xref: /openbmc/u-boot/doc/README.plan9 (revision eeaef5e4305497537bd47308724de39c7d6cbf19)
1*eeaef5e4SSteven StallionPlan 9 from Bell Labs kernel images require additional setup to pass
2*eeaef5e4SSteven Stallionconfiguration information to the kernel.  An environment variable named
3*eeaef5e4SSteven Stallionconfaddr must be defined with the same value as CONFADDR (see mem.h).
4*eeaef5e4SSteven StallionUse of this facility is optional, but should be preferable to manual
5*eeaef5e4SSteven Stallionconfiguration.
6*eeaef5e4SSteven Stallion
7*eeaef5e4SSteven StallionWhen booting an image, arguments supplied to the bootm command will be
8*eeaef5e4SSteven Stallioncopied to CONFADDR.  If no arguments are specified, the contents of the
9*eeaef5e4SSteven Stallionbootargs environment variable will be copied.
10*eeaef5e4SSteven Stallion
11*eeaef5e4SSteven StallionIf no command line arguments or bootargs are defined, CONFADDR is left
12*eeaef5e4SSteven Stallionuninitialized to permit manual configuration.  For example, PC-style
13*eeaef5e4SSteven Stallionconfiguration could be simulated by issuing a fatload in bootcmd:
14*eeaef5e4SSteven Stallion
15*eeaef5e4SSteven Stallion  # setenv bootcmd fatload mmc 0 $confaddr plan9.ini; ...; bootm
16*eeaef5e4SSteven Stallion
17*eeaef5e4SSteven StallionSteven Stallion
18*eeaef5e4SSteven StallionJune 2013
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