MIPS

Back from the land of GUI software. I have bought one more Flyswatter JTAG recently and now have two boards connected to my home box. Unfortunately both Flyswatters got the same USB serial number so stock openocd opens only the first device it stumbles upon. Here is small patch that adds ft2232_index command to OpenOCD FTDI driver that allows to point at specific device to open. Works only with libftdi. In the same directory you can find my configs for AR71XX-based RouterStation Pro and Portwell’s CAM-0010 device based on Octeon CN3010

All changes from projects/mips has been merged to HEAD. Kudos go to imp@ for sieving through mergeinfo mess projects/mips has been.

Good news: LLVM builds fine on RouterStation Pro with root mounted over NFS. Bad news: it segfaults on some tests and when trying to build hello world application. Stay tuned

http://people.freebsd.org/~gonzo/mips/routerstation.log Some issues still pending though. Cache management is major one. Things seemed to work fine in emulation but backfired into face with real hardware. I ran into several “random” bugs that were narrowed down to caches. More to go :( Also ethernet driver performance is low but it’s easier then hunting down ethereal cache matters. Or so I think. This weekend will be dedicated to making openocd work with routerstation, learning debugging and profiling techniques for MIPS hardware and improving FreeBSD/MIPS pieces of DDB.

Well, I was overly optimistic. OpenOCD can halt CPU, reset, examine registers and perform software breakpoints. Trying to figure out what’s wrong with EJTAG support I skimmed the code and the state of it is, well, poor. Current implementation assumes that target is of the same endianness as host. That’s why number of HW breakpoints/watchpoints was detected wrong. But even fixing (endianness and breakpoints) and implementing(watchpoints) in hack’n’slash mode didn’t help. I still can’t get bp/wp to work. But I’ll definitely try. May be next weekend.

As it was mentioned earlier now I have new cool toy to play with. Flyswatter JTAG with MIPS14 adapter. Though Tin Can Tools kindly warned me that OpenOCD did not support EJTAG/MIPS I decided to order it and it turned to be a good deal. Why? Because there is EJTAG/MIPS support for OpenOCD as of 0.1.0. Moreover it works really nice with FreeBSD port of libftdi. So all I had to do was to make devel/openocd port and tweak some configs. And that’s it. Stock gdb for MIPS is not ready yet, but one can attach, examine registers, single step using telnet interface to daemon: ...

So it has been a month since last post about this device and I think it’s time to announce current state of affairs. At the moment further progress was blocked with something that looks like memory corruption. It’s hard to trace with ktr(4) and printf(9) so I ordered Flyswatter JTAG adapter and MIPS14 adapter from Tin Can Tools. I was warned that Flyswatter/MIPS combination is not supported by OpenOCD but I’d better spend some time making it work then tracing obscure memory corruptions in the wild.

In last two months I’ve got two new toys: WGT634U from bms@ and Ubiquity Networks’ Router Station 2 provided by manufacturer. The first one is Broadcom’s Sentry5 based and the second one is built on Atheros’ AR7100 chip. As AR7100 is more advanced technology (and has less obscure design, at least it seams less obscure to me) I decided to pick up this low hanging fruit. So far so good: kernel boots, PCI bridge detects Atheros miniPCI wireless card. GigE driver is on its way.

Juniper released FreeBSD/MIPS port to public. There are no references to JNPR-specific hardware pieces but a lot of mature code for generic MIPS devices that mips2 tree lacks: VM/pmap, libc, FPU support. Nice gift, thanks JNPR!

Today I managed to get shell prompt on Mikrotik’s Routerboard 532. So now we have 3 platforms with single user mode for FreeBSD/mips, not very useful :) The last problem was getting high-level console interface working. I always fell lost when it comes to resource allocation and uart stuff. I should write a couple of posts on these subjects to memorize all details better.