4BA: Basic support for 4-bytes addressing mode extensions

If flash chip is switched to 4-bytes addressing mode then all
read/erase/program instructions will be switched from 3-bytes mode
to 4-bytes mode. Then well known instructions like 03h (Read),
02h (Program) and 20h,52h,D8h (Erase) will become one byte longer
and accept 4-bytes address instead of 3-bytes.

This patch provides support for well known instructions in 4-bytes
addressing mode. Also here is the code to enter 4-bytes addressing
mode by execute the instruction B7h (Enter 4-bytes mode).

Patched files
-------------
chipdrivers.h
+ added functions declarations for spi4ba.c

flash.h
+ feature definitions added

Makefile
+ added spi4ba.c

Added files
-----------
spi4ba.h
+ definitions for 4-bytes addressing JEDEC commands
+ functions declarations from spi4ba.c (same as in chipdrivers.h, just to see)

spi4ba.c
+ functions for enter 4-bytes addressing mode
+ functions for read/write/erase in 4-bytes addressing mode

Change-Id: Ie72e2a89cd75fb4d09f48e81c4c1d927c317b7a7
Signed-off-by: Boris Baykov <dev@borisbaykov.com>, Russia, Jan 2014
[clg: ported from
      https://www.flashrom.org/pipermail/flashrom/2015-January/013199.html ]
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-on: https://review.coreboot.org/20513
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

flash.h

@@ -119,6 +119,9 @@ enum write_granularity {
 #define FEATURE_WRSR_EITHER	(FEATURE_WRSR_EWSR | FEATURE_WRSR_WREN)
 #define FEATURE_OTP		(1 << 8)
 #define FEATURE_QPI		(1 << 9)
+/* Feature bits used for 4-bytes addressing mode */
+#define FEATURE_4BA_SUPPORT		(1 << 10)
+#define FEATURE_4BA_ONLY 		(1 << 11)
 
 enum test_state {
 	OK = 0,