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Re: Debugger fails when I add kernel support


On Tue, 07 Apr 2009 16:01:35 +0200, Sergei Gavrikov <sergei.gavrikov@gmail.com> wrote:

On Tue, Apr 07, 2009 at 02:58:44PM +0200, Robert Brusa wrote:
On Mon, 06 Apr 2009 23:39:24 +0200, Sergei Gavrikov
<sergei.gavrikov@gmail.com> wrote:

..<cut>
>>Robert, of course, the right way is to define own macro (= CDL rule) in
>>the plf's stuff. But, that's not possible without a tweaking plf's code.
>>I thought about a froud hack: to add something like the below in CFLAGS
>>
>> -D"HAL_IDLE_THREAD_ACTION(x)={}"
>>
>>Well, it's ugly, but, if you do not want to mess up 3.0 sources, it
>>would
>>be a way.
>>
>>Perhaps, eCos veterans know about another way.
>>
>
>It's just for reference how it was done for lpc2xxx variants:
>packages/hal/arm/lpc2xxx/var/current/include/var_arch.h:63
>
>So, I can use
>
>cdl_option CYGHWR_HAL_ARM_LPC2XXX_IDLE_PWRSAVE {
> user_value 0
>};
>
>for my target to disable that "odd" mode. Certainly it can be disabled
>with `configtool' too.
>
>Sergei


Sergei, I did it with brutal force: I modified the lines inside var_arch.h
in directory ecos/packages/hal/arm/at91/var/current/include such that the
macro
HAL_IDLE_THREAD_ACTION(_counter_) is no longer generated. Then I created a
new ecos and linked my little project with this new ecos. The results are
mixed:
a) As before, when switching power on with no JTAG debugger (BDI2000)
connected, the program launches and works fine.


b) With the JTAG debugger connected, I am no longer in a position to
launch it with the BDI go 0 command (via telnet). No output at all.

IMHO, it is a JTAG issue, jtag cannot halt CPU. Usually, they recommend that your early startup has a loop in assembler during a few time to give a chance JTAG halt CPU. A few ms it's enougth. You can put this in your hal_platform_startup.s (before any initialization, it should be just a loop in asm).

==> The BDI is configured to stop the target when it comes out of reset. And that it does wunderfully. I then click the run button and that's were the problems start :-(

c) I can set breakpoints in cyg_user_start and the output of the
diag_printf statement in this routine appear - but
   the output of the diag_printf routines in the thread created and
resumed from this reoutine do not appear - although I can catch
   breakpoints in this thread.

Not a very clear situation. Do you have a good idea? Thanks and regards
   Robert

diag_printf() is good for asserts, diagnostic output, etc., i.e. for debugging only. What is a reason to use it inside the threads?

every plf. diagnostic "putc" is something like this blocking loop:

	do {
	    // check UART status
	} while (!can_send);


It's not good for multi-threads applications. It blocks eCos, so, use printf() inside the threads, interrupt-driven and non-blocking serial I/O. Use a mutex to share printf() between the threads. I do not think that eCos's the floating-points-less printf() is heavy stuff. Robert, that is just my thoughts about your implementation. This is not JTAG related things.


Sergei

Hi Sergei


Well, I used to have printf-statements in all my programs. But since working with the new arm-eabi toolchain, I found that all my programs crash in this printf statement. I reported this in the arm_gnu forum, but got no useful answer. :-(

Right now I have kicked out all diag_printf statements in the thread and put printf instead - No output in no case.
Then I changed it to fprintf(... and already the statement


fuser = fopen("/dev/ser1", "w");

comes back with fuser == 0 - even so I enabled ser0 and ser1 - the interrupt driven version at91serial - in configtool ...

Something very basic must be wrong in my case. If only I knew what?????? :-(
Robert




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