linux-mips
[Top] [All Lists]

Re: [PATCH 1/2][MIPS] replace c0_compare acknowledge by c0_timer_ack()

To: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Subject: Re: [PATCH 1/2][MIPS] replace c0_compare acknowledge by c0_timer_ack()
From: Ralf Baechle <ralf@linux-mips.org>
Date: Tue, 18 Mar 2008 13:27:09 +0000
Cc: linux-mips <linux-mips@linux-mips.org>
In-reply-to: <200803180447.m2I4lJ40005091@po-mbox301.hop.2iij.net>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <20080317234740.705a8a34.yoichi_yuasa@tripeaks.co.jp> <20080317161635.GA25549@linux-mips.org> <200803180447.m2I4lJ40005091@po-mbox301.hop.2iij.net>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mutt/1.5.17 (2007-11-01)
On Tue, Mar 18, 2008 at 01:47:20PM +0900, Yoichi Yuasa wrote:

> On Mon, 17 Mar 2008 16:16:35 +0000
> Ralf Baechle <ralf@linux-mips.org> wrote:
> 
> > On Mon, Mar 17, 2008 at 11:47:40PM +0900, Yoichi Yuasa wrote:
> > 
> > > VR41xx, CP0 hazard is necessary between read_c0_count() and 
> > > write_c0_compare().
> > 
> > Interesting.  I wonder why you need this patch but nobody else?
> 
> Three NOP are necessary on the TB0287(VR4131 board).

That much was obvious from your patch.  I was more wondering about this
change:

-               write_c0_compare(read_c0_count());
+               c0_timer_ack();

c0_timer_ack is defined as

static void c0_timer_ack(void)
{
        write_c0_compare(read_c0_compare());
}

so your patch does a functional change there - even though it should not
actually matter.  So I was wondering if for some reason you need that
change.

Just interested - it looks a bit cleaner so I'm leaning to apply this
change anyway.

  Ralf

<Prev in Thread] Current Thread [Next in Thread>