This updates the DMA API documentation to address a few issues:
- The dma_map_sg() call results are used like pci_map_sg() results:
using sg_dma_address() and sg_dma_len(). That's not wholly obvious
to folk reading _only_ the "new" DMA-API.txt writeup.
- Buffers allocated by dma_alloc_coherent() may not be completely
free of coherency concerns ... some CPUs also have write buffers
that may need to be flushed.
- Cacheline coherence issues are now mentioned as being among issues
which affect dma buffers, and complicate/prevent using of static and
(especially) stack based buffers with the DMA calls.
I don't think many drivers currently need to worry about flushing write
buffers, but I did hit it with one SOC using external SDRAM for DMA
descriptors: without explicit writebuffer flushing, the on-chip DMA
controller accessed descriptors before the CPU completed the writes.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The attached patch fixes the following spelling errors in Documentation/
- double "the"
- Several misspellings of function/functionality
- infomation
- memeory
- Recieved
- wether
and possibly others which I forgot ;-)
Trailing whitespaces on the same line as the typo are also deleted.
Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
David Brownell
Tobias Klauser
Linus Torvalds