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To: "Kamal R. Prasad" <kamalp@acm.org>
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Subject: Re: mmap()
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Kamal R. Prasad wrote:

>
> My usb device probably doesn't have a dma controller, so I don't think 
> the bulk pipe can use any memory allocated by bus_dma. [Pl. correct me 
> if Im wrong this].
> thanks
> -kamal
>
all USB devices use full scatter-gather DMA.  UHCI and OHCI are limitted 
I believe to 4GB of ram.
EHCI (USB2) has a 64 bit extension that allows all DMAs  of data to be 
64 bit addresses.
I don't know however which chips support the 64 bit extensions.