> -----Original Message----- > From: Russell King - ARM Linux [mailto:linux@xxxxxxxxxxxxxxxx] > Sent: Monday, January 24, 2011 4:41 PM > To: Santosh Shilimkar > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; catalin.marinas@xxxxxxx; > ccross@xxxxxxxxxxx; linus.ml.walleij@xxxxxxxxx; linux- > omap@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 3/5] ARM: twd: Add context save restore support > > On Mon, Jan 24, 2011 at 11:06:09AM +0000, Russell King - ARM Linux > wrote: > > On Mon, Jan 24, 2011 at 02:21:17PM +0530, Santosh Shilimkar wrote: > > > In CPU low power state, local timer looses its register context. > This > > > patch adds context save restore hooks which can be used by > platforms > > > appropriately. > > > > I thought the whole point of CLOCK_EVT_FEAT_C3STOP was that the > generic > > timer stuff wouldn't rely on it being kept alive? > > > > Hmm, it looks like we bypass the clockevents code by only setting > the > > TWD load value at initialization time, not when we switch to > periodic > > mode. We really ought to rewrite it whenever we switch back to > periodic > > mode. > > > > I suspect fixing that means you won't need this save/restore > support. > > Untested, but should do what's required. :) I was just typing an email and you sent a patch. Will test this and update you. > > diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c > index fd91566..60636f4 100644 > --- a/arch/arm/kernel/smp_twd.c > +++ b/arch/arm/kernel/smp_twd.c > @@ -36,6 +36,7 @@ static void twd_set_mode(enum clock_event_mode > mode, > /* timer load already set up */ > ctrl = TWD_TIMER_CONTROL_ENABLE | > TWD_TIMER_CONTROL_IT_ENABLE > | TWD_TIMER_CONTROL_PERIODIC; > + __raw_writel(twd_timer_rate / HZ, twd_base + > TWD_TIMER_LOAD); > break; > case CLOCK_EVT_MODE_ONESHOT: > /* period set, and timer enabled in 'next_event' hook */ > @@ -81,7 +82,7 @@ int twd_timer_ack(void) > > static void __cpuinit twd_calibrate_rate(void) > { > - unsigned long load, count; > + unsigned long count; > u64 waitjiffies; > > /* > @@ -116,10 +117,6 @@ static void __cpuinit twd_calibrate_rate(void) > printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000, > (twd_timer_rate / 1000000) % 100); > } > - > - load = twd_timer_rate / HZ; > - > - __raw_writel(load, twd_base + TWD_TIMER_LOAD); > } > > /* -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
