mtd: nand: NFC drivers for RK3308, RK2928 and others

This driver supports Rockchip NFC (NAND Flash Controller) found on
RK3308, RK2928, RKPX30, RV1108 and other SOCs. The driver has been
tested using 8-bit NAND interface on the ARM based RK3308 platform.

Support Rockchip SoCs and NFC versions:
- PX30 and RK3326(NFCv900).
	ECC: 16/40/60/70 bits/1KB.
	CLOCK: ahb and nfc.
- RK3308 and RV1108(NFCv800).
	ECC: 16 bits/1KB.
	CLOCK: ahb and nfc.
- RK3036 and RK3128(NFCv622).
	ECC: 16/24/40/60 bits/1KB.
	CLOCK: ahb and nfc.
- RK3066, RK3188 and RK2928(NFCv600).
	ECC: 16/24/40/60 bits/1KB.
	CLOCK: ahb.

Supported features:
- Read full page data by DMA.
- Support HW ECC(one step is 1KB).
- Support 2 - 32K page size.
- Support 8 CS(depend on SoCs)

Limitations:
- No support for the ecc step size is 512.
- Untested on some SoCs.
- No support for subpages.
- No support for the builtin randomizer.
- The original bad block mask is not supported. It is recommended to
  use  the BBT(bad block table).

Signed-off-by: Yifeng Zhao <yifeng.zhao@rock-chips.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

drivers/mtd/nand/raw/Kconfig

@@ -333,6 +333,22 @@ config CORTINA_NAND
 	  The controller supports a maximum 8k page size and supports
 	  a maximum 40-bit error correction per sector of 1024 bytes.
 
+config ROCKCHIP_NAND
+	bool "Support for NAND controller on Rockchip SoCs"
+	depends on ARCH_ROCKCHIP
+	select SYS_NAND_SELF_INIT
+	select DM_MTD
+	imply CMD_NAND
+	help
+	  Enables support for NAND Flash chips on Rockchip SoCs platform.
+	  This controller is found on Rockchip SoCs.
+	  There are four different versions of NAND FLASH Controllers,
+	  including:
+	    NFC v600: RK2928, RK3066, RK3188
+	    NFC v622: RK3036, RK3128
+	    NFC v800: RK3308, RV1108
+	    NFC v900: PX30, RK3326
+
 comment "Generic NAND options"
 
 config SYS_NAND_BLOCK_SIZE

drivers/mtd/nand/raw/Makefile

@@ -70,6 +70,7 @@ obj-$(CONFIG_NAND_SUNXI) += sunxi_nand.o
 obj-$(CONFIG_NAND_ZYNQ) += zynq_nand.o
 obj-$(CONFIG_NAND_STM32_FMC2) += stm32_fmc2_nand.o
 obj-$(CONFIG_CORTINA_NAND) += cortina_nand.o
+obj-$(CONFIG_ROCKCHIP_NAND) += rockchip_nfc.o
 
 else  # minimal SPL drivers