[coreboot-gerrit] Change in coreboot[master]: soc/amd/common: Correct SPI FIFO size check

[Marshall Dawson (Code Review)]

Marshall Dawson has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/37721 )

Change subject: soc/amd/common: Correct SPI FIFO size check
......................................................................

soc/amd/common: Correct SPI FIFO size check

When checking that command and data fit in the FIFO, don't count the first
byte.  The command doesn't go through the FIFO.

TEST=confirm error (4+68>71) goes away on Mandolin
BUG=b:146225550

Change-Id: Ica2ca514deea401c9c5396913087e07a12ab3cf3
Signed-off-by: Marshall Dawson 
---
M src/soc/amd/common/block/spi/fch_spi_flash.c
1 file changed, 2 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/21/37721/1

diff --git a/src/soc/amd/common/block/spi/fch_spi_flash.c b/src/soc/amd/common/block/spi/fch_spi_flash.c
index 72bc5d6..93b8a14 100644
--- a/src/soc/amd/common/block/spi/fch_spi_flash.c
+++ b/src/soc/amd/common/block/spi/fch_spi_flash.c
@@ -39,7 +39,8 @@
    int ret;
    u8 buff[SPI_FIFO_DEPTH + 1];

-	if ((cmd_len + data_len) > SPI_FIFO_DEPTH)
+	/* Ensure FIFO is large enough.  First byte of command does not go in the FIFO. */
+	if ((cmd_len - 1 + data_len) > SPI_FIFO_DEPTH)
    	return -1;
    memcpy(buff, cmd, cmd_len);
    memcpy(buff + cmd_len, data, data_len);