Re: [RFC PATCH 2/4] ASoC: soc-generic-dmaengine-pcm: Add custom prepare and submit function

On Tue, Nov 17, 2020 at 04:03:48PM +0800, Michael Sit Wei Hong wrote:

Enabling custom prepare and submit function to overcome DMA limitation.

In the Intel KeemBay solution, the DW AXI-based DMA has a limitation on the number of DMA blocks per transfer. In the case of 16 bit audio ASoC would allocate blocks exceeding the DMA block limitation.

I'm still not sure the hardware has such a limitation.

The Synopsys IP supports linked list (LLI) transfers and I hardly can imagine the list has any limitation. Even though, one can always emulate LLI in software how it's done in the DesignWare AHB DMA driver.

I have briefly read chapter 4.6 "AXI_DMA" of Keem Bay TRM and didn't find any errata or limits like this.