[M] Change in coreboot[main]: mb/google/nissa/var/rull: Match VBT with SSFC

[Subrata Banik (Code Review)]

Attention is currently required from: Dinesh Gehlot, Eric Lai, Jayvik Desai, Kun Liu, Nick Vaccaro, Rui Zhou.

Subrata Banik has posted comments on this change by Rui Zhou. ( https://review.coreboot.org/c/coreboot/+/85875?usp=email )

Change subject: mb/google/nissa/var/rull: Match VBT with SSFC
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Patch Set 2:

(1 comment)

File src/mainboard/google/brya/variants/rull/variant.c:

https://review.coreboot.org/c/coreboot/+/85875/comment/c6fc5470_25032065?usp... :
PS2, Line 47: 
            : static int get_ssfc(uint32_t *val)
            : {
            : 	static uint32_t known_value;
            : 	static enum {
            : 		SSFC_NOT_READ,
            : 		SSFC_AVAILABLE,
            : 	} ssfc_state = SSFC_NOT_READ;
            : 
            : 	if (ssfc_state == SSFC_AVAILABLE) {
            : 		*val = known_value;
            : 		return 0;
            : 	}
            : 
            : 	/*
            : 	 * If SSFC field is not in the CBI then the value of SSFC will be 0 for
            : 	 * further processing later since 0 of each bits group means default
            : 	 * component in a variant. For more detail, please refer to cbi_ssfc.h.
            : 	 */
            : 	if (google_chromeec_cbi_get_ssfc(&known_value) != 0) {
            : 		printk(BIOS_DEBUG, "SSFC not set in CBI\n");
            : 		return -1;
            : 	}
            : 
            : 	ssfc_state = SSFC_AVAILABLE;
            : 	*val = known_value;
            : 	printk(BIOS_INFO, "SSFC 0x%x.\n", known_value);
            : 	return 0;
            : }
> But here we are just calling it once.

that would be many other reason to read SSFC in AP FW scope (i mean for boot flow)

marking it resolve to allow ODM team to land this CL