[3.16.y-ckt stable] Patch "powerpc/cell: Fix cell iommu after it_page_shift changes" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    powerpc/cell: Fix cell iommu after it_page_shift changes

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt11.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 2d6f59f867a736f8ac90e86b68ab96e8314786c5 Mon Sep 17 00:00:00 2001
From: Michael Ellerman <mpe at ellerman.id.au>
Date: Fri, 3 Apr 2015 14:11:54 +1100
Subject: powerpc/cell: Fix cell iommu after it_page_shift changes

commit 7261b956b276aa97fbf60d00f1d7717d2ea6ee78 upstream.

The patch to add it_page_shift incorrectly changed the increment of
uaddr to use it_page_shift, rather then (1 << it_page_shift).

This broke booting on at least some Cell blades, as the iommu was
basically non-functional.

Fixes: 3a553170d35d ("powerpc/iommu: Add it_page_shift field to determine iommu page size")
Signed-off-by: Michael Ellerman <michael at ellerman.id.au>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/powerpc/platforms/cell/iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/cell/iommu.c b/arch/powerpc/platforms/cell/iommu.c
index 2b90ff8a93be..59ef76c5f4f4 100644
--- a/arch/powerpc/platforms/cell/iommu.c
+++ b/arch/powerpc/platforms/cell/iommu.c
@@ -197,7 +197,7 @@ static int tce_build_cell(struct iommu_table *tbl, long index, long npages,

 	io_pte = (unsigned long *)tbl->it_base + (index - tbl->it_offset);

-	for (i = 0; i < npages; i++, uaddr += tbl->it_page_shift)
+	for (i = 0; i < npages; i++, uaddr += (1 << tbl->it_page_shift))
 		io_pte[i] = base_pte | (__pa(uaddr) & CBE_IOPTE_RPN_Mask);

 	mb();