debug board setup / turning aux led on very late in the suspend path

[Vasily Khoruzhick]

On Thursday 04 November 2010 16:09:32 Timo Juhani Lindfors wrote:
> Hi,
> 
> I used the debug board today after a long pause so I thought I might
> want to document the steps I had to do to get it to work:
> 
> 1) boot openmoko normally
> 2) (openmoko) sudo /etc/init.d/watchdog stop
> 3) (openmoko) sudo killall wd_keepalive
> 4) (openmoko) sudo sh -c 'echo -n V > /dev/watchdog'2) connect debug board
> to PC 5) connect debug board to openmoko
> 6) (PC) cat > openocd.cfg <<EOF
> 
> interface ft2232
> ft2232_device_desc "Debug Board for Neo1973 A"
> ft2232_layout "jtagkey"
> ft2232_vid_pid 0x1457 0x5118
> 
> source [find target/samsung_s3c2440.cfg]
> 
> reset_config trst_and_srst
> 
> #jtag_khz 0
> 
> gdb_port 3333
> tcl_port 6666
> telnet_port 4444
> EOF
> 7) (PC) sudo openocd
> 8) (PC) run arm-linux-gnueabi-gdb
> 9) (gdb) target remote localhost:3333
> 10) (gdb) continue
> 11) (gdb) ctrl-c
> 12) (gdb) monitor gdb_breakpoint_override hard
> 13) (gdb) monitor arm7_9 dbgrq enable
> 14) (gdb) continue
> 15) (gdb) ctrl-c
> 16) (gdb) break s3c_pm_save_gpios
> 17) (gdb) continue
> 18) (openmoko) sudo sh -c 'echo mem > /sys/power/state'
> 19) (gdb) define xsi
> si
> x/3i $pc
> end
> 20) (gdb) single step the suspend process with this new "xsi" command
> 
> Version information:
> PC is debian gnu/linux stable with openocd 0.4.0-1+nmu1 running from a
> debian unstable chroot
> 
> openmoko is gta02v5 running debian unstable with 2.6.34 kernel
> branched from radekp's qtmoko27 branch
> 
> debug board is version 2
> 
> 
> My original goal was to turn the AUX led ON very late in the suspend
> path so that I could distinguish between failed and working suspend by
> looking at the led. I assumed I could just add 0x4 to 0x56000014 but
> for some reason even trying to read from this address apparently
> causes a fault or something:
> 
> 
> (gdb) xsi
> 0xc0035bac in s3c_cpu_save ()
> 0xc0035bac <s3c_cpu_save+28>:   ldr     r0, [pc, #8]    ; 0xc0035bbc
> <resume_with_mmu+4> 0xc0035bb0 <s3c_cpu_save+32>:   ldr     r0, [r0]
> 0xc0035bb4 <s3c_cpu_save+36>:   mov     pc, r0
> (gdb) xsi
> 0xc0035bb0 in s3c_cpu_save ()
> 0xc0035bb0 <s3c_cpu_save+32>:   ldr     r0, [r0]
> 0xc0035bb4 <s3c_cpu_save+36>:   mov     pc, r0
> 0xc0035bb8 <resume_with_mmu>:   pop     {r4, r5, r6, r7, r8, r9, r10, r11,
> r12, pc} (gdb)
> 0xc0035bb4 in s3c_cpu_save ()
> 0xc0035bb4 <s3c_cpu_save+36>:   mov     pc, r0
> 0xc0035bb8 <resume_with_mmu>:   pop     {r4, r5, r6, r7, r8, r9, r10, r11,
> r12, pc} 0xc0035bbc <resume_with_mmu+4>: eorsgt  r11, lr, r0, lsr r8
> (gdb)
> 0xc0032860 in s3c2410_cpu_suspend ()
> 0xc0032860 <s3c2410_cpu_suspend>:       mov     r4, #1442840576 ;
> 0x56000000 0xc0032864 <s3c2410_cpu_suspend+4>:     ldr     r5, [r4, #20]
> 0xc0032868 <s3c2410_cpu_suspend+8>:     orr     r5, r5, #4      ; 0x4
> (gdb)
> 0xc0032864 in s3c2410_cpu_suspend ()
> 0xc0032864 <s3c2410_cpu_suspend+4>:     ldr     r5, [r4, #20]
> 0xc0032868 <s3c2410_cpu_suspend+8>:     orr     r5, r5, #4      ; 0x4
> 0xc003286c <s3c2410_cpu_suspend+12>:    str     r5, [r4, #20]
> (gdb) p $r4
> $3 = 1442840576
> (gdb) p/x $r4
> $4 = 0x56000000
> (gdb) xsi
>   C-c C-cHalt timed out, wake up GDB.
> 
> 
> What am I missing here?

Maybe I'm wrong, but you can't debug suspend/resume sequence via JTAG, as in 
suspend ARM core is completely disabled.

Regards
Vasily