[RFC] MXS/i.MX23: detecting the boot source

[Sascha Hauer]

On Fri, May 17, 2013 at 10:18:39AM +0200, Juergen Beisert wrote:
> The boot source for the i.MX23 is configured via a few GPIOs, which are later
> be used for different purposes (like LCD data for example). The SoC internal
> ROM reads these GPIOs and uses the selected boot source.
> 
> For various reasons the boot source is also of interest when Barebox is running.
> This detection approach reads again the GPIOs. It switches temporarily the pins
> to act as GPIOs and input, reads their values, and switches back to their
> previous functions.
> 
> Could this be a reliable way to detect the boot source?

I don't know. Are the bootstrap pins used as outputs only in the normal
usecase? Otherwise I could imagine that something is overriding the
bootstrap pins by the time you read them.

> 
> BTW: is there a reason why the bootsource will create environment variables,
> while other detected features find their way to the "global" device?

No, at least not a good one ;)

> +static uint32_t mxs23_boot_save_loc(void)

Should you continue working on this please change the name to something
like mx23_get_bootsource(). This function does not save anything.

Sascha

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