DMA questions (invalidate_dcache and flush_dcache)
DMA questions (invalidate_dcache and flush_dcache)
- Subject: DMA questions (invalidate_dcache and flush_dcache)
- From: Ryan Rempel <email@hidden>
- Date: Mon, 08 Sep 2003 15:19:42 -0500
I'm updating a driver for the new memory mapping limitations, and I've
got a couple of DMA-related questions.
The driver uses a couple of functions in <osfmk/ppc/pmap.h>, namely:
extern void invalidate_dcache(vm_offset_t va, unsigned length,
boolean_t phys);
extern void flush_dcache(vm_offset_t va, unsigned length, boolean_t
phys);
The calls to invalidate_dcache are accompanied by this comment "Purge
cache references for the DBDMA entry we are about to look at".
The calls to flush_dcache are accompanied by this comnment "Push DMA
commands to physical memory".
In both cases, the "phys" argument is set to 0.
What I'm wondering is whether the recent memory management changes
would affect this kind of code. Or, indeed, whether there is a
different or better way to accomplish what this code is accomplishing.
_______________________________________________
darwin-kernel mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/darwin-kernel
Do not post admin requests to the list. They will be ignored.