[ECOS] Making support for different flash sizes.

[ECOS] Making support for different flash sizes.

[Rene Nielsen]

Hi,

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

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

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

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

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

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

Thanks,
René Schipp von Branitz Nielsen 
Vitesse Semiconductors

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

[Bart Veer]

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>>>>> "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

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

[Rene Nielsen]

> 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.
Thanks for your advice, but we'd like to stick to the V1 flash drivers
for the time being and move over to V2 at a later stage.

I think, I've found the answer in the meanwhile:
In flash_abc.cdl, leave out the "requires CYGHWR_DEVS_FLASH_xxx" lines
and add cdl_options for the required devices in the *.ecm files instead.

Regards,
Rene Schipp von Branitz Nielsen
Vitesse Semiconductors

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