Hi Randy, On Thu, Oct 13, 2011 at 4:00 AM, Randy Dunlap rdunlap@xenotime.net wrote:
On 10/11/2011 02:23 AM, Sumit Semwal wrote:
Add documentation for dma buffer sharing framework, explaining the various operations, members and API of the dma buffer sharing framework.
Signed-off-by: Sumit Semwal sumit.semwal@linaro.org Signed-off-by: Sumit Semwal sumit.semwal@ti.com
Documentation/dma-buf-sharing.txt | 210 +++++++++++++++++++++++++++++++++++++
<snip>
- if the new buffer-user has stricter 'backing-storage constraints', and the
- exporter can handle these constraints, the exporter can just stall on the
- get_scatterlist till all outstanding access is completed (as signalled by
until
Thanks for your review; I will update all these in the next version.
- put_scatterlist).
- Once all ongoing access is completed, the exporter could potentially move
- the buffer to the stricter backing-storage, and then allow further
- {get,put}_scatterlist operations from any buffer-user from the migrated
- backing-storage.
- If the exporter cannot fulfill the backing-storage constraints of the new
- buffer-user device as requested, dma_buf_attach() would return an error to
- denote non-compatibility of the new buffer-sharing request with the current
- buffer.
- If the exporter chooses not to allow an attach() operation once a
- get_scatterlist has been called, it simply returns an error.
+- mmap file operation
- An mmap() file operation is provided for the fd associated with the buffer.
- If the exporter defines an mmap operation, the mmap() fop calls this to allow
- mmap for devices that might need it; if not, it returns an error.
+References: +[1] struct dma_buf_ops in include/linux/dma-buf.h +[2] All interfaces mentioned above defined in include/linux/dma-buf.h
-- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***
Best regards, ~Sumit.