mtd: rawnand: stm32_fmc2: add STM32 FMC2 NAND flash controller driver

The driver adds the support for the STMicroelectronics FMC2 NAND
Controller found on STM32MP SOCs.

This patch adds the polling mode, a basic mode that do not need
any DMA channels.

Only NAND_ECC_HW mode is actually supported.
The driver supports a maximum 8k page size.
The following ECC strength and step size are currently supported:
 - nand-ecc-strength = <8>, nand-ecc-step-size = <512> (BCH8)
 - nand-ecc-strength = <4>, nand-ecc-step-size = <512> (BCH4)
 - nand-ecc-strength = <1>, nand-ecc-step-size = <512> (Extended ECC
   based on Hamming)

This patch has been tested on Micron MT29F8G08ABACAH4.

Signed-off-by: Christophe Kerello <christophe.kerello@st.com>

drivers/mtd/nand/raw/Kconfig

@@ -256,6 +256,17 @@ config NAND_ZYNQ_USE_BOOTLOADER1_TIMINGS
 	  This flag prevent U-boot reconfigure NAND flash controller and reuse
 	  the NAND timing from 1st stage bootloader.
 
+config NAND_STM32_FMC2
+	bool "Support for NAND controller on STM32MP SoCs"
+	depends on ARCH_STM32MP
+	select SYS_NAND_SELF_INIT
+	imply CMD_NAND
+	help
+	  Enables support for NAND Flash chips on SoCs containing the FMC2
+	  NAND controller. This controller is found on STM32MP SoCs.
+	  The controller supports a maximum 8k page size and supports
+	  a maximum 8-bit correction error per sector of 512 bytes.
+
 comment "Generic NAND options"
 
 config SYS_NAND_BLOCK_SIZE

drivers/mtd/nand/raw/Makefile

@@ -65,6 +65,7 @@ obj-$(CONFIG_NAND_OMAP_ELM) += omap_elm.o
 obj-$(CONFIG_NAND_PLAT) += nand_plat.o
 obj-$(CONFIG_NAND_SUNXI) += sunxi_nand.o
 obj-$(CONFIG_NAND_ZYNQ) += zynq_nand.o
+obj-$(CONFIG_NAND_STM32_FMC2) += stm32_fmc2_nand.o
 
 else  # minimal SPL drivers