[PATCH V2] powerpc/infiniband: Use cache inhibitted and guarded mapping on powerpc

[Aneesh Kumar K.V]

The driver was requesting for a writethrough mapping. But with thoses
flags we will end up with a SAO mapping because we now have memory
conherence always enabled. ie, the existing mapping will end up with
a WIMG value 0b1110 which is Strong Access Order.

Update this to use cache inhibitted guarded mapping

Cc: Mike Marciniszyn <infinipath at intel.com>
Cc: Doug Ledford <dledford at redhat.com>
Cc: Sean Hefty <sean.hefty at intel.com>
Cc: Hal Rosenstock <hal.rosenstock at gmail.com>
Cc: linux-rdma at vger.kernel.org
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
---
Changes from v1:
* resend because V1 never reached mailing list.

NOTE: This is only compile tested and I am also not sure why ppc64 needs special handling.
We need this patch because the series at http://mid.gmane.org/1460182444-2468-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
will drop _PAGE_WRITETHRU

 drivers/infiniband/hw/qib/qib_file_ops.c | 5 +----
 drivers/infiniband/hw/qib/qib_pcie.c     | 6 ------
 2 files changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
index e449e394963f..a3d593f546ec 100644
--- a/drivers/infiniband/hw/qib/qib_file_ops.c
+++ b/drivers/infiniband/hw/qib/qib_file_ops.c
@@ -822,10 +822,7 @@ static int mmap_piobufs(struct vm_area_struct *vma,
 	phys = dd->physaddr + piobufs;
 
 #if defined(__powerpc__)
-	/* There isn't a generic way to specify writethrough mappings */
-	pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE;
-	pgprot_val(vma->vm_page_prot) |= _PAGE_WRITETHRU;
-	pgprot_val(vma->vm_page_prot) &= ~_PAGE_GUARDED;
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 #endif
 
 	/*
diff --git a/drivers/infiniband/hw/qib/qib_pcie.c b/drivers/infiniband/hw/qib/qib_pcie.c
index 4758a3801ae8..6abe1c621aa4 100644
--- a/drivers/infiniband/hw/qib/qib_pcie.c
+++ b/drivers/infiniband/hw/qib/qib_pcie.c
@@ -144,13 +144,7 @@ int qib_pcie_ddinit(struct qib_devdata *dd, struct pci_dev *pdev,
 	addr = pci_resource_start(pdev, 0);
 	len = pci_resource_len(pdev, 0);
 
-#if defined(__powerpc__)
-	/* There isn't a generic way to specify writethrough mappings */
-	dd->kregbase = __ioremap(addr, len, _PAGE_NO_CACHE | _PAGE_WRITETHRU);
-#else
 	dd->kregbase = ioremap_nocache(addr, len);
-#endif
-
 	if (!dd->kregbase)
 		return -ENOMEM;
 
-- 
2.5.0