From: Benjamin Herrenschmidt <benh@kernel•crashing.org>
To: Arnd Bergmann <arnd@arndb•de>
Cc: linuxppc-dev@ozlabs•org,
openipmi-developer@lists•sourceforge.net,
Christian Krafft <krafft@de•ibm.com>
Subject: Re: [Openipmi-developer] [patch 1/1] ipmi: add autosensing of ipmi device on powerpc using device-tree
Date: Sat, 09 Dec 2006 13:14:18 +1100 [thread overview]
Message-ID: <1165630458.1103.109.camel@localhost.localdomain> (raw)
In-Reply-To: <200612090100.09380.arnd@arndb.de>
On Sat, 2006-12-09 at 01:00 +0100, Arnd Bergmann wrote:
> On Friday 08 December 2006 23:50, Benjamin Herrenschmidt wrote:
> >
> > >
> > > + info->io.regsize = resource0.end - resource0.start + 1;
> > > + info->io.regspacing = resource1.start - resource0.start;
> > >
> > > Are you sure this is a reliable way to check the register spacing and
> > > register size? Register size means "how big is a register (8, 16, 32
> > > bits)". Register spacing means (how many bytes are there between
> > > registers. If you had two registers that were 8 bits and 4 bytes
> > > apart, for instance, I don't believe the above calculations would work.
> >
> > How many registers do we expect here ? Might be better to have one
> > resource represent the whole MMIO area, and have a separate property
> > that indicates the stride between 2 registers.
>
> I think the current representation is perfect. AFAICS, there are always
> two registers, but depending on the HW implementation, they may be
> between 1 and 4 bytes wide, and can have a different spacing.
>
> By having two separate areas in the reg property, the driver can
> easily determine both the size and the spacing. It will then do
> a single ioremap that spans both anyway.
For only 2 registers, it makes sense yes.
Ben.
next prev parent reply other threads:[~2006-12-09 2:14 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-07 16:22 [patch 0/1] ipmi: add autosensing of ipmi device on powerpc using device-tree Christian Krafft
2006-12-07 16:24 ` [patch 1/1] " Christian Krafft
2006-12-08 10:24 ` Heiko Joerg Schick
2006-12-08 17:19 ` [Openipmi-developer] " Corey Minyard
2006-12-11 12:13 ` Christian Krafft
2006-12-08 18:59 ` Corey Minyard
2006-12-08 19:49 ` Arnd Bergmann
2006-12-08 22:50 ` Benjamin Herrenschmidt
2006-12-09 0:00 ` Arnd Bergmann
2006-12-09 0:07 ` Corey Minyard
2006-12-09 11:44 ` Arnd Bergmann
2006-12-10 18:42 ` Heiko J Schick
2006-12-11 10:11 ` Arnd Bergmann
2006-12-11 13:01 ` Heiko J Schick
2006-12-11 13:37 ` Segher Boessenkool
2006-12-11 13:18 ` Segher Boessenkool
2006-12-11 14:25 ` Arnd Bergmann
2006-12-11 16:28 ` Heiko J Schick
2006-12-11 16:58 ` Segher Boessenkool
2006-12-11 17:20 ` Christian Krafft
2006-12-11 16:54 ` Segher Boessenkool
2006-12-09 2:14 ` Benjamin Herrenschmidt [this message]
2006-12-09 9:46 ` Segher Boessenkool
2006-12-09 11:46 ` Arnd Bergmann
2006-12-08 0:41 ` [patch 0/1] " Paul Mackerras
2006-12-08 14:04 ` Arnd Bergmann
2006-12-08 17:17 ` [Openipmi-developer] " Corey Minyard
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=1165630458.1103.109.camel@localhost.localdomain \
--to=benh@kernel$(echo .)crashing.org \
--cc=arnd@arndb$(echo .)de \
--cc=krafft@de$(echo .)ibm.com \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=openipmi-developer@lists$(echo .)sourceforge.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox