Re: Microblaze, DMA and cache: Lack of sync functions?

[Michal Simek <michal.simek@petalogix.com>]

Eli Billauer wrote:
> Hello,
> 
> 
> Before I make a needless hack, please correct me if I'm wrong: in 
> arch/microblaze/kernel/dma.c, the sync_single_for_cpu, 
> sync_single_for_device and friends are not set in the dma_direct_ops 
> structure (and not implemented), so calls from drivers to the 
> corresponding functions will do nothing. Since the Microblaze cache 
> doesn't update automatically on DMA operations, this looks like a bug to 
> me: The driver thinks the cache has been flushed or updated, but it 
> actually hasn't.
> 
> 
> Map and unmap methods are indeed implemented and registered, and they 
> both call an internal function to sync the cache. So why are there no 
> sync functions?
> 

It is not the bug just unimplemented feature and I haven't had any problem
that these functions are not implemented.
Implementation should be pretty straight forward. Patches welcomed.

Thanks,
Michal




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Michal Simek, Ing. (M.Eng)
PetaLogix - Linux Solutions for a Reconfigurable World
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