On Sun, Apr 14, 2013 at 09:53:57AM -0500, Timur Tabi wrote:
Markus Pargmann wrote:
In general, imx27 does support SSI with DMA, for example MACH_IMX27_VISSTRIM_M10 does use SSI with DMA. But there are special boards like Eukrea TLV320 and phycore-ac97 that have to use FIQ instead. All of them have a imx27 chip.
Why is the decision to use FIQ board-specific? All of the hardware is inside the SoC itself. How could a board make using DMA impossible?
I only ported the imx-ssi ac97 driver code and tested twice using DMA without success. But there is a good description of the problem in imx-ssi:
" The WM9712 with which this driver was developed with always sends GPIO status data in slot 12 which we receive in our (PCM-) data stream. The only chance we have is to manually skip this data in the FIQ handler."
Regards,
Markus