Re: [PATCH 2/2] ARM: dts: imx7: add DMA properties for ECSPI

[Trent Piepho]

On Mon, 2019-02-11 at 19:34 -0200, Fabio Estevam wrote:
> Hi Trent,
> 
> On Mon, Feb 11, 2019 at 6:44 PM Trent Piepho <tpiepho@xxxxxxxxxx> wrote:
> 
> > I've had more time to test.
> > 
> > Without DMA, I can reload my FPGA hundreds of times and get days of
> > uptime using linux-next.
> > 
> > With DMA, loading is unreliable.  The higher the SPI speed, the less
> > reliable it is.  Unfortunately, it's hard to duplicate the problem with
> > a small amount of data, and with a large amount of data I can't examine
> > it in depth enough to determine if the problem is related to SPI bus
> > timing or IMX sDMA sending the wrong bytes to the spi controller.
> > 
> > Using DMA with SPI causes kernel panics.  Not always immediately, but
> > after using DMA it's a smaller of minutes before something crashes.
> > The backtraces are all over the place and don't usually point back into
> > SPI.  It does seem like they usually hit something has allocated or is
> > allocating DMA memory.
> 
> Did you test with an external SDMA firmware or with the ROM SDMA firmware?
> 
> Just trying to understand if the SDMA firmware plays a role on this
> behavior or not.

The ROM firmware only.