MIPS: DMA: Add cma support

Adds cma support to the MIPS architecture.

cma uses memblock. However, mips uses bootmem.
bootmem is informed about any regions reserved by memblock

dma api is modified to use cma reserved memory regions when available

Tested using cma_test. cma_test is a simple driver that assigns blocks
of memory from cma reserved sections.

Signed-off-by: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: catalin.marinas@arm.com
Cc: will.deacon@arm.com
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: arnd@arndb.de
Cc: gregkh@linuxfoundation.org
Cc: m.szyprowski@samsung.com
Cc: x86@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-arch@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7360/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/setup.c

@@ -24,6 +24,8 @@
 #include <linux/debugfs.h>
 #include <linux/kexec.h>
 #include <linux/sizes.h>
+#include <linux/device.h>
+#include <linux/dma-contiguous.h>
 
 #include <asm/addrspace.h>
 #include <asm/bootinfo.h>
@@ -476,6 +478,7 @@ static void __init bootmem_init(void)
  *  o bootmem_init()
  *  o sparse_init()
  *  o paging_init()
+ *  o dma_continguous_reserve()
  *
  * At this stage the bootmem allocator is ready to use.
  *
@@ -609,6 +612,7 @@ static void __init request_crashkernel(struct resource *res)
 
 static void __init arch_mem_init(char **cmdline_p)
 {
+	struct memblock_region *reg;
 	extern void plat_mem_setup(void);
 
 	/* call board setup routine */
@@ -675,6 +679,11 @@ static void __init arch_mem_init(char **cmdline_p)
 	sparse_init();
 	plat_swiotlb_setup();
 	paging_init();
+
+	dma_contiguous_reserve(PFN_PHYS(max_low_pfn));
+	/* Tell bootmem about cma reserved memblock section */
+	for_each_memblock(reserved, reg)
+		reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
 }
 
 static void __init resource_init(void)