[PATCH net-next] net: xilinx: axienet: Treat xlnx,rxmem as a required property

[Suraj Gupta <suraj.gupta2@amd.com>]

"xlnx,rxmem" device-tree property is used to learn the size of the Rx/Tx
packet buffer built into the ethernet IP, but return value of
of_property_read_u32() is ignored. When the property is absent lp->rxmem is
left at 0, which silently limits the interface to the default MTU and
disables jumbo frames with no indication of the misconfiguration.

"xlnx,rxmem" has been documented as a required property since the binding
was introduced. Check the return value of of_property_read_u32() and fail
probe when the property is missing, so a misconfigured device tree is
reported rather than silently degrading functionality.

Signed-off-by: Suraj Gupta <suraj.gupta2@amd.com>
---
 drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index fcf517069d16..1722b7038f34 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -2898,7 +2898,10 @@ static int axienet_probe(struct platform_device *pdev)
 	 * Here we check for memory allocated for Rx/Tx in the hardware from
 	 * the device-tree and accordingly set flags.
 	 */
-	of_property_read_u32(pdev->dev.of_node, "xlnx,rxmem", &lp->rxmem);
+	ret = of_property_read_u32(pdev->dev.of_node, "xlnx,rxmem", &lp->rxmem);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "failed to read xlnx,rxmem property\n");
 
 	lp->switch_x_sgmii = of_property_read_bool(pdev->dev.of_node,
 						   "xlnx,switch-x-sgmii");
-- 
2.25.1