diff options
Diffstat (limited to 'drivers/watchdog')
-rw-r--r-- | drivers/watchdog/rc32434_wdt.c | 158 |
1 files changed, 64 insertions, 94 deletions
diff --git a/drivers/watchdog/rc32434_wdt.c b/drivers/watchdog/rc32434_wdt.c index 57027f4653ce..f1f98cd757c6 100644 --- a/drivers/watchdog/rc32434_wdt.c +++ b/drivers/watchdog/rc32434_wdt.c @@ -34,104 +34,89 @@ #include <asm/time.h> #include <asm/mach-rc32434/integ.h> -#define MAX_TIMEOUT 20 -#define RC32434_WDT_INTERVAL (15 * HZ) - -#define VERSION "0.2" +#define VERSION "0.3" static struct { - struct completion stop; - int running; - struct timer_list timer; - int queue; - int default_ticks; unsigned long inuse; } rc32434_wdt_device; static struct integ __iomem *wdt_reg; -static int ticks = 100 * HZ; static int expect_close; -static int timeout; + +/* Board internal clock speed in Hz, + * the watchdog timer ticks at. */ +extern unsigned int idt_cpu_freq; + +/* translate wtcompare value to seconds and vice versa */ +#define WTCOMP2SEC(x) (x / idt_cpu_freq) +#define SEC2WTCOMP(x) (x * idt_cpu_freq) + +/* Use a default timeout of 20s. This should be + * safe for CPU clock speeds up to 400MHz, as + * ((2 ^ 32) - 1) / (400MHz / 2) = 21s. */ +#define WATCHDOG_TIMEOUT 20 + +static int timeout = WATCHDOG_TIMEOUT; static int nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); +/* apply or and nand masks to data read from addr and write back */ +#define SET_BITS(addr, or, nand) \ + writel((readl(&addr) | or) & ~nand, &addr) static void rc32434_wdt_start(void) { - u32 val; - - if (!rc32434_wdt_device.inuse) { - writel(0, &wdt_reg->wtcount); + u32 or, nand; - val = RC32434_ERR_WRE; - writel(readl(&wdt_reg->errcs) | val, &wdt_reg->errcs); + /* zero the counter before enabling */ + writel(0, &wdt_reg->wtcount); - val = RC32434_WTC_EN; - writel(readl(&wdt_reg->wtc) | val, &wdt_reg->wtc); - } - rc32434_wdt_device.running++; -} + /* don't generate a non-maskable interrupt, + * do a warm reset instead */ + nand = 1 << RC32434_ERR_WNE; + or = 1 << RC32434_ERR_WRE; -static void rc32434_wdt_stop(void) -{ - u32 val; + /* reset the ERRCS timeout bit in case it's set */ + nand |= 1 << RC32434_ERR_WTO; - if (rc32434_wdt_device.running) { + SET_BITS(wdt_reg->errcs, or, nand); - val = ~RC32434_WTC_EN; - writel(readl(&wdt_reg->wtc) & val, &wdt_reg->wtc); + /* reset WTC timeout bit and enable WDT */ + nand = 1 << RC32434_WTC_TO; + or = 1 << RC32434_WTC_EN; - val = ~RC32434_ERR_WRE; - writel(readl(&wdt_reg->errcs) & val, &wdt_reg->errcs); + SET_BITS(wdt_reg->wtc, or, nand); +} - rc32434_wdt_device.running = 0; - } +static void rc32434_wdt_stop(void) +{ + /* Disable WDT */ + SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN); } -static void rc32434_wdt_set(int new_timeout) +static int rc32434_wdt_set(int new_timeout) { - u32 cmp = new_timeout * HZ; - u32 state, val; + int max_to = WTCOMP2SEC((u32)-1); + if (new_timeout < 0 || new_timeout > max_to) { + printk(KERN_ERR KBUILD_MODNAME + ": timeout value must be between 0 and %d", + max_to); + return -EINVAL; + } timeout = new_timeout; - /* - * store and disable WTC - */ - state = (u32)(readl(&wdt_reg->wtc) & RC32434_WTC_EN); - val = ~RC32434_WTC_EN; - writel(readl(&wdt_reg->wtc) & val, &wdt_reg->wtc); - - writel(0, &wdt_reg->wtcount); - writel(cmp, &wdt_reg->wtcompare); - - /* - * restore WTC - */ - - writel(readl(&wdt_reg->wtc) | state, &wdt_reg); -} + writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare); -static void rc32434_wdt_reset(void) -{ - ticks = rc32434_wdt_device.default_ticks; + return 0; } -static void rc32434_wdt_update(unsigned long unused) +static void rc32434_wdt_ping(void) { - if (rc32434_wdt_device.running) - ticks--; - writel(0, &wdt_reg->wtcount); - - if (rc32434_wdt_device.queue && ticks) - mod_timer(&rc32434_wdt_device.timer, - jiffies + RC32434_WDT_INTERVAL); - else - complete(&rc32434_wdt_device.stop); } static int rc32434_wdt_open(struct inode *inode, struct file *file) @@ -142,19 +127,23 @@ static int rc32434_wdt_open(struct inode *inode, struct file *file) if (nowayout) __module_get(THIS_MODULE); + rc32434_wdt_start(); + rc32434_wdt_ping(); + return nonseekable_open(inode, file); } static int rc32434_wdt_release(struct inode *inode, struct file *file) { - if (expect_close && nowayout == 0) { + if (expect_close == 42) { rc32434_wdt_stop(); printk(KERN_INFO KBUILD_MODNAME ": disabling watchdog timer\n"); module_put(THIS_MODULE); - } else + } else { printk(KERN_CRIT KBUILD_MODNAME ": device closed unexpectedly. WDT will not stop !\n"); - + rc32434_wdt_ping(); + } clear_bit(0, &rc32434_wdt_device.inuse); return 0; } @@ -174,10 +163,10 @@ static ssize_t rc32434_wdt_write(struct file *file, const char *data, if (get_user(c, data + i)) return -EFAULT; if (c == 'V') - expect_close = 1; + expect_close = 42; } } - rc32434_wdt_update(0); + rc32434_wdt_ping(); return len; } return 0; @@ -197,11 +186,11 @@ static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd, }; switch (cmd) { case WDIOC_KEEPALIVE: - rc32434_wdt_reset(); + rc32434_wdt_ping(); break; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: - value = readl(&wdt_reg->wtcount); + value = 0; if (copy_to_user(argp, &value, sizeof(int))) return -EFAULT; break; @@ -218,6 +207,7 @@ static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd, break; case WDIOS_DISABLECARD: rc32434_wdt_stop(); + break; default: return -EINVAL; } @@ -225,11 +215,9 @@ static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd, case WDIOC_SETTIMEOUT: if (copy_from_user(&new_timeout, argp, sizeof(int))) return -EFAULT; - if (new_timeout < 1) + if (rc32434_wdt_set(new_timeout)) return -EINVAL; - if (new_timeout > MAX_TIMEOUT) - return -EINVAL; - rc32434_wdt_set(new_timeout); + /* Fall through */ case WDIOC_GETTIMEOUT: return copy_to_user(argp, &timeout, sizeof(int)); default: @@ -262,7 +250,7 @@ static int rc32434_wdt_probe(struct platform_device *pdev) int ret; struct resource *r; - r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb500_wdt_res"); + r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res"); if (!r) { printk(KERN_ERR KBUILD_MODNAME "failed to retrieve resources\n"); @@ -277,24 +265,12 @@ static int rc32434_wdt_probe(struct platform_device *pdev) } ret = misc_register(&rc32434_wdt_miscdev); - if (ret < 0) { printk(KERN_ERR KBUILD_MODNAME "failed to register watchdog device\n"); goto unmap; } - init_completion(&rc32434_wdt_device.stop); - rc32434_wdt_device.queue = 0; - - clear_bit(0, &rc32434_wdt_device.inuse); - - setup_timer(&rc32434_wdt_device.timer, rc32434_wdt_update, 0L); - - rc32434_wdt_device.default_ticks = ticks; - - rc32434_wdt_start(); - printk(banner, timeout); return 0; @@ -306,14 +282,8 @@ unmap: static int rc32434_wdt_remove(struct platform_device *pdev) { - if (rc32434_wdt_device.queue) { - rc32434_wdt_device.queue = 0; - wait_for_completion(&rc32434_wdt_device.stop); - } misc_deregister(&rc32434_wdt_miscdev); - iounmap(wdt_reg); - return 0; } |