Hi all,
finally this is what seems to happen:
1. U-boot setup timer 2 using LEVEL 7 autovectored interrupt. For this case the uClinux " movew #0x2700, %sr " in head.S don't disable the timer interrupt. 2. execution of uClinux proceed into head.S, rewriting %a7 (%sp) just after writing %sr. 3. at a certain (probably variable) moment, timer interrupt happen, and since the stack pointer is no more valid, it seems to get stucked and can't return correctly.
Solution (temporary, RFC) uBoot command bootm allows an "arch_preboot_os()":
cmd_bootm.c
case BOOTM_STATE_OS_GO: disable_interrupts(); arch_preboot_os(); boot_fn(BOOTM_STATE_OS_GO, argc, argv, &images); break;
I used it to disable LEVEL7 interrupt. Next os loading works.
NOTE: For this issue using command "go" is not possible, since it is not meant for os loading, and don't do any arch_preboot_os(); .
What i still don't understand is why this issue is not happening on other coldfire models that have UBoot and uClinux. Probably they are faster, and head.S can be processed and timers re-initialized before interrupt occours.
Let me know your thoughts.
Regards, angelo
On 03/08/2011 14:50, Greg Ungerer wrote:
Hi Angelo,
On 08/03/2011 06:09 PM, angelo wrote:
i am reporting the following issue, maybe related to something wrong in my new mcf5307 support addition (still under testing), or maybe not:
- U-Boot run correctly, timer2 is enabled as a system timestamp
counter. 2. I load a uClinux bianry from flash to SDRAM with "cp.l FLASH_ADDR SDRAM_ADDR SIZE/4 3. i launch the binary with "go SDRAM_ADDR"
First startup of linux (head.S) is locked, since U-boot timer2 interrupt happen, exactly while linux startup (in head.S) is moving ROMFS inside sdram. After the interrupt happen, i was assuming it return correctly allowing linux to load, but execution is locked inside this ROMFS copy of head.S.
Disabling the timer2 init in board.c, linux is loaded as expected.
Shouldn't timer2 be disabled for al coldfire models before loading linux ?
What interrupt level is timer2 set to?
The second instruction into running uClinux is:
movew #0x2700, %srwhich will disable all interrupts - excepting anything set to the non-maskable level 7.
Regards Greg
Greg Ungerer -- Principal Engineer EMAIL: gerg@snapgear.com SnapGear Group, McAfee PHONE: +61 7 3435 2888 8 Gardner Close, FAX: +61 7 3891 3630 Milton, QLD, 4064, Australia WEB: http://www.SnapGear.com
