[DMA Engine Framework] status report #1

[Jakub Klama]

Done this week:
* Created early skeleton of API for DMA engine drivers 
  (Milesone M1: in progress)
* Written basic working driver for DaVinci EDMA3 engine using above mentioned 
  API (Milestone M2: in progress)
* Written basic character device driver to test some transfers
* Submitted first DMA transfers and got correct results. :-)

Plans for next week:
* Improve DMA engine drivers API:
  - get information from DMA engine about supported transfer types
  - think about some transfer validation mechanism (eg. "this transfer can't be
    done using this device" or "this is illegal transfer because address ranges
    overlap") [1]
* Write some skeleton of DMA engine API for use in various kernel subsystems
  and device drivers.
* Think about DMA transfer descriptor structure - can we simplify it?

Potential problems:
* [1] - transfer descriptors are somewhat complex and transfer validation
  can be complex too (checking address ranges, stride sizes/spacings,
  FIFO widths, etc on source and destination buffers)

-- 
Jakub Klama.