[U-Boot] [RFC][PATCH v3] net: nfs: make NFS_TIMEOUT configurable

[Tetsuyuki Kobayashi <koba@kmckk.co.jp>]

NFS_TIMEOUT is constant value defined in net/nfs.c. But sometimes it needs to adjust.
This patch enables to override NFS_TIMEOUT by defining CONFIG_NFS_TIMEOUT in a board specific config file.

Signed-off-by: Tetsuyuki Kobayashi <koba@kmckk.co.jp>
---
Changes for v2:
   - remove a wrong #error line
Changes for v3:
   - add CONFIG_NFS_TIMEOUT after CONFIG_ARP_TIMEOUT in README file
   - align #ifndef - #else - #endif format as same as tftp.c

 README    |    7 +++++++
 net/nfs.c |    6 +++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/README b/README
index 67dc444..9a18a5c 100644
--- a/README
+++ b/README
@@ -2140,6 +2140,13 @@ The following options need to be configured:
 
 		Timeout waiting for an ARP reply in milliseconds.
 
+		CONFIG_NFS_TIMEOUT
+
+		Timeout in milliseconds used in NFS protocol.
+		If you encounter "ERROR: Cannot umount" in nfs command,
+		try longer timeout such as
+		#define CONFIG_NFS_TIMEOUT 10000UL
+
 - Command Interpreter:
 		CONFIG_AUTO_COMPLETE
 
diff --git a/net/nfs.c b/net/nfs.c
index 5b99763..7f2393f 100644
--- a/net/nfs.c
+++ b/net/nfs.c
@@ -31,7 +31,11 @@
 
 #define HASHES_PER_LINE 65	/* Number of "loading" hashes per line	*/
 #define NFS_RETRY_COUNT 30
-#define NFS_TIMEOUT 2000UL
+#ifndef CONFIG_NFS_TIMEOUT
+# define NFS_TIMEOUT 2000UL
+#else
+# define NFS_TIMEOUT CONFIG_NFS_TIMEOUT
+#endif
 
 static int fs_mounted;
 static unsigned long rpc_id;
-- 
1.7.9.5