4BA: Allow disabling 4-byte address mode for SPI flash

This allows us to support flash chips in any of the following
configurations, regardless of whether the chip powers up in 3-byte or
4-byte address mode.

- standard commands with extended address register (*_4ba_ereg) or
  direct commands (*_4ba_direct) in 3-byte address mode (.set_4ba =
  spi_exit_4ba_*)
- standard commands (*_4ba) or direct commands (*_4ba_direct) in
  4-byte address mode (.set_4ba = spi_enter_4ba_*)
- direct commands (*_4ba_direct) in either address mode (.set_4ba =
  NULL)

Change-Id: I0b25309d731426940fc50956b744b681ab599e87
Signed-off-by: Ed Swierk <eswierk@skyportsystems.com>
Reviewed-on: https://review.coreboot.org/20510
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 10 insertions, 46 deletions

diff --git a/flash.h b/flash.h
index 52f0d49f6..dfda9d253 100644
--- a/flash.h
+++ b/flash.h
@@ -119,14 +119,7 @@ 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)
-#define FEATURE_4BA_EXTENDED_ADDR_REG	(1 << 12)
-#define FEATURE_4BA_DIRECT_READ		(1 << 13)
-#define FEATURE_4BA_DIRECT_WRITE	(1 << 14)
-#define FEATURE_4BA_ALL_ERASERS_DIRECT  (1 << 15)
-#define FEATURE_4BA_ALL_DIRECT  (FEATURE_4BA_DIRECT_READ | FEATURE_4BA_DIRECT_WRITE | FEATURE_4BA_ALL_ERASERS_DIRECT)
+#define FEATURE_4BA_SUPPORT	(1 << 10)
 
 enum test_state {
 	OK = 0,
@@ -174,7 +167,7 @@ struct flashchip {
 
 	/* set of function pointers to use in 4-bytes addressing mode */
 	struct four_bytes_addr_funcs_set {
-		int (*enter_4ba) (struct flashctx *flash);
+		int (*set_4ba) (struct flashctx *flash);
 		int (*read_nbyte) (struct flashctx *flash, unsigned int addr, uint8_t *bytes, unsigned int len);
 		int (*program_byte) (struct flashctx *flash, unsigned int addr, const uint8_t databyte);
 		int (*program_nbyte) (struct flashctx *flash, unsigned int addr, const uint8_t *bytes, unsigned int len);
diff --git a/flashchips.c b/flashchips.c
index 345ef88c2..e5cf8a4ae 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -14597,10 +14597,10 @@ const struct flashchip flashchips[] = {
 		/* supports SFDP */
 		/* OTP: 1024B total, 256B reserved; read 0x48; write 0x42, erase 0x44, read ID 0x4B */
 		/* FOUR_BYTE_ADDR: supports 4-bytes addressing mode */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA_SUPPORT | FEATURE_4BA_DIRECT_READ,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA_SUPPORT,
 		.four_bytes_addr_funcs =
 		{
-			.enter_4ba = spi_enter_4ba_b7_we, /* enter 4-bytes addressing mode by CMD B7 + WREN */
+			.set_4ba = spi_enter_4ba_b7_we, /* enter 4-bytes addressing mode by CMD B7 + WREN */
 			.read_nbyte = spi_nbyte_read_4ba_direct, /* read directly from any mode, no need to enter 4ba */
 			.program_byte = spi_byte_program_4ba, /* write from 4-bytes addressing mode */
 			.program_nbyte = spi_nbyte_program_4ba /* write from 4-bytes addressing mode */
diff --git a/flashrom.c b/flashrom.c
index 8569a4960..4f17382dc 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -2223,41 +2223,12 @@ int prepare_flash_access(struct flashctx *const flash,
 	if (flash->chip->unlock)
 		flash->chip->unlock(flash);
 
-	/* Switching to 4-Bytes Addressing mode if flash chip supports it */
-	if(flash->chip->feature_bits & FEATURE_4BA_SUPPORT) {
-		/* Do not switch if chip is already in 4-bytes addressing mode */
-		if (flash->chip->feature_bits & FEATURE_4BA_ONLY) {
-			msg_cdbg("Flash chip is already in 4-bytes addressing mode.\n");
-		}
-		/* Do not switch to 4-Bytes Addressing mode if using Extended Address Register */
-		else if(flash->chip->feature_bits & FEATURE_4BA_EXTENDED_ADDR_REG) {
-			msg_cdbg("Using 4-bytes addressing with extended address register.\n");
-		}
-		/* Go to 4-Bytes Addressing mode if selected
-		   operation requires 4-Bytes Addressing mode
-		   (no need if functions are direct-4BA) */
-		else if(((read_it || verify_it)
-			&& (!(flash->chip->feature_bits & FEATURE_4BA_DIRECT_READ)))
-		   || ((erase_it || write_it)
-			&& ((flash->chip->feature_bits & FEATURE_4BA_ALL_DIRECT) != FEATURE_4BA_ALL_DIRECT))) {
-
-			if (!flash->chip->four_bytes_addr_funcs.enter_4ba) {
-				msg_cerr("No function for Enter 4-bytes addressing mode for this flash chip.\n"
-					"Please report to flashrom@flashrom.org\n");
-				return 1;
-			}
-
-			if(flash->chip->four_bytes_addr_funcs.enter_4ba(flash)) {
-				msg_cerr("Switching to 4-bytes addressing mode failed!\n");
-				return 1;
-			}
-
-			msg_cdbg("Switched to 4-bytes addressing mode.\n");
-		}
-		/* Do not switch to 4-Bytes Addressing mode if all instructions are direct-4BA
-		   or if the flash chip is 4-Bytes Addressing Only and always in 4BA-mode */
-		else {
-			msg_cdbg2("No need to switch to 4-bytes addressing mode.\n");
+	/* Enable/disable 4-byte addressing mode if flash chip supports it */
+	if ((flash->chip->feature_bits & FEATURE_4BA_SUPPORT) &&
+	    flash->chip->four_bytes_addr_funcs.set_4ba) {
+		if (flash->chip->four_bytes_addr_funcs.set_4ba(flash)) {
+			msg_cerr("Enabling/disabling 4-byte addressing mode failed!\n");
+			return 1;
 		}
 	}