MIPS: Loongon64: DMA functions cleanup

Split the common dma.c which shared by Loongson-2E and Loongson-2F,
since the code in 'common' directory is assumed be shared by all 64bit
Loongson platforms (but Loongson-3 doesn't use it now). By the way,
Loongson-2E and Loongson-2F have already dropped 32bit kernel support,
so CONFIG_64BIT isn't needed.

Signed-off-by: Huacai Chen <[e-mail]>
Signed-off-by: Paul Burton <[e-mail]>
Patchwork: https://patchwork.linux-mips.org/patch/20302/
Cc: Ralf Baechle <[e-mail]>
Cc: James Hogan <[e-mail]>
Cc: [e-mail]
Cc: Fuxin Zhang <[e-mail]>
Cc: Zhangjin Wu <[e-mail]>
Cc: Huacai Chen <[e-mail]>

arch/mips/loongson64/common/Makefile

···
 obj-y += setup.o init.o cmdline.o env.o time.o reset.o irq.o \
     bonito-irq.o mem.o machtype.o platform.o serial.o
 obj-$(CONFIG_PCI) += pci.o
-obj-$(CONFIG_CPU_LOONGSON2) += dma.o
 
 #
 # Serial port support

arch/mips/loongson64/common/dma.c arch/mips/loongson64/lemote-2f/dma.c

···
 
 phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
 {
-#if defined(CONFIG_CPU_LOONGSON2F) && defined(CONFIG_64BIT)
 	if (dma_addr > 0x8fffffff)
 		return dma_addr;
 	return dma_addr & 0x0fffffff;
-#else
-	return dma_addr & 0x7fffffff;
-#endif
 }

arch/mips/loongson64/fuloong-2e/Makefile

···
 # Makefile for Lemote Fuloong2e mini-PC board.
 #
 
-obj-y += irq.o reset.o
+obj-y += irq.o reset.o dma.o

arch/mips/loongson64/fuloong-2e/dma.c

···
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/dma-direct.h>
+
+dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
+{
+	return paddr | 0x80000000;
+}
+
+phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
+{
+	return dma_addr & 0x7fffffff;
+}

arch/mips/loongson64/lemote-2f/Makefile

···
 # Makefile for lemote loongson2f family machines
 #
 
-obj-y += clock.o machtype.o irq.o reset.o ec_kb3310b.o
+obj-y += clock.o machtype.o irq.o reset.o dma.o ec_kb3310b.o
 
 #
 # Suspend Support