net/bnxt: enforce IO barrier for doorbell command

The doorbell ringing operation requires a rte_io_mb immediately to make
the command complete and visible to the device before reading the
response, otherwise it may read stale or invalid responses.

Fixes: ca241d9a0952 ("net/bnxt: use I/O device memory read/write API")
Cc: stable@dpdk.org
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Acked-by: Ajit Khaparde <ajit.khaparde@broadcom.com>

diff --git a/drivers/net/bnxt/bnxt_hwrm.c b/drivers/net/bnxt/bnxt_hwrm.c
index d7c33d21e24710239454df41cb3037986655c8cd..cdb6fa4f7e0bb7f4cda43ef62eb8fa111c72fc67 100644 (file)
--- a/drivers/net/bnxt/bnxt_hwrm.c
+++ b/drivers/net/bnxt/bnxt_hwrm.c
@@ -146,6 +146,12 @@ static int bnxt_hwrm_send_message(struct bnxt *bp, void *msg,
        /* Ring channel doorbell */
        bar = (uint8_t *)bp->bar0 + mb_trigger_offset;
        rte_write32(1, bar);
+       /*
+        * Make sure the channel doorbell ring command complete before
+        * reading the response to avoid getting stale or invalid
+        * responses.
+        */
+       rte_io_mb();
 
        /* Poll for the valid bit */
        for (i = 0; i < timeout; i++) {