Re: [ECOS] Making support for different flash sizes.

[Bart Veer <bartv at ecoscentric dot com>]

>>>>> "Rene" == Rene Nielsen <rbn@vitesse.com> writes:

    Rene> Suppose you have created a HAL Variant named "abc". And
    Rene> suppose that it supports a range of different 16 MByte flash
    Rene> devices, and that these devices are specified in
    Rene> .../devs/flash/<arch>/abc/current/cdl/flash_abc.cdl.

    Rene> Now suppose that your sales organization says: Hey, please
    Rene> squeeze your code into an 8 MByte flash device, so that we
    Rene> can save some bucks.

    Rene> For reasons other than the flash-size issue, I'd like to
    Rene> create a new redboot_ROMRAM.cdl file for the board equipped
    Rene> with the 8MByte flash. Let's call this
    Rene> redboot_ROMRAM_8MB_flash.ecm and place it next to the
    Rene> original redboot_ROMRAM.ecm file.

    Rene> The original redboot_ROMRAM.ecm file contains a line like the following:
    Rene>   package -hardware CYGPKG_DEVS_FLASH_<ARCH>_ABC current ;

    Rene> I would perfer *not* to list both the 8 and 16 MByte flash
    Rene> devices in the same flash_abc.cdl file. So my question is:

    Rene> Is it possible to create a new file next to flash_abc.cdl
    Rene> called e.g. flash_abc_8mb_flash.cdl and point that out from
    Rene> redboot_ROMRAM_8MB_flash.ecm, or will I have to create a
    Rene> completely new /devs/flash/<arch>/abc_XXX branch? Or is
    Rene> there a better way to handle this?

The preferred way these days is to use the V2 flash drivers, either
CYGPKG_DEVS_FLASH_AMD_AM29XXXXX_V2 or CYGPKG_DEVS_FLASH_STRATA_V2.
Both drivers support CFI initialization, so the driver will query the
flash chip at run-time to determine size and block layout. That is
much simpler than the old V1 flash way of supporting multiple devices.

Bart

-- 
Bart Veer                                   eCos Configuration Architect
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