Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754780AbbKMQoh (ORCPT ); Fri, 13 Nov 2015 11:44:37 -0500 Received: from devils.ext.ti.com ([198.47.26.153]:34492 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754112AbbKMQof (ORCPT ); Fri, 13 Nov 2015 11:44:35 -0500 From: Felipe Balbi To: Grygorii Strashko , , Daniel Lezcano , Thomas Gleixner , Srinivas Kandagatla , Maxime Coquelin CC: , , , , Grygorii Strashko , Arnd Bergmann , John Stultz , Tony Lindgren Subject: Re: [PATCH] clocksource: arm_global_timer: fix suspend resume In-Reply-To: <1447431951-23713-1-git-send-email-grygorii.strashko@ti.com> References: <1447431951-23713-1-git-send-email-grygorii.strashko@ti.com> User-Agent: Notmuch/0.21 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-pc-linux-gnu) Date: Fri, 13 Nov 2015 10:43:39 -0600 Message-ID: <87a8qhq284.fsf@saruman.tx.rr.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3901 Lines: 108 --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, Grygorii Strashko writes: > Now the System stall is observed on TI AM437x based board > (am437x-gp-evm) during resuming from System suspend when ARM Global > timer is selected as clocksource device - SysRq are working, but > nothing else. The reason of stall is that ARM Global timer loses its > contexts. > > The reason of stall is that ARM Global timer loses its contexts during > System suspend: > GT_CONTROL.TIMER_ENABLE =3D 0 (unbanked) > GT_COUNTERx =3D 0 > > Hence, update ARM Global timer driver to reflect above behaviour > - save GT_CONTROL.TIMER_ENABLE during suspend and restore on resume; > - ensure clocksource and clockevent devices have coresponding flags > (CLOCK_SOURCE_SUSPEND_NONSTOP and CLOCK_EVT_FEAT_C3STOP) set > depending on presence of "always-on" DT property. > > CC: Arnd Bergmann > Cc: John Stultz > Cc: Felipe Balbi > Cc: Tony Lindgren > Signed-off-by: Grygorii Strashko > --- > drivers/clocksource/arm_global_timer.c | 23 +++++++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/drivers/clocksource/arm_global_timer.c b/drivers/clocksource= /arm_global_timer.c > index a2cb6fa..1bbaf64 100644 > --- a/drivers/clocksource/arm_global_timer.c > +++ b/drivers/clocksource/arm_global_timer.c > @@ -51,6 +51,8 @@ static void __iomem *gt_base; > static unsigned long gt_clk_rate; > static int gt_ppi; > static struct clock_event_device __percpu *gt_evt; > +static bool gt_always_on; > +static u32 gt_control; >=20=20 > /* > * To get the value from the Global Timer Counter register proceed as fo= llows: > @@ -168,6 +170,9 @@ static int gt_clockevents_init(struct clock_event_dev= ice *clk) > { > int cpu =3D smp_processor_id(); >=20=20 > + if (!gt_always_on) > + clk->features |=3D CLOCK_EVT_FEAT_C3STOP; > + > clk->name =3D "arm_global_timer"; > clk->features =3D CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | > CLOCK_EVT_FEAT_PERCPU; > @@ -195,12 +200,25 @@ static cycle_t gt_clocksource_read(struct clocksour= ce *cs) > return gt_counter_read(); > } >=20=20 > +static void gt_suspend(struct clocksource *cs) > +{ > + gt_control =3D readl(gt_base + GT_CONTROL); > +} > + > +static void gt_resume(struct clocksource *cs) > +{ > + /* enables timer on all the cores */ > + writel(gt_control & GT_CONTROL_TIMER_ENABLE, gt_base + GT_CONTROL); do you really need to save context if all you restore is TIMER_ENABLE bit ? seems like you could skip gt_suspend altogether. Is there really a situation where this driver is running and GT isn't enabled ? =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJWRhM7AAoJEIaOsuA1yqREYMAP/As3r9Vlx2ZxjmsQ14Rfh/5P ZdDbsJdFTR+QalJFumHSSgj5a+L3D+8XWVL50jI6iZgIamSisDSY13b6KX+YE1ef rDTRf1kqG6cY8dJaHmO+kMzHarxVgXYKDGdsk65YTbCumq4UTN/gUh1hptYqrpMt aRjsZFaI0TkiuMuOmytiKzcEJ9ipiwolKHJm0veGYccZ9cbH6z5izYhR+2vrAcu1 MRPYyjyzSg1QyDGx0Vuty9q7DzUrjKfwxSxBhwTlShwvR0uvD1H00eqjtH2HGWUF yjjeehE47NpCImopAkYadj3rH6TCQjyNZ2LUHzL9+CWZOQjorzzZYaN/6hvg/Uqi Rkgb6fiMQnAv1AVcVBGzCX2o+mJukGKoj3q/5fGHjC+vRjQRwJZ+xdbQfqrZztPl b8gHdwXHiBzbSdZdFy0nDK5UEXcioWX0y1JwoCHFKWrWmoK0AJsY1JaerW1UREjE cbxhC4tYitq92GOXfqEIfuFzx4ZUfEQFA5dtJ/YxOdgx+ZeWEVk2IjZwrP9kAqc0 4WI2o3lWGx0oRGIiQEUvwRIqSwOCOeoMyuDg9UY2p/e75E8ZBOzWM9LVN6fDbl8z 0eDRmiEhWP5B73Z8Lw2oKwBbHz7GGw2mQnqJCzQL+klGSh4v6Y/Xzfb75JupWvvZ t4aPHJB2GUddruyWocrN =gioG -----END PGP SIGNATURE----- --=-=-=-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/