diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
index 2c85e78..16a6a69 100644
--- a/drivers/pci/pci-uclass.c
+++ b/drivers/pci/pci-uclass.c
@@ -286,6 +286,8 @@
 	ops = pci_get_ops(bus);
 	if (!ops->write_config)
 		return -ENOSYS;
+	if (offset < 0 || offset >= 4096)
+		return -EINVAL;
 	return ops->write_config(bus, bdf, offset, value, size);
 }
 
@@ -364,8 +366,14 @@
 	struct dm_pci_ops *ops;
 
 	ops = pci_get_ops(bus);
-	if (!ops->read_config)
+	if (!ops->read_config) {
+		*valuep = pci_conv_32_to_size(~0, offset, size);
 		return -ENOSYS;
+	}
+	if (offset < 0 || offset >= 4096) {
+		*valuep = pci_conv_32_to_size(0, offset, size);
+		return -EINVAL;
+	}
 	return ops->read_config(bus, bdf, offset, valuep, size);
 }