On Tue, 2016-10-25 at 18:40 +0200, Stefan Roese wrote: > Hi Vinod, > > > Here the current PCI setup: > > $ lspci > ... > 00:18.0 DMA controller: Intel Corporation Atom Processor Z36xxx/Z37xxx > Series LPIO2 DMA Controller (rev 11) > > I'm trying to use one of the 2 DMA controllers above (00:18.0 or > 00.1e.0). You may bind to 18.0, since I2C driver doesn't support DMA (in Linux) at all. > > > These controllers can access system memory as dmatest worked fine in > > your > > test. As Andy replied, the peripheral request lines are hard wired > > to specific > > peripherals so if you do not have request lines hooked up, DMA will > > not > > work.. > > I do not have request line hooked up so this means that a memory BAR > of an external PCI device can not be accessed via these DW DMA > controllers. This is very unfortunate but can't be helped. We need > to think a a different solution to provide a DMA controller in this > system in this case. > Perhaps we'll integrate one in the FPGA itself. As far as I can tell it's most common solution. USB, SDHCI, SATA, ... have their own DMA engine. -- Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
