From: David Hawkins <dwh@ovro.caltech.edu>
To: Timur Tabi <timur@freescale.com>
Cc: linuxppc-dev@ozlabs.org, Dan Williams <dan.j.williams@intel.com>,
Liu Dave-R63238 <DaveLiu@freescale.com>,
linux-kernel@vger.kernel.org, Ira Snyder <iws@ovro.caltech.edu>
Subject: Re: [PATCH] fsldma: use PCI Read Multiple command
Date: Mon, 27 Apr 2009 13:41:35 -0700 [thread overview]
Message-ID: <49F6187F.8020703@ovro.caltech.edu> (raw)
In-Reply-To: <49F614FC.70000@freescale.com>
Hi Timur,
>> PRC_RM - PCI read multiple
>> The default PCI read command used by the DMA controller is
>> PCI Read (PCI command 6h). When the burst length is 32-bytes
>> or longer, PCI Read Line (PCI command Eh) is used (undocumented
>> feature of the controller). Using PCI read multiple
>> (PCI command Ch) results in high-performance across PCI
>> bridges. DMA transfers to non-prefetchable PCI registers
>> should not result in prefetched reads, even when using
>> the PCI read multiple command.
>
> I was thinking more along the lines of:
>
> "This driver tells the DMA controller to use the PCI Read Multiple
> command, instead of the PCI Read Line command, for PCI read operations.
> Please be aware that this setting may result in read pre-fetching on
> some platforms."
Ok, thanks.
Ira will add your comment to the body of the code near
the PRC_RM command and submit a new patch.
Cheers,
Dave
WARNING: multiple messages have this Message-ID (diff)
From: David Hawkins <dwh@ovro.caltech.edu>
To: Timur Tabi <timur@freescale.com>
Cc: Liu Dave-R63238 <DaveLiu@freescale.com>,
Ira Snyder <iws@ovro.caltech.edu>,
linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH] fsldma: use PCI Read Multiple command
Date: Mon, 27 Apr 2009 13:41:35 -0700 [thread overview]
Message-ID: <49F6187F.8020703@ovro.caltech.edu> (raw)
In-Reply-To: <49F614FC.70000@freescale.com>
Hi Timur,
>> PRC_RM - PCI read multiple
>> The default PCI read command used by the DMA controller is
>> PCI Read (PCI command 6h). When the burst length is 32-bytes
>> or longer, PCI Read Line (PCI command Eh) is used (undocumented
>> feature of the controller). Using PCI read multiple
>> (PCI command Ch) results in high-performance across PCI
>> bridges. DMA transfers to non-prefetchable PCI registers
>> should not result in prefetched reads, even when using
>> the PCI read multiple command.
>
> I was thinking more along the lines of:
>
> "This driver tells the DMA controller to use the PCI Read Multiple
> command, instead of the PCI Read Line command, for PCI read operations.
> Please be aware that this setting may result in read pre-fetching on
> some platforms."
Ok, thanks.
Ira will add your comment to the body of the code near
the PRC_RM command and submit a new patch.
Cheers,
Dave
next prev parent reply other threads:[~2009-04-27 20:41 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-24 18:35 [PATCH] fsldma: use PCI Read Multiple command Ira Snyder
2009-04-24 18:35 ` Ira Snyder
2009-04-27 7:48 ` Li Yang
2009-04-27 7:48 ` Li Yang
2009-04-27 9:09 ` Liu Dave-R63238
2009-04-27 9:09 ` Liu Dave-R63238
2009-04-27 10:16 ` Li Yang
2009-04-27 10:16 ` Li Yang
2009-04-27 14:31 ` Timur Tabi
2009-04-27 14:31 ` Timur Tabi
2009-04-27 19:34 ` David Hawkins
2009-04-27 19:34 ` David Hawkins
2009-04-27 19:40 ` Timur Tabi
2009-04-27 19:40 ` Timur Tabi
2009-04-27 19:48 ` David Hawkins
2009-04-27 19:54 ` Kumar Gala
2009-04-27 19:54 ` Kumar Gala
2009-04-27 20:00 ` David Hawkins
2009-04-27 20:01 ` David Hawkins
2009-04-28 2:06 ` Liu Dave-R63238
2009-04-28 2:06 ` Liu Dave-R63238
2009-04-27 20:02 ` Kumar Gala
2009-04-27 20:12 ` David Hawkins
2009-04-27 20:04 ` Timur Tabi
2009-04-27 20:47 ` Scott Wood
2009-04-27 20:47 ` Scott Wood
2009-04-27 20:49 ` Timur Tabi
2009-04-27 20:49 ` Timur Tabi
2009-04-27 20:22 ` David Hawkins
2009-04-27 20:22 ` David Hawkins
2009-04-27 20:26 ` Timur Tabi
2009-04-27 20:26 ` Timur Tabi
2009-04-27 20:41 ` David Hawkins [this message]
2009-04-27 20:41 ` David Hawkins
2009-04-27 20:42 ` Timur Tabi
2009-04-27 20:42 ` Timur Tabi
2009-04-27 20:44 ` David Hawkins
2009-04-27 20:44 ` David Hawkins
2009-04-27 20:42 ` Ira Snyder
2009-04-27 20:42 ` Ira Snyder
2009-04-27 20:47 ` Timur Tabi
2009-04-27 20:47 ` Timur Tabi
2009-04-27 20:49 ` Dan Williams
2009-04-27 20:49 ` Dan Williams
2009-06-11 2:45 ` Kumar Gala
2009-06-11 2:45 ` Kumar Gala
2009-06-11 15:17 ` Ira Snyder
2009-06-11 15:17 ` Ira Snyder
2009-06-12 9:23 ` Li Yang
2009-06-12 9:23 ` Li Yang
2009-06-12 15:03 ` Kumar Gala
2009-06-12 15:03 ` Kumar Gala
2009-06-12 17:38 ` Dan Williams
2009-06-12 17:38 ` Dan Williams
2009-06-12 18:01 ` Kumar Gala
2009-06-12 18:01 ` Kumar Gala
2009-04-28 1:48 ` Liu Dave-R63238
2009-04-28 1:48 ` Liu Dave-R63238
2009-04-28 2:08 ` David Hawkins
2009-04-28 2:08 ` David Hawkins
2009-04-27 21:59 ` Liu Dave-R63238
2009-04-28 1:31 ` Liu Dave-R63238
2009-04-28 1:31 ` Liu Dave-R63238
2009-04-28 1:36 ` David Hawkins
2009-04-28 1:36 ` David Hawkins
2009-04-28 13:43 ` Timur Tabi
2009-04-28 13:43 ` Timur Tabi
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