From nobody Wed Apr 8 14:11:53 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91887C433FE for ; Wed, 26 Oct 2022 15:18:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234524AbiJZPSZ (ORCPT ); Wed, 26 Oct 2022 11:18:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234514AbiJZPSX (ORCPT ); Wed, 26 Oct 2022 11:18:23 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C860E12A36A for ; Wed, 26 Oct 2022 08:18:22 -0700 (PDT) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1oniAZ-0004pf-Vl; Wed, 26 Oct 2022 17:18:16 +0200 Received: from [2a0a:edc0:0:900:1d::77] (helo=ptz.office.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1oniAa-000X4i-1W; Wed, 26 Oct 2022 17:18:15 +0200 Received: from ukl by ptz.office.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1oniAY-00Aq9z-4i; Wed, 26 Oct 2022 17:18:14 +0200 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= To: Michael Turquette , Stephen Boyd Cc: linux-doc@vger.kernel.org, linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@pengutronix.de, Jonathan Corbet Subject: [PATCH v3] clk: expand clk_ignore_unused mechanism to keep only a few clks on Date: Wed, 26 Oct 2022 17:18:12 +0200 Message-Id: <20221026151812.1042052-1-u.kleine-koenig@pengutronix.de> X-Mailer: git-send-email 2.37.2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Allow to pass an integer n that results in only keeping n unused clocks enabled. This helps to debug the problem if you only know that clk_ignore_unused helps but you have no clue yet which clock is the culprit. Signed-off-by: Uwe Kleine-K=C3=B6nig --- Hello, compared to v2 sent in August 2021 this is a trivial rebase on top of v6.1-rc1. I pinged that one repeatedly, I'm now trying with resending and calling the rebased patch v3 to maybe get some feedback. :-\ Best regards Uwe Documentation/driver-api/clk.rst | 4 +++- drivers/clk/clk.c | 33 ++++++++++++++++++++++++-------- 2 files changed, 28 insertions(+), 9 deletions(-) diff --git a/Documentation/driver-api/clk.rst b/Documentation/driver-api/cl= k.rst index 3cad45d14187..65ae7c3e2b33 100644 --- a/Documentation/driver-api/clk.rst +++ b/Documentation/driver-api/clk.rst @@ -259,7 +259,9 @@ the disabling means that the driver will remain functio= nal while the issues are sorted out. =20 To bypass this disabling, include "clk_ignore_unused" in the bootargs to t= he -kernel. +kernel. If you pass "clk_ignore_unused=3Dn" (where n is an integer) the fi= rst n +found clocks are not disabled which can be useful for bisecting over the u= nused +clks if you don't know yet which of them is reponsible for your problem. =20 Locking =3D=3D=3D=3D=3D=3D=3D diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index c3c3f8c07258..356119a7e5fe 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1322,6 +1322,8 @@ static void __init clk_unprepare_unused_subtree(struc= t clk_core *core) clk_pm_runtime_put(core); } =20 +static unsigned clk_unused_keep_on __initdata; + static void __init clk_disable_unused_subtree(struct clk_core *core) { struct clk_core *child; @@ -1352,12 +1354,17 @@ static void __init clk_disable_unused_subtree(struc= t clk_core *core) * back to .disable */ if (clk_core_is_enabled(core)) { - trace_clk_disable(core); - if (core->ops->disable_unused) - core->ops->disable_unused(core->hw); - else if (core->ops->disable) - core->ops->disable(core->hw); - trace_clk_disable_complete(core); + if (clk_unused_keep_on) { + pr_warn("Keep unused clk \"%s\" on\n", core->name); + clk_unused_keep_on -=3D 1; + } else { + trace_clk_disable(core); + if (core->ops->disable_unused) + core->ops->disable_unused(core->hw); + else if (core->ops->disable) + core->ops->disable(core->hw); + trace_clk_disable_complete(core); + } } =20 unlock_out: @@ -1369,9 +1376,17 @@ static void __init clk_disable_unused_subtree(struct= clk_core *core) } =20 static bool clk_ignore_unused __initdata; -static int __init clk_ignore_unused_setup(char *__unused) +static int __init clk_ignore_unused_setup(char *keep) { - clk_ignore_unused =3D true; + if (*keep =3D=3D '=3D') { + int ret; + + ret =3D kstrtouint(keep + 1, 0, &clk_unused_keep_on); + if (ret < 0) + pr_err("Warning: failed to parse clk_ignore_unused parameter, ignoring"= ); + } else { + clk_ignore_unused =3D true; + } return 1; } __setup("clk_ignore_unused", clk_ignore_unused_setup); @@ -1383,6 +1398,8 @@ static int __init clk_disable_unused(void) if (clk_ignore_unused) { pr_warn("clk: Not disabling unused clocks\n"); return 0; + } else if (clk_unused_keep_on) { + pr_warn("clk: Not disabling %u unused clocks\n", clk_unused_keep_on); } =20 clk_prepare_lock(); --=20 2.37.2