On Mon, 2014-10-13 at 20:00 +1100, Michael Ellerman wrote: > On Mon, 2014-10-13 at 18:14 +1100, Anton Blanchard wrote: > > Hi Scott, > > > > > Platform code can call limit_zone_pfn() to set appropriate limits > > > for ZONE_DMA and ZONE_DMA32, and dma_direct_alloc_coherent() will > > > select a suitable zone based on a device's mask and the pfn limits > > > that platform code has configured. > > > > This patch breaks my POWER8 box: > > > > ipr 0001:08:00.0: Using 64-bit DMA iommu bypass > > ipr 0001:08:00.0: dma_direct_alloc_coherent: No suitable zone for pfn > > 0x10000 > > ipr 0001:08:00.0: Couldn't allocate enough memory for device driver! > > ipr: probe of 0001:08:00.0 failed with error -12 > > > > ipr isn't setting a coherent mask, but we shouldn't care on these boxes. > > Could we ignore the coherent mask or copy the dma mask to it? > > Talking to Ben the answer seems to be "it's complicated". > > We shouldn't be ignoring the coherent mask, but we have been, and have been > getting away with it. > > The PCI code sets a default 32-bit mask, so we can't even detect when a device > hasn't set it. Though maybe the powernv PCI code could be initialising it to > 64-bit ? > > For this cycle I'm thinking of the below patch. > > Scott & Anton can you test please? > > Also the depends on FSL_PCI was totally a guess, so please correct that if > it's > wrong Scott.
We need the DMA zone for non-PCI devices, so FSL_SOC would be a better choice. > diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c > index adac9dc54aee..bd443a2e4426 100644 > --- a/arch/powerpc/kernel/dma.c > +++ b/arch/powerpc/kernel/dma.c > @@ -53,6 +53,7 @@ void *dma_direct_alloc_coherent(struct device *dev, size_t > size, > #else > struct page *page; > int node = dev_to_node(dev); > +#ifdef CONFIG_ZONE_DMA32 > u64 pfn = get_pfn_limit(dev); > int zone; > > @@ -67,12 +68,11 @@ void *dma_direct_alloc_coherent(struct device *dev, > size_t size, > case ZONE_DMA: > flag |= GFP_DMA; > break; > -#ifdef CONFIG_ZONE_DMA32 > case ZONE_DMA32: > flag |= GFP_DMA32; > break; > -#endif > }; > +#endif /* CONFIG_ZONE_DMA32 */ For a short-term workaround, I'd rather leave CONFIG_ZONE_DMA32 where it is and put #ifdef CONFIG_FSL_SOC (with a comment) around the whole thing. -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
