Hi Bin, On 27 May 2015 at 10:17, Bin Meng <[email protected]> wrote: > Hi Simon, > > On Wed, May 27, 2015 at 11:37 PM, Simon Glass <[email protected]> wrote: >> Hi Bin, >> >> On 26 May 2015 at 21:50, Bin Meng <[email protected]> wrote: >>> Hi Simon, >>> >>> On Wed, May 27, 2015 at 11:13 AM, Simon Glass <[email protected]> wrote: >>>> Hi Bin, >>>> >>>> On 25 May 2015 at 08:36, Bin Meng <[email protected]> wrote: >>>>> Writing 0xcb to I/O port 0xb2 (Advanced Power Management Control) causes >>>>> U-Boot to hang on QEMU q35 target. Disable the writing for QEMU targets. >>>>> >>>>> Signed-off-by: Bin Meng <[email protected]> >>>>> --- >>>>> >>>>> arch/x86/cpu/coreboot/coreboot.c | 4 ---- >>>>> 1 file changed, 4 deletions(-) >>>>> >>>>> diff --git a/arch/x86/cpu/coreboot/coreboot.c >>>>> b/arch/x86/cpu/coreboot/coreboot.c >>>>> index 4cdd0d4..2234cf0 100644 >>>>> --- a/arch/x86/cpu/coreboot/coreboot.c >>>>> +++ b/arch/x86/cpu/coreboot/coreboot.c >>>>> @@ -85,10 +85,6 @@ void board_final_cleanup(void) >>>>> wrmsrl(MTRR_PHYS_MASK_MSR(top_mtrr), 0); >>>>> mtrr_close(&state); >>>>> } >>>>> - >>>>> - /* Issue SMI to Coreboot to lock down ME and registers */ >>>>> - printf("Finalizing Coreboot\n"); >>>>> - outb(0xcb, 0xb2); >>>>> } >>>>> >>>>> void panic_puts(const char *str) >>>>> -- >>>>> 1.8.2.1 >>>>> >>>> >>>> But how does this run with coreboot on platforms that need it? Should >>>> this be controlled by a device tree settings, perhaps? >>>> >>> >>> I am not sure if the lock down should be done by the coreboot in the >>> first place. IMHO U-Boot as the coreboot payload should not touch such >>> low-level stuff. >> >> Well it is telling coreboot that it is about to boot the kernel. I >> think this is an x86 thing and we should support it. >> > > What happens if coreboot directly boot into the kernel? Does coreboot > do the same 'outb(0xcb, 0xb2)' thing before jumping to kernel? My
Kind of, although in that case it is just a function call within coreboot. > understanding is that coreboot payload is to enhance coreboot's > functionality as a system BIOS (either having legacy BIOS interface > with the help of a SeaBIOS payload, or having UEFI interface with the > help of a TinaoCore payload). coreboot itself does the mainboard > initialization and payload does something that is not hardware > dependent. Right, but we need to tell coreboot that we have finished with the ME / registers, etc. It can't lock them before calling U-Boot since we may adjust them. Regards, Simon _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
