IB/mthca: Avoid alignment traps when writing doorbells

Architectures such as ia64 see alignment traps when doing a 64-bit 
read from __be32 doorbell[2] arrays to do doorbell writes in 
mthca_write64().  Fix this by just passing the two halves of the 
doorbell value into mthca_write64().  This actually improves the 
generated code by allowing the compiler to see what's going on better.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_doorbell.h b/drivers/infiniband/hw/mthca/mthca_doorbell.h
index dd9a44d170c9..b374dc395be1 100644
--- a/drivers/infiniband/hw/mthca/mthca_doorbell.h
+++ b/drivers/infiniband/hw/mthca/mthca_doorbell.h
@@ -58,10 +58,10 @@ static inline void mthca_write64_raw(__be64 val, void __iomem *dest)
         __raw_writeq((__force u64) val, dest);
 }
 
-static inline void mthca_write64(__be32 val[2], void __iomem *dest,
+static inline void mthca_write64(u32 hi, u32 lo, void __iomem *dest,
                                  spinlock_t *doorbell_lock)
 {
-        __raw_writeq(*(u64 *) val, dest);
+        __raw_writeq((__force u64) cpu_to_be64((u64) hi << 32 | lo), dest);
 }
 
 static inline void mthca_write_db_rec(__be32 val[2], __be32 *db)
@@ -87,14 +87,17 @@ static inline void mthca_write64_raw(__be64 val, void __iomem *dest)
         __raw_writel(((__force u32 *) &val)[1], dest + 4);
 }
 
-static inline void mthca_write64(__be32 val[2], void __iomem *dest,
+static inline void mthca_write64(u32 hi, u32 lo, void __iomem *dest,
                                  spinlock_t *doorbell_lock)
 {
         unsigned long flags;
 
+        hi = (__force u32) cpu_to_be32(hi);
+        lo = (__force u32) cpu_to_be32(lo);
+
         spin_lock_irqsave(doorbell_lock, flags);
-        __raw_writel((__force u32) val[0], dest);
-        __raw_writel((__force u32) val[1], dest + 4);
+        __raw_writel(hi, dest);
+        __raw_writel(lo, dest + 4);
         spin_unlock_irqrestore(doorbell_lock, flags);
 }