From: Breno Lima breno.lima@nxp.com
According to i.MX7ULP Reference Manual the second word write for both UNLOCK and REFRESH operations must occur in maximum 16 bus clock.
The current code is using writel() function which has a DMB barrier to order the memory access. The DMB between two words write may introduce some delay in certain circumstance, causing a WDOG timeout due to 16 bus clock window requirement.
Replace writel() function by __raw_writel() to achieve a faster memory access and avoid such issue.
Reviewed-by: Ye Li ye.li@nxp.com Signed-off-by: Breno Lima breno.lima@nxp.com --- drivers/watchdog/ulp_wdog.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/watchdog/ulp_wdog.c b/drivers/watchdog/ulp_wdog.c index 6f63b11b9f..490a2c94ec 100644 --- a/drivers/watchdog/ulp_wdog.c +++ b/drivers/watchdog/ulp_wdog.c @@ -52,8 +52,10 @@ void hw_watchdog_reset(void) { struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
- writel(REFRESH_WORD0, &wdog->cnt); - writel(REFRESH_WORD1, &wdog->cnt); + dmb(); + __raw_writel(REFRESH_WORD0, &wdog->cnt); + __raw_writel(REFRESH_WORD1, &wdog->cnt); + dmb(); }
void hw_watchdog_init(void) @@ -61,8 +63,10 @@ void hw_watchdog_init(void) u8 val; struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
- writel(UNLOCK_WORD0, &wdog->cnt); - writel(UNLOCK_WORD1, &wdog->cnt); + dmb(); + __raw_writel(UNLOCK_WORD0, &wdog->cnt); + __raw_writel(UNLOCK_WORD1, &wdog->cnt); + dmb();
val = readb(&wdog->cs2); val |= WDGCS2_FLG; @@ -81,8 +85,10 @@ void reset_cpu(void) { struct wdog_regs *wdog = (struct wdog_regs *)WDOG_BASE_ADDR;
- writel(UNLOCK_WORD0, &wdog->cnt); - writel(UNLOCK_WORD1, &wdog->cnt); + dmb(); + __raw_writel(UNLOCK_WORD0, &wdog->cnt); + __raw_writel(UNLOCK_WORD1, &wdog->cnt); + dmb();
hw_watchdog_set_timeout(5); /* 5ms timeout */ writel(0, &wdog->win);