2024-06-14 17:23:11

by Ben Walsh

[permalink] [raw]
Subject: [PATCH] platform/chrome: cros_ec_lpc: Handle zero length read/write

cros_ec_lpc_mec_read_bytes and cros_ec_lpc_mec_write_bytes call
cros_ec_lpc_mec_in_range, which checks if addresses are in the MEC
address range, and returns -EINVAL if the range given is not sensible.

However cros_ec_lpc_mec_in_range was also returning -EINVAL for a zero
length range.

A zero length range should not be an error condition.
cros_ec_lpc_mec_in_range now returns 1 in this case.
cros_ec_lpc_io_bytes_mec checks for zero length, and returns
immediately without beginning a transfer.

Signed-off-by: Ben Walsh <[email protected]>
---
drivers/platform/chrome/cros_ec_lpc_mec.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/cros_ec_lpc_mec.c b/drivers/platform/chrome/cros_ec_lpc_mec.c
index dfad934e65ca..a56584171168 100644
--- a/drivers/platform/chrome/cros_ec_lpc_mec.c
+++ b/drivers/platform/chrome/cros_ec_lpc_mec.c
@@ -93,9 +93,6 @@ static void cros_ec_lpc_mec_emi_write_address(u16 addr,
*/
int cros_ec_lpc_mec_in_range(unsigned int offset, unsigned int length)
{
- if (length == 0)
- return -EINVAL;
-
if (WARN_ON(mec_emi_base == 0 || mec_emi_end == 0))
return -EINVAL;

@@ -132,6 +129,9 @@ int cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
enum cros_ec_lpc_mec_emi_access_mode access, new_access;
int ret;

+ if (length == 0)
+ return 0;
+
/* Return checksum of 0 if window is not initialized */
WARN_ON(mec_emi_base == 0 || mec_emi_end == 0);
if (mec_emi_base == 0 || mec_emi_end == 0)

base-commit: 77a714325d09e1527d865dc011ef91c4972ffedd
--
2.45.1