Add support for the JEDEC RES

Add support for the JEDEC RES (Read Electronic Signature and Resume from
Powerdown) SPI command to identify older SPI chips which can't handle
JEDEC RDID.

Since RES gives a one-byte identifier which is shared among many
different vendors and even different sizes, we want to match RES as a
last resort if RDID returns 0xff 0xff 0xff.

Corresponding to flashrom svn r235 and coreboot v2 svn r3320.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Peter Stuge <peter@stuge.se>

This is a heavily reworked version of a patch by Fredrik Tolf, which was
Signed-off-by: Fredrik Tolf <fredrik@dolda2000.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/spi.h b/spi.h
index 15bac4e..f5c877c 100644
--- a/spi.h
+++ b/spi.h
@@ -29,6 +29,11 @@
 #define JEDEC_RDID_OUTSIZE	0x01
 #define JEDEC_RDID_INSIZE	0x03
 
+/* Read Electronic Signature */
+#define JEDEC_RES		0xab
+#define JEDEC_RES_OUTSIZE	0x04
+#define JEDEC_RES_INSIZE	0x01
+
 /* Write Enable */
 #define JEDEC_WREN		0x06
 #define JEDEC_WREN_OUTSIZE	0x01