Messages in this thread | | | Date | Fri, 25 Jul 2008 15:41:59 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] add iommu_num_pages helper function |
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On Fri, Jul 25, 2008 at 10:34:57PM +0900, FUJITA Tomonori wrote: > On Fri, 25 Jul 2008 15:21:21 +0200 > Joerg Roedel <joerg.roedel@amd.com> wrote: > > > On Fri, Jul 25, 2008 at 10:15:06PM +0900, FUJITA Tomonori wrote: > > > On Fri, 25 Jul 2008 14:57:58 +0200 > > > Joerg Roedel <joerg.roedel@amd.com> wrote: > > > > > > > Calculating the number of pages from given address and length numbers is a task > > > > required in multiple IOMMU implementations. So implement this as a generic > > > > function into the IOMMU helper code. > > > > > > > > Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> > > > > Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> > > > > --- > > > > include/linux/iommu-helper.h | 1 + > > > > lib/iommu-helper.c | 8 ++++++++ > > > > 2 files changed, 9 insertions(+), 0 deletions(-) > > > > > > Thanks. I planed to work on this after rc1. You beat me. :) > > > > > > > > > > diff --git a/include/linux/iommu-helper.h b/include/linux/iommu-helper.h > > > > index c975caf..f8598f5 100644 > > > > --- a/include/linux/iommu-helper.h > > > > +++ b/include/linux/iommu-helper.h > > > > @@ -8,3 +8,4 @@ extern unsigned long iommu_area_alloc(unsigned long *map, unsigned long size, > > > > unsigned long align_mask); > > > > extern void iommu_area_free(unsigned long *map, unsigned long start, > > > > unsigned int nr); > > > > +extern unsigned long iommu_num_pages(unsigned long addr, unsigned long len); > > > > diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c > > > > index a3b8d4c..889ddce 100644 > > > > --- a/lib/iommu-helper.c > > > > +++ b/lib/iommu-helper.c > > > > @@ -80,3 +80,11 @@ void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr) > > > > } > > > > } > > > > EXPORT_SYMBOL(iommu_area_free); > > > > + > > > > +unsigned long iommu_num_pages(unsigned long addr, unsigned long len) > > > > +{ > > > > + unsigned long size = roundup((addr & ~PAGE_MASK) + len, PAGE_SIZE); > > > > + > > > > + return size >> PAGE_SHIFT; > > > > +} > > > > +EXPORT_SYMBOL(iommu_num_pages); > > > > > > This doesn't work since PAGE_SIZE != IOMMU_PAGE_SIZE on the majority > > > of architectures. > > > > A quick grep in include/ tells me that only powerpc is declaring > > IOMMU_PAGE_SIZE by now. > > Ah, I just meant the I/O size of IOMMUs. > > This macro doesn't work for IA64, POWER, and SPARC.
Is there any other architecture independent way to find out the page size the IOMMU is using? If yes I can rework that patchset. If not, I suggest that we (you?) introduce one in a follow-on patch series and fix the iommu_num_pages function then.
Joerg
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