From owner-freebsd-arm@FreeBSD.ORG Tue Apr 8 01:41:26 2014 Return-Path: Delivered-To: freebsd-arm@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 573C0692 for ; Tue, 8 Apr 2014 01:41:26 +0000 (UTC) Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 2AF601034 for ; Tue, 8 Apr 2014 01:41:25 +0000 (UTC) Received: by mail-pa0-f47.google.com with SMTP id lj1so280865pab.34 for ; Mon, 07 Apr 2014 18:41:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:content-type:mime-version:subject:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to; bh=dquYMmjlksJjN3Um0UNjCjGkTyNhCnU6bGmSJGzx5Hs=; b=abM4mCCXOiCs99rGLrnxJKLzLvJFK7kGo+l42/9GunuVod5knafJymQaO/fpsug6vX YFX3OrL5SrMSsiZfPCSOSqWClxTx+uPCm9g03eMO8TSm1jt8dVF4maLZ87KuhHCUkCzy QtiYv0qHPMg1p7nK2cW9iMT/rUWA/AJFiazwf2zNI1RJIOesyYd8dPEpB6POcVH1PImE IQrWHJqEfR2qvvhn8Lre7tMWAy18GiUSYC5KCQln6taqfmq8fgc6rBufW95bmWLiJsHW mxUIE5wRkrfqJpVFmrSwQwl1puBscBwUYzwwO+x+Ui74hr5elbvMjtKPW0h0UHRUTcKB sMeA== X-Gm-Message-State: ALoCoQmIr1QR++11x2YsbH5/+tbPvQD/M6elXWOCcYkeoMU3fJskI3UXdWS78m/fEGKKAd0j6Act X-Received: by 10.66.141.12 with SMTP id rk12mr931777pab.152.1396921279249; Mon, 07 Apr 2014 18:41:19 -0700 (PDT) Received: from [192.168.1.3] (c-50-156-22-189.hsd1.ca.comcast.net. [50.156.22.189]) by mx.google.com with ESMTPSA id j3sm790366pbh.38.2014.04.07.18.41.18 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 07 Apr 2014 18:41:18 -0700 (PDT) Sender: Tim Kientzle Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 7.2 \(1874\)) Subject: Re: [BeagleBone Black Test PATCH 0/2] port latest u-boot From: Tim Kientzle In-Reply-To: <1396862732-4961-1-git-send-email-xbing6@gmail.com> Date: Mon, 7 Apr 2014 18:41:16 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: References: <1396862732-4961-1-git-send-email-xbing6@gmail.com> To: Xuebing Wang X-Mailer: Apple Mail (2.1874) Cc: freebsd-arm@freebsd.org X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Apr 2014 01:41:26 -0000 On Apr 7, 2014, at 2:25 AM, Xuebing Wang wrote: > Hi Tim and all, >=20 > This is for discussion only. Would you please advice? >=20 > This is motivated by trying to increase CPU frequency for BeagleBone = Black. >=20 > AM335x cpufreq is not supported yet. In order to achieve the goal to = increase > CPU freq, I am thinking of a 2-step approach: > 1) port latest u-boot, which have cpufreq better organized > 2) tweak u-boot opp/freq later Setting the processor frequency after the OS is running is not difficult. The AM335x TRM shows exactly how to do it. I would not change U-Boot but rather implement a FreeBSD driver that exposed a read/write sysctl to reprogram the CPU frequency. Getting powerd to work with this should be straightforward. Tim