[U-Boot-Users] Re: Trouble in cfi_flash, help please!

[Yuli Barcohen]

>>>>> Yusuf Ibrahim Ozkok writes:

    Yusuf> Thanks for your reply. I'm also still working on, to find out
    Yusuf> the magic. And I'm getting crazy, since it's a very easy
    Yusuf> issue I couldn't over come it :-(

    Yusuf> I have downloaded the last version of cfi_flash.c from
    Yusuf> CVS. So now it includes all the accepted patches.

    Yusuf> Below you can find the debug output. I defined "DEBUG" in
    Yusuf> include/common.h. I couldn't see any other command (0xff as
    Yusuf> you said) between 0x60 and 0xd0.

It was in your previous mail. Probably some lines were not printed so it
looked like a 0xff in the middle.

    Yusuf> So there shouldn't be a command sequence error actually.

    Yusuf> An other thing, I couldn't understand why we need to re
    Yusuf> protect all other sectors again in "flash_real_protect()".

    Yusuf> There is a comment in the code /* Intel's unprotect
    Yusuf> unprotects all locking */

    Yusuf> But I tried it and found that other sectors are not being
    Yusuf> unlocked!

...

It depends on the chip. For some chips, all sectors are unprotected, for
others (like the chip you're working with) only one sector is
unprotected. What I see from the debug prints is what I suspected:
unprotect works OK but protecting already protected sector results in
time-out (though Intel's docs don't say it's a forbidden
operation). Note: time-out appears after 0x60 0x01 sequence, not after
0x60 0xD0. If you try to write/erase the sector which you tried to
unprotect, I think you'll succeed. All sectors (on this chip) are
protected after power-up so `protect off' will try to re-protect
them. Correct operation would be reading sector protection status (it's
available after Read ID command) and comparing it to the flash info
structure. If the flash info indicates that the sector should be
protected but it's unprotected, only then should the driver issue
protect command. As a "quick and dirty" workaround, just `protect off
all'.

-- 
========================================================================
 Yuli Barcohen       | Phone +972-9-765-1788 |  Software Project Leader
 yuli at arabellasw.com | Fax   +972-9-765-7494 | Arabella Software, Israel
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