From: Sergei Gavrikov <w3sg@SoftHome.net>
To: wang cui <iucgnaw@msn.com>
CC: w3sg@SoftHome.net, ecos-discuss@ecos.sourceware.org
Subject: Re: [ECOS] LPC2XXX: Spurious Interrupts Issue
Date: Sat, 3 Feb 2007 00:39:19 +0200 (EET)
On Fri, 2 Feb 2007, wang cui wrote:
Thanks, I brief look at the patch. You fix the LPC2XX vector table.
...
I raised discrssion about this issue serval months ago:
http://sources.redhat.com/ml/ecos-discuss/2006-08/msg00225.html I
think Gary's advice is a good solution, and I just havn't done it yet.
So still leave this piece of ugly code here. :-)
As I need burn the image into off-chip flash, so the ARM_VECTOR_0x14
should be set correctly without rely on burner. Of cource, your
suggestion of do it with a script in "make" process is good, but how
about Redboot(I don't think modify Redboot's make process is
resonable)? And other newbies may be very hard to catch this
problem(because they can't find any info from CVS except search
maillist).
So I suggest to solve it in Gary's way. We add a CDL interface in ARM
arch package to allow user configure ARM_VECTOR_0x14, then add a CDL
implemention in LPC2XXX's variant package.
What is your opinion? Hope we can solve this issue.
I did miss that issue. I read, thanks, So, there is an inclusion
of the <pkgconf/hal.h> at first in vector.S, therefore, to wrap
'unused' vector at 0x14 (as Gary suggested) by that condition in
vector.S would be enough for everybody
#ifdef CYGSEM_HAL_ARM_VECTOR_0x14
.word CYGSEM_HAL_ARM_VECTOR_0x14
#else
.word 0
#endif
IMO, such a CDL option would be introduced in variant, that will
be in cyg/hal/hal_arm_lpc2xxx.h (= hal.h) then
cdl_option CYGSEM_HAL_ARM_VECTOR_0x14 {
display "Default value of unused vector"
flavor data
default_value <today value>
description "
In order to detect if a valid program is present, every
user program must have a program signature. This signature
is a word-wide number that is stored in the unused
location in the ARM7 vector table at 0x00000014. The
program signature is the two's compliment of the checksum
of the ARM vector table."
}
Gary pointed out then
Gary> The other problem I see is that this may not
Gary> be constant as you have made it. Would it not
Gary> change if the various other vector handlers move
Gary> around, i.e. if 'abort_data' changes address,
Gary> etc? Would it not need to be [re]calculated?
Well, we know that <cyg/hal/hal_platform_setup.h> include itself in
vector.S then (after hal.h), therefore, the target specific assembler
code would contain a commented note (at EOF), like a memory stick
#if 0
#undef CYGSEM_HAL_ARM_VECTOR_0x14
// In order to detect if a valid program is present,
// every user program must have a program signature. This
// signature is a word-wide number that is stored
// in the unused location in the ARM7 vector table
// at 0x00000014. The program signature is the two's
// compliment of the checksum of the ARM vector table.
#define CYSEM_HAL_ARM_VECTOR_0x14 <tommorow value>
#endif
In this case an advanced user would be overwrite that then without
reconfigure build tree.