On Sat, 2015-02-21 at 19:26 +0800, Kevin Hao wrote: > On Fri, Feb 20, 2015 at 07:35:25PM +1100, Benjamin Herrenschmidt wrote: > > We do this for consistency and also in order to support the use of a > > consistent mask smaller than the dma mask in subsequent patches. > > > > Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org> > > --- > > arch/powerpc/kernel/dma-swiotlb.c | 3 --- > > arch/powerpc/mm/mem.c | 6 ++++++ > > 2 files changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/arch/powerpc/kernel/dma-swiotlb.c > > b/arch/powerpc/kernel/dma-swiotlb.c > > index 7359797..cb92f94 100644 > > --- a/arch/powerpc/kernel/dma-swiotlb.c > > +++ b/arch/powerpc/kernel/dma-swiotlb.c > > @@ -110,9 +110,6 @@ void __init swiotlb_detect_4g(void) > > { > > if ((memblock_end_of_DRAM() - 1) > 0xffffffff) { > > ppc_swiotlb_enable = 1; > > -#ifdef CONFIG_ZONE_DMA32 > > - limit_zone_pfn(ZONE_DMA32, (1ULL << 32) >> PAGE_SHIFT); > > -#endif > > } > > } > > > > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > > index b7285a5..f146ef0 100644 > > --- a/arch/powerpc/mm/mem.c > > +++ b/arch/powerpc/mm/mem.c > > @@ -307,6 +307,12 @@ void __init paging_init(void) > > printk(KERN_DEBUG "Memory hole size: %ldMB\n", > > (long int)((top_of_ram - total_ram) >> 20)); > > > > +#ifdef CONFIG_ZONE_DMA32 > > + /* Default limit for ZONE_DMA32, platform might limit it > > + * further due to PCI bridge addressing limitations > > + */ > > + limit_zone_pfn(ZONE_DMA32, (1ULL << 32) >> PAGE_SHIFT); > > +#endif > > #ifdef CONFIG_HIGHMEM > > Hmm, won't this break the PCI on the fsl SoCs? The ZONE_DMA32 is set to > 2GB due to the PCI inbound window limitation on fsl SoCs. This will override > that unconditionally. Please see the commit 84f44cc56c09 ("powerpc/fsl-pci: > Limit ZONE_DMA32 to 2GiB on 64-bit platforms") for more detail.
No it won't, or am I missing something ? Ie, limit_zone_pfn() will only reduce the size of the window, never increase it. Cheers, Ben. > Thanks, > Kevin _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev