Always read the flash chip before writing

This will allow flashrom to skip erase of already-erased blocks and to
skip write of blocks which already have the wanted contents.

Avoid emergency messages by checking if the chip contents after a failed
write operation (erase/write) are unchanged.

Keep the emergency messages after a failed pure erase. That part is
debatable because if someone wants erase, he pretty sure doesn't care
about the flash contents anymore.

Please note that this introduces additional overhead of a full chip read
before write. This is frowned upon by people with slow programmers. A
followup patch will make this configurable.

Corresponding to flashrom svn r1215.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Reinauer <stepan@coreboot.org>

1 files changed, 4 insertions, 5 deletions

diff --git a/layout.c b/layout.c
index c01e09c..b24e4dd 100644
--- a/layout.c
+++ b/layout.c
@@ -205,7 +205,7 @@ int find_romentry(char *name)
 	return -1;
 }
 
-int handle_romentries(uint8_t *buffer, struct flashchip *flash)
+int handle_romentries(struct flashchip *flash, uint8_t *oldcontents, uint8_t *newcontents)
 {
 	int i;
 
@@ -225,13 +225,12 @@ int handle_romentries(uint8_t *buffer, struct flashchip *flash)
 	// normal will be updated and the rest will be kept.
 
 	for (i = 0; i < romimages; i++) {
-
 		if (rom_entries[i].included)
 			continue;
 
-		flash->read(flash, buffer + rom_entries[i].start,
-			    rom_entries[i].start,
-			    rom_entries[i].end - rom_entries[i].start + 1);
+		memcpy(newcontents + rom_entries[i].start, 
+		       oldcontents + rom_entries[i].start,
+		       rom_entries[i].end - rom_entries[i].start + 1);
 	}
 
 	return 0;