net: lwip: nfs: Port the NFS code to work with lwIP

After the preparatory patches moved most of the NFS code into common
files we now add the code to enable NFS support with lwIP.

Signed-off-by: Andrew Goodbody <andrew.goodbody@linaro.org>
Acked-by: Jerome Forissier <jerome.forissier@linaro.org>

cmd/Kconfig

@@ -2116,20 +2116,6 @@ config CMD_RARP
 	help
 	  Boot image via network using RARP/TFTP protocol
 
-config CMD_NFS
-	bool "nfs"
-	help
-	  Boot image via network using NFS protocol.
-
-config NFS_TIMEOUT
-	int "Timeout in milliseconds for NFS mounts"
-	depends on CMD_NFS
-	default 2000
-	help
-	  Timeout in milliseconds used in NFS protocol.  If you encounter
-	  "ERROR: Cannot umount" in nfs command, try longer timeout such as
-	  10000.
-
 config SYS_DISABLE_AUTOLOAD
 	bool "Disable automatically loading files over the network"
 	depends on CMD_BOOTP || CMD_DHCP || CMD_NFS || CMD_RARP
@@ -2224,6 +2210,20 @@ config CMD_MDIO
 	  The MDIO interface is orthogonal to the MII interface and extends
 	  it by adding access to more registers through indirect addressing.
 
+config CMD_NFS
+	bool "nfs"
+	help
+	  Boot image via network using NFS protocol.
+
+config NFS_TIMEOUT
+	int "Timeout in milliseconds for NFS mounts"
+	depends on CMD_NFS
+	default 2000
+	help
+	  Timeout in milliseconds used in NFS protocol.  If you encounter
+	  "ERROR: Cannot umount" in nfs command, try longer timeout such as
+	  10000.
+
 config CMD_PING
 	bool "ping"
 	select PROT_RAW_LWIP if NET_LWIP

cmd/lwip/Makefile

@@ -1,5 +1,6 @@
 obj-$(CONFIG_CMD_DHCP) += dhcp.o
 obj-$(CONFIG_CMD_DNS) += dns.o
+obj-$(CONFIG_CMD_NFS) += nfs.o
 obj-$(CONFIG_CMD_PING) += ping.o
 obj-$(CONFIG_CMD_SNTP) += sntp.o
 obj-$(CONFIG_CMD_TFTPBOOT) += tftp.o

cmd/lwip/nfs.c

@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright (C) 2025 Linaro Ltd. */
+
+#include <command.h>
+#include <net.h>
+
+U_BOOT_CMD(nfs,	3,	1,	do_nfs,
+	   "boot image via network using NFS protocol",
+	   "[loadAddress] [[hostIPaddr:]bootfilename]"
+	  );
+