Change in flashrom[master]: flashchips.c: Drop incorrect `FEATURE_4BA_ENTER_EAR7` uses

[Angel Pons (Code Review)]

Attention is currently required from: Nico Huber, Thomas Heijligen.
Hello Nico Huber, Thomas Heijligen,

I'd like you to do a code review. Please visit

https://review.coreboot.org/c/flashrom/+/64424

to review the following change.

Change subject: flashchips.c: Drop incorrect `FEATURE_4BA_ENTER_EAR7` uses
......................................................................

flashchips.c: Drop incorrect `FEATURE_4BA_ENTER_EAR7` uses

Using `FEATURE_4BA_ENTER_EAR7` along with `FEATURE_4BA` does not make
sense, as `FEATURE_4BA` implies `FEATURE_4BA_ENTER` and the `spi25.c`
function `spi_enter_exit_4ba()` only handles `FEATURE_4BA_ENTER_EAR7`
if `FEATURE_4BA_ENTER` is not set.

Besides, the datasheet for the two affected chips says the following:

Note: The EN4B instruction will set the Bit 7 (EXTADD) of the
        volatile Bank Address Register to "1", but will not change
        the non-volatile Bank Address Register.

This means the chip itself will set the bit that flashrom would set to
enable 4BA mode when `FEATURE_4BA_ENTER_EAR7` is effective. This seems
to be some sort of backwards compatibility behavior with software that
uses the EXTADD bit to know whether the flash chip is in 4BA mode.

Change-Id: I5510bab25dbb04c12ef8d6bd3fcb6faa51d6a1e8
Signed-off-by: Angel Pons 
---
M flashchips.c
1 file changed, 2 insertions(+), 2 deletions(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/24/64424/1

diff --git a/flashchips.c b/flashchips.c
index d155b24..dfa717b 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -7470,7 +7470,7 @@
    	/* supports SFDP */
    	/* OTP: 1024B total; read 0x68; write 0x62, erase 0x64, read ID 0x4B */
    	/* FOUR_BYTE_ADDR: supports 4-bytes addressing mode */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA | FEATURE_4BA_ENTER_EAR7,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA,
    	.tested		= TEST_OK_PREW,
    	.probe		= probe_spi_rdid,
    	.probe_timing	= TIMING_ZERO,
@@ -7646,7 +7646,7 @@
    	/* supports SFDP */
    	/* OTP: 1024B total; read 0x68; write 0x62, erase 0x64, read ID 0x4B */
    	/* FOUR_BYTE_ADDR: supports 4-bytes addressing mode */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA | FEATURE_4BA_ENTER_EAR7,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA,
    	.tested		= TEST_OK_PREW,
    	.probe		= probe_spi_rdid,
    	.probe_timing	= TIMING_ZERO,