Re: [PATCH 07/25] dmaengine: dw-edma: Don't permit non-inc interleaved xfers

Manivannan Sadhasivam
2022-03-24T17:15:24Z

On Thu, Mar 24, 2022 at 04:48:18AM +0300, Serge Semin wrote:
> DW eDMA controller always increments both source and destination
> addresses. Permitting DMA interleaved transfers with no src_inc/dst_inc
> flags set may lead to unexpected behaviour for the device users. Let's fix
> that by terminating the interleaved transfers if at least one of the
> dma_interleaved_template.{src_inc,dst_inc} flag is initialized with false
> value. Note in addition to that we need we need to increase the source and
> destination addresses accordingly after each iteration.
>

Can you please point me where this gets documented in databook?

Thanks,
Mani

> Fixes: 85e7518f42c8 ("dmaengine: dw-edma: Add device_prep_interleave_dma() support")
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> ---
> drivers/dma/dw-edma/dw-edma-core.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c
> index 2010d7f8191f..f41bde27795c 100644
> --- a/drivers/dma/dw-edma/dw-edma-core.c
> +++ b/drivers/dma/dw-edma/dw-edma-core.c
> @@ -386,6 +386,8 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
> return NULL;
> if (xfer->xfer.il->numf > 0 && xfer->xfer.il->frame_size > 0)
> return NULL;
> + if (!xfer->xfer.il->src_inc || !xfer->xfer.il->dst_inc)
> + return NULL;
> } else {
> return NULL;
> }
> @@ -485,15 +487,13 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer)
> struct dma_interleaved_template *il = xfer->xfer.il;
> struct data_chunk *dc = &il->sgl[i];
>
> - if (il->src_sgl) {
> - src_addr += burst->sz;
> + src_addr += burst->sz;
> + if (il->src_sgl)
> src_addr += dmaengine_get_src_icg(il, dc);
> - }
>
> - if (il->dst_sgl) {
> - dst_addr += burst->sz;
> + dst_addr += burst->sz;
> + if (il->dst_sgl)
> dst_addr += dmaengine_get_dst_icg(il, dc);
> - }
> }
> }
>
> --
> 2.35.1
>