On 04/29/2015 02:04 PM, David Gibson wrote:
On Sat, Apr 25, 2015 at 10:14:41PM +1000, Alexey Kardashevskiy wrote:
This replaces direct accesses to TCE table with a helper which
returns an TCE entry address. This does not make difference now but will
when multi-level TCE tables get introduces.

No change in behavior is expected.

Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>

Reviewed-by: David Gibson <da...@gibson.dropbear.id.au>


---
Changes:
v9:
* new patch in the series to separate this mechanical change from
functional changes; this is not right before
"powerpc/powernv: Implement multilevel TCE tables" but here in order
to let the next patch - "powerpc/iommu/powernv: Release replaced TCE" -
use pnv_tce() and avoid changing the same code twice
---
  arch/powerpc/platforms/powernv/pci.c | 34 +++++++++++++++++++++-------------
  1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci.c 
b/arch/powerpc/platforms/powernv/pci.c
index 84b4ea4..ba75aa5 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -572,38 +572,46 @@ struct pci_ops pnv_pci_ops = {
        .write = pnv_pci_write_config,
  };

+static __be64 *pnv_tce(struct iommu_table *tbl, long idx)
+{
+       __be64 *tmp = ((__be64 *)tbl->it_base);
+
+       return tmp + idx;
+}
+
  int pnv_tce_build(struct iommu_table *tbl, long index, long npages,
                unsigned long uaddr, enum dma_data_direction direction,
                struct dma_attrs *attrs)
  {
        u64 proto_tce = iommu_direction_to_tce_perm(direction);
-       __be64 *tcep;
-       u64 rpn;
+       u64 rpn = __pa(uaddr) >> tbl->it_page_shift;

I guess this was a problem in the existing code, not this patch.  But
"uaddr" is a really bad name (and unsigned long is a bad type) for
what must actually be a kernel linear mapping address.


Yes and may be one day I'll clean this up. s/uaddr/linear/ and s/hwaddr/hpa/ are the first things to do globally but not in this patchset.



+       long i;

-       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 newtce = proto_tce |
+                       ((rpn + i) << tbl->it_page_shift);
+               unsigned long idx = index - tbl->it_offset + i;

+               *(pnv_tce(tbl, idx)) = cpu_to_be64(newtce);
+       }

        return 0;
  }

  void pnv_tce_free(struct iommu_table *tbl, long index, long npages)
  {
-       __be64 *tcep;
+       long i;

-       tcep = ((__be64 *)tbl->it_base) + index - tbl->it_offset;
+       for (i = 0; i < npages; i++) {
+               unsigned long idx = index - tbl->it_offset + i;

-       while (npages--)
-               *(tcep++) = cpu_to_be64(0);
+               *(pnv_tce(tbl, idx)) = cpu_to_be64(0);
+       }
  }

  unsigned long pnv_tce_get(struct iommu_table *tbl, long index)
  {
-       return ((u64 *)tbl->it_base)[index - tbl->it_offset];
+       return *(pnv_tce(tbl, index - tbl->it_offset));
  }

  void pnv_pci_setup_iommu_table(struct iommu_table *tbl,



--
Alexey
--
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