Re: [PATCH 3/3] dmaengine: Add Freescale i.MX SDMA support

[Baruch Siach <baruch@tkos.co.il>]

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:
> > 2010/8/16 Sascha Hauer <s.hauer@pengutronix.de>:
> > > 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

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