From: David Howells <dhowells@redhat.com>
To: Dominik Brodowski <linux@dominikbrodowski.de>
Cc: davej@redhat.com, uclinux-dev@uclinux.org,
cpufreq@www.linux.org.uk, linux-kernel@vger.kernel.org
Subject: Re: FRV and CPU frequency scaling
Date: Tue, 02 Nov 2004 13:35:37 +0000 [thread overview]
Message-ID: <14027.1099402537@redhat.com> (raw)
In-Reply-To: <20041102123509.GA8259@dominikbrodowski.de>
> 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
WARNING: multiple messages have this Message-ID (diff)
From: David Howells <dhowells@redhat.com>
To: Dominik Brodowski <linux@dominikbrodowski.de>
Cc: cpufreq@www.linux.org.uk, davej@redhat.com,
linux-kernel@vger.kernel.org, uclinux-dev@uclinux.org
Subject: Re: FRV and CPU frequency scaling
Date: Tue, 02 Nov 2004 13:35:37 +0000 [thread overview]
Message-ID: <14027.1099402537@redhat.com> (raw)
In-Reply-To: <20041102123509.GA8259@dominikbrodowski.de>
> 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
next prev parent reply other threads:[~2004-11-02 13:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-02 12:35 FRV and CPU frequency scaling Dominik Brodowski
2004-11-02 12:35 ` Dominik Brodowski
2004-11-02 13:35 ` David Howells [this message]
2004-11-02 13:35 ` David Howells
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=14027.1099402537@redhat.com \
--to=dhowells@redhat.com \
--cc=cpufreq@www.linux.org.uk \
--cc=davej@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@dominikbrodowski.de \
--cc=uclinux-dev@uclinux.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.