From: Milton Miller <miltonm@bga•com>
To: Olof Johansson <olof@lixom•net>
Cc: ppcdev <linuxppc-dev@ozlabs•org>, Christoph Hellwig <hch@lst•de>
Subject: Re: [PATCH v2] pcmcia: CompactFlash driver for PA Semi Electra boards
Date: Wed, 27 Jun 2007 06:20:38 -0500 [thread overview]
Message-ID: <3d37f1da59dc2a063a06bbd6092ed96a@bga.com> (raw)
In-Reply-To: <20070625171221.GA6684@lixom.net>
> On Mon, Jun 25, 2007 at 08:39:09PM +0100, Christoph Hellwig wrote:
>> On Mon, Jun 25, 2007 at 12:12:21PM -0500, Olof Johansson wrote:
>>> Driver for the CompactFlash slot on the PA Semi Electra eval board.
>>> It's
>>> a simple device sitting on localbus, with interrupts and
>>> detect/voltage
>>> control over GPIO.
>>>
>>> The driver is implemented as an of_platform driver, and adds localbus
>>> as a bus being probed by the of_platform framework.
>>
>> Looks good to me. The only odd thing is the inconsistant use of
>> #ifdef CONFIG_PCMCIA in setup.c.
>
> The ifdef is needed since for CONFIG_PCMCIA=n builds, the bus notifier
> isn't available. I wanted to do the bus notifier registration
> explicitly
> before the of_platform bus probe to avoid later surprises due to
> reordered
> initcalls in case it was split up in it's own initcall.
If CONFIG_PCMCIA=m then your notifier is not registered. The modprobe
of your of_driver loads ds.ko, registers the bus, then registers your
driver. When the socket driver tries to dma, the BUG in dma_64 for no
archdata.dma_ops triggers.
It seems like we need
(1) a notifier that a bus is registered, run before allowing any
devices, so that platforms can register bus notifiers by bus name
before the devices and drivers are registered.
(2) a powerpc64 generic pcmcia bus notifier that copys the dma ops from
the parent socket.
(3) something to set the dma_ops to direct_dma_ops on the of device.
If we don't want (3) to be in the driver (as Christoph previosly
mentioned), then it needs to be a seperate bus that reuses the of
matching. This would be similar to how ibmebus is setup. If I
remember the discussion, ibmebus is to provide the alternate dma ops
and steals match etc code from the of_platform bus type.
Oh, is this why you have depends on PCMCIA=y ?
> I could add the code under ifdef as well, but it didn't seem too
> critical. Once the second major board comes along I'll probably move it
> out to a per-board file, there's no real need for it just yet.
milton
next prev parent reply other threads:[~2007-06-27 11:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-25 1:03 [PATCH] pcmcia: CompactFlash driver for PA Semi Electra boards Olof Johansson
2007-06-25 5:56 ` Christoph Hellwig
2007-06-25 15:50 ` Olof Johansson
2007-06-25 17:12 ` [PATCH v2] " Olof Johansson
2007-06-25 19:39 ` Christoph Hellwig
2007-06-25 20:43 ` Olof Johansson
2007-07-05 14:49 ` [PATCH v3] " Olof Johansson
2007-07-20 23:48 ` Andrew Morton
2007-07-21 20:18 ` Olof Johansson
2007-08-31 2:43 ` [PATCH -mm] pcmcia: Updates to electra_cf driver Olof Johansson
2007-06-27 11:20 ` Milton Miller [this message]
2007-07-05 14:37 ` [PATCH v2] pcmcia: CompactFlash driver for PA Semi Electra boards Olof Johansson
2007-06-27 11:20 ` [PATCH] " Milton Miller
2007-07-05 14:36 ` Olof Johansson
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