Re: [PATCH][RFC] drivers: sh: late disabling of clocks

[Simon Horman <horms@verge.net.au>]

On Thu, Jun 16, 2011 at 07:54:38AM +0900, Simon Horman wrote:
> On Wed, Jun 15, 2011 at 11:21:40PM +0900, Magnus Damm wrote:
> > On Tue, Jun 14, 2011 at 3:41 PM, Simon Horman <horms@verge.net.au> wrote:
> > > On Mon, Jun 13, 2011 at 05:59:08PM +0900, Simon Horman wrote:
> > >> On Thu, Jun 09, 2011 at 06:13:39PM +0900, Magnus Damm wrote:
> > >> > From: Magnus Damm <damm@opensource.se>
> > >> >
> > >> > This RFC patch kills two birds with one stone:
> > >> >
> > >> > 1) Fix existing issue where in-use clocks without software
> > >> >    reference are disabled during boot. One example of this
> > >> >    is the handling of the Mackerel serial console output.
> > >> >
> > >> > 2) Make sure so far unused clocks actually get turned off
> > >>
> > >> Is access to allow_disable SMP-safe?
> > >> In particular, does the the access in clk_late_init()
> > >> need to be guarded by clock_lock as calls to __clk_disable() are?
> > >
> > > On reflection I think that the problem is a bit deeper.
> > >
> > > I think allow_disable is set to 1 prematurely, as it indicates
> > > to __clk_disable() that calling clk->ops->disable(clk) is allowed,
> > > even if the iteration of the loop in clk_late_init() is not complete.
> > >
> > > My proposed re-working of clk_late_init() is below.
> > > Completely untested.
> > 
> > Right, I was thinking something along those lines too. The spinlock
> > should make sure we're serialized.
> 
> Great. Feel free to take my ideas verbatim if it helps.

Hi Magnus,

have you had time to look into this?