ionic: no fw read when PCI reset failed

If there was a failed attempt to reset the PCI connection,
don't later try to read from PCI as the space is unmapped
and will cause a paging request crash.  When clearing the PCI
setup we can clear the dev_info register pointer, and check
it before using it in the fw_running test.

Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c

@@ -215,6 +215,11 @@ static int ionic_sriov_configure(struct pci_dev *pdev, int num_vfs)
 
 static void ionic_clear_pci(struct ionic *ionic)
 {
+	ionic->idev.dev_info_regs = NULL;
+	ionic->idev.dev_cmd_regs = NULL;
+	ionic->idev.intr_status = NULL;
+	ionic->idev.intr_ctrl = NULL;
+
 	ionic_unmap_bars(ionic);
 	pci_release_regions(ionic->pdev);
 

drivers/net/ethernet/pensando/ionic/ionic_dev.c

@@ -165,16 +165,31 @@ void ionic_dev_teardown(struct ionic *ionic)
 }
 
 /* Devcmd Interface */
-bool ionic_is_fw_running(struct ionic_dev *idev)
+static bool __ionic_is_fw_running(struct ionic_dev *idev, u8 *status_ptr)
 {
-	u8 fw_status = ioread8(&idev->dev_info_regs->fw_status);
+	u8 fw_status;
+
+	if (!idev->dev_info_regs) {
+		if (status_ptr)
+			*status_ptr = 0xff;
+		return false;
+	}
+
+	fw_status = ioread8(&idev->dev_info_regs->fw_status);
+	if (status_ptr)
+		*status_ptr = fw_status;
 
 	/* firmware is useful only if the running bit is set and
 	 * fw_status != 0xff (bad PCI read)
 	 */
 	return (fw_status != 0xff) && (fw_status & IONIC_FW_STS_F_RUNNING);
 }
 
+bool ionic_is_fw_running(struct ionic_dev *idev)
+{
+	return __ionic_is_fw_running(idev, NULL);
+}
+
 int ionic_heartbeat_check(struct ionic *ionic)
 {
 	unsigned long check_time, last_check_time;
@@ -199,10 +214,8 @@ int ionic_heartbeat_check(struct ionic *ionic)
 		goto do_check_time;
 	}
 
-	fw_status = ioread8(&idev->dev_info_regs->fw_status);
-
 	/* If fw_status is not ready don't bother with the generation */
-	if (!ionic_is_fw_running(idev)) {
+	if (!__ionic_is_fw_running(idev, &fw_status)) {
 		fw_status_ready = false;
 	} else {
 		fw_generation = fw_status & IONIC_FW_STS_F_GENERATION;