[U-Boot] [RFC PATCH v2 1/6] fdt: ARM: Add device tree control of U-Boot (CONFIG_OF_CONTROL)

[Wolfgang Denk]

Dear Simon Glass,

In message <CAPnjgZ0FvaM-dM0Af_ZiAT9EKho+zeT4HF_Vx9AqSXALp0pVhA at mail.gmail.com> you wrote:
> 
> Oh OK, well that's actually quite good then. For one thing it means
> that the idea of init order is perhaps not so critical, since we
> actually want to remove most of this mandatory init. I mean that if we
> are not trying to replicate the init sequence in board_init_r (but in
> fact remove most of it) then things are simpler, and perhaps even fall
> back to a call to the board code and not much else.

I think there are at least two parts of it.  One is driver init stuff.
Here it should indeed be sufficient when each command that tries to
open a driver will trigger the initialization of the device if thios
has not been done before (this sounds simple enough, but I see some
complexity because some of these things _will_ be done before
relocation, i. e. without BSS and without writable data segment, so we
only havce the space-limited gd ...).

The other part is board specific dependencies that are not that easy
to detect.

I consider it a pity that Detlev's suggestion went by uncommented:

http://thread.gmane.org/gmane.comp.boot-loaders.u-boot/105824/focus=106328

The "init a driver when it's needed" is some automatic part of such
dependency base intialization.  Eventually we should follow that
method for the remaining parts, too.

Best regards,

Wolfgang Denk

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