Messages in this thread | | | Date | Tue, 31 Jul 2012 09:33:08 -0700 | From | Jon Mason <> | Subject | Re: [RFC v2 1/2] PCI-Express Non-Transparent Bridge Support |
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On Tue, Jul 31, 2012 at 11:35:33AM +0800, Jianbin Kang wrote: > > I've tried to make it all generic enough that non-Intel NTBs should plug in with > > minimal changes to ntb_hw.c. If their design is too divergent, then a slight > > redesign of ntb_hw.c might be necessary. But from what I've seen of other > > designs on the internet, they appear to be extremely similar. The transport and > > client drivers were written with the hardware abstracted away as much as > > possible to prevent the need to modify it for different hardware. If there is > > anything which is Intel hardware specific, I'd be happy to change it to make it > > more generic. > In ntb_process_tx(), ntb uses hard-coding 'memcpy_toio' to copy data > to remote. > Is it better to provide a function pointer like 'tx()' and call qp->tx(). > memcpy_toio is a slow operation. Some hardware can setup a dma > transfer and wait. > > IMHO, the best way is to handle tx in async mode. But it requires > lots of modification.
Actually this is what I'm working on now, using async_tx to replace the memcpy. I believe the changes shouldn't be that significant.
Is the "hardware that can setup dma" you refer to something that does not use this interface?
Thanks, Jon
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