mirror of
https://github.com/AsahiLinux/u-boot
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92 lines
3 KiB
Text
92 lines
3 KiB
Text
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In U-Boot, we implemented the networked console via the standard
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"devices" mechanism, which means that you can switch between the
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serial and network input/output devices by adjusting the 'stdin' and
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'stdout' environment variables. To switch to the networked console,
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set either of these variables to "nc". Input and output can be
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switched independently.
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We use an environment variable 'ncip' to set the IP address and the
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port of the destination. The format is <ip_addr>:<port>. If <port> is
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omitted, the value of 6666 is used. If the env var doesn't exist, the
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broadcast address and port 6666 are used. If it is set to an IP
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address of 0 (or 0.0.0.0) then no messages are sent to the network.
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On the host side, please use this script to access the console:
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+++++++++++++++++++++++++++++++++++++++++++
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#! /bin/bash
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TARGET_IP=$1
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stty -icanon -echo intr ^T
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nc -u -l -p 6666 < /dev/null &
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nc -u ${TARGET_IP} 6666
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stty icanon echo intr ^C
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+++++++++++++++++++++++++++++++++++++++++++
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It turns out that 'netcat' cannot be used to listen to broadcast
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packets. We developed our own tool 'ncb' (see tools directory) that
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listens to broadcast packets on a given port and dumps them to the
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standard output. use it as follows:
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+++++++++++++++++++++++++++++++++++++++++++
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#! /bin/bash
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stty icanon echo intr ^T
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./ncb &
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nc -u mpc5200 6666
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stty icanon echo intr ^C
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kill 0
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+++++++++++++++++++++++++++++++++++++++++++
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For Linux, the network-based console needs special configuration.
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Minimally, the host IP address needs to be specified. This can be
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done either via the kernel command line, or by passing parameters
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while loading the netconsole.o module (when used in a loadable module
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configuration). Please refer to Documentation/networking/logging.txt
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file for the original Ingo Molnar's documentation on how to pass
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parameters to the loadable module.
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The format of the kernel command line parameter (for the static
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configuration) is as follows:
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netconsole=[src-port]@[src-ip]/[<dev>],[tgt-port]@<tgt-ip>/[tgt-macaddr]
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where
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src-port source for UDP packets
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(defaults to 6665)
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src-ip source IP to use
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(defaults to the interface's address)
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dev network interface
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(defaults to eth0)
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tgt-port port for logging agent
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(defaults to 6666)
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tgt-ip IP address for logging agent
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(this is the required parameter)
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tgt-macaddr ethernet MAC address for logging agent
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(defaults to broadcast)
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Examples:
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netconsole=4444@10.0.0.1/eth1,9353@10.0.0.2/12:34:56:78:9a:bc
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or
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netconsole=@/,@192.168.3.1/
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Please note that for the Linux networked console to work, the
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ethernet interface has to be up by the time the netconsole driver is
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initialized. This means that in case of static kernel configuration,
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the respective Ethernet interface has to be brought up using the "IP
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Autoconfiguration" kernel feature, which is usually done by defaults
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in the ELDK-NFS-based environment.
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To browse the Linux network console output, use the 'netcat' tool invoked
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as follows:
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nc -u -l -p 6666
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Note that unlike the U-Boot implementation the Linux netconsole is
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unidirectional, i. e. you have console output only in Linux.
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