From: James Bottomley <James.Bottomley@steeleye.com>
To: Ian Molton <spyro@f2s.com>
Cc: david-b@pacbell.net, Linux Kernel <linux-kernel@vger.kernel.org>,
greg@kroah.com, tony@atomide.com, jamey.hicks@hp.com,
joshua@joshuawise.com
Subject: Re: DMA API issues
Date: 18 Jun 2004 22:49:49 -0500 [thread overview]
Message-ID: <1087616990.2078.240.camel@mulgrave> (raw)
In-Reply-To: <20040619011416.64d16c4e.spyro@f2s.com>
On Fri, 2004-06-18 at 19:14, Ian Molton wrote:
> On 18 Jun 2004 19:04:11 -0500
> James Bottomley <James.Bottomley@SteelEye.com> wrote:
>
> > Because the piece of memory you wish to access is bus remote.
>
> No, its *not*
>
> my CPU can write there directly.
>
> no strings attached.
>
> the DMA API just only understands how to map from RAM, not anything
> else.
I think you'll actually find that it is. OHCI is a device (representing
a USB hub), it's attached to the system by some interface that
constitutes a bus (the bus interface transforming the CPU access cycles
to device access cycles, translating interrupts etc.).
But even if you've somehow managed to glue an OHCI directly on to the
system memory controller, from the point of view of the DMA API, the
memory the device contains is still bus remote. To be useful, the API
has to deal with bus remote memory in all its forms.
James
next prev parent reply other threads:[~2004-06-19 3:50 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-18 18:20 DMA API issues James Bottomley
2004-06-18 18:35 ` Ian Molton
2004-06-18 18:52 ` James Bottomley
2004-06-18 18:57 ` Ian Molton
2004-06-18 19:20 ` David Brownell
2004-06-18 19:44 ` Ian Molton
2004-06-18 19:57 ` James Bottomley
2004-06-18 21:08 ` David Brownell
2004-06-18 21:14 ` James Bottomley
2004-06-18 22:38 ` David Brownell
2004-06-18 23:07 ` James Bottomley
2004-06-18 23:31 ` Ian Molton
2004-06-19 18:23 ` David Brownell
2004-06-19 20:41 ` Russell King
2004-06-19 21:46 ` James Bottomley
2004-06-19 22:49 ` Ian Molton
2004-06-20 13:37 ` James Bottomley
2004-06-20 15:50 ` Ian Molton
2004-06-20 16:26 ` Jeff Garzik
2004-06-20 16:57 ` Ian Molton
2004-06-20 20:15 ` David Brownell
2004-06-20 16:46 ` James Bottomley
2004-06-20 18:02 ` Oliver Neukum
2004-06-20 19:27 ` James Bottomley
2004-06-20 19:34 ` Oliver Neukum
2004-06-20 20:07 ` David Brownell
2004-06-20 20:18 ` David Brownell
2004-06-20 20:02 ` David Brownell
2004-06-18 23:25 ` Ian Molton
2004-06-18 23:29 ` James Bottomley
2004-06-18 23:51 ` Ian Molton
2004-06-19 0:04 ` James Bottomley
2004-06-19 0:14 ` Ian Molton
2004-06-19 3:49 ` James Bottomley [this message]
2004-06-20 20:59 ` Jamey Hicks
2004-06-19 15:11 ` DMA API issues... summary Ian Molton
2004-06-20 20:49 ` Joshua Wise
2004-06-18 19:30 ` DMA API issues James Bottomley
2004-06-18 19:56 ` Ian Molton
2004-06-18 19:22 ` Jamey Hicks
2004-06-18 19:41 ` James Bottomley
2004-06-18 20:02 ` Oliver Neukum
2004-06-18 20:07 ` James Bottomley
2004-06-18 20:14 ` Benjamin Herrenschmidt
2004-06-18 20:24 ` James Bottomley
2004-06-18 21:20 ` Russell King
2004-06-18 23:20 ` Ian Molton
2004-06-20 18:25 ` Deepak Saxena
-- strict thread matches above, loose matches on Subject: below --
2004-06-18 16:59 Ian Molton
2004-06-18 18:07 ` Matt Porter
2004-06-18 18:19 ` Ian Molton
2004-06-18 18:58 ` Matt Porter
2004-06-18 18:33 ` Jamey Hicks
2004-06-18 19:21 ` Matt Porter
2004-06-18 19:43 ` Russell King
2004-06-21 13:35 ` Takashi Iwai
2004-06-21 23:08 ` Russell King
2004-06-22 2:06 ` Jeff Garzik
2004-06-22 3:18 ` Linus Torvalds
2004-06-22 3:26 ` Linus Torvalds
2004-06-22 10:40 ` Takashi Iwai
2004-06-23 12:34 ` Russell King
2004-06-23 15:36 ` Takashi Iwai
2004-06-23 15:44 ` Russell King
2004-06-23 16:01 ` Takashi Iwai
2004-06-23 16:10 ` Russell King
2004-06-22 10:48 ` Takashi Iwai
2004-06-18 19:48 ` Jamey Hicks
2004-06-18 21:08 ` Jeff Garzik
2004-06-18 22:12 ` Richard B. Johnson
2004-06-18 23:27 ` Ian Molton
2004-06-18 23:26 ` Ian Molton
2004-06-18 23:30 ` James Bottomley
2004-06-18 23:32 ` Jeff Garzik
[not found] ` <20040619005714.37b68453.spyro@f2s.com>
[not found] ` <40D3838B.2070608@pobox.com>
[not found] ` <20040619011621.4491600a.spyro@f2s.com>
[not found] ` <40D3872F.5010007@pobox.com>
2004-06-19 0:34 ` Ian Molton
2004-06-19 21:15 ` Tony Lindgren
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