Hi Cloudy, On Wed, Jun 20, 2012 at 09:31:10PM +0800, cloudy.linux wrote: > On 2012-6-19 4:12, Simon Baatz wrote: > > I see one effect that I don't fully understand. > > Similar to the previous implementation, the system is mostly in > > kernel space when accessing an encrypted dm-crypt device: > > Today I also compiled the patched 3.5.0-rc3 for another NAS box with > MV88F6282-Rev-A0 (LS-WVL), I noticed one thing that when the CESA engine > was used, the interrupt number of mv_crypto kept rising, but the > interrupt number of mv_tdma was always zero. Yes, that is exactly how it should be: the DMA engine is configured to run "attached" to CESA, meaning that when CESA is triggered from mv_cesa.c, it first enables the DMA engine. Using a special descriptor in the chain, the DMA engine knows when to stop and signals CESA again so it can start the crypto operation. Afterwards, CESA triggers the DMA engine again for copying back the results (or more specific: process the remaining descriptors in the chain after the special one). After a descriptor with it's next descriptor field being zero has been handled, CESA is signaled again which in turn generates the interrupt to signal the software. So no DMA interrupt needed, and no software interaction in between data copying and crypto operation, of course. :) Greetings, Phil PS: I am currently working at the address decoding problem, will get back to in a few days when I have something to test. So stay tuned! Phil Sutter Software Engineer -- Viprinet GmbH Mainzer Str. 43 55411 Bingen am Rhein Germany Phone/Zentrale: +49-6721-49030-0 Direct line/Durchwahl: +49-6721-49030-134 Fax: +49-6721-49030-209 phil.sutter@xxxxxxxxxxxx http://www.viprinet.com Registered office/Sitz der Gesellschaft: Bingen am Rhein Commercial register/Handelsregister: Amtsgericht Mainz HRB40380 CEO/Geschäftsführer: Simon Kissel -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
