[spi-devel-general] Re: [PATCH 2.6-git] SPI core refresh

[Stephen S. <st...@st...>]

On Wed, 2005-11-30 at 13:36 -0800, David Brownell wrote:
> > - it is DMA-safe
> 
> Which as I pointed out is incorrect.  The core API (async) has always
> been fully DMA-safe.  And a **LOT** lower overhead than yours, which
> allocates buffers behind the back of drivers, and encourages lots of
> memcpy rather than just doing DMA directly to/from the buffers that
> are provided by the SPI protocol drivers.

Minimal (or no) core intervention on the DMA code path is a good thing.
I need to fix some broken hardware with software and must to move 96
bytes from one SPI device to another on the same SPI bus every for 4ms.
Needless memcpy's will cause substantial performance problems in my
application. Thinner is definitely better.

-Stephen