More on OpenOCD and MIPS/EJTAG

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.

JTAG, OpenOCD & FreeBSD

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:

[gonzo@figaro:][~/FreeBSD]
% telnet localhost 4444
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Open On-Chip Debugger
> halt
target state: halted
target halted due to debug-request, pc: 0x8023b974

> reg
(0) zero (/32): 0x00000000 (dirty: 0, valid: 1)
(1) at (/32): 0x802c0000 (dirty: 0, valid: 1)
(2) v0 (/32): 0x00000001 (dirty: 0, valid: 1)
(3) v1 (/32): 0x00000000 (dirty: 0, valid: 1)
(4) a0 (/32): 0x00000000 (dirty: 0, valid: 1)
(5) a1 (/32): 0x00000000 (dirty: 0, valid: 1)
(6) a2 (/32): 0x80280b28 (dirty: 0, valid: 1)
(7) a3 (/32): 0x00000602 (dirty: 0, valid: 1)
(8) t0 (/32): 0x802c10b0 (dirty: 0, valid: 1)
(9) t1 (/32): 0x00000000 (dirty: 0, valid: 1)
(10) t2 (/32): 0x00000000 (dirty: 0, valid: 1)
(11) t3 (/32): 0x00000000 (dirty: 0, valid: 1)
(12) t4 (/32): 0x00000000 (dirty: 0, valid: 1)
(13) t5 (/32): 0x00000001 (dirty: 0, valid: 1)
(14) t6 (/32): 0x00000000 (dirty: 0, valid: 1)
(15) t7 (/32): 0x00000000 (dirty: 0, valid: 1)
(16) s0 (/32): 0xc082abe0 (dirty: 0, valid: 1)
(17) s1 (/32): 0x801312a8 (dirty: 0, valid: 1)
(18) s2 (/32): 0x00000000 (dirty: 0, valid: 1)
(19) s3 (/32): 0xc0828b20 (dirty: 0, valid: 1)
(20) s4 (/32): 0xc0793ea0 (dirty: 0, valid: 1)
(21) s5 (/32): 0x00000000 (dirty: 0, valid: 1)
(22) s6 (/32): 0x00000000 (dirty: 0, valid: 1)
(23) s7 (/32): 0x00000000 (dirty: 0, valid: 1)
(24) t8 (/32): 0x02887fa0 (dirty: 0, valid: 1)
(25) t9 (/32): 0x00000002 (dirty: 0, valid: 1)
(26) k0 (/32): 0x8024e3a0 (dirty: 0, valid: 1)
(27) k1 (/32): 0x00000000 (dirty: 0, valid: 1)
(28) gp (/32): 0x00000000 (dirty: 0, valid: 1)
(29) sp (/32): 0xc0793e30 (dirty: 0, valid: 1)
(30) fp (/32): 0x00000000 (dirty: 0, valid: 1)
(31) ra (/32): 0x8023b964 (dirty: 0, valid: 1)
(32) status (/32): 0x0000ff01 (dirty: 0, valid: 1)
(33) lo (/32): 0x0000001c (dirty: 0, valid: 1)
(34) hi (/32): 0x00000020 (dirty: 0, valid: 1)
(35) badvaddr (/32): 0xc0797dc8 (dirty: 0, valid: 1)
(36) cause (/32): 0x40008000 (dirty: 0, valid: 1)
(37) pc (/32): 0x8023b974 (dirty: 0, valid: 1)
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