Fscking OMAP

[Russell King - ARM Linux]

On Mon, Apr 20, 2015 at 04:49:13PM +0100, Russell King - ARM Linux wrote:
> Guys,
> 
> If you're going to introduce a dependency on some infrastructure which
> you absolutely require for booting, then _please_ ensure that the
> configuration system is updated such that pre-existing kernel
> configurations continue to work.
> 
> Don't leave it such that the infrastructure ends up returning -ENOSYS,
> which then filters down into your SoC specific code, and aborts the
> initialisation of critical infrastructure, leaving you with a totally
> silent boot failure.
> 
> In this case, it's the addition of syscon to OMAP internals,
> specifically in omap_control_init().
> 
> This is explicitly targetted at OMAP people, who have wasted much of
> my day today investigating why their platforms no longer boot in DT
> mode.

Let's be clear about how this needs to be fixed:

1. OMAP must select MFD_SYSCON in its Kconfig when DT is enabled, since
   OMAP silently fails to boot when this symbol is not enabled.

2. omap_clk_init() really needs to have some diagnostic printk()s in
   it to indicate when something like omap_control_init() fails.

3. omap_clk_init() probably should _not_ return immediately when one
   of the children (such as omap_control_init) fails to initialise, as
   omitting the clocks pretty much ensures that the kernel will BUG()
   a few moments later in the timer code.

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