Hi Rob, On 27/03/17 15:34, Rob Herring wrote: > On Sat, Mar 25, 2017 at 12:31 AM, Oza Pawandeep <oza.oza@xxxxxxxxxxxx> wrote: >> it jumps to the parent node without examining the child node. >> also with that, it throws "no dma-ranges found for node" >> for pci dma-ranges. >> >> this patch fixes device node traversing for dma-ranges. > > What's the DT look like that doesn't work? The problem is the bodge in pci_dma_configure() where we don't have an OF node for the actual device itself, so pass in the host bridge's OF node instead. This happens to work well enough for dma-coherent, but I don't think dma-ranges was even considered at the time. As it happens I'm currently halfway through writing an experiment wherein pci_dma_configure() creates a temporary child node for the of_dma_configure() call if no other suitable alternative (e.g. some intermediate bridge node) exists. How hard are you likely to NAK that approach? ;) > dma-ranges is supposed to be a bus property, not a device's property. > So looking at the parent is correct behavior generally. Indeed, this patch as-is will break currently correct DTs (because we won't find dma-ranges on the device, so will bail before even looking at the parent as we should). Robin. > > Rob >
