From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Howells Subject: Re: FRV and CPU frequency scaling Date: Tue, 02 Nov 2004 13:35:37 +0000 Message-ID: <14027.1099402537@redhat.com> References: <20041102123509.GA8259@dominikbrodowski.de> Mime-Version: 1.0 (generated by SEMI 1.14.5 - "Awara-Onsen") Return-path: In-Reply-To: <20041102123509.GA8259@dominikbrodowski.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@www.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=gmane.org@www.linux.org.uk Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Dominik Brodowski Cc: davej@redhat.com, uclinux-dev@uclinux.org, cpufreq@www.linux.org.uk, linux-kernel@vger.kernel.org > While reading through the FRV Documentation patch I stumbled across the file > "clock.txt" file which says: > > + (*) clock.txt > + > + A description of the CPU clock scaling interface. > + > > Could you use the generic cpufreq core (drivers/cpufreq/) for this, please? Maybe. I'm not sure how simple it will be to adapt, since there are several "clocks", and the setting changes the ratios between them. > And could you explain the difference between p0, cm and cmode settings to > me, and how they can be combined, please? Or is the following assumption > correct? > > The CPU core frequency can only be modified on FR405 CPUs, while p0 and cm > are available on all CPUs and allow for modification of the frequency of > some sort of external busses. It's quite complicated. There are 16 clock ratio mode settings, a bus speed doubler and a raw clock speed indicator. The mode table varies from CPU to CPU, and not all modes are available on all CPUs. David