From: Bill Gatliff <bgat@billgatliff.com>
To: Bruce_Leonard@selinc.com
Cc: Scott Wood <scottwood@freescale.com>, linuxppc-embedded@ozlabs.org
Subject: Re: Using DMA
Date: Thu, 06 Nov 2008 15:42:17 -0600 [thread overview]
Message-ID: <491364B9.607@billgatliff.com> (raw)
In-Reply-To: <OF4C3103D2.DABB64DF-ON882574F9.00733B0E-882574F9.00733B48@selinc.com>
Bruce_Leonard@selinc.com wrote:
> Bill Gatliff <bgat@billgatliff.com> wrote on 11/06/2008 10:36:58 AM:
>
>> Scott Wood wrote:
>>> Bruce_Leonard@selinc.com wrote:
>>>> In the Cafe driver, Linux Device Drivers 3rd Edition, and
>>>> DMA-mapping.txt everyone talks about how to allocate buffers using
>>>> dma/pci_alloc_coherent(), but no one talks about how to actually use
>>>> it. I'm pretty sure (even in my ignorance) that just allocating a DMA
>>>> coherent buffer and then copying in and out of it does NOT actually
>>>> engage the underlying hardware and perform a DMA transfer.
>> Does the "adma" stuff address this any?
>>
>
> What is "adma"?
>
> Bruce
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>
Asynchronous DMA. See this paper, for example:
http://www.power.org/devcon/07/Session_Downloads/PADC07_Aytac_Haluk_09_13_07_layout_FINAL.pdf
It looks like the structure of interest is async_tx_submit. Beyond
that, I can't offer much because I haven't used it.
b.g.
--
Bill Gatliff
bgat@billgatliff.com
next prev parent reply other threads:[~2008-11-06 21:42 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-06 2:07 Using DMA Bruce_Leonard
2008-11-06 18:29 ` Scott Wood
2008-11-06 18:36 ` Bill Gatliff
2008-11-06 20:58 ` Bruce_Leonard
2008-11-06 21:42 ` Bill Gatliff [this message]
2008-11-07 15:43 ` Timur Tabi
2008-11-07 21:31 ` Bruce_Leonard
2008-11-07 21:46 ` Timur Tabi
2008-11-07 22:12 ` Bruce_Leonard
2008-11-07 22:28 ` Timur Tabi
2008-11-07 22:37 ` Bruce_Leonard
2008-11-09 3:26 ` Bill Gatliff
2008-11-09 3:25 ` Bill Gatliff
2008-11-10 0:09 ` Bruce_Leonard
2008-11-10 14:35 ` Timur Tabi
2008-11-10 17:58 ` Bruce_Leonard
2008-11-11 9:09 ` Rajasekaran Kaliyaperumal, Chennai
2008-11-11 10:22 ` Porting Linux to 8051 [ was:Re: Using DMA ] Martyn Welch
2008-11-10 22:06 ` Using DMA Bruce_Leonard
2008-11-11 14:51 ` Timur Tabi
2008-11-11 18:19 ` Bruce_Leonard
2008-11-11 19:22 ` Timur Tabi
2008-11-11 21:46 ` Bruce_Leonard
2008-11-11 21:54 ` Timur Tabi
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