powerpc: Add support for swiotlb on 32-bit

This patch includes the basic infrastructure to use swiotlb
bounce buffering on 32-bit powerpc.  It is not yet enabled on
any platforms.  Probably the most interesting bit is the
addition of addr_needs_map to dma_ops - we need this as
a dma_op because the decision of whether or not an addr
can be mapped by a device is device-specific.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/setup_64.c

@@ -61,6 +61,7 @@
 #include <asm/xmon.h>
 #include <asm/udbg.h>
 #include <asm/kexec.h>
+#include <asm/swiotlb.h>
 
 #include "setup.h"
 
@@ -527,6 +528,11 @@ void __init setup_arch(char **cmdline_p)
 	if (ppc_md.setup_arch)
 		ppc_md.setup_arch();
 
+#ifdef CONFIG_SWIOTLB
+	if (ppc_swiotlb_enable)
+		swiotlb_init();
+#endif
+
 	paging_init();
 	ppc64_boot_msg(0x15, "Setup Done");
 }