Date: Sun, 11 Jan 1998 10:20:09 -0700 From: Ian Logan <ian@nmsu.edu> To: Jason Evans <jasone@canonware.com> Cc: freebsd-sparc@FreeBSD.ORG, Chris Toshok <toshok@hungry.com> Subject: Re: How UltraAX boots Message-ID: <34B8FF49.42027ECC@nmsu.edu> References: <Pine.BSF.3.96.980111042449.533O-100000@mozart.canonware.com>
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Jason Evans wrote: > We're going to be facing a big bang problem as far as booting goes. In > order to get a serial console working, it looks like we'll have to have > the UPA, PCI, and EBus code working, in addition to serial code (just need > to port the serial code). So, we'll pretty much have to make the whole > motherboard work all at once, unless we can route the console through OBP > (seems unlikely, or at least problematic). Yuck. Actually it shouldn't be too bad :) OBP has functions that work almost like printf and they automaticly send their output to whatever output device is set in the enviroment variables, I believe they are output-device and input-device. For example, the startup code in sys/sparc/sparc/locore.s uses these functions to printout a message if it's running on a unsupported CPU. In Linux they wrote a little library of interface functions for the prom, so we could do the same thing. Then just pick our output function based on a #define. ie. #if defined(PROM_DEBUG) prom_printf(...) #else printf(...) #endif Of course this is still pretty ugly, but it could be a lot worse. Ian -- Ian Logan Computing & Networking New Mexico State University Email: ian@nmsu.edu Phone: 505-646-6034 Fax: 505-646-5278
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