mtd: atmel_nand: add a new dt binding item for nand dma support

This patch will set the nand dma support in dts. Since we will not use
cpu_is_xxx() in nand driver. We needn't include the mach/cpu.h any more.

Signed-off-by: Josh Wu <[e-mail]>
Signed-off-by: Artem Bityutskiy <[e-mail]>
Signed-off-by: David Woodhouse <[e-mail]>

Documentation/devicetree/bindings/mtd/atmel-nand.txt

···
   optional gpio and may be set to 0 if not present.
 
 Optional properties:
+- atmel,nand-has-dma : boolean to support dma transfer for nand read/write.
 - nand-ecc-mode : String, operation mode of the NAND ecc mode, soft by default.
   Supported values are: "none", "soft", "hw", "hw_syndrome", "hw_oob_first",
   "soft_bch".

drivers/mtd/nand/atmel_nand.c

···
 #include <linux/platform_data/atmel.h>
 #include <linux/pinctrl/consumer.h>
 
-#include <mach/cpu.h>
-
 static int use_dma = 1;
 module_param(use_dma, int, 0);
 
···
 };
 
 static struct nand_ecclayout atmel_pmecc_oobinfo;
-
-static int cpu_has_dma(void)
-{
-	return cpu_is_at91sam9rl() || cpu_is_at91sam9g45();
-}
 
 /*
  * Enable NAND.
···
 
 	board->on_flash_bbt = of_get_nand_on_flash_bbt(np);
 
+	board->has_dma = of_property_read_bool(np, "atmel,nand-has-dma");
+
 	if (of_get_nand_bus_width(np) == 16)
 		board->bus_width_16 = 1;
 
···
 		nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
 	}
 
-	if (!cpu_has_dma())
+	if (!host->board.has_dma)
 		use_dma = 0;
 
 	if (use_dma) {

include/linux/platform_data/atmel.h

···
 	u8		on_flash_bbt;		/* bbt on flash */
 	struct mtd_partition *parts;
 	unsigned int	num_parts;
+	bool		has_dma;		/* support dma transfer */
 
 	/* default is false, only for at32ap7000 chip is true */
 	bool		need_reset_workaround;