[PATCH] EEPROM support: handle implicit erase

[Carl-Daniel Hailfinger]

Add support for EEPROMs with 1 byte granularity and implicit erase on
write. flashrom will not try to erase before write on these chips.
Explicitly requested erase is done by writing 0xff.

Signed-off-by: Carl-Daniel Hailfinger

Index: flashrom-no_implicit_erase/flash.h
===================================================================
--- flashrom-no_implicit_erase/flash.h	(Revision 1821)
+++ flashrom-no_implicit_erase/flash.h	(Arbeitskopie)
@@ -87,6 +87,7 @@
    write_gran_528bytes,	/* If less than 528 bytes are written, the unwritten bytes are undefined. */
    write_gran_1024bytes,	/* If less than 1024 bytes are written, the unwritten bytes are undefined. */
    write_gran_1056bytes,	/* If less than 1056 bytes are written, the unwritten bytes are undefined. */
+	write_gran_1byte_implicit_erase, /* EEPROMs and other chips with implicit erase and 1-byte writes. */
 };

/*
Index: flashrom-no_implicit_erase/flashrom.c
===================================================================
--- flashrom-no_implicit_erase/flashrom.c	(Revision 1821)
+++ flashrom-no_implicit_erase/flashrom.c	(Arbeitskopie)
@@ -766,6 +766,10 @@
    case write_gran_1056bytes:
    	result = need_erase_gran_bytes(have, want, len, 1056);
    	break;
+	case write_gran_1byte_implicit_erase:
+		/* Do not erase, handle content changes from anything->0xff by writing 0xff. */
+		result = 0;
+		break;
    default:
    	msg_cerr("%s: Unsupported granularity! Please report a bug at "
    		 "[e-mail]\n", __func__);
@@ -807,6 +811,7 @@
    switch (gran) {
    case write_gran_1bit:
    case write_gran_1byte:
+	case write_gran_1byte_implicit_erase:
    	stride = 1;
    	break;
    case write_gran_256bytes:

[Carl-Daniel Hailfinger]

Am 16.06.2014 23:06 schrieb Carl-Daniel Hailfinger:
> Add support for EEPROMs with 1 byte granularity and implicit erase on
> write. flashrom will not try to erase before write on these chips.
> Explicitly requested erase is done by writing 0xff.
>
> Signed-off-by: Carl-Daniel Hailfinger

Acked-by: Stefan Tauner 
on IRC.

Thanks for the review, committed in r1822.

Regards,
Carl-Daniel