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From: pacman@kosh•dhis.org
To: benh@kernel•crashing.org (Benjamin Herrenschmidt)
Cc: linuxppc-dev@lists•ozlabs.org, linux-kernel@vger•kernel.org
Subject: Re: PROBLEM: memory corrupting bug, bisected to 6dda9d55
Date: Fri, 22 Oct 2010 04:15:19 -0500 (GMT+5)	[thread overview]
Message-ID: <20101022091519.1924.qmail@kosh.dhis.org> (raw)
In-Reply-To: <1287608215.2198.23.camel@pasglop>

Benjamin Herrenschmidt writes:
> 
> On Wed, 2010-10-20 at 13:33 -0500, pacman@kosh•dhis.org wrote:
> > > Just try :-) "quiesce" is something that afaik only apple ever
> > > implemented anyways. It uses hooks inside their OF to shut down all
> > > drivers that do bus master (among other HW sanitization tasks).
> > 
> > I booted a version with a prom_close_stdout after the last prom_debug. It
> > didn't have any effect. That 1000Hz clock was still ticking. 
> 
> Ok so you'll have to make up a "workaround" in prom_init that looks for
> OHCI's in the device-tree and disable them.

I'm a long way from understanding how to do that.

> 
> Check if the OHCI node has some existing f-code words you can use for
> that with "dev /path-to-ohci words" in OF for example. If not, you may

Nothing there but open close decode-unit encode-unit

> need to use the low level register accessors. Use OF client interface
> "interpret" to run forth code from C.

Here are the major problems:

1. How do I locate all usb nodes in the device tree?

2. How do I know if a particular usb node is OHCI?

3. Knowing that a node is OHCI, how do I know where its control registers
are? I'm sure this is calculated from the "reg" property but I don't see how.

4. Knowing where the control registers are, how do I access them? Do I need
to request a virt-to-phys mapping or can I assume that it's already mapped,
or that the "rl!" command will do the right thing with a physical address?

5. Which control register should I use to tell the OHCI to be quiet? Just do
a general reset, or is there something that specifically turns off the
counter that's been causing the trouble?

-- 
Alan Curry

  reply	other threads:[~2010-10-22  9:15 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20101009095718.1775.qmail@kosh.dhis.org>
     [not found] ` <20101011143022.GD30667@csn.ul.ie>
2010-10-11 21:00   ` PROBLEM: memory corrupting bug, bisected to 6dda9d55 Andrew Morton
2010-10-13 14:40     ` Mel Gorman
2010-10-13 17:52       ` pacman
2010-10-18 11:33         ` Mel Gorman
2010-10-18 19:10           ` pacman
2010-10-18 21:10             ` Benjamin Herrenschmidt
2010-10-18 21:33               ` pacman
2010-10-19 10:16                 ` Benjamin Herrenschmidt
2010-10-19 18:10                   ` pacman
2010-10-19 20:47                     ` Segher Boessenkool
2010-10-19 21:02                       ` Benjamin Herrenschmidt
2010-10-20  3:23                         ` pacman
2010-10-20 10:32                           ` Benjamin Herrenschmidt
2010-10-20 18:33                             ` pacman
2010-10-20 20:56                               ` Benjamin Herrenschmidt
2010-10-22  9:15                                 ` pacman [this message]
2010-10-27  8:57                                 ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, bisected to 6dda9d55) pacman
2010-10-27 10:13                                   ` Olaf Hering
2010-10-27 21:04                                     ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, pacman
2010-10-27 22:05                                       ` Segher Boessenkool
2010-10-27 22:58                                         ` pacman
2010-10-27 23:33                                           ` Segher Boessenkool
2010-10-28  1:11                                             ` pacman
2010-10-28 19:50                                               ` Segher Boessenkool
2010-10-28 21:07                                                 ` pacman
2010-10-29  0:16                                                   ` Segher Boessenkool
2010-11-05  6:43                                                     ` pacman
2010-11-29  5:44                                                       ` Benjamin Herrenschmidt
2010-10-27 13:27                                   ` Pegasos OHCI bug (was Re: PROBLEM: memory corrupting bug, bisected to 6dda9d55) Benjamin Herrenschmidt
2010-10-19 20:58                     ` PROBLEM: memory corrupting bug, bisected to 6dda9d55 Benjamin Herrenschmidt
2010-10-18 19:37           ` Andrew Morton
2010-10-18 21:02             ` Benjamin Herrenschmidt
2010-10-18 21:55             ` Thomas Gleixner
2010-10-19 16:24               ` Helmut Grohne
2010-10-19 16:42                 ` Thomas Gleixner
2010-10-18 20:59       ` Benjamin Herrenschmidt

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