Re: [U-Boot] [PATCH u-boot sunxi 3/4] sunxi: Implement reset_cpu

sön 2014-03-16 klockan 14:53 +0100 skrev Hans de Goede:

void reset_cpu(ulong addr) {

• static const struct sunxi_wdog *wdog =

•  &((struct sunxi_timer_reg *)SUNXI_TIMER_BASE)->wdog;
  

• /* Set the watchdog for its shortest interval (.5s) and wait */
• writel(WDT_MODE_RESET_EN | WDT_MODE_EN, &wdog->mode);
• writel(WDT_CTRL_RESTART, &wdog->ctl);
• while (1);

This code is incomplete and do not reload the watchdog if already running. wdog->ctl is locked by a magic key. Should use

writel(WDT_CTRL_KEY | WDT_CTRL_RESTART, &wdog->ctl);

where

#define WDT_CTRL_KEY (0x0a57 << 1)

Unfortunatley Allwinner kindly omitted this little detail from the User Manual.

Found out while trying to use the watchdog as a watchdog and not only reset. Asked Tom while he still was at Allwinner and got clarification on how to use the watchdog control register.

Regards Henrik