From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_MED, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB592C5CFC1 for ; Tue, 19 Jun 2018 13:41:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 74339204EC for ; Tue, 19 Jun 2018 13:41:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=baylibre-com.20150623.gappssmtp.com header.i=@baylibre-com.20150623.gappssmtp.com header.b="rTXOBJcC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 74339204EC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=baylibre.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937743AbeFSNlL (ORCPT ); Tue, 19 Jun 2018 09:41:11 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:35020 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937695AbeFSNlH (ORCPT ); Tue, 19 Jun 2018 09:41:07 -0400 Received: by mail-wm0-f68.google.com with SMTP id j15-v6so566225wme.0 for ; Tue, 19 Jun 2018 06:41:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=O9CgGsxjPmXSJzKHBcIzvkjp9vRQY5ar1a5/jpyGPWw=; b=rTXOBJcCwtd7UV0iGy1AhM0DKWC1S733yQT8EFg3NbCXowIDQ8d3pR6vB8XkYmOz8e Jo9n5WnYwSQ9p9zSuKRGDP5v4FHLzYncskdRvkK8uA8wTVxUPWvph+vI9vuZwTTpjPDG 6XSSjW1g+cEAErn3J9Lihbq7k/+RUIHVaGEX1TSf0P1AQV+TWFC3PVQr/rPkGHud3Z3X yHqAn+mqEHgapkekpKH+t8dRobSpswHJHazWP96IVQNHO68URpVMENopk0v4/yQSzoUb uUYiVSvxZB5Jhb6uQJCcvFKsjV2ts2s+rlL1TQm9Osm2L3kgsZDaIXfb5W6uibKwrRXd qPug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=O9CgGsxjPmXSJzKHBcIzvkjp9vRQY5ar1a5/jpyGPWw=; b=sItRIUyIvxqokV4OUZZ0arMNYKqVh6ANkMvFykBwhs0kIo7RehQoEe4IsQkQjD9Fni MUJIXVVob6beW/0Pj1BHEQ1sI1niqY4mmsjqlvU95GUH8e+CBVGmQWIeDetLLx4YUgkz zMUPIs/cXMOirUOQEJfOhVE/VkBYElBYX3Ub5Ss57ToyioYaEwtLDxMubsBceu6NPokv XZW8iK6gTeVokFWs4ExllcVAy8ewORfeFXUfzdp3jQaT4kzBi3sIEfCGgRlxAkK1OLgj Z5NZ+ySQ+TEtoXzdot1Z21+EsT8uh/+OJOMZs093iNk/zLlcooqDCGqzVp9ruBGtmDIL ndxA== X-Gm-Message-State: APt69E0YBcf+hR2NxGG4ZuAwWDexd/XzXt+YcM/7zDxKlNbnkCwUZeW4 lwP1i+ESLXC7vRipnOPcCJt0WRoh X-Google-Smtp-Source: ADUXVKLHjePjXdNrnjjYHL7uKRjr0rOJ2r7VnYuNndCSTMwbHLVC1RkEujVoPCmU34G9dkPbTb+/sg== X-Received: by 2002:a1c:470b:: with SMTP id u11-v6mr11499989wma.49.1529415665755; Tue, 19 Jun 2018 06:41:05 -0700 (PDT) Received: from boomer.baylibre.local ([90.63.244.31]) by smtp.googlemail.com with ESMTPSA id t10-v6sm17196154wrq.74.2018.06.19.06.41.04 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 19 Jun 2018 06:41:05 -0700 (PDT) From: Jerome Brunet To: Michael Turquette , Stephen Boyd Cc: Jerome Brunet , linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, linux-soc@vger.kernel.org, David Brown , Andy Gross , Linus Walleij , Quentin Schulz , Maxime Ripard Subject: [PATCH 2/2] clk: fix CLK_SET_RATE_GATE with clock rate protection Date: Tue, 19 Jun 2018 15:40:51 +0200 Message-Id: <20180619134051.16726-3-jbrunet@baylibre.com> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180619134051.16726-1-jbrunet@baylibre.com> References: <20180619134051.16726-1-jbrunet@baylibre.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org CLK_SET_RATE_GATE should prevent any operation which may result in a rate change or glitch while the clock is prepared/enabled. IOW, the following sequence is not allowed anymore with CLK_SET_RATE_GATE: * clk_get() * clk_prepare_enable() * clk_get_rate() * clk_set_rate() At the moment this is enforced on the leaf clock of the operation, not along the tree. This problematic because, if a PLL has the CLK_RATE_GATE, it won't be enforced if the clk_set_rate() is called on its child clocks. Using clock rate protection, we can now enforce CLK_SET_RATE_GATE along the clock tree Acked-by: Linus Walleij Tested-by: Quentin Schulz Tested-by: Maxime Ripard Signed-off-by: Jerome Brunet --- drivers/clk/clk.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 9760b526ca31..97c09243fb21 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -691,6 +691,9 @@ static void clk_core_unprepare(struct clk_core *core) "Unpreparing critical %s\n", core->name)) return; + if (core->flags & CLK_SET_RATE_GATE) + clk_core_rate_unprotect(core); + if (--core->prepare_count > 0) return; @@ -765,6 +768,16 @@ static int clk_core_prepare(struct clk_core *core) core->prepare_count++; + /* + * CLK_SET_RATE_GATE is a special case of clock protection + * Instead of a consumer claiming exclusive rate control, it is + * actually the provider which prevents any consumer from making any + * operation which could result in a rate change or rate glitch while + * the clock is prepared. + */ + if (core->flags & CLK_SET_RATE_GATE) + clk_core_rate_protect(core); + return 0; unprepare: clk_core_unprepare(core->parent); @@ -1888,9 +1901,6 @@ static int clk_core_set_rate_nolock(struct clk_core *core, if (clk_core_rate_is_protected(core)) return -EBUSY; - if ((core->flags & CLK_SET_RATE_GATE) && core->prepare_count) - return -EBUSY; - /* calculate new rates and get the topmost changed clock */ top = clk_calc_new_rates(core, req_rate); if (!top) -- 2.14.3