[coreboot] How to trigger SMI and implement SMM

[Stefan Reinauer]

* Yu-Cheng Liu <peter90609 at gmail.com> [150721 11:04]:
> Hello,
> 
> I purpose to trigger SMI event and do something in SMM mode .
> 
>  
> 
> I trace the coreboot source code and found that, during the coreboot
> environment setup, the file locate at southbridge/intel/i82801ix/smi.c  will be
> excute. Is it enough for SMI/SMM operation?

That is just the code that installs the SMM handler (well, part of it)

> I didn’t see the code under cpu/smm be locate in the ramstage.debug symbol.

The SMM handler is a separate module.

> What is the different purpose between southbridge/intel/i82801ix/smi.c and /cpu
> /x86/smm?

The code in southbridge/intel/i82801ix/smi.c is the chipset specific SMI
initialization. southbridge/intel/i82801ix/smihandler.c is the chipset
specific SMI handler.

The code under cpu/x86/smm is generic for the x86 architecture.

> How do I trigger the SMI event?

Typically hardware triggers an SMI, e.g. on a GPE event, timeout, or
such. See southbridge/intel/i82801ix/smihandler.c for a more
comprehensive list of southbridge SMI sources.

You can also use the APMC SMI command mechanism to manually trigger
SMIs, see southbridge_smi_apmc(void) for details.

Stefan