[coreboot] [PATCH] cs5536: Make NAND code optional and implement timing setting

Mart Raudsepp mart.raudsepp at artecdesign.ee
Fri Feb 20 19:47:14 CET 2009

On T, 2009-02-17 at 15:01 +0200, Mart Raudsepp wrote:
> cs5536: Make NAND code optional and implement timing setting
> The reset value for NAND timings is the slowest possible for Flash interface.
> Implement optionally setting it to a different value inside the NAND device.
> Set it to appropriate values for Artec Group DBE61 and DBE62.
> This results in a roughly two times quicker read time as measured by hdparm
> for these boards.
> Because we can not cast to southbridge_amd_cs5536_nand_config if the board dts
> does not have an entry for the NAND device, this change proposes a method for
> reasonably clean way to only optionally compile in support for certain devices:
> If a board wants to support an optional device, its Kconfig entry can select
> that configuration. If it's optional even across the same board, it can expose
> a subconfig option of the board, that describes it and if chosen selects the
> device config. The source code for that device is conditionally compiled only
> if the Kconfig option gets enabled by the configuration for the board.
> A requirement is that if the board configuration can enable a device, it is
> contained in the boards dts file as well.
> A perhaps better long-term alternative for this could be making dtc generate
> preprocessor definitions for each device_configuration struct that it creates.
> Then the source code file is always enabled, but that file can be wrapped
> around a simple #ifdef check in its entirety.
> Conversion to the alternative approach from the short-term Kconfig approach
> proposed here should be relatively easy, as to not block inclusion of the
> Kconfig approach in the short term.
> Signed-off-by: Mart Raudsepp <mart.raudsepp at artecdesign.ee>

Any comments, acks, rejections, anything? :)


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