[at91sam9g45] fail to start second kernel via kexec if watchdog is enabled

[Yegor Yefremov]

>>> I have problem booting the second kernel after enabling the watchdog following these steps: http://www.at91.com/index.php?option=com_jfusion&Itemid=57&jfile=viewtopic.php&f=12&t=5551&p=29283&hilit=watchdog+bootstrap#p29283
>>> Bootstrap: don't touch watchdog
>>> U-Boot: configure watchdog and set the timer counter value to 16 seconds
>>> Linux: keep pinging the watchdog
>>>
>>> The first kernel (booted from u-boot) is working as expected, but if I start the new one using kexec it gets only till frame buffer init:
>>>
>>> ....
>>> NetWinder Floating Point Emulator V0.97 (double precision)
>>> Slow work thread pool: Starting up
>>> Slow work thread pool: Ready
>>> JFFS2 version 2.2. (NAND) -¬ 2001-2006 Red Hat, Inc.
>>> msgmni has been set to 245
>>> io scheduler noop registered
>>> io scheduler anticipatory registered (default)
>>> atmel_lcdfb atmel_lcdfb.0: backlight control is not available
>>> atmel_lcdfb atmel_lcdfb.0: 510KiB frame buffer at 77980000 (mapped at ffa00000)
>>> Start AT91Bootstrap...
>>>
>>> Without watchdog there is no problem. Both kernels (2.6.32-rc5) are the same. Any idea?
>> do you enable the watchdog in the send kernel?
> 
> Yes. But as you can see from the bootlog, the system reboots before watchdog driver will be initialized. I'll try to tap watchdog in the board init part. Maybe it will help.


It works! I just inserted watchdog reset statement into arch/arm/mach-at91/board-sam9m10g45ek.c->ek_board_init() routine:

static void __init ek_board_init(void)
{
	/* Serial */
	at91_add_device_serial();
.....
	/* LEDs */
	at91_gpio_leds(ek_leds, ARRAY_SIZE(ek_leds));
	at91_pwm_leds(ek_pwm_led, ARRAY_SIZE(ek_pwm_led));
	at91_sys_write(AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
}

It is actually a workaround, but till the real reason is figures out, it keeps the system working.

Regards,
Yegor