Subject: Re: [PATCH v2 2/2] Crypto: Talitos: Support for 
Async_tx XOR offload

On Wed, Dec 16, 2009 at 03:47:48PM -0700, Dan Williams wrote:

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Kumar Gala wrote:

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Changes with respect to v1 as per comments received o. 

Rebased to 

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linux-next as of 20091216 o. The selection is based exclusive of 
fsldma o. Intoduced a new Kernel Configuration variable
  *. This enables selecting the Cryptographic functionality
     of Talitos along with fsldma.
  *. Disables the XOR parity calculation offload, if 

fsldma enabled

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     either as kernel in-built or as a module
  *. Once the inter-operability with fsldma is resolved, 

this option

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     can be removed

wait, why can't the interoperability bug be fixed in the 

first place?

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I agree w/Kim.  We need to better understand what the bug 

is and how to reproduce it so we can get to the root cause.

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Paper taping over it by disabling fsldma is not the right solution.

Hopefully this prompts fsldma authors to get involved because the 
interoperability issue has been out there without comment*, just 
band-aids, since October.

--
Dan

* well one comment from Ira saying the interrupt 

functionality worked 

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for him.

Yes, I have used the device_prep_dma_interrupt() functionality 
quite a while back. However, I found it to be pretty much 
useless. Any functionality I need is covered by adding a 
callback to the last DMA
memcpy() operation. Since the operations happen in-order, I 
can be sure that the entire set of memcpy()s cas completed. I 
never needed the capability to generate an interrupt without a 
memcpy().

I agree that the fsldma driver could use some love. There are 
places where I am still not confident in the locking. Perhaps 
I can find some time over Christmas to work on it, but I need 
someone with 85xx/86xx hardware to test the changes. I only 
have 83xx hardware.

I can also help with the 85xx testing when I finish the busy project
soon.

- Leo