[flashrom] [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 <c-d.hailfinger.devel.2006 at gmx.net>

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 "
 			 "flashrom at flashrom.org\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:

-- 
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