[XL] Change in flashrom[master]: ite_ecfw: Implement support for flashing ITE ECs found on TUXEDO laptops

[Michael Niewöhner (Code Review)]

Attention is currently required from: Nico Huber, Michał Żygowski, Paul Menzel.

Michael Niewöhner has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/55715 )

Change subject: ite_ecfw: Implement support for flashing ITE ECs found on TUXEDO laptops
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Patch Set 30:

(1 comment)

File ite_ecfw.c:

https://review.coreboot.org/c/flashrom/+/55715/comment/07a44f68_aab65bf2 
PS29, Line 696: 	}
> Does it show something useful yet?

AFAICS the firmware only returns one (hardcoded) byte 0xef [2], even though uEcFlash reads 3 bytes. When you read more you get unreliable results for the second and third byte ofc.

I'm unsure what 0xef stands for tbh. One can read the eFlash id (RDID) via the DBGR interface like iteflash does (sending SPI cmd 0x9f). [1] My IT5570 on L140MU returns FF FF FE, which matches "EFLASH TYPE = 8315" in iteflash. I have no idea what that 8315 means. (KGD is "Known-Good-Die" by ESMT (vendor ID 0x8c) and/or Winbond (0xef).)

The vendor id of my eFlash (0xff) matches "ITEID" in one of ITE's many flash tool implementations. Maybe they just forgot to update that hardcoded value to 0xff (=ITE)?

Anyway, even uEcFlash is not doing anything with that value.

[1] https://chromium.googlesource.com/chromiumos/platform/ec/+/master/util/itefl...

[2]
```
code:00005EA2 dat_04_get_flash_id:                                                                      ; CODE XREF: FlashECCodeNew+3D↑j
code:00005EA2                 mov     DPTR, #SPIIDBuf
code:00005EA5                 mov     A, #0xEF
code:00005EA7                 movx    @DPTR, A
code:00005EA8                 jnb     Ext_Cb1.3, FlashECCodeNew_PM1
code:00005EAB                 movx    A, @DPTR
code:00005EAC                 mov     DPTR, #PM2DO
code:00005EAF                 movx    @DPTR, A
code:00005EB0                 ljmp    next
code:00005EB3 ; ---------------------------------------------------------------------------
code:00005EB3
code:00005EB3 FlashECCodeNew_PM1:                                                                                ; CODE XREF: FlashECCodeNew+98↑j
code:00005EB3                 mov     DPTR, #SPIIDBuf
code:00005EB6                 movx    A, @DPTR
code:00005EB7                 mov     DPTR, #PM1DO
code:00005EBA                 movx    @DPTR, A
code:00005EBB                 ljmp    next
```