Re: [PATCH] dmaengine: sprd: Add wrap address support for link-list mode
From: (Exiting) Baolin Wang
Date: Thu Nov 14 2019 - 00:33:45 EST
On Thu, 14 Nov 2019 at 12:50, Vinod Koul <vkoul@xxxxxxxxxx> wrote:
>
> On 23-10-19, 14:31, Baolin Wang wrote:
> > From: Eric Long <eric.long@xxxxxxxxxx>
> >
> > The Spreadtrum Audio compress offload mode will use 2-stage DMA transfer
> > to save power. That means we can request 2 dma channels, one for source
> > channel, and another one for destination channel. Once the source channel's
> > transaction is done, it will trigger the destination channel's transaction
> > automatically by hardware signal.
> >
> > In this case, the source channel will transfer data from IRAM buffer to
> > the DSP fifo to decoding/encoding, once IRAM buffer is empty by transferring
> > done, the destination channel will start to transfer data from DDR buffer
> > to IRAM buffer. Since the destination channel will use link-list mode to
> > fill the IRAM data, and IRAM buffer is allocated by 32K, and DDR buffer
> > is larger to 2M, that means we need lots of link-list nodes to do a cyclic
> > transfer, instead wasting lots of link-list memory, we can use wrap address
> > support to reduce link-list node number, which means when the transfer
> > address reaches the wrap address, the transfer address will jump to the
> > wrap_to address specified by wrap_to register, and only 2 link-list nodes
> > can do a cyclic transfer to transfer data from DDR to IRAM.
> >
> > Thus this patch adds wrap address to support this case.
>
> This fails to apply, can you please rebase and resend!
Sure, sorry for the trouble. Will rebase and resend. Thanks.
--
Baolin Wang
Best Regards