powerpc: Fix swiotlb to respect the boot option

powerpc initializes swiotlb before parsing the kernel boot options so
swiotlb options (e.g. specifying the swiotlb buffer size) are ignored.

Any time before freeing bootmem works for swiotlb so this patch moves
powerpc's swiotlb initialization after parsing the kernel boot
options, mem_init (as x86 does).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Tested-by: Becky Bruce <beckyb@kernel.crashing.org>
Tested-by: Albert Herranz <albert_herranz@yahoo.es>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/kernel/setup_32.c

@@ -39,7 +39,6 @@
 #include <asm/serial.h>
 #include <asm/udbg.h>
 #include <asm/mmu_context.h>
-#include <asm/swiotlb.h>
 
 #include "setup.h"
 
@@ -343,11 +342,6 @@ void __init setup_arch(char **cmdline_p)
 		ppc_md.setup_arch();
 	if ( ppc_md.progress ) ppc_md.progress("arch: exit", 0x3eab);
 
-#ifdef CONFIG_SWIOTLB
-	if (ppc_swiotlb_enable)
-		swiotlb_init(1);
-#endif
-
 	paging_init();
 
 	/* Initialize the MMU context management stuff */

arch/powerpc/kernel/setup_64.c

@@ -61,7 +61,6 @@
 #include <asm/xmon.h>
 #include <asm/udbg.h>
 #include <asm/kexec.h>
-#include <asm/swiotlb.h>
 #include <asm/mmu_context.h>
 
 #include "setup.h"
@@ -541,11 +540,6 @@ 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(1);
-#endif
-
 	paging_init();
 
 	/* Initialize the MMU context management stuff */

arch/powerpc/mm/mem.c

@@ -48,6 +48,7 @@
 #include <asm/sparsemem.h>
 #include <asm/vdso.h>
 #include <asm/fixmap.h>
+#include <asm/swiotlb.h>
 
 #include "mmu_decl.h"
 
@@ -320,6 +321,11 @@ void __init mem_init(void)
 	struct page *page;
 	unsigned long reservedpages = 0, codesize, initsize, datasize, bsssize;
 
+#ifdef CONFIG_SWIOTLB
+	if (ppc_swiotlb_enable)
+		swiotlb_init(1);
+#endif
+
 	num_physpages = lmb.memory.size >> PAGE_SHIFT;
 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);