[coreboot-gerrit] Change in coreboot[master]: [WIP] sb/intel/common: limit smbus block read bytes according to slave

[Arthur Heymans (Code Review)]

Arthur Heymans has uploaded this change for review. ( https://review.coreboot.org/20879


Change subject: [WIP] sb/intel/common: limit smbus block read bytes according to slave
......................................................................

[WIP] sb/intel/common: limit smbus block read bytes according to slave

Should it also limit to 32?
Should it report to the user if slave bytes is less than function
input?

Change-Id: If9e5d24255a0a03039b52d2863bc278d0eefc311
Signed-off-by: Arthur Heymans <arthur at aheymans.xyz>
---
M src/southbridge/intel/common/smbus.c
1 file changed, 7 insertions(+), 2 deletions(-)



  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/79/20879/1

diff --git a/src/southbridge/intel/common/smbus.c b/src/southbridge/intel/common/smbus.c
index cac9ba7..cb884dc 100644
--- a/src/southbridge/intel/common/smbus.c
+++ b/src/southbridge/intel/common/smbus.c
@@ -193,13 +193,14 @@
 }
 
 int do_smbus_block_read(unsigned int smbus_base, u8 device, u8 cmd,
-			unsigned int bytes, u8 *buf)
+			unsigned int max_bytes, u8 *buf)
 {
 	u8 status;
 	int bytes_read = 0;
 	unsigned int loops = SMBUS_TIMEOUT;
 	if (smbus_wait_until_ready(smbus_base) < 0)
 		return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
+	u8 slave_bytes;
 
 	/* Set up transaction */
 	/* Disable interrupts */
@@ -223,6 +224,10 @@
 	if (smbus_wait_until_active(smbus_base) < 0)
 		return SMBUS_WAIT_UNTIL_ACTIVE_TIMEOUT;
 
+	slave_bytes = inb(smbus_base + SMBHSTDAT0);
+	if (slave_bytes < max_bytes)
+		max_bytes = slave_bytes;
+
 	/* Poll for transaction completion */
 	do {
 		loops--;
@@ -236,7 +241,7 @@
 			*buf = inb(smbus_base + SMBBLKDAT);
 			buf++;
 			bytes_read++;
-			if (--bytes == 1) {
+			if (--max_bytes == 1) {
 				/* indicate that next byte is the last one */
 				outb(inb(smbus_base + SMBHSTCTL)
 					| SMBHSTCNT_LAST_BYTE,

-- 
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Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: If9e5d24255a0a03039b52d2863bc278d0eefc311
Gerrit-Change-Number: 20879
Gerrit-PatchSet: 1
Gerrit-Owner: Arthur Heymans <arthur at aheymans.xyz>
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