[PATCH 5.19 690/717] hwmon (occ): Retry for checksum failure

Greg Kroah-Hartman
2022-10-22T08:50:01Z

From: Eddie James <eajames@linux.ibm.com>

[ Upstream commit dbed963ed62c4c2b8870a02c8b7dcb0c2af3ee0b ]

Due to the OCC communication design with a shared SRAM area,
checkum errors are expected due to corrupted buffer from OCC
communications with other system components. Therefore, retry
the command twice in the event of a checksum failure.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220426154956.27205-3-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwmon/occ/p9_sbe.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/hwmon/occ/p9_sbe.c b/drivers/hwmon/occ/p9_sbe.c
index a91937e28e12..775147f31cb1 100644
--- a/drivers/hwmon/occ/p9_sbe.c
+++ b/drivers/hwmon/occ/p9_sbe.c
@@ -14,6 +14,8 @@

#include "common.h"

+#define OCC_CHECKSUM_RETRIES 3
+
struct p9_sbe_occ {
struct occ occ;
bool sbe_error;
@@ -81,18 +83,23 @@ static bool p9_sbe_occ_save_ffdc(struct p9_sbe_occ *ctx, const void *resp,
static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd, size_t len,
void *resp, size_t resp_len)
{
+ size_t original_resp_len = resp_len;
struct p9_sbe_occ *ctx = to_p9_sbe_occ(occ);
- int rc;
+ int rc, i;

- rc = fsi_occ_submit(ctx->sbe, cmd, len, resp, &resp_len);
- if (rc < 0) {
+ for (i = 0; i < OCC_CHECKSUM_RETRIES; ++i) {
+ rc = fsi_occ_submit(ctx->sbe, cmd, len, resp, &resp_len);
+ if (rc >= 0)
+ break;
if (resp_len) {
if (p9_sbe_occ_save_ffdc(ctx, resp, resp_len))
sysfs_notify(&occ->bus_dev->kobj, NULL,
bin_attr_ffdc.attr.name);
+ return rc;
}
-
- return rc;
+ if (rc != -EBADE)
+ return rc;
+ resp_len = original_resp_len;
}

switch (((struct occ_response *)resp)->return_status) {
--
2.35.1