[U-Boot] [RFC PATCH v3 09/11] net: IPv6 documentation

[Chris Packham]

Signed-off-by: Chris Packham <judge.packham at gmail.com>
---

Changes in v3:
- Add brief testing section

Changes in v2: None

 README          |  3 +++
 doc/README.ipv6 | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+)
 create mode 100644 doc/README.ipv6

diff --git a/README b/README
index a95348a876b4..4ab4a0e74f32 100644
--- a/README
+++ b/README
@@ -922,6 +922,7 @@ The following options need to be configured:
 		CONFIG_CMD_MTDPARTS	* MTD partition support
 		CONFIG_CMD_NAND		* NAND support
 		CONFIG_CMD_NET		  bootp, tftpboot, rarpboot
+		CONFIG_CMD_NET6		* tftpboot6
 		CONFIG_CMD_NFS		  NFS support
 		CONFIG_CMD_PCA953X	* PCA953x I2C gpio commands
 		CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
@@ -929,6 +930,8 @@ The following options need to be configured:
 		CONFIG_CMD_PCMCIA		* PCMCIA support
 		CONFIG_CMD_PING		* send ICMP ECHO_REQUEST to network
 					  host
+		CONFIG_CMD_PING6	* send ICMPv6 ECHO_REQUEST to network
+					  host
 		CONFIG_CMD_PORTIO	* Port I/O
 		CONFIG_CMD_READ		* Read raw data from partition
 		CONFIG_CMD_REGINFO	* Register dump
diff --git a/doc/README.ipv6 b/doc/README.ipv6
new file mode 100644
index 000000000000..b7c2bc417645
--- /dev/null
+++ b/doc/README.ipv6
@@ -0,0 +1,55 @@
+IPv6 Support in U-boot
+----------------------
+IPv6 support in U-boot can be considered experimental. The commands
+currently supported are tftpboot6 and ping6.
+
+The following environment variables are used
+- ip6addr - IPv6 address of the device
+- gatewayip6 - IPv6 address of the default gateway
+- serverip6 - IPv6 of the tftp server
+
+Configuration
+-------------
+The following configuration option needs to be selected to support IPv6.
+- CONFIG_CMD_NET6
+Optionally the following can also be selected to enable the ping6
+command.
+- CONFIG_CMD_PING6
+
+TFTP Server Configuration
+-------------------------
+At the time of writing U-boot has been tested against tftp-hpa
+(https://www.kernel.org/pub/software/network/tftp/) the default Debian
+package sets TFTP_ADDRESS=0.0.0.0:69 (in /etc/default/tftpd-hpa) to
+support both IPv4 and IPv6 this need to be changed to ':69'.
+
+Ethernet Driver Requirements
+----------------------------
+For IPv6 to operate correctly the Ethernet device needs to support
+transmission and reception of L2 multicast packets. Transmission is
+usually not a problem. To receive multicast packets the driver needs to
+enable promiscuous mode (some devices have the option of just enabling
+promiscuous multicast reception).
+
+Testing using QEMU
+------------------
+Refer to README.x86 for instructions on building u-boot for QEMU. Add
+the relevant IPv6 configuration to the configuration (CONFIG_CMD_NET6,
+CONFIG_CMD_PING6) and build.
+
+On the host system run
+
+  sudo qemu-system-i386 -nographic -bios u-boot.rom -net nic -net tap
+
+At the u-boot command line run
+
+  setenv ipaddr 192.168.1.100
+  setenv ip6addr 3ffe::100/64
+
+On the host system run
+
+  sudo ip addr add 3ffe::1/64 dev tap0
+  sudo ip addr add 192.168.1.1
+
+It should now be possible to use ping6 and tftpboot6 to communicate with
+the host system from the emulated u-boot environment.
-- 
2.11.0.24.ge6920cf