README: improve documentation of network related CONFIG_ settings

Add documentation for CONFIG_GATEWAYIP and CONFIG_NETMASK;
also add information which environment variables are set.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: Simon Glass <sjg@chromium.org>

diff --git a/README b/README
index 9e0ab5860ce586caf81e78b2bf5a454dbb4f7479..60a105fb1b313c3dedbbc0d6e62ab087aac8e451 100644 (file)
--- a/README
+++ b/README
@@ -1432,18 +1432,37 @@ The following options need to be configured:
                Define a default value for the IP address to use for
                the default Ethernet interface, in case this is not
                determined through e.g. bootp.
+               (Environment variable "ipaddr")
 
 - Server IP address:
                CONFIG_SERVERIP
 
                Defines a default value for the IP address of a TFTP
                server to contact when using the "tftboot" command.
+               (Environment variable "serverip")
 
                CONFIG_KEEP_SERVERADDR
 
                Keeps the server's MAC address, in the env 'serveraddr'
                for passing to bootargs (like Linux's netconsole option)
 
+- Gateway IP address:
+               CONFIG_GATEWAYIP
+
+               Defines a default value for the IP address of the
+               default router where packets to other networks are
+               sent to.
+               (Environment variable "gatewayip")
+
+- Subnet mask:
+               CONFIG_NETMASK
+
+               Defines a default value for the subnet mask (or
+               routing prefix) which is used to determine if an IP
+               address belongs to the local subnet or needs to be
+               forwarded through a router.
+               (Environment variable "netmask")
+
 - Multicast TFTP Mode:
                CONFIG_MCAST_TFTP