[ECOS] Re: Limit region of flash used by RedBoot for FIS?

[Grant Edwards <grante at visi dot com>]

In gmane.os.ecos.general, you wrote:

>>> CYGNUM_REDBOOT_FIS_DIRECTORY_BLOCK - default value is (-1) which
>>> puts the FIS directory in the last erase block of the device.
>>> Just set it to -(N+1), where N is the number of erase blocks that
>>> you don't want RedBoot to touch.
>> 
>> Ah. Thanks.  It wasn't apparent (at least to me) from the
>> documentation for that option that anything beyond that block
>> would be untouched.  It might be good to add that useful bit of
>> info to the comment for that option.
>
> Im not actually sure this is true. I suggest you look
> carefully at the code before you accidental stomp over your
> top 1Mbyte.

I've already stomped on it, and my board is now floating
belly-up.  I'm going to drop if off with the HW guy and have it
re-programmed -- I can't get the Altera JTAG flash-programmer
program to work under Linux, and I'm too stubborn to install
Windows and several gigabytes (literally!) of Altera SW.

> In fact a quick examination of fis_init() suggests it does
> erase after the end of the cfg/fis blocks.

Sure looks like it always erases all the way to the end in
the following snippet from fis_init()

482             // Lastly, anything at the end, if there is any
483             if ( erase_start < (((CYG_ADDRESS)flash_end)+1) ) {
484                 erase_size = ((CYG_ADDRESS)flash_end - erase_start) + 1;
485                 if ((stat = flash_erase((void *)erase_start, erase_size,
486                                         (void **)&err_addr)) != 0) {
487                     diag_printf("   initialization failed at %p: %s\n",
488                                 err_addr, flash_errmsg(stat));
489                 }
490             }

Previously, there's a section that calculates fis_addr based on
CYGNUM_REDBOOT_FIS_DIRECTORY_BLOCK, but flash_end isn't
affected by CYGNUM_REDBOOT_FIS_DIRECTORY_BLOCK.

For a short-term fix, I'm going to change the value
CYGNUM_FLASH_BASE_MASK to make the strata driver ignore the top
half of the flash.

-- 
Grant Edwards                   grante             Yow!  PUNK ROCK!! DISCO
                                  at               DUCK!! BIRTH CONTROL!!
                               visi.com            

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