topic Re: DMA assignment in Vybrid Processors

DMA assignment

carlovalgocela — Sat, 13 Jun 2015 06:13:21 GMT

In the timesys BSP User Guide BSP User Guide for Freescale TWR-VF65GS10 | Timesys Embedded Linux

Linux uses DMA channels on DMA engine 0,mux 0

UART1 RX - Channel 4
UART1 TX - Channel 5

DSPI0 RX - Channel 12
DSPI0 TX - Channel 13

SAI2 (I2S2) RX - Channel 20
SAI2 (I2S2) TX - Channel 21

But when i checked the in the linux # ls -1 /sys/class/dma

I can see that there are DMA assigned on DMA1:

dma1chan0

dma1chan1

dma1chan10

dma1chan11

dma1chan12

dma1chan13

dma1chan14

I would like to ask if it is possible to reroute DMA1 to DMA0?

I want to configure the Linux to only use DMA0 and the MQX to DMA1.

Re: DMA assignment

karina_valencia — Mon, 22 Jun 2015 17:08:22 GMT

timesyssupport can you help to attend this case?

Re: DMA assignment

timesyssupport — Mon, 22 Jun 2015 18:46:35 GMT

Hello Carlo,

Which kernel version is this in regards to? This is the same query in your ticket in our queue, correct?

Thank you,

Timesys Support

Re: DMA assignment

carlovalgocela — Tue, 23 Jun 2015 02:03:32 GMT

Hello timesyssupport,

In this test, i'm using the Kernel 3.1.13.

Re: DMA assignment

jackblather — Tue, 23 Jun 2015 02:08:34 GMT

I think you meant the 3.13-x kernel.

Re: DMA assignment

carlovalgocela — Tue, 23 Jun 2015 02:17:06 GMT

Jack Blather

Yes you are correct.

Thanks for the correction

Re: DMA assignment

jackblather — Tue, 23 Jun 2015 02:22:12 GMT

You're Welcome.

Re: DMA assignment

karina_valencia — Mon, 29 Jun 2015 18:45:47 GMT

timesyssupport please continue with the follow up.

Re: DMA assignment

timesyssupport — Thu, 02 Jul 2015 16:40:48 GMT

Hello Carlo,

Please find the attached patch, where Linux will no longer initialize DMA1. This modifies the vf610 device tree includes file, so all you need to do is apply this patch to your kernel sources, then rebuild your device tree blob for the hardware target (pcm052).

Thanks,

Timesys Support