qed: Fix VF probe failure while FLR

VFs may hit VF-PF channel timeout while probing, as in some
cases it was observed that VF FLR and VF "acquire" message
transaction (i.e first message from VF to PF in VF's probe flow)
could occur simultaneously which could lead VF to fail sending
"acquire" message to PF as VF is marked disabled from HW perspective
due to FLR, which will result into channel timeout and VF probe failure.

In such cases, try retrying VF "acquire" message so that in later
attempts it could be successful to pass message to PF after the VF
FLR is completed and can be probed successfully.
Signed-off-by: NManish Chopra <manishc@marvell.com>
Signed-off-by: NAriel Elior <aelior@marvell.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qed/qed_vf.c

@@ -261,6 +261,7 @@ static int qed_vf_pf_acquire(struct qed_hwfn *p_hwfn)
 	struct pfvf_acquire_resp_tlv *resp = &p_iov->pf2vf_reply->acquire_resp;
 	struct pf_vf_pfdev_info *pfdev_info = &resp->pfdev_info;
 	struct vf_pf_resc_request *p_resc;
+	u8 retry_cnt = VF_ACQUIRE_THRESH;
 	bool resources_acquired = false;
 	struct vfpf_acquire_tlv *req;
 	int rc = 0, attempts = 0;
@@ -314,6 +315,15 @@ static int qed_vf_pf_acquire(struct qed_hwfn *p_hwfn)
 
 		/* send acquire request */
 		rc = qed_send_msg2pf(p_hwfn, &resp->hdr.status, sizeof(*resp));
+
+		/* Re-try acquire in case of vf-pf hw channel timeout */
+		if (retry_cnt && rc == -EBUSY) {
+			DP_VERBOSE(p_hwfn, QED_MSG_IOV,
+				   "VF retrying to acquire due to VPC timeout\n");
+			retry_cnt--;
+			continue;
+		}
+
 		if (rc)
 			goto exit;