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Re: [PATCH][MIPS] add GT641xx timer0 clockevent

To: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Subject: Re: [PATCH][MIPS] add GT641xx timer0 clockevent
From: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Date: Tue, 23 Oct 2007 09:55:55 +0900
Cc: yoichi_yuasa@tripeaks.co.jp, ralf@linux-mips.org, linux-mips@linux-mips.org
In-reply-to: <20071022.234755.45745247.anemo@mba.ocn.ne.jp>
Organization: TriPeaks Corporation
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20071022194315.f75738ba.yoichi_yuasa@tripeaks.co.jp> <20071022.234755.45745247.anemo@mba.ocn.ne.jp>
Sender: linux-mips-bounce@linux-mips.org
On Mon, 22 Oct 2007 23:47:55 +0900 (JST)
Atsushi Nemoto <anemo@mba.ocn.ne.jp> wrote:

> On Mon, 22 Oct 2007 19:43:15 +0900, Yoichi Yuasa 
> <yoichi_yuasa@tripeaks.co.jp> wrote:
> > +static int gt641xx_timer0_set_next_event(unsigned long delta,
> > +                                    struct clock_event_device *evt)
> > +{
> > +   unsigned long flags;
> > +   u32 ctrl;
> > +
> > +   spin_lock_irqsave(&gt641xx_timer_lock, flags);
> > +
> > +   ctrl = GT_READ(GT_TC_CONTROL_OFS);
> > +   ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
> > +   ctrl |= GT_TC_CONTROL_ENTC0_MSK;
> > +
> > +   GT_WRITE(GT_TC0_OFS, delta);
> > +   GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
> > +
> > +   spin_unlock_irqrestore(&gt641xx_timer_lock, flags);
> > +
> > +   return 0;
> > +}
> > +
> > +static void gt641xx_timer0_set_mode(enum clock_event_mode mode,
> > +                               struct clock_event_device *evt)
> > +{
> > +   unsigned long flags;
> > +   u32 ctrl;
> > +
> > +   spin_lock_irqsave(&gt641xx_timer_lock, flags);
> > +
> > +   ctrl = GT_READ(GT_TC_CONTROL_OFS);
> > +   ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
> > +
> > +   switch (mode) {
> > +   case CLOCK_EVT_MODE_PERIODIC:
> > +           ctrl |= GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK;
> > +           break;
> > +   case CLOCK_EVT_MODE_ONESHOT:
> > +           ctrl |= GT_TC_CONTROL_ENTC0_MSK;
> > +           break;
> > +   default:
> > +           break;
> > +   }
> > +
> > +   GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
> > +
> > +   spin_unlock_irqrestore(&gt641xx_timer_lock, flags);
> > +}
> 
> These clockevent routines are always called with interrupt disabled,
> so I suppose those spin_lock_irqsave/spin_unlock_irqrestore pairs can
> be omitted. (or this timer can be used on SMP?)

Yes, it can be used on Malta(SMP).

> > +   cd = &gt641xx_timer0_clockevent;
> > +   cd->rating = 200 + gt641xx_base_clock / 10000000;
> > +   cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
> > +   cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
> > +   clockevent_set_clock(cd, gt641xx_base_clock);
> 
> clockevent_delta2ns() use shift and mult value.  So you should call
> clockevent_set_clock() first.

Thank you for your comment.
I'll fix it up.

Yoichi

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