On Tue, Sep 24, 2019 at 1:12 PM Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx> wrote: > > Hi All, > this series tries to address one of the issues blocking us from > upstreaming Broadcom's STB PCIe controller[1]. Namely, the fact that > devices not represented in DT which sit behind a PCI bus fail to get the > bus' DMA addressing constraints. > > This is due to the fact that of_dma_configure() assumes it's receiving a > DT node representing the device being configured, as opposed to the PCIe > bridge node we currently pass. This causes the code to directly jump > into PCI's parent node when checking for 'dma-ranges' and misses > whatever was set there. > > To address this I create a new API in OF - inspired from Robin Murphys > original proposal[2] - which accepts a bus DT node as it's input in > order to configure a device's DMA constraints. The changes go deep into > of/address.c's implementation, as a device being having a DT node > assumption was pretty strong. > > On top of this work, I also cleaned up of_dma_configure() removing its > redundant arguments and creating an alternative function for the special cases > not applicable to either the above case or the default usage. > > IMO the resulting functions are more explicit. They will probably > surface some hacky usages that can be properly fixed as I show with the > DT fixes on the Layerscape platform. > > This was also tested on a Raspberry Pi 4 with a custom PCIe driver and > on a Seattle AMD board. Humm, I've been working on this issue too. Looks similar though yours has a lot more churn and there's some other bugs I've found. Can you test out this branch[1]. I don't have any h/w needing this, but wrote a unittest and tested with modified QEMU. Rob [1] git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git dma-masks
