diff options
Diffstat (limited to 'drivers/char/watchdog')
| -rw-r--r-- | drivers/char/watchdog/mv64x60_wdt.c | 90 |
1 files changed, 54 insertions, 36 deletions
diff --git a/drivers/char/watchdog/mv64x60_wdt.c b/drivers/char/watchdog/mv64x60_wdt.c index 07582bb..0365c31 100644 --- a/drivers/char/watchdog/mv64x60_wdt.c +++ b/drivers/char/watchdog/mv64x60_wdt.c @@ -29,75 +29,95 @@ #define MV64x60_WDT_WDC_OFFSET 0 -/* MV64x60 WDC (config) register access definitions */ -#define MV64x60_WDC_CTL1_MASK (3 << 24) -#define MV64x60_WDC_CTL1(val) ((val & 3) << 24) -#define MV64x60_WDC_CTL2_MASK (3 << 26) -#define MV64x60_WDC_CTL2(val) ((val & 3) << 26) +/* + * The watchdog configuration register contains a pair of 2-bit fields, + * 1. a reload field, bits 27-26, which triggers a reload of + * the countdown register, and + * 2. an enable field, bits 25-24, which toggles between + * enabling and disabling the watchdog timer. + * Bit 31 is a read-only field which indicates whether the + * watchdog timer is currently enabled. + * + * The low 24 bits contain the timer reload value. + */ +#define MV64x60_WDC_ENABLE_SHIFT 24 +#define MV64x60_WDC_SERVICE_SHIFT 26 +#define MV64x60_WDC_ENABLED_SHIFT 31 + +#define MV64x60_WDC_ENABLED_TRUE 1 +#define MV64x60_WDC_ENABLED_FALSE 0 /* Flags bits */ #define MV64x60_WDOG_FLAG_OPENED 0 -#define MV64x60_WDOG_FLAG_ENABLED 1 static unsigned long wdt_flags; static int wdt_status; static void __iomem *mv64x60_wdt_regs; static int mv64x60_wdt_timeout; +static int mv64x60_wdt_count; static unsigned int bus_clk; static char expect_close; +static DEFINE_SPINLOCK(mv64x60_wdt_spinlock); 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) ")"); -static void mv64x60_wdt_reg_write(u32 val) +static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift) { - /* Allow write only to CTL1 / CTL2 fields, retaining values in - * other fields. - */ - u32 data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); - data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK); - data |= val; - writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); + u32 data; + u32 enabled; + int ret = 0; + + spin_lock(&mv64x60_wdt_spinlock); + data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); + enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1; + + /* only toggle the requested field if enabled state matches predicate */ + if ((enabled ^ enabled_predicate) == 0) { + /* We write a 1, then a 2 -- to the appropriate field */ + data = (1 << field_shift) | mv64x60_wdt_count; + writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); + + data = (2 << field_shift) | mv64x60_wdt_count; + writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); + ret = 1; + } + spin_unlock(&mv64x60_wdt_spinlock); + + return ret; } static void mv64x60_wdt_service(void) { - /* Write 01 followed by 10 to CTL2 */ - mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01)); - mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02)); + mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE, + MV64x60_WDC_SERVICE_SHIFT); } -static void mv64x60_wdt_handler_disable(void) +static void mv64x60_wdt_handler_enable(void) { - if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) { - /* Write 01 followed by 10 to CTL1 */ - mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01)); - mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02)); - printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n"); + if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE, + MV64x60_WDC_ENABLE_SHIFT)) { + mv64x60_wdt_service(); + printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n"); } } -static void mv64x60_wdt_handler_enable(void) +static void mv64x60_wdt_handler_disable(void) { - if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) { - /* Write 01 followed by 10 to CTL1 */ - mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01)); - mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02)); - printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n"); - } + if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE, + MV64x60_WDC_ENABLE_SHIFT)) + printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n"); } -static void mv64x60_wdt_set_timeout(int timeout) +static void mv64x60_wdt_set_timeout(unsigned int timeout) { /* maximum bus cycle count is 0xFFFFFFFF */ if (timeout > 0xFFFFFFFF / bus_clk) timeout = 0xFFFFFFFF / bus_clk; + mv64x60_wdt_count = timeout * bus_clk >> 8; mv64x60_wdt_timeout = timeout; - writel((timeout * bus_clk) >> 8, - mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET); - mv64x60_wdt_service(); } static int mv64x60_wdt_open(struct inode *inode, struct file *file) @@ -108,7 +128,6 @@ static int mv64x60_wdt_open(struct inode *inode, struct file *file) if (nowayout) __module_get(THIS_MODULE); - mv64x60_wdt_service(); mv64x60_wdt_handler_enable(); return nonseekable_open(inode, file); @@ -270,7 +289,6 @@ static int __devexit mv64x60_wdt_remove(struct platform_device *dev) { misc_deregister(&mv64x60_wdt_miscdev); - mv64x60_wdt_service(); mv64x60_wdt_handler_disable(); iounmap(mv64x60_wdt_regs); |