On Tue, 29 May 2018 18:21:40 +0300
Eugen Hristev <eugen.hris...@microchip.com> wrote:
> On 29.05.2018 18:15, Boris Brezillon wrote:
> > On Tue, 29 May 2018 18:01:40 +0300
> > Eugen Hristev <eugen.hris...@microchip.com> wrote:
> >
> >> [...]
> >>
> >>
> >>>
> >>> I think you're missing something here. We use the DMA engine in memcpy
> >>> mode (SRAM -> DRAM), not in device mode (dev -> DRAM or DRAM -> dev).
> >>> So there's no dmas prop defined in the DT and there should not be.
> >>>
> >>> Regards,
> >>>
> >>> Boris
> >>>
> >>
> >> Ok, so the memcpy SRAM <-> DRAM will hog the transfer between DRAM and
> >> LCD if my understanding is correct. That's the DMA that Peter wants to
> >> disable with his patch ?
> >>
> >> Then we can then try to force NFC SRAM DMA channels to use just DDR port
> >> 1 or 2 for memcpy ?
> >
> > You mean the dmaengine? According to "14.1.3 Master to Slave Access"
> > that's already the case.
> >
> > Only DMAC0 can access the NFC SRAM and it's done through DMAC0:IF0,
> > then access to DDR is going through port DDR port 1 (DMAC0:IF1) or 2
> > (DMAC0:IF0).
>
> If we can make NFC use port 1 only, then HLCDC could have two ports as
> master 8 & 9, maybe a better bandwidth.
Peter, can you try with the following patch?
--->8---
diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
index ef3f227ce3e6..2a48e870f292 100644
--- a/drivers/dma/at_hdmac_regs.h
+++ b/drivers/dma/at_hdmac_regs.h
@@ -124,8 +124,8 @@
#define ATC_SIF(i) (0x3 & (i)) /* Src tx done via
AHB-Lite Interface i */
#define ATC_DIF(i) ((0x3 & (i)) << 4) /* Dst tx done
via AHB-Lite Interface i */
/* Specify AHB interfaces */
-#define AT_DMA_MEM_IF 0 /* interface 0 as memory interface */
-#define AT_DMA_PER_IF 1 /* interface 1 as peripheral interface */
+#define AT_DMA_MEM_IF 1 /* interface 0 as memory interface */
+#define AT_DMA_PER_IF 0 /* interface 1 as peripheral interface */
#define ATC_SRC_PIP (0x1 << 8) /* Source
Picture-in-Picture enabled */
#define ATC_DST_PIP (0x1 << 12) /* Destination
Picture-in-Picture enabled */
