[PATCH] omap: wd_timer: Fix crash frm wdt_probe when !CONFIG_RUNTIME_PM

[Santosh Shilimkar]

> -----Original Message-----
> From: Kevin Hilman [mailto:khilman at ti.com]
> Sent: Wednesday, January 05, 2011 11:23 PM
> To: Santosh Shilimkar
> Cc: Paul Walmsley; linux-arm-kernel at lists.infradead.org; linux-
> omap at vger.kernel.org
> Subject: Re: [PATCH] omap: wd_timer: Fix crash frm wdt_probe when
> !CONFIG_RUNTIME_PM
>
> Santosh Shilimkar <santosh.shilimkar at ti.com> writes:
>
> > Commit ff2516fb 'wd_timer: disable on boot via hwmod postsetup
> mechanism'
> > introduced watchdog timer state state management using
> postsetup_state.
> > This was done to allow some board files to support watchdog
> coverage
> > throughout kernel initialization and it work as intended when
> RUNTIME_PM
> > is enabled.
> >
> > With !CONFIG_RUNTIME_PM and no board is specifically requests
> watchdog
> > to remain enabled the omap_wdt_probe crashesh. This is because
> hwmod
> > in absense of runtime PM unable to turn watchdog clocks because
> it's
> > state is set to be disabled. For rest of the device, the state is
> > set as enabled in absense of RUNTIME_PM
> >
> > [    1.372558] Unhandled fault: imprecise external abort (0x1406)
> at
> > 0xad733eeb
> > [    1.379913] Internal error: : 1406 [#1] SMP
> > [    1.384277] last sysfs file:
> > [    1.387359] Modules linked in:
> > [    1.390563] CPU: 0    Tainted: G        W
> > (2.6.37-rc7-00265-g4298a4c-dirty #23)
> > [    1.398468] PC is at omap_wdt_disable+0x2c/0x3c
> > [    1.403198] LR is at omap_wdt_probe+0x124/0x1e0
> > [    1.407928] pc : [<c02f5bf4>]    lr : [<c03be10c>]    psr:
> 60000013
> > [    1.407958] sp : df833f00  ip : 00000000  fp : 00000000
> > [    1.419921] r10: c0ac57ac  r9 : df959e00  r8 : 00000000
> > [    1.425384] r7 : df959e08  r6 : df8000c0  r5 : df95bebc  r4 :
> df87dde0
> > [    1.432189] r3 : fc314000  r2 : 00005555  r1 : fc314034  r0 :
> df87dde0
> >
> > This patch make the default watchdog state to be enabled in case
> of
> > !CONFIG_RUNTIME_PM. This fixes the crash
> >
> > Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
> > Cc: Paul Walmsley <paul at pwsan.com>
> > ---
> > Paul, I am not too sure if it breaks your _shutdown idea of
> watchdog
> > timer.  Patch generated against 'omap-for-linus' branch and boot
> > tested on OMAP4 with and without CONFIG_OMAP_WATCHDOG.
> >
> >  arch/arm/mach-omap2/io.c |    4 ++++
> >  1 files changed, 4 insertions(+), 0 deletions(-)
> >
> > diff --git a/arch/arm/mach-omap2/io.c b/arch/arm/mach-omap2/io.c
> > index e66687b..b879a16 100644
> > --- a/arch/arm/mach-omap2/io.c
> > +++ b/arch/arm/mach-omap2/io.c
> > @@ -378,7 +378,11 @@ void __init
> omap2_init_common_infrastructure(void)
> >  	 * XXX ideally we could detect whether the MPU WDT was
> currently
> >  	 * enabled here and make this conditional
> >  	 */
> > +#ifdef CONFIG_PM_RUNTIME
> >  	postsetup_state = _HWMOD_STATE_DISABLED;
> > +#else
> > +	postsetup_state = _HWMOD_STATE_ENABLED;
> > +#endif
>
> You shouldn't need the 'else' part of this since the default a few
> lines
> above this code is already setting that for the !CONFIG_PM_RUNTIME
> case.
Yep. Just 'CONFIG_PM_RUNTIME' wrapping is enough.