diff options
Diffstat (limited to 'drivers/watchdog/rc32434_wdt.c')
-rw-r--r-- | drivers/watchdog/rc32434_wdt.c | 275 |
1 files changed, 141 insertions, 134 deletions
diff --git a/drivers/watchdog/rc32434_wdt.c b/drivers/watchdog/rc32434_wdt.c index 57027f4653c..f6cccc9df02 100644 --- a/drivers/watchdog/rc32434_wdt.c +++ b/drivers/watchdog/rc32434_wdt.c @@ -17,121 +17,127 @@ * */ -#include <linux/module.h> -#include <linux/types.h> -#include <linux/kernel.h> -#include <linux/fs.h> -#include <linux/mm.h> -#include <linux/miscdevice.h> -#include <linux/watchdog.h> -#include <linux/reboot.h> -#include <linux/smp_lock.h> -#include <linux/init.h> -#include <linux/platform_device.h> -#include <linux/uaccess.h> - -#include <asm/bootinfo.h> -#include <asm/time.h> -#include <asm/mach-rc32434/integ.h> - -#define MAX_TIMEOUT 20 -#define RC32434_WDT_INTERVAL (15 * HZ) - -#define VERSION "0.2" +#include <linux/module.h> /* For module specific items */ +#include <linux/moduleparam.h> /* For new moduleparam's */ +#include <linux/types.h> /* For standard types (like size_t) */ +#include <linux/errno.h> /* For the -ENODEV/... values */ +#include <linux/kernel.h> /* For printk/panic/... */ +#include <linux/fs.h> /* For file operations */ +#include <linux/miscdevice.h> /* For MODULE_ALIAS_MISCDEV + (WATCHDOG_MINOR) */ +#include <linux/watchdog.h> /* For the watchdog specific items */ +#include <linux/init.h> /* For __init/__exit/... */ +#include <linux/platform_device.h> /* For platform_driver framework */ +#include <linux/spinlock.h> /* For spin_lock/spin_unlock/... */ +#include <linux/uaccess.h> /* For copy_to_user/put_user/... */ + +#include <asm/mach-rc32434/integ.h> /* For the Watchdog registers */ + +#define PFX KBUILD_MODNAME ": " + +#define VERSION "1.0" static struct { - struct completion stop; - int running; - struct timer_list timer; - int queue; - int default_ticks; unsigned long inuse; + spinlock_t io_lock; } 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; +module_param(timeout, int, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default=" + 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) +static int rc32434_wdt_set(int new_timeout) { - u32 val; - - if (!rc32434_wdt_device.inuse) { - writel(0, &wdt_reg->wtcount); + int max_to = WTCOMP2SEC((u32)-1); - val = RC32434_ERR_WRE; - writel(readl(&wdt_reg->errcs) | val, &wdt_reg->errcs); - - val = RC32434_WTC_EN; - writel(readl(&wdt_reg->wtc) | val, &wdt_reg->wtc); + if (new_timeout < 0 || new_timeout > max_to) { + printk(KERN_ERR PFX "timeout value must be between 0 and %d", + max_to); + return -EINVAL; } - rc32434_wdt_device.running++; + timeout = new_timeout; + spin_lock(&rc32434_wdt_device.io_lock); + writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare); + spin_unlock(&rc32434_wdt_device.io_lock); + + return 0; } -static void rc32434_wdt_stop(void) +static void rc32434_wdt_start(void) { - u32 val; + u32 or, nand; - if (rc32434_wdt_device.running) { + spin_lock(&rc32434_wdt_device.io_lock); - val = ~RC32434_WTC_EN; - writel(readl(&wdt_reg->wtc) & val, &wdt_reg->wtc); + /* zero the counter before enabling */ + writel(0, &wdt_reg->wtcount); - val = ~RC32434_ERR_WRE; - writel(readl(&wdt_reg->errcs) & val, &wdt_reg->errcs); + /* don't generate a non-maskable interrupt, + * do a warm reset instead */ + nand = 1 << RC32434_ERR_WNE; + or = 1 << RC32434_ERR_WRE; - rc32434_wdt_device.running = 0; - } -} + /* reset the ERRCS timeout bit in case it's set */ + nand |= 1 << RC32434_ERR_WTO; -static void rc32434_wdt_set(int new_timeout) -{ - u32 cmp = new_timeout * HZ; - u32 state, val; + SET_BITS(wdt_reg->errcs, or, nand); - 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); + /* set the timeout (either default or based on module param) */ + rc32434_wdt_set(timeout); - writel(0, &wdt_reg->wtcount); - writel(cmp, &wdt_reg->wtcompare); + /* reset WTC timeout bit and enable WDT */ + nand = 1 << RC32434_WTC_TO; + or = 1 << RC32434_WTC_EN; - /* - * restore WTC - */ + SET_BITS(wdt_reg->wtc, or, nand); - writel(readl(&wdt_reg->wtc) | state, &wdt_reg); + spin_unlock(&rc32434_wdt_device.io_lock); + printk(KERN_INFO PFX "Started watchdog timer.\n"); } -static void rc32434_wdt_reset(void) +static void rc32434_wdt_stop(void) { - ticks = rc32434_wdt_device.default_ticks; + spin_lock(&rc32434_wdt_device.io_lock); + + /* Disable WDT */ + SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN); + + spin_unlock(&rc32434_wdt_device.io_lock); + printk(KERN_INFO PFX "Stopped watchdog timer.\n"); } -static void rc32434_wdt_update(unsigned long unused) +static void rc32434_wdt_ping(void) { - if (rc32434_wdt_device.running) - ticks--; - + spin_lock(&rc32434_wdt_device.io_lock); 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); + spin_unlock(&rc32434_wdt_device.io_lock); } static int rc32434_wdt_open(struct inode *inode, struct file *file) @@ -142,19 +148,22 @@ 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 - printk(KERN_CRIT KBUILD_MODNAME - ": device closed unexpectedly. WDT will not stop !\n"); - + } else { + printk(KERN_CRIT PFX + "device closed unexpectedly. WDT will not stop!\n"); + rc32434_wdt_ping(); + } clear_bit(0, &rc32434_wdt_device.inuse); return 0; } @@ -174,10 +183,10 @@ 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; @@ -196,19 +205,16 @@ static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd, .identity = "RC32434_WDT Watchdog", }; switch (cmd) { - case WDIOC_KEEPALIVE: - rc32434_wdt_reset(); + case WDIOC_GETSUPPORT: + if (copy_to_user(argp, &ident, sizeof(ident))) + return -EFAULT; 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; - case WDIOC_GETSUPPORT: - if (copy_to_user(argp, &ident, sizeof(ident))) - return -EFAULT; - break; case WDIOC_SETOPTIONS: if (copy_from_user(&value, argp, sizeof(int))) return -EFAULT; @@ -218,18 +224,20 @@ static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd, break; case WDIOS_DISABLECARD: rc32434_wdt_stop(); + break; default: return -EINVAL; } break; + case WDIOC_KEEPALIVE: + rc32434_wdt_ping(); + break; 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: @@ -239,7 +247,7 @@ static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd, return 0; } -static struct file_operations rc32434_wdt_fops = { +static const struct file_operations rc32434_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = rc32434_wdt_write, @@ -254,47 +262,46 @@ static struct miscdevice rc32434_wdt_miscdev = { .fops = &rc32434_wdt_fops, }; -static char banner[] = KERN_INFO KBUILD_MODNAME - ": Watchdog Timer version " VERSION ", timer margin: %d sec\n"; +static char banner[] __devinitdata = KERN_INFO PFX + "Watchdog Timer version " VERSION ", timer margin: %d sec\n"; -static int rc32434_wdt_probe(struct platform_device *pdev) +static int __devinit 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"); + printk(KERN_ERR PFX "failed to retrieve resources\n"); return -ENODEV; } wdt_reg = ioremap_nocache(r->start, r->end - r->start); if (!wdt_reg) { - printk(KERN_ERR KBUILD_MODNAME - "failed to remap I/O resources\n"); + printk(KERN_ERR PFX "failed to remap I/O resources\n"); return -ENXIO; } - ret = misc_register(&rc32434_wdt_miscdev); + spin_lock_init(&rc32434_wdt_device.io_lock); + + /* Make sure the watchdog is not running */ + rc32434_wdt_stop(); + + /* Check that the heartbeat value is within it's range; + * if not reset to the default */ + if (rc32434_wdt_set(timeout)) { + rc32434_wdt_set(WATCHDOG_TIMEOUT); + printk(KERN_INFO PFX + "timeout value must be between 0 and %d\n", + WTCOMP2SEC((u32)-1)); + } + ret = misc_register(&rc32434_wdt_miscdev); if (ret < 0) { - printk(KERN_ERR KBUILD_MODNAME - "failed to register watchdog device\n"); + printk(KERN_ERR PFX "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; @@ -304,35 +311,35 @@ unmap: return ret; } -static int rc32434_wdt_remove(struct platform_device *pdev) +static int __devexit 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; } -static struct platform_driver rc32434_wdt = { - .probe = rc32434_wdt_probe, - .remove = rc32434_wdt_remove, - .driver = { - .name = "rc32434_wdt", +static void rc32434_wdt_shutdown(struct platform_device *pdev) +{ + rc32434_wdt_stop(); +} + +static struct platform_driver rc32434_wdt_driver = { + .probe = rc32434_wdt_probe, + .remove = __devexit_p(rc32434_wdt_remove), + .shutdown = rc32434_wdt_shutdown, + .driver = { + .name = "rc32434_wdt", } }; static int __init rc32434_wdt_init(void) { - return platform_driver_register(&rc32434_wdt); + return platform_driver_register(&rc32434_wdt_driver); } static void __exit rc32434_wdt_exit(void) { - platform_driver_unregister(&rc32434_wdt); + platform_driver_unregister(&rc32434_wdt_driver); } module_init(rc32434_wdt_init); |