i.MX ProcessorsのトピックRe: imx6 spi read/write dma support

imx6 spi read/write dma support

xiongweihuang — Mon, 12 Aug 2013 02:48:06 GMT

Hello all
From http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/drivers/spi/spi_imx.c?h=imx_3.0.35_4.0.0

seems spi-imx.c don't have the DMA support while spi transfer ?

Does anybody know if Freescale will plan to support this ?

Or , that's it ??

Re: imx6 spi read/write dma support

SergioSolis — Tue, 13 Aug 2013 15:12:56 GMT

Hello Xiong,

As of today, there are no plans to add DMA support, there are no plans to add functionality to these drivers.

Please let me know if you have any other question.

Re: imx6 spi read/write dma support

howardhsu — Fri, 01 Nov 2013 09:00:39 GMT

Hello all,

I am working to improve boot time on the target with iMX6SL+SPI NOR flash.

In out rest, loading 4.501MB images takes about 2.297 secs.

According 30MHz SPI read clock, the actual transfer time is 1.2 secs.

It shows the overhead in spi_xfer takes about 1 seconds (u-boot/drivers/spi/imx_ecspi.c).

I want to reduce this overhead by applying DMA.

Q1: Is there any reference code for ecspi dma ?

I am trying to use SDMA SDMA_SHP_2_MCU in u-boot now.

First I am trying RX DMA --> but it stucks with BUSY status after starting dma transferring ...

Q2: How to proper set the chan_desc watermark level and and ECSPIx_DMAREG ( RXTDEN, RX_DMA_DMA_LENGTH, RXDEN, RX_THRESHOLD) to perform a ecspi rx dma operation ?

Thank you.

Re: imx6 spi read/write dma support

fork — Sat, 02 Nov 2013 01:17:16 GMT

The iMX6 Platform SDK has a SPI DMA example which works.

Re: imx6 spi read/write dma support

laufei — Thu, 12 Dec 2013 01:44:00 GMT

Hi, fork

Can you send the link where is the SPI DMA example or the right link of iMX6 Platfrom SDK?

Thank you for your support!

Re: imx6 spi read/write dma support

zunli — Fri, 13 Dec 2013 02:37:11 GMT

Hi fork,

Currently I am also debugging SPI with DMA access and could not find the example in I.MX6 platform SDK you mentioned. Could you please share the link? Thank you very much!

Re: imx6 spi read/write dma support

fork — Fri, 13 Dec 2013 02:45:24 GMT

You can download the platform SDK here:

i.MX6 Platform SDK 1.1 Release

Then look at sdk/drivers/sdma/test/spi_lpb.c

Re: imx6 spi read/write dma support

zunli — Fri, 13 Dec 2013 03:05:54 GMT

Hi fork,

Thanks very much for your kind help. I have already found that file.

Best regards!

Re: imx6 spi read/write dma support

xiongweihuang — Tue, 17 Dec 2013 09:44:28 GMT

So , sdma firmware from git tree should have espi support already ,right ?

http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/firmware/imx/sdma/sdma-imx6q-to1.bin.ihex?h=imx_3.0.35_4.0.0

Re: imx6 spi read/write dma support

xiongweihuang — Tue, 17 Dec 2013 09:58:35 GMT

And I try to compare

imx6_platform_sdk_v1.1.0.tar\iMX6_Platform_SDK\sdk\drivers\sdma\src\sdma_script_code_mx6dq.h

with

http://git.freescale.com/git/cgit.cgi/imx/linux-2.6-imx.git/tree/firmware/imx/sdma/sdma-imx6q-to1.bin.ihex?h=imx_3.0.35_4.0.0

seems like firmware binary is different ??

Re: imx6 spi read/write dma support

zunli — Fri, 20 Dec 2013 01:22:27 GMT

Sorry, I did not test the firmware you mentioned, I just refer the sdma design of spi_lpb.c in the sdk.

But unfortunately, the file is not designed under linux originally, so you could not use it directly.

Re: imx6 spi read/write dma support

arnoutdiels — Tue, 30 May 2017 13:37:31 GMT

For anyone who still finds his way to this question, in 2014 DMA support was added in spi-imx.c for imx6