cxgb4: Check for firmware errors in the mailbox command loop

Check for firmware errors in the mailbox command loop and report
them differently rather than simply timing out when the firmware goes
belly up.
Signed-off-by: NHariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/t4_hw.c

@@ -293,6 +293,7 @@ int t4_wr_mbox_meat_timeout(struct adapter *adap, int mbox, const void *cmd,
 	u32 data_reg = PF_REG(mbox, CIM_PF_MAILBOX_DATA_A);
 	u32 ctl_reg = PF_REG(mbox, CIM_PF_MAILBOX_CTRL_A);
 	__be64 cmd_rpl[MBOX_LEN / 8];
+	u32 pcie_fw;
 
 	if ((size & 15) || size > MBOX_LEN)
 		return -EINVAL;
@@ -331,7 +332,10 @@ int t4_wr_mbox_meat_timeout(struct adapter *adap, int mbox, const void *cmd,
 	delay_idx = 0;
 	ms = delay[0];
 
-	for (i = 0; i < timeout; i += ms) {
+	for (i = 0;
+	     !((pcie_fw = t4_read_reg(adap, PCIE_FW_A)) & PCIE_FW_ERR_F) &&
+	     i < timeout;
+	     i += ms) {
 		if (sleep_ok) {
 			ms = delay[delay_idx];  /* last element may repeat */
 			if (delay_idx < ARRAY_SIZE(delay) - 1)
@@ -366,7 +370,7 @@ int t4_wr_mbox_meat_timeout(struct adapter *adap, int mbox, const void *cmd,
 		}
 	}
 
-	ret = -ETIMEDOUT;
+	ret = (pcie_fw & PCIE_FW_ERR_F) ? -ENXIO : -ETIMEDOUT;
 	t4_record_mbox(adap, cmd, MBOX_LEN, access, ret);
 	dev_err(adap->pdev_dev, "command %#x in mailbox %d timed out\n",
 		*(const u8 *)cmd, mbox);