[U-Boot-Users] [PATCH] cfi_flash.c patches

[Yuli Barcohen]

>>>>> Wolfgang Denk writes:

...

    Wolfgang> Not for me. I don't like the hardware doing magic things
    Wolfgang> to me.  I want to be in control over the hardware - not
    Wolfgang> vice versa.

    Tolunay> While you see it important to protect U-Boot environment
    Tolunay> (for various reasons and I agree), you do not seem to
    Tolunay> consider consistent protection for another area of flash
    Tolunay> that may be storing equally vital information for software
    Tolunay> system. Why?

    Wolfgang> Not on a *automatic* base.  I accept this only if
    Wolfgang> explicitely requested by the user (by using the "protect
    Wolfgang> on" command) *and* the board designer (by providing a
    Wolfgang> flash implementation that supports hardware write
    Wolfgang> protection both in hardware [by selcting appropriate flash
    Wolfgang> chips] and in software [by enabling the needed features in
    Wolfgang> U-Boot]).

...

There are two main types of Intel flashes (AMD/Spansion do not provide
software-controllable hardware protection): flash files (uniform
sectors) and boot blocks. The former come out of reset unprotected, the
latter - protected. If the above mentioned board designer chooses to use
a boot block, he/she selects flash which is protected by default. If
U-Boot must automatically change this behaviour, why to use such a flash
in the first place? Regarding the implementation, unprotecting the flash
on U-Boot's start up requires exactly the same operations as implemented
in the flash_real_protect function (which is controlled by
CFG_FLASH_PROTECTION) so IMHO the same function must be used for
automatic unprotection too to avoid code duplication though I agree with
Tolunay that defining CFG_FLASH_PROTECTION and calling "protect off" is
the way to go.

-- 
========================================================================
 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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