ionic: check cmd_regs before copying in or out

Since we now have potential cases of NULL cmd_regs and info_regs
during a reset recovery, and left NULL if a reset recovery has
failed, we need to check that they exist before we use them.
Most of the cases were covered in the original patch where we
verify before doing the ioreadb() for health or cmd status.
However, we need to protect a few uses of io mem that could
be hit in error recovery or asynchronous threads calls as well
(e.g. ethtool or devlink handlers).

Fixes: 219e183272b4 ("ionic: no fw read when PCI reset failed")
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

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

@@ -319,22 +319,32 @@ do_check_time:
 
 u8 ionic_dev_cmd_status(struct ionic_dev *idev)
 {
+	if (!idev->dev_cmd_regs)
+		return (u8)PCI_ERROR_RESPONSE;
 	return ioread8(&idev->dev_cmd_regs->comp.comp.status);
 }
 
 bool ionic_dev_cmd_done(struct ionic_dev *idev)
 {
+	if (!idev->dev_cmd_regs)
+		return false;
 	return ioread32(&idev->dev_cmd_regs->done) & IONIC_DEV_CMD_DONE;
 }
 
 void ionic_dev_cmd_comp(struct ionic_dev *idev, union ionic_dev_cmd_comp *comp)
 {
+	if (!idev->dev_cmd_regs)
+		return;
 	memcpy_fromio(comp, &idev->dev_cmd_regs->comp, sizeof(*comp));
 }
 
 void ionic_dev_cmd_go(struct ionic_dev *idev, union ionic_dev_cmd *cmd)
 {
 	idev->opcode = cmd->cmd.opcode;
+
+	if (!idev->dev_cmd_regs)
+		return;
+
 	memcpy_toio(&idev->dev_cmd_regs->cmd, cmd, sizeof(*cmd));
 	iowrite32(0, &idev->dev_cmd_regs->done);
 	iowrite32(1, &idev->dev_cmd_regs->doorbell);

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

@@ -90,18 +90,23 @@ static void ionic_get_regs(struct net_device *netdev, struct ethtool_regs *regs,
 			   void *p)
 {
 	struct ionic_lif *lif = netdev_priv(netdev);
+	struct ionic_dev *idev;
 	unsigned int offset;
 	unsigned int size;
 
 	regs->version = IONIC_DEV_CMD_REG_VERSION;
 
+	idev = &lif->ionic->idev;
+	if (!idev->dev_info_regs)
+		return;
+
 	offset = 0;
 	size = IONIC_DEV_INFO_REG_COUNT * sizeof(u32);
 	memcpy_fromio(p + offset, lif->ionic->idev.dev_info_regs->words, size);
 
 	offset += size;
 	size = IONIC_DEV_CMD_REG_COUNT * sizeof(u32);
-	memcpy_fromio(p + offset, lif->ionic->idev.dev_cmd_regs->words, size);
+	memcpy_fromio(p + offset, idev->dev_cmd_regs->words, size);
 }
 
 static void ionic_get_link_ext_stats(struct net_device *netdev,

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

@@ -109,6 +109,11 @@ int ionic_firmware_update(struct ionic_lif *lif, const struct firmware *fw,
 	dl = priv_to_devlink(ionic);
 	devlink_flash_update_status_notify(dl, "Preparing to flash", NULL, 0, 0);
 
+	if (!idev->dev_cmd_regs) {
+		err = -ENXIO;
+		goto err_out;
+	}
+
 	buf_sz = sizeof(idev->dev_cmd_regs->data);
 
 	netdev_dbg(netdev,

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

@@ -416,6 +416,9 @@ static void ionic_dev_cmd_clean(struct ionic *ionic)
 {
 	struct ionic_dev *idev = &ionic->idev;
 
+	if (!idev->dev_cmd_regs)
+		return;
+
 	iowrite32(0, &idev->dev_cmd_regs->doorbell);
 	memset_io(&idev->dev_cmd_regs->cmd, 0, sizeof(idev->dev_cmd_regs->cmd));
 }