Hi Sascha,

On Mon, Aug 16, 2010 at 04:15:40PM +0200, Sascha Hauer wrote:

On Mon, Aug 16, 2010 at 02:21:06PM +0200, Linus Walleij wrote:

quoted

2010/8/16 Sascha Hauer [off-list ref]:

quoted

The SDMA engine is a scatter/gather DMA engine which is implemented
as a seperate coprocessor. SDMA needs its own firmware which is
requested using the standard request_firmware mechanism. The firmware
has different entry points for each peripheral type, so drivers
have to pass the peripheral type to the DMA engine which in turn
picks the correct firmware entry point from a table contained in
the firmware image itself.

Quite fun, if the spec for the microcode is open this opens up
for dynamic firmware generation for specific DMA jobs does it
not?

Unfortunately the specs are not open, so we are sticked to the binary
microcode from Freescale. I'm pretty sure though that the SDMA engine
could do at least a device_prep_dma_xor operation.

Chapter 38 in the i.MX25 Reference Manual seems to include almost everything 
there is to know about the SDMA. Isn't this enough for writing custom SDMA 
microcodes?

baruch

-- 
                                                     ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -