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Date: Thu, 29 Jan 2009 16:51:43 -0000 (UTC)
Subject: Re: [PATCH RFC] sh: maple: Add support for SEGA Dreamcast VMU and  
         clean up maple bus driver (1/3)
From: "Adrian McMenamin" <adrian@newgolddream.dyndns.info>
To: "Adrian McMenamin" <adrian@newgolddream.dyndns.info>
Cc: "Paul Mundt" <lethal@linux-sh.org>, "Greg KH" <greg@kroah.com>,
       "Dmitry Torokhov" <dmitry.torokhov@gmail.com>,
       "dwmw2" <dwmw2@infradead.org>, "linux-sh" <linux-sh@vger.kernel.org>,
       "LKML" <linux-kernel@vger.kernel.org>,
       "linux-input" <linux-input@vger.kernel.org>,
       "linux-mtd" <linux-mtd@vger.kernel.org>
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On Thu, January 29, 2009 4:43 pm, Adrian McMenamin wrote:
> On Thu, January 29, 2009 3:13 am, Paul Mundt wrote:
>> On Wed, Jan 28, 2009 at 11:57:49PM +0000, Adrian McMenamin wrote:
>>> Rework the maple bus driver to support block reads and writes, while
>>> also cleaning up the code and aiming for a consistent namespace for
>>> functions.
>>>
>>> -	mutex_init(&mq->mutex);
>>> +	mq->recvbuf->buf = (void *)P2SEGADDR(&((mq->recvbuf->bufx)[0]));
>>>
>> Please do not abuse P2SEGADDR in this fashion. No new code should be
>> using P2SEGADDR anyways. maple is particularly abusive in this case
>> since
>> it bounces back and forth between P2SEGADDR and PHYSADDR to try and
>> ignore the fact cache flushing has to be handled.
>>
>> You may also wish to consider ioremap/ioremap_nocache().
>>
>
> Can I just use dma_cache_sync before each dma run and then use the P1
> address space?
>

After the dma run I mean - the cache is flushed before the run - but not
after.

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