Messages in this thread | | | Date | Wed, 13 Sep 2006 00:04:10 -0400 | From | Jeff Garzik <> | Subject | Re: [PATCH 08/19] dmaengine: enable multiple clients and operations |
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Dan Williams wrote: > On 9/11/06, Roland Dreier <rdreier@cisco.com> wrote: >> Jeff> Are we really going to add a set of hooks for each DMA >> Jeff> engine whizbang feature? > ...ok, but at some level we are going to need a file that has: > EXPORT_SYMBOL_GPL(dma_whizbang_op1) > . . . > EXPORT_SYMBOL_GPL(dma_whizbang_opX) > correct?
If properly modularized, you'll have multiple files with such exports.
Or perhaps you won't have such exports at all, if it is hidden inside a module-specific struct-of-hooks.
> I understand what you are saying Jeff, the implementation can be made > better, but something I think is valuable is the ability to write > clients once like NET_DMA and RAID5_DMA and have them run without > modification on any platform that can provide the engine interface > rather than needing a client per architecture > IOP_RAID5_DMA...FOO_X_RAID5_DMA.
It depends on the situation.
The hardware capabilities exported by each platform[or device] vary greatly, not only in the raw capabilities provided, but also in the level of offload.
In general, we don't want to see hardware-specific stuff in generic code, though...
> Or is this an example of the where "Do What You Must, And No More" > comes in, i.e. don't worry about making a generic RAID5_DMA while > there is only one implementation existence?
> I also want to pose the question of whether the dmaengine interface > should handle cryptographic transforms? We already have Acrypto: > http://tservice.net.ru/~s0mbre/blog/devel/acrypto/index.html. At the > same time since IOPs can do Galois Field multiplication and XOR it > would be nice to take advantage of that for crypto acceleration, but > this does not fit the model of a device that Acrypto supports.
It would be quite interesting to see where the synergies are between the two, at the very least. "async [transform|sum]" is a superset of "async crypto" after all.
Jeff
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