[2/6] 4BA: Flashrom integration for the 4-bytes addressing extensions

diff --git a/flash.h b/flash.h
index 7bd4b1376d40..38b30f8d8a51 100644
--- a/flash.h
+++ b/flash.h
@@ -170,6 +170,14 @@  struct flashchip {
 	unsigned int page_size;
 	int feature_bits;
 
+	/* set of function pointers to use in 4-bytes addressing mode */
+	struct four_bytes_addr_funcs_set {
+		int (*enter_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);
+	} four_bytes_addr_funcs;
+
 	/* Indicate how well flashrom supports different operations of this flash chip. */
 	struct tested {
 		enum test_state probe;
diff --git a/flashrom.c b/flashrom.c
index 25e53f20c059..c84843fa7c4a 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -2001,6 +2001,29 @@  int doit(struct flashctx *flash, int force, const char *filename, int read_it,
 	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");
+		}
+		/* Go to 4-Bytes Addressing mode */
+		else {
+			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");
+		}
+	}
+
 	if (read_it) {
 		return read_flash_to_file(flash, filename);
 	}
diff --git a/serprog.c b/serprog.c
index 98aac8314ff0..c9d98bf099fc 100644
--- a/serprog.c
+++ b/serprog.c
@@ -945,7 +945,10 @@  static int serprog_spi_read(struct flashctx *flash, uint8_t *buf,
 	for (i = 0; i < len; i += cur_len) {
 		int ret;
 		cur_len = min(max_read, (len - i));
-		ret = spi_nbyte_read(flash, start + i, buf + i, cur_len);
+		ret = (flash->chip->feature_bits & FEATURE_4BA_SUPPORT) == 0
+			? spi_nbyte_read(flash, start + i, buf + i, cur_len)
+			: flash->chip->four_bytes_addr_funcs.read_nbyte(flash,
+						 start + i, buf + i, cur_len);
 		if (ret)
 			return ret;
 	}
diff --git a/spi.c b/spi.c
index 894f73f60f43..0a4a6184c06e 100644
--- a/spi.c
+++ b/spi.c
@@ -110,7 +110,10 @@  int spi_chip_read(struct flashctx *flash, uint8_t *buf, unsigned int start,
 	 * means 0xffffff, the highest unsigned 24bit number.
 	 */
 	addrbase = spi_get_valid_read_addr(flash);
-	if (addrbase + flash->chip->total_size * 1024 > (1 << 24)) {
+	/* Show flash chip size warning if flash chip doesn't support
+	   4-Bytes Addressing mode and last address excedes 24 bits */
+	if (!(flash->chip->feature_bits & FEATURE_4BA_SUPPORT) &&
+	    addrbase + flash->chip->total_size * 1024 > (1 << 24)) {
 		msg_perr("Flash chip size exceeds the allowed access window. ");
 		msg_perr("Read will probably fail.\n");
 		/* Try to get the best alignment subject to constraints. */
diff --git a/spi25.c b/spi25.c
index af4b6db0ea09..b38c7444e873 100644
--- a/spi25.c
+++ b/spi25.c
@@ -28,6 +28,7 @@ 
 #include "chipdrivers.h"
 #include "programmer.h"
 #include "spi.h"
+#include "spi4ba.h"
 
 static int spi_rdid(struct flashctx *flash, unsigned char *readarr, int bytes)
 {
@@ -966,7 +967,10 @@  int spi_read_chunked(struct flashctx *flash, uint8_t *buf, unsigned int start,
 		lenhere = min(start + len, (i + 1) * page_size) - starthere;
 		for (j = 0; j < lenhere; j += chunksize) {
 			toread = min(chunksize, lenhere - j);
-			rc = spi_nbyte_read(flash, starthere + j, buf + starthere - start + j, toread);
+			rc = (flash->chip->feature_bits & FEATURE_4BA_SUPPORT) == 0
+				? spi_nbyte_read(flash, starthere + j, buf + starthere - start + j, toread)
+				: flash->chip->four_bytes_addr_funcs.read_nbyte(flash, starthere + j,
+					buf + starthere - start + j, toread);
 			if (rc)
 				break;
 		}
@@ -1011,7 +1015,10 @@  int spi_write_chunked(struct flashctx *flash, const uint8_t *buf, unsigned int s
 		lenhere = min(start + len, (i + 1) * page_size) - starthere;
 		for (j = 0; j < lenhere; j += chunksize) {
 			towrite = min(chunksize, lenhere - j);
-			rc = spi_nbyte_program(flash, starthere + j, buf + starthere - start + j, towrite);
+			rc = (flash->chip->feature_bits & FEATURE_4BA_SUPPORT) == 0
+				? spi_nbyte_program(flash, starthere + j, buf + starthere - start + j, towrite)
+				: flash->chip->four_bytes_addr_funcs.program_nbyte(flash, starthere + j,
+					buf + starthere - start + j, towrite);
 			if (rc)
 				break;
 			while (spi_read_status_register(flash) & SPI_SR_WIP)
@@ -1037,7 +1044,9 @@  int spi_chip_write_1(struct flashctx *flash, const uint8_t *buf, unsigned int st
 	int result = 0;
 
 	for (i = start; i < start + len; i++) {
-		result = spi_byte_program(flash, i, buf[i - start]);
+		result = (flash->chip->feature_bits & FEATURE_4BA_SUPPORT) == 0
+			? spi_byte_program(flash, i, buf[i - start])
+			: flash->chip->four_bytes_addr_funcs.program_byte(flash, i, buf[i - start]);
 		if (result)
 			return 1;
 		while (spi_read_status_register(flash) & SPI_SR_WIP)