Re: [PATCH] [RFC] ARM: shmobile: koelsch-reference: Work around core clock issues

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Geert,

On Friday 14 March 2014 13:39:43 Geert Uytterhoeven wrote:
> On Fri, Mar 14, 2014 at 12:10 PM, Ben Dooks wrote:
> > On 14/03/14 11:02, Laurent Pinchart wrote:
> >> On Thursday 13 March 2014 15:29:30 Geert Uytterhoeven wrote:
> >>> From: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
> >>> 
> >>> Due to issues with runtime PM clock management, clocks not explicitly
> >>> managed by their drivers may not be enabled at all, or be inadvertently
> >>> disabled by the clk_disable_unused() late initcall.
> >>> 
> >>> Until this is fixed, add a temporary workaround, calling
> >>> shmobile_clk_workaround() with enable = true.
> >>> 
> >>> For now this enables the clocks for: ether, i2c2, msiof0, qspi_mod, and
> >>> thermal. More clocks can be added if needed.
> >> 
> >> This should do the job, but as you mentioned, it's a crude hack. As we're
> >> targeting v3.16, is there a chance we could fix the problem properly
> >> instead ?
> 
> Of course the goal is to fix it for real, so the crude hack will no longer
> be needed. But for now, it looks like a good short-term workaround.
> 
> > The best fix would be to re-enable the PM and find out what is
> 
> Sure, but in a multiplatform-aware way.

Of course. Are you working on that, or should I give it a try ? Would you like 
to discuss this ?

> > actually causing the external abort. However currently there is
> > no information in the manuals about anything we could find out from
> > the AXI busses as to what the source actually is.
> 
> I re-applied your patch "ARM: shmobile: compile drivers/sh for
> CONFIG_ARCH_SHMOBILE_MULTI", and surprisingly, I no longer get the external
> abort.
> 
> Some experimenting revealed it's due to the "ether" clock in the
> clk_enables[] array. As long as that's enabled early, the system seems to
> boot fine with your patch.

At what point do you get the external abort without the ether clock workaround 
?

-- 
Regards,

Laurent Pinchart