Hi Trent, On Mon, Feb 11, 2019 at 6:44 PM Trent Piepho <tpie...@impinj.com> 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.
