From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753669AbbJETlx (ORCPT ); Mon, 5 Oct 2015 15:41:53 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:37803 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753641AbbJETlv (ORCPT ); Mon, 5 Oct 2015 15:41:51 -0400 From: Felipe Balbi To: Arnd Bergmann CC: , Tony Lindgren , , Linux Kernel Mailing List , , Linux OMAP Mailing List Subject: Re: [RFC/PATCH 11/11] arm: boot: dts: omap: add missing default status for 32k counter In-Reply-To: <20151005175230.GG18784@saruman.tx.rr.com> References: <1443559446-26969-1-git-send-email-balbi@ti.com> <4815825.NCBBBMgLGf@wuerfel> <20150930141209.GB31865@saruman.tx.rr.com> <22213826.1MtkNIZ6W3@wuerfel> <20151005175230.GG18784@saruman.tx.rr.com> User-Agent: Notmuch/0.20.2 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-pc-linux-gnu) Date: Mon, 5 Oct 2015 14:41:07 -0500 Message-ID: <87io6lf6i4.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-Type: text/plain Content-Transfer-Encoding: quoted-printable Felipe Balbi writes: > On Wed, Sep 30, 2015 at 11:58:16PM +0200, Arnd Bergmann wrote: >> On Wednesday 30 September 2015 09:12:09 Felipe Balbi wrote: >> > On Wed, Sep 30, 2015 at 10:15:25AM +0200, Arnd Bergmann wrote: >> > > On Tuesday 29 September 2015 15:44:06 Felipe Balbi wrote: >> > > > All devices should have a default status. Ignoring >> > > > the arguments if it should be 'okay' or 'disabled' >> > > > by default, let's set them all the 'disabled' and >> > > > have boards enable 32k counter. >> > > >=20 >> > > > Signed-off-by: Felipe Balbi >> > > >=20 >> > >=20 >> > > The patch looks good, but the description is slightly incorrect: >> > > There is no reason to list "status=3D'okay'" other than overriding >> > > the 'disabled' status. >> > >=20 >> > > I'd phrase it something like: >> > >=20 >> > > "We want the use of the 32k counter to be a per-board setting, >> > > so let's disable it by default in each dtsi file and override the >> > > setting in the boards. Any board that does not wire up the counter >> > > should leave it disabled". >> > >=20 >> > > However, if you really want all boards to provide the counter all >> > > the time, I'd argue that we're better off dropping this patch. We >> > > use the status=3D"disabled" trick for anything that may or may not >> > > be working based on the board design, but things that are present >> > > everywhere don't need this. >> >=20 >> > okay, so here's the thing. While fiddling with the 32k counter, I noti= ced >> > that even though there was no status listed, the thing still initializ= es >> > fine. However, when moving 32k to drivers/clocksource and using >> > CLOCKSOURCE_OF_DECLARE(), 32k would *NOT* probe unless I had an explic= it >> > status =3D "okay" in DT. >>=20 >> Very strange, that sounds like a bug in the clocksource probe code. >> Can you check how this happens? > > seems like something overwrites counter's status field, here's a snippet = of boot > log: > > [ 0.000000] =3D=3D=3D> counter is available ?? > [ 0.000000] =3D=3D=3D> no status -> TRUE!! > [ 0.000000] =3D=3D=3D> searching for timer > [ 0.000000] =3D=3D=3D> timer is available ?? > [ 0.000000] =3D=3D=3D> no status -> TRUE!! > [ 0.000005] sched_clock: 64 bits at 1000MHz, resolution 1ns, wraps eve= ry 4398046511103ns > [ 0.000014] clocksource: arm_global_timer: mask: 0xffffffffffffffff ma= x_cycles: 0x1cd42e4dffb, max_idle_ns: 881590591483 ns > [ 0.000047] =3D=3D=3D> searching for timer > [ 0.000051] =3D=3D=3D> timer is available ?? > [ 0.000054] =3D=3D=3D> no status -> TRUE!! > [ 0.000307] =3D=3D=3D> searching for counter > [ 0.000311] =3D=3D=3D> counter is available ?? > [ 0.000315] =3D=3D=3D> counter status disabled > [ 0.000318] =3D=3D=3D=3D> counter NOT available > > note that first time around counter had no status and later it got a stat= us > disabled from somewhere. found it. arch/arm/mach-omap2/timer.c is the culprit: /** * omap_get_timer_dt - get a timer using device-tree * @match - device-tree match structure for matching a device type * @property - optional timer property to match * * Helper function to get a timer during early boot using device-tree for u= se * as kernel system timer. Optionally, the property argument can be used to * select a timer with a specific property. Once a timer is found then mark * the timer node in device-tree as disabled, to prevent the kernel from * registering this timer as a platform device and so no one else can use i= t. */ static struct device_node * __init omap_get_timer_dt(const struct of_device= _id *match, const char *property) { struct device_node *np; for_each_matching_node(np, match) { if (!of_device_is_available(np)) continue; if (property && !of_get_property(np, property, NULL)) continue; if (!property && (of_get_property(np, "ti,timer-alwon", NULL) || of_get_property(np, "ti,timer-dsp", NULL) || of_get_property(np, "ti,timer-pwm", NULL) || of_get_property(np, "ti,timer-secure", NULL))) continue; of_add_property(np, &device_disabled); return np; } return NULL; } I'll patch this up and drop $subject =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJWEtJUAAoJEIaOsuA1yqREst0P/j4iFxhOkXXpJ1mxeBqKv76a 4i52T9OljTSPV76Kp2ko7WZ9eP8wYBfkES7ZQANOw0kCQHfWmWNOEWT4wmhsgyb8 si6Al3u/FjP4wKpVYTfhlXfOZ/cvEei4gcz5sA664DkO4dBcfxWGVMiMSfYOWO89 ErdHdTAJcgEF+UOarXDVAQw2zDkUOrcvIEj5O0sWrdUYyRxzhQOPf4+H7PdMlkYD tj7cKNYWdmgdv1AkviQayMU118WOkRIBv5ja0jg1MLrJdGuFN2ZKg+bW5NuVj2jR l0Z4DmzTqVoVEuXuyrYBzIM3wuM5/b2y7332m8h2w73o1J07xWER2gk6iy/d7J3y d2MuAESk+8TGeIm5h1CgKxV8BLv7I/ybUhg2/qN8KMEMxySnLeFfjEy5CB35dAOs odwWBJHpVXPPpDuWNZGHjEl8nFCM3vIGsbQ5O4ATXGJMhiNjKfFDTre9S34gyEs2 i4f68D2n+E4ekHz5C4V7jj5wThB59PmICXTkG2hWZbkD5qgC/yG8geU7/1xf/Nee t2wFOgLjvDNciGBSFnMURvOv9syrFRhDLmV5wgfvrB1yNuIJ7ES+tx09ZKQYrbEt gxOk9nTg3Axr+UcftXv8jI3pEUR4qPznDyc0MzRjpu5r8UYhHBkxKtJ7qE0KFAj7 bppd2X8fAK5fj6abATVq =er7O -----END PGP SIGNATURE----- --=-=-=--