Re: PCI DMA to small buffers on cache-incoherent arch

David S. Miller
2002-06-11T07:42:43Z

From: Oliver Neukum <oliver@neukum.name>
Date: Tue, 11 Jun 2002 09:38:52 +0200

You don't have to fully expose it. We make a simple rule like:
If you want to do DMA to a variable it needs "DMA_ALIGN after the
name in the declaration". Architectures could define it, with generic nop.
People will get it wrong by doing DMA to members of structures
otherwise. There's no really painless way to solve this.
You have to introduce a new rule anyway.

The DMA_ALIGN attribute doesn't work, on some systems the PCI
cacheline size is determined at boot time not compile time.