[IA64-SGI] disable TIOCA GART TLB prefetching

Patch to disable SGI TIOCA GART TLB prefetching due to hw bug.

Signed-off-by: Mark Maule <maule@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/arch/ia64/sn/pci/tioca_provider.c b/arch/ia64/sn/pci/tioca_provider.c
index 2234d61..54a0dd4 100644 (file)
--- a/arch/ia64/sn/pci/tioca_provider.c
+++ b/arch/ia64/sn/pci/tioca_provider.c
@@ -171,15 +171,15 @@ tioca_gart_init(struct tioca_kernel *tioca_kern)
         *      use agp op-combining
         *      use GET semantics to fetch memory
         *      participate in coherency domain
-        *      prefetch TLB entries
+        *      DISABLE GART PREFETCHING due to hw bug tracked in SGI PV930029
         */
 
        ca_base->ca_control1 |= CA_AGPDMA_OP_ENB_COMBDELAY;     /* PV895469 ? */
        ca_base->ca_control2 &= ~(CA_GART_MEM_PARAM);
        ca_base->ca_control2 |= (0x2ull << CA_GART_MEM_PARAM_SHFT);
        tioca_kern->ca_gart_iscoherent = 1;
-       ca_base->ca_control2 |=
-           (CA_GART_WR_PREFETCH_ENB | CA_GART_RD_PREFETCH_ENB);
+       ca_base->ca_control2 &=
+           ~(CA_GART_WR_PREFETCH_ENB | CA_GART_RD_PREFETCH_ENB);
 
        /*
         * Unmask GART fetch error interrupts.  Clear residual errors first.