From owner-freebsd-arm@FreeBSD.ORG Tue Apr 8 13:06:06 2014 Return-Path: Delivered-To: freebsd-arm@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 17943875; Tue, 8 Apr 2014 13:06:06 +0000 (UTC) Received: from mho-01-ewr.mailhop.org (mho-03-ewr.mailhop.org [204.13.248.66]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id DF5B51E72; Tue, 8 Apr 2014 13:06:05 +0000 (UTC) Received: from c-24-8-230-52.hsd1.co.comcast.net ([24.8.230.52] helo=damnhippie.dyndns.org) by mho-01-ewr.mailhop.org with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.72) (envelope-from ) id 1WXVj2-00025u-M7; Tue, 08 Apr 2014 13:06:04 +0000 Received: from [172.22.42.240] (revolution.hippie.lan [172.22.42.240]) by damnhippie.dyndns.org (8.14.3/8.14.3) with ESMTP id s38D62xL092689; Tue, 8 Apr 2014 07:06:02 -0600 (MDT) (envelope-from ian@FreeBSD.org) X-Mail-Handler: Dyn Standard SMTP by Dyn X-Originating-IP: 24.8.230.52 X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/sendlabs/outbound_abuse.html for abuse reporting information) X-MHO-User: U2FsdGVkX1/Bv17/p7phZqBNSi0Lq+Jv Subject: Re: [BeagleBone Black Test PATCH 0/2] port latest u-boot From: Ian Lepore To: Tim Kientzle In-Reply-To: References: <1396862732-4961-1-git-send-email-xbing6@gmail.com> Content-Type: text/plain; charset="us-ascii" Date: Tue, 08 Apr 2014 07:06:01 -0600 Message-ID: <1396962361.81853.409.camel@revolution.hippie.lan> Mime-Version: 1.0 X-Mailer: Evolution 2.32.1 FreeBSD GNOME Team Port Content-Transfer-Encoding: 7bit Cc: freebsd-arm@FreeBSD.org, Xuebing Wang 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 13:06:06 -0000 On Mon, 2014-04-07 at 18:41 -0700, Tim Kientzle wrote: > On Apr 7, 2014, at 2:25 AM, Xuebing Wang wrote: > > > Hi Tim and all, > > > > This is for discussion only. Would you please advice? > > > > This is motivated by trying to increase CPU frequency for BeagleBone Black. > > > > 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 > I agree with this, we should handle the frequency change in the kernel rather than in u-boot. On the other hand, I'm all for updating to a newer u-boot for other reasons. I did that for imx6, updating to 2014.01 in place of the 2013.04 that wandboard was using, and it went well. In fact, pretty much all I had to do was remove all the patches I had been using for 2013.04 except for turning on the API option and a couple other options. There apparently have been recent fixes to some of the API stuff, such as how storage devices are enumerated, which will help with the new features added to ubldr that let you choose which device to load the kernel from with u-boot env vars. -- Ian