[PATCH] fsldma: use PCI Read Multiple command
David Hawkins
dwh at ovro.caltech.edu
Tue Apr 28 06:41:35 EST 2009
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
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