iteflash: speed up flash read

To save time, this patch removes unnecessary i2c transactions
in reading (verifying) flash.

BUG=none
BRANCH=none
TEST=Read 512k bytes without/with this patch:

======without patch / with patch=============
servo v2   :    36s /    14s (   22s reduced)
servo micro: 2m:13s / 1m:04s (1m:09s reduced)
c2d2       :    81s /    23s (   58s reduced)

Change-Id: I9dc05e107eaf004c4c2017de9ffe9aa97a0d9c68
Signed-off-by: Dino Li <Dino.Li@ite.com.tw>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2379368
Reviewed-by: Jett Rink <jettrink@chromium.org>
Commit-Queue: Jett Rink <jettrink@chromium.org>

1 files changed, 31 insertions, 20 deletions

diff --git a/util/iteflash.c b/util/iteflash.c
index b2c4161f1f..36e45c2012 100644
--- a/util/iteflash.c
+++ b/util/iteflash.c
@@ -1135,13 +1135,34 @@ static void draw_spinner(uint32_t remaining, uint32_t size)
 	windex %= sizeof(wheel);
 }
 
+/* Note: this function must be called in follow mode */
+static int spi_send_cmd_fast_read(struct common_hnd *chnd, uint32_t addr)
+{
+	int ret = 0;
+	uint8_t cmd = 0x9;
+
+	/* Fast Read command */
+	ret = spi_flash_command_short(chnd, SPI_CMD_FAST_READ, "fast read");
+	/* Send address */
+	ret |= i2c_write_byte(chnd, 0x08, ((addr >> 16) & 0xff)); /* addr_h */
+	ret |= i2c_write_byte(chnd, 0x08, ((addr >> 8) & 0xff));  /* addr_m */
+	ret |= i2c_write_byte(chnd, 0x08, (addr & 0xff));         /* addr_l */
+	/* fake byte */
+	ret |= i2c_write_byte(chnd, 0x08, 0x00);
+	/* use i2c block read command */
+	ret |= i2c_byte_transfer(chnd, I2C_CMD_ADDR, &cmd, 1, 1);
+	if (ret < 0)
+		fprintf(stderr, "Send fast read command failed\n");
+
+	return ret;
+}
+
 static int command_read_pages(struct common_hnd *chnd, uint32_t address,
 			      uint32_t size, uint8_t *buffer)
 {
 	int res = -EIO;
 	uint32_t remaining = size;
 	int cnt;
-	uint8_t addr_H, addr_M;
 
 	if (address & 0xFF) {
 		fprintf(stderr, "page read requested at non-page boundary: "
@@ -1152,30 +1173,14 @@ static int command_read_pages(struct common_hnd *chnd, uint32_t address,
 	if (spi_flash_follow_mode(chnd, "fast read") < 0)
 		goto failed_read;
 
-	while (remaining) {
-		uint8_t cmd = 0x9;
+	if (spi_send_cmd_fast_read(chnd, address) < 0)
+		goto failed_read;
 
+	while (remaining) {
 		cnt = (remaining > PAGE_SIZE) ? PAGE_SIZE : remaining;
-		addr_H = (address >> 16) & 0xFF;
-		addr_M = (address >> 8) & 0xFF;
-
 		draw_spinner(remaining, size);
 
-		/* Fast Read command */
-		if (spi_flash_command_short(chnd, SPI_CMD_FAST_READ,
-			"fast read") < 0)
-			goto failed_read;
-		res = i2c_write_byte(chnd, 0x08, addr_H);
-		res += i2c_write_byte(chnd, 0x08, addr_M);
-		res += i2c_write_byte(chnd, 0x08, 0x00);  /* addr_L */
-		res += i2c_write_byte(chnd, 0x08, 0x00);
-		if (res < 0) {
-			fprintf(stderr, "page address set failed\n");
-			goto failed_read;
-		}
-
 		/* read page data */
-		res = i2c_byte_transfer(chnd, I2C_CMD_ADDR, &cmd, 1, 1);
 		res = i2c_byte_transfer(chnd, I2C_BLOCK_ADDR, buffer, 0, cnt);
 		if (res < 0) {
 			fprintf(stderr, "page data read failed\n");
@@ -1185,6 +1190,12 @@ static int command_read_pages(struct common_hnd *chnd, uint32_t address,
 		address += cnt;
 		remaining -= cnt;
 		buffer += cnt;
+
+		/* We need to resend fast read command at 256KB boundary. */
+		if (!(address % 0x40000) && remaining) {
+			if (spi_send_cmd_fast_read(chnd, address) < 0)
+				goto failed_read;
+		}
 	}
 	/* No error so far */
 	res = size;