { + if (code == SYS_DOWN || code == SYS_HALT) sh_wdt_stop(); - } return NOTIFY_DONE; } @@ -351,10 +391,12 @@ static const struct file_operations sh_wdt_fops = { .ioctl = sh_wdt_ioctl, .open = sh_wdt_open, .release = sh_wdt_close, + .mmap = sh_wdt_mmap, }; static struct watchdog_info sh_wdt_info = { - .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | + WDIOF_MAGICCLOSE, .firmware_version = 1, .identity = "SH WDT", }; @@ -371,7 +413,6 @@ static struct miscdevice sh_wdt_miscdev = { /** * sh_wdt_init - Initialize module - * * Registers the device and notifier handler. Actual device * initialization is handled by sh_wdt_open(). */ @@ -381,15 +422,15 @@ static int __init sh_wdt_init(void) if ((clock_division_ratio < 0x5) || (clock_division_ratio > 0x7)) { clock_division_ratio = WTCSR_CKS_4096; - printk(KERN_INFO PFX "clock_division_ratio value must be 0x5<=x<=0x7, using %d\n", - clock_division_ratio); + printk(KERN_INFO PFX "clock_division_ratio value must " + "be 0x5<=x<=0x7, using %d\n", clock_division_ratio); } - if (sh_wdt_set_heartbeat(heartbeat)) - { + rc = sh_wdt_set_heartbeat(heartbeat); + if (unlikely(rc)) { heartbeat = WATCHDOG_HEARTBEAT; - printk(KERN_INFO PFX "heartbeat value must be 1<=x<=3600, using %d\n", - heartbeat); + printk(KERN_INFO PFX "heartbeat value must " + "be 1<=x<=3600, using %d\n", heartbeat); } init_timer(&timer); @@ -397,15 +438,16 @@ static int __init sh_wdt_init(void) timer.data = 0; rc = register_reboot_notifier(&sh_wdt_notifier); - if (rc) { - printk(KERN_ERR PFX "Can't register reboot notifier (err=%d)\n", rc); + if (unlikely(rc)) { + printk(KERN_ERR PFX "Can't register reboot notifier (err=%d)\n", + rc); return rc; } rc = misc_register(&sh_wdt_miscdev); - if (rc) { - printk(KERN_ERR PFX "Can't register miscdev on minor=%d (err=%d)\n", - sh_wdt_miscdev.minor, rc); + if (unlikely(rc)) { + printk(KERN_ERR PFX "Can't register miscdev on " + "minor=%d (err=%d)\n", sh_wdt_miscdev.minor, rc); unregister_reboot_notifier(&sh_wdt_notifier); return rc; } @@ -418,7 +460,6 @@ static int __init sh_wdt_init(void) /** * sh_wdt_exit - Deinitialize module - * * Unregisters the device and notifier handler. Actual device * deinitialization is handled by sh_wdt_close(). */ @@ -434,14 +475,13 @@ MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); module_param(clock_division_ratio, int, 0); -MODULE_PARM_DESC(clock_division_ratio, "Clock division ratio. Valid ranges are from 0x5 (1.31ms) to 0x7 (5.25ms). Defaults to 0x7."); +MODULE_PARM_DESC(clock_division_ratio, "Clock division ratio. Valid ranges are from 0x5 (1.31ms) to 0x7 (5.25ms). (default=" __MODULE_STRING(clock_division_ratio) ")"); module_param(heartbeat, int, 0); MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (1<=heartbeat<=3600, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")"); module_param(nowayout, int, 0); -MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); module_init(sh_wdt_init); module_exit(sh_wdt_exit); - |