From patchwork Fri Dec 6 11:57:07 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 3295341 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 8A441C0D4A for ; Fri, 6 Dec 2013 11:57:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6A932204E4 for ; Fri, 6 Dec 2013 11:57:57 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3D6C420453 for ; Fri, 6 Dec 2013 11:57:56 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Vou2W-0005r5-QN; Fri, 06 Dec 2013 11:57:48 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Vou2U-0002pb-9m; Fri, 06 Dec 2013 11:57:46 +0000 Received: from [2001:41c8:1:5384::2] (helo=cassiel.sirena.org.uk) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Vou2R-0002pH-9Q for linux-arm-kernel@lists.infradead.org; Fri, 06 Dec 2013 11:57:44 +0000 Received: from cpc11-sgyl31-2-0-cust68.sgyl.cable.virginm.net ([94.175.92.69] helo=debutante.sirena.org.uk) by cassiel.sirena.org.uk with esmtpsa (TLS1.2:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1Vou1s-0004wp-M0; Fri, 06 Dec 2013 11:57:10 +0000 Received: from broonie by debutante.sirena.org.uk with local (Exim 4.82) (envelope-from ) id 1Vou1r-0006n0-IR; Fri, 06 Dec 2013 11:57:07 +0000 From: Mark Brown To: Lorenzo Pieralisi , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala Date: Fri, 6 Dec 2013 11:57:07 +0000 Message-Id: <1386331027-26065-1-git-send-email-broonie@kernel.org> X-Mailer: git-send-email 1.8.5.1 X-SA-Exim-Connect-IP: 94.175.92.69 X-SA-Exim-Mail-From: broonie@sirena.org.uk X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Subject: [PATCH] ARM: cpu: Document and tweak clock-frequency property X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:57:07 +0000) X-SA-Exim-Scanned: Yes (on cassiel.sirena.org.uk) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20131206_065743_660857_E3072652 X-CRM114-Status: GOOD ( 13.29 ) X-Spam-Score: -1.1 (-) Cc: devicetree@vger.kernel.org, linaro-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Mark Brown X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Mark Brown The ARMv7 topology code uses the ePAPR specified mandatory clock-frequency property to determine the relative performances of the CPUs along with the CPU type. However with FDT we don't update to take account of the current speed and if the cores are not running at full speed on boot then a device tree which is accurate on boot can provide incorrect information about the relative performances of the cores. Document the current usage both to override ePAPR and to make the binding within the kernel more complete. Ideally the kernel would use information from the CPU frequency scaling drivers here but they may in turn consider this property and such changes are likely to be part of the energy aware scheduling work so not immediately available. Signed-off-by: Mark Brown --- Documentation/devicetree/bindings/arm/cpus.txt | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt index 91304353eea4..e3726f6bca92 100644 --- a/Documentation/devicetree/bindings/arm/cpus.txt +++ b/Documentation/devicetree/bindings/arm/cpus.txt @@ -191,6 +191,15 @@ nodes to be present and contain the properties described below. property identifying a 64-bit zero-initialised memory location. + - clock-frequency + Usage: required + Value type: or + Definition: + This is specified in ePAPR as the current clock + frequency of the CPU. When used with these + extensions it should reflect the maximum clock + frequency for the CPU. + Example 1 (dual-cluster big.LITTLE system 32-bit): cpus {