On Wed, 2014-07-30 at 19:31 +1000, Alexey Kardashevskiy wrote:
>
> static int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
> - unsigned long uaddr, enum dma_data_direction
> direction,
> + unsigned long uaddr, unsigned long *old_tces,
> + enum dma_data_direction direction,
> struct dma_attrs *attrs, bool rm)
> {
> u64 proto_tce;
> __be64 *tcep, *tces;
> u64 rpn;
> + long i;
>
> proto_tce = TCE_PCI_READ; // Read allowed
>
> @@ -587,9 +589,13 @@ static int pnv_tce_build(struct iommu_table *tbl, long
> index, long npages,
> tces = tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
> rpn = __pa(uaddr) >> tbl->it_page_shift;
>
> - while (npages--)
> - *(tcep++) = cpu_to_be64(proto_tce |
> - (rpn++ << tbl->it_page_shift));
> + for (i = 0; i < npages; i++) {
> + unsigned long oldtce = xchg(tcep, cpu_to_be64(proto_tce |
> + (rpn++ << tbl->it_page_shift)));
> + if (old_tces)
> + old_tces[i] = (unsigned long) __va(oldtce);
> + tcep++;
> + }
xchg() is slow, please keep separate implementation for build and
set_and_get() to avoid the performance loss on normal TCE host
operations.
Cheers,
Ben.
> pnv_tce_invalidate(tbl, tces, tcep - 1, rm);
>
> @@ -601,8 +607,18 @@ static int pnv_tce_build_vm(struct iommu_table *tbl,
> long index, long npages,
> enum dma_data_direction direction,
> struct dma_attrs *attrs)
> {
> - return pnv_tce_build(tbl, index, npages, uaddr, direction, attrs,
> - false);
> + return pnv_tce_build(tbl, index, npages, uaddr, NULL, direction,
> + attrs, false);
> +}
> +
> +static int pnv_tce_set_and_get_vm(struct iommu_table *tbl, long index,
> + long npages,
> + unsigned long uaddr, unsigned long
> *old_tces,
> + enum dma_data_direction direction,
> + struct dma_attrs *attrs)
> +{
> + return pnv_tce_build(tbl, index, npages, uaddr, old_tces, direction,
> + attrs, false);
> }
>
> static void pnv_tce_free(struct iommu_table *tbl, long index, long npages,
> @@ -630,6 +646,7 @@ static unsigned long pnv_tce_get(struct iommu_table *tbl,
> long index)
>
> struct iommu_table_ops pnv_iommu_ops = {
> .set = pnv_tce_build_vm,
> + .set_and_get = pnv_tce_set_and_get_vm,
> .clear = pnv_tce_free_vm,
> .get = pnv_tce_get,
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
