[coreboot-gerrit] Change in coreboot[master]: soc/intel/common/cse: Add `cse_send_end_of_post()` a public function

[Subrata Banik (Code Review)]

Attention is currently required from: Tim Wawrzynczak, Angel Pons, Nick Vaccaro, Werner Zeh, Patrick Rudolph, EricR Lai.
Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/61519 )

Change subject: soc/intel/common/cse: Add `cse_send_end_of_post()` a public function
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Patch Set 4:

(1 comment)

File src/soc/intel/common/block/cse/cse_eop.c:

https://review.coreboot.org/c/coreboot/+/61519/comment/27ac9ec2_e9b54bd2 
PS4, Line 199: 
             : 	if (eop_sent) {
             : 		printk(BIOS_ERR, "EOP already sent\n");
             : 		return;
             : 	}
             :
> Why add the static variable and the check here? We should definitely ensure that the code isn't call […]

IMO, we should check for HW mechanism, asked Intel for sharing some insights.

I had below logic in mind
1. ideally, all HMRFPO command shouldn't pass after EOP being done. hence, sending the same command can work as indicator
2. There is one function in cse.c that checks if HMRFPO is allow, ideally this function return false post EOP.

I would prefer HW mechanism to guard the EOP calling more than once because sending more than one would trigger failure and results into recovery.