From: Scott Wood <scottwood@freescale.com>
To: Wang Dongsheng-B40534 <B40534@freescale.com>
Cc: Wood Scott-B07421 <B07421@freescale.com>,
Gala Kumar-B11780 <B11780@freescale.com>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
Li Yang-R58472 <r58472@freescale.com>
Subject: Re: [PATCH 2/3] powerpc/mpic: add global timer support
Date: Wed, 27 Mar 2013 12:11:35 -0500 [thread overview]
Message-ID: <1364404295.31930.1@snotra> (raw)
In-Reply-To: <ABB05CD9C9F68C46A5CEDC7F15439259EBB72D@039-SN2MPN1-022.039d.mgd.msft.net> (from B40534@freescale.com on Tue Mar 26 22:23:38 2013)
On 03/26/2013 10:23:38 PM, Wang Dongsheng-B40534 wrote:
>=20
>=20
> > -----Original Message-----
> > From: Wood Scott-B07421
> > Sent: Wednesday, March 27, 2013 1:32 AM
> > To: Wang Dongsheng-B40534
> > Cc: Wood Scott-B07421; Gala Kumar-B11780; =20
> linuxppc-dev@lists.ozlabs.org;
> > Li Yang-R58472
> > Subject: Re: [PATCH 2/3] powerpc/mpic: add global timer support
> >
> > On 03/25/2013 10:29:58 PM, Wang Dongsheng-B40534 wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Wood Scott-B07421
> > > > Sent: Saturday, March 23, 2013 6:30 AM
> > > > To: Wang Dongsheng-B40534
> > > > Cc: Wood Scott-B07421; Gala Kumar-B11780;
> > > linuxppc-dev@lists.ozlabs.org;
> > > > Li Yang-R58472
> > > > Subject: Re: [PATCH 2/3] powerpc/mpic: add global timer support
> > > >
> > > > On 03/22/2013 01:14:51 AM, Wang Dongsheng-B40534 wrote:
> > > > >
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Wood Scott-B07421
> > > > > > Sent: Thursday, March 21, 2013 7:00 AM
> > > > > > To: Wang Dongsheng-B40534
> > > > > > Cc: Wood Scott-B07421; Gala Kumar-B11780;
> > > > > linuxppc-dev@lists.ozlabs.org;
> > > > > > Li Yang-R58472
> > > > > > Subject: Re: [PATCH 2/3] powerpc/mpic: add global timer =20
> support
> > > > > >
> > > > > > BTW, the input clock frequency has been similarly scaled, =20
> yet
> > > you
> > > > > don't
> > > > > > try to scrounge up that information to get further =20
> precision...
> > > > > >
> > > > > Let's go back patch, do you think the code is repeated?
> > > > > I will remove "if (!(priv->flags & FSL_GLOBAL_TIMER))" branch,
> > > there
> > > > > will be no redundant code.
> > > >
> > > > I'd rather that branch be kept and the more complicated branch
> > > deleted,
> > > > and priv->timerfreq frequency be adjusted on initialization to
> > > account
> > > > for the scaler.
> > >
> > > static void convert_ticks_to_time(struct timer_group_priv *priv,
> > > const u64 ticks, struct timeval *time) {
> > > u64 tmp_sec;
> > >
> > > time->tv_sec =3D (__kernel_time_t)div_u64(ticks,
> > > priv->timerfreq);
> > > tmp_sec =3D (u64)time->tv_sec * (u64)priv->timerfreq;
> > >
> > > time->tv_usec =3D (__kernel_suseconds_t)
> > > div_u64((ticks - tmp_sec) * 1000000, =20
> priv->timerfreq);
> > >
> > > return;
> > > }
> > >
> > > timer_group_get_freq() {
> > > ...
> > > if (priv->flags & FSL_GLOBAL_TIMER) {
> > > div =3D (1 << (MPIC_TIMER_TCR_CLKDIV_64 >> 8)) * 8;
> > > priv->timerfreq /=3D div;
> > > }
> > > ...
> > > }
> > > Do you want to do that?
> >
> > if (priv->flags & FSL_GLOBAL_TIMER)
> > priv->timerfreq /=3D 64;
> >
> > ...but otherwise yes.
> Ok, I would like do this.
>=20
> if (priv->flags & FSL_GLOBAL_TIMER) {
> div =3D (1 << (MPIC_TIMER_TCR_CLKDIV_64 >> 8)) * 8;
> priv->timerfreq /=3D div;
Why? What do you get out of that obfuscation?
-Scott=
next prev parent reply other threads:[~2013-03-27 17:11 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-08 7:38 [PATCH 1/3] powerpc/mpic: add irq_set_wake support Wang Dongsheng
2013-03-08 7:38 ` [PATCH 2/3] powerpc/mpic: add global timer support Wang Dongsheng
2013-03-18 23:46 ` Scott Wood
2013-03-19 7:55 ` Wang Dongsheng-B40534
2013-03-19 22:59 ` Scott Wood
2013-03-20 6:45 ` Wang Dongsheng-B40534
2013-03-20 22:59 ` Scott Wood
2013-03-22 6:14 ` Wang Dongsheng-B40534
2013-03-22 22:29 ` Scott Wood
2013-03-26 3:29 ` Wang Dongsheng-B40534
2013-03-26 17:31 ` Scott Wood
2013-03-27 3:23 ` Wang Dongsheng-B40534
2013-03-27 17:11 ` Scott Wood [this message]
2013-03-28 2:29 ` Wang Dongsheng-B40534
2013-03-28 19:47 ` Scott Wood
2013-03-29 1:58 ` Wang Dongsheng-B40534
2013-03-08 7:38 ` [PATCH 3/3] powerpc/fsl: add MPIC timer wakeup support Wang Dongsheng
2013-03-19 0:30 ` Scott Wood
2013-03-19 6:25 ` Wang Dongsheng-B40534
2013-03-19 22:54 ` Scott Wood
2013-03-20 3:48 ` Wang Dongsheng-B40534
2013-03-20 21:48 ` Scott Wood
2013-03-22 5:46 ` Wang Dongsheng-B40534
2013-03-22 22:11 ` Scott Wood
2013-03-26 3:27 ` Wang Dongsheng-B40534
2013-03-26 17:35 ` Scott Wood
2013-03-27 3:21 ` Wang Dongsheng-B40534
2013-03-27 20:25 ` Scott Wood
2013-03-28 3:09 ` Wang Dongsheng-B40534
2013-03-18 9:28 ` [PATCH 1/3] powerpc/mpic: add irq_set_wake support Wang Dongsheng-B40534
2013-03-18 14:41 ` Benjamin Herrenschmidt
2013-03-18 14:44 ` Gala Kumar-B11780
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