[linux dev-4.19 03/15] mtd: spi-nor: add NPCM FIU controller driver

[Tomer Maimon <tmaimon77@gmail.com>]

Add Nuvoton NPCM BMC Flash Interface Unit(FIU) SPI-NOR
controller driver

The FIU supports single, dual or quad communication interface.

the FIU controller can operate in following modes:
- User Mode Access(UMA): provides flash access by using an
  indirect address/data mechanism.
- direct rd/wr mode: maps the flash memory into the core
  address space.
- SPI-X mode: used for an expansion bus to an ASIC or CPLD.

Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
---
 drivers/mtd/spi-nor/Kconfig    |   8 +
 drivers/mtd/spi-nor/Makefile   |   1 +
 drivers/mtd/spi-nor/npcm-fiu.c | 930 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 939 insertions(+)
 create mode 100644 drivers/mtd/spi-nor/npcm-fiu.c

diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
index 37775fc09e09..5af9d5f77076 100644
--- a/drivers/mtd/spi-nor/Kconfig
+++ b/drivers/mtd/spi-nor/Kconfig
@@ -75,6 +75,14 @@ config SPI_HISI_SFC
 	help
 	  This enables support for hisilicon SPI-NOR flash controller.
 
+config SPI_NPCM_FIU
+	tristate "NPCM FLASH Interface unit(FIU) controller "
+	depends on ARCH_NPCM || COMPILE_TEST
+	help
+	  This enables support for the FLASH Interface unit(FIU) controller.
+	  This driver does not support generic SPI. The implementation only
+	  supports SPI NOR.
+
 config SPI_NXP_SPIFI
 	tristate "NXP SPI Flash Interface (SPIFI)"
 	depends on OF && (ARCH_LPC18XX || COMPILE_TEST)
diff --git a/drivers/mtd/spi-nor/Makefile b/drivers/mtd/spi-nor/Makefile
index f4c61d282abd..fe0e2bdef9cd 100644
--- a/drivers/mtd/spi-nor/Makefile
+++ b/drivers/mtd/spi-nor/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_SPI_CADENCE_QUADSPI)	+= cadence-quadspi.o
 obj-$(CONFIG_SPI_FSL_QUADSPI)	+= fsl-quadspi.o
 obj-$(CONFIG_SPI_HISI_SFC)	+= hisi-sfc.o
 obj-$(CONFIG_MTD_MT81xx_NOR)    += mtk-quadspi.o
+obj-$(CONFIG_SPI_NPCM_FIU)	+= npcm-fiu.o
 obj-$(CONFIG_SPI_NXP_SPIFI)	+= nxp-spifi.o
 obj-$(CONFIG_SPI_INTEL_SPI)	+= intel-spi.o
 obj-$(CONFIG_SPI_INTEL_SPI_PCI)	+= intel-spi-pci.o
diff --git a/drivers/mtd/spi-nor/npcm-fiu.c b/drivers/mtd/spi-nor/npcm-fiu.c
new file mode 100644
index 000000000000..9b6e7747d678
--- /dev/null
+++ b/drivers/mtd/spi-nor/npcm-fiu.c
@@ -0,0 +1,930 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Nuvoton Technology corporation.
+
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/of_irq.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/spi-nor.h>
+#include <linux/vmalloc.h>
+#include <linux/regmap.h>
+#include <linux/log2.h>
+#include <linux/mod_devicetable.h>
+#include <linux/of_device.h>
+
+#include <asm/sizes.h>
+#include <mtd/mtd-abi.h>
+
+/* Flash Interface Unit (FIU) Registers */
+#define NPCM_FIU_DRD_CFG		0x00
+#define NPCM_FIU_DWR_CFG		0x04
+#define NPCM_FIU_UMA_CFG		0x08
+#define NPCM_FIU_UMA_CTS		0x0C
+#define NPCM_FIU_UMA_CMD		0x10
+#define NPCM_FIU_UMA_ADDR		0x14
+#define NPCM_FIU_PRT_CFG		0x18
+#define NPCM_FIU_UMA_DW0		0x20
+#define NPCM_FIU_UMA_DW1		0x24
+#define NPCM_FIU_UMA_DW2		0x28
+#define NPCM_FIU_UMA_DW3		0x2C
+#define NPCM_FIU_UMA_DR0		0x30
+#define NPCM_FIU_UMA_DR1		0x34
+#define NPCM_FIU_UMA_DR2		0x38
+#define NPCM_FIU_UMA_DR3		0x3C
+#define NPCM_FIU_MAX_REG_LIMIT		0x80
+
+/* FIU Direct Read Configuration Register */
+#define NPCM_FIU_DRD_CFG_LCK		BIT(31)
+#define NPCM_FIU_DRD_CFG_R_BURST	GENMASK(25, 24)
+#define NPCM_FIU_DRD_CFG_ADDSIZ		GENMASK(17, 16)
+#define NPCM_FIU_DRD_CFG_DBW		GENMASK(13, 12)
+#define NPCM_FIU_DRD_CFG_ACCTYPE	GENMASK(9, 8)
+#define NPCM_FIU_DRD_CFG_RDCMD		GENMASK(7, 0)
+#define NPCM_FIU_DRD_ADDSIZ_SHIFT	16
+#define NPCM_FIU_DRD_DBW_SHIFT		12
+#define NPCM_FIU_DRD_ACCTYPE_SHIFT	8
+
+/* FIU Direct Write Configuration Register */
+#define NPCM_FIU_DWR_CFG_LCK		BIT(31)
+#define NPCM_FIU_DWR_CFG_W_BURST	GENMASK(25, 24)
+#define NPCM_FIU_DWR_CFG_ADDSIZ		GENMASK(17, 16)
+#define NPCM_FIU_DWR_CFG_ABPCK		GENMASK(11, 10)
+#define NPCM_FIU_DWR_CFG_DBPCK		GENMASK(9, 8)
+#define NPCM_FIU_DWR_CFG_WRCMD		GENMASK(7, 0)
+#define NPCM_FIU_DWR_ADDSIZ_SHIFT	16
+#define NPCM_FIU_DWR_ABPCK_SHIFT	10
+#define NPCM_FIU_DWR_DBPCK_SHIFT	8
+
+/* FIU UMA Configuration Register */
+#define NPCM_FIU_UMA_CFG_LCK		BIT(31)
+#define NPCM_FIU_UMA_CFG_CMMLCK		BIT(30)
+#define NPCM_FIU_UMA_CFG_RDATSIZ	GENMASK(28, 24)
+#define NPCM_FIU_UMA_CFG_DBSIZ		GENMASK(23, 21)
+#define NPCM_FIU_UMA_CFG_WDATSIZ	GENMASK(20, 16)
+#define NPCM_FIU_UMA_CFG_ADDSIZ		GENMASK(13, 11)
+#define NPCM_FIU_UMA_CFG_CMDSIZ		BIT(10)
+#define NPCM_FIU_UMA_CFG_RDBPCK		GENMASK(9, 8)
+#define NPCM_FIU_UMA_CFG_DBPCK		GENMASK(7, 6)
+#define NPCM_FIU_UMA_CFG_WDBPCK		GENMASK(5, 4)
+#define NPCM_FIU_UMA_CFG_ADBPCK		GENMASK(3, 2)
+#define NPCM_FIU_UMA_CFG_CMBPCK		GENMASK(1, 0)
+#define NPCM_FIU_UMA_CFG_ADBPCK_SHIFT	2
+#define NPCM_FIU_UMA_CFG_WDBPCK_SHIFT	4
+#define NPCM_FIU_UMA_CFG_DBPCK_SHIFT	6
+#define NPCM_FIU_UMA_CFG_RDBPCK_SHIFT	8
+#define NPCM_FIU_UMA_CFG_ADDSIZ_SHIFT	11
+#define NPCM_FIU_UMA_CFG_WDATSIZ_SHIFT	16
+#define NPCM_FIU_UMA_CFG_DBSIZ_SHIFT	21
+#define NPCM_FIU_UMA_CFG_RDATSIZ_SHIFT	24
+
+/* FIU UMA Control and Status Register */
+#define NPCM_FIU_UMA_CTS_RDYIE		BIT(25)
+#define NPCM_FIU_UMA_CTS_RDYST		BIT(24)
+#define NPCM_FIU_UMA_CTS_SW_CS		BIT(16)
+#define NPCM_FIU_UMA_CTS_DEV_NUM	GENMASK(9, 8)
+#define NPCM_FIU_UMA_CTS_EXEC_DONE	BIT(0)
+#define NPCM_FIU_UMA_CTS_DEV_NUM_SHIFT	8
+
+/* FIU UMA Command Register */
+#define NPCM_FIU_UMA_CMD_DUM3		GENMASK(31, 24)
+#define NPCM_FIU_UMA_CMD_DUM2		GENMASK(23, 16)
+#define NPCM_FIU_UMA_CMD_DUM1		GENMASK(15, 8)
+#define NPCM_FIU_UMA_CMD_CMD		GENMASK(7, 0)
+
+/* FIU UMA Address Register */
+#define NPCM_FIU_UMA_ADDR_UMA_ADDR	GENMASK(31, 0)
+#define NPCM_FIU_UMA_ADDR_AB3		GENMASK(31, 24)
+#define NPCM_FIU_UMA_ADDR_AB2		GENMASK(23, 16)
+#define NPCM_FIU_UMA_ADDR_AB1		GENMASK(15, 8)
+#define NPCM_FIU_UMA_ADDR_AB0		GENMASK(7, 0)
+
+/* FIU UMA Write Data Bytes 0-3 Register */
+#define NPCM_FIU_UMA_DW0_WB3		GENMASK(31, 24)
+#define NPCM_FIU_UMA_DW0_WB2		GENMASK(23, 16)
+#define NPCM_FIU_UMA_DW0_WB1		GENMASK(15, 8)
+#define NPCM_FIU_UMA_DW0_WB0		GENMASK(7, 0)
+
+/* FIU UMA Write Data Bytes 4-7 Register */
+#define NPCM_FIU_UMA_DW1_WB7		GENMASK(31, 24)
+#define NPCM_FIU_UMA_DW1_WB6		GENMASK(23, 16)
+#define NPCM_FIU_UMA_DW1_WB5		GENMASK(15, 8)
+#define NPCM_FIU_UMA_DW1_WB4		GENMASK(7, 0)
+
+/* FIU UMA Write Data Bytes 8-11 Register */
+#define NPCM_FIU_UMA_DW2_WB11		GENMASK(31, 24)
+#define NPCM_FIU_UMA_DW2_WB10		GENMASK(23, 16)
+#define NPCM_FIU_UMA_DW2_WB9		GENMASK(15, 8)
+#define NPCM_FIU_UMA_DW2_WB8		GENMASK(7, 0)
+
+/* FIU UMA Write Data Bytes 12-15 Register */
+#define NPCM_FIU_UMA_DW3_WB15		GENMASK(31, 24)
+#define NPCM_FIU_UMA_DW3_WB14		GENMASK(23, 16)
+#define NPCM_FIU_UMA_DW3_WB13		GENMASK(15, 8)
+#define NPCM_FIU_UMA_DW3_WB12		GENMASK(7, 0)
+
+/* FIU UMA Read Data Bytes 0-3 Register */
+#define NPCM_FIU_UMA_DR0_RB3		GENMASK(31, 24)
+#define NPCM_FIU_UMA_DR0_RB2		GENMASK(23, 16)
+#define NPCM_FIU_UMA_DR0_RB1		GENMASK(15, 8)
+#define NPCM_FIU_UMA_DR0_RB0		GENMASK(7, 0)
+
+/* FIU UMA Read Data Bytes 4-7 Register */
+#define NPCM_FIU_UMA_DR1_RB15		GENMASK(31, 24)
+#define NPCM_FIU_UMA_DR1_RB14		GENMASK(23, 16)
+#define NPCM_FIU_UMA_DR1_RB13		GENMASK(15, 8)
+#define NPCM_FIU_UMA_DR1_RB12		GENMASK(7, 0)
+
+/* FIU UMA Read Data Bytes 8-11 Register */
+#define NPCM_FIU_UMA_DR2_RB15		GENMASK(31, 24)
+#define NPCM_FIU_UMA_DR2_RB14		GENMASK(23, 16)
+#define NPCM_FIU_UMA_DR2_RB13		GENMASK(15, 8)
+#define NPCM_FIU_UMA_DR2_RB12		GENMASK(7, 0)
+
+/* FIU UMA Read Data Bytes 12-15 Register */
+#define NPCM_FIU_UMA_DR3_RB15		GENMASK(31, 24)
+#define NPCM_FIU_UMA_DR3_RB14		GENMASK(23, 16)
+#define NPCM_FIU_UMA_DR3_RB13		GENMASK(15, 8)
+#define NPCM_FIU_UMA_DR3_RB12		GENMASK(7, 0)
+
+/* FIU Read Mode */
+enum {
+	DRD_SINGLE_WIRE_MODE	= 0,
+	DRD_DUAL_IO_MODE	= 1,
+	DRD_QUAD_IO_MODE	= 2,
+	DRD_SPI_X_MODE		= 3,
+};
+
+enum {
+	DWR_ABPCK_BIT_PER_CLK	= 0,
+	DWR_ABPCK_2_BIT_PER_CLK	= 1,
+	DWR_ABPCK_4_BIT_PER_CLK	= 2,
+};
+
+enum {
+	DWR_DBPCK_BIT_PER_CLK	= 0,
+	DWR_DBPCK_2_BIT_PER_CLK	= 1,
+	DWR_DBPCK_4_BIT_PER_CLK	= 2,
+};
+
+#define NPCM_FIU_DRD_16_BYTE_BURST	0x3000000
+#define NPCM_FIU_DWR_16_BYTE_BURST	0x3000000
+
+#define MAP_SIZE_128MB			0x8000000
+#define MAP_SIZE_16MB			0x1000000
+#define MAP_SIZE_8MB			0x800000
+
+#define NUM_BITS_IN_BYTE		8
+#define FIU_DRD_MAX_DUMMY_NUMBER	3
+#define NPCM_MAX_CHIP_NUM		4
+#define CHUNK_SIZE			16
+#define UMA_MICRO_SEC_TIMEOUT		150
+
+enum {
+	FIU0 = 0,
+	FIU3,
+	FIUX,
+};
+
+struct npcm_fiu_info {
+	char *name;
+	u32 fiu_id;
+	u32 max_map_size;
+	u32 max_cs;
+};
+
+struct fiu_data {
+	const struct npcm_fiu_info *npcm_fiu_data_info;
+	int fiu_max;
+};
+
+static const struct npcm_fiu_info npxm7xx_fiu_info[] = {
+	{.name = "FIU0", .fiu_id = FIU0,
+		.max_map_size = MAP_SIZE_128MB, .max_cs = 2},
+	{.name = "FIU3", .fiu_id = FIU3,
+		.max_map_size = MAP_SIZE_128MB, .max_cs = 4},
+	{.name = "FIUX", .fiu_id = FIUX,
+		.max_map_size = MAP_SIZE_16MB, .max_cs = 2} };
+
+static const struct fiu_data npxm7xx_fiu_data = {
+	.npcm_fiu_data_info = npxm7xx_fiu_info,
+	.fiu_max = 3,
+};
+
+struct npcm_fiu_bus;
+
+struct npcm_chip {
+	void __iomem *flash_region_mapped_ptr;
+	enum spi_nor_protocol direct_rd_proto;
+	struct npcm_fiu_bus *host;
+	struct spi_nor nor;
+	bool direct_read;
+	u32 read_proto;
+	u32 chipselect;
+	u32 clkrate;
+};
+
+struct npcm_fiu_bus {
+	struct npcm_chip *chip[NPCM_MAX_CHIP_NUM];
+	enum spi_nor_protocol direct_rd_proto;
+	const struct npcm_fiu_info *info;
+	struct resource *res_mem;
+	resource_size_t iosize;
+	struct regmap *regmap;
+	void __iomem *regbase;
+	u32 direct_read_proto;
+	struct device *dev;
+	struct mutex lock;	/* controller access mutex */
+	struct clk *clk;
+	bool spix_mode;
+	int id;
+};
+
+static const struct regmap_config npcm_mtd_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = NPCM_FIU_MAX_REG_LIMIT,
+};
+
+static int npcm_fiu_direct_read(struct mtd_info *mtd, loff_t from, size_t len,
+				size_t *retlen, u_char *buf)
+{
+	struct spi_nor *nor = mtd->priv;
+	struct npcm_chip *chip = nor->priv;
+
+	memcpy_fromio(buf, chip->flash_region_mapped_ptr + from, len);
+
+	*retlen = len;
+	return 0;
+}
+
+static int npcm_fiu_direct_write(struct mtd_info *mtd, loff_t to, size_t len,
+				 size_t *retlen, const u_char *buf)
+{
+	struct spi_nor *nor = mtd->priv;
+	struct npcm_chip *chip = nor->priv;
+
+	memcpy_toio(chip->flash_region_mapped_ptr + to, buf, len);
+
+	*retlen = len;
+	return 0;
+}
+
+static int npcm_fiu_uma_read(struct spi_nor *nor, u8 transaction_code,
+			     u32 address, bool is_address_size, u8 *data,
+			     u32 data_size)
+{
+	struct npcm_chip *chip = nor->priv;
+	struct npcm_fiu_bus *host = chip->host;
+	u32 uma_cfg = BIT(10);
+	u32 dummy_bytes;
+	u32 data_reg[4];
+	int ret;
+	u32 val;
+	u32 i;
+
+	regmap_update_bits(host->regmap, NPCM_FIU_UMA_CTS,
+			   NPCM_FIU_UMA_CTS_DEV_NUM,
+			   (chip->chipselect <<
+			    NPCM_FIU_UMA_CTS_DEV_NUM_SHIFT));
+	regmap_update_bits(host->regmap, NPCM_FIU_UMA_CMD,
+			   NPCM_FIU_UMA_CMD_CMD, transaction_code);
+	regmap_write(host->regmap, NPCM_FIU_UMA_ADDR, address);
+
+	if (is_address_size) {
+		uma_cfg |=
+			ilog2(spi_nor_get_protocol_inst_nbits(nor->read_proto));
+		uma_cfg |=
+			ilog2(spi_nor_get_protocol_addr_nbits(nor->read_proto))
+		<< NPCM_FIU_UMA_CFG_ADBPCK_SHIFT;
+		uma_cfg |=
+			ilog2(spi_nor_get_protocol_addr_nbits(nor->read_proto))
+		<< NPCM_FIU_UMA_CFG_DBPCK_SHIFT;
+		uma_cfg |=
+			ilog2(spi_nor_get_protocol_data_nbits(nor->read_proto))
+		<< NPCM_FIU_UMA_CFG_RDBPCK_SHIFT;
+		dummy_bytes =
+			(nor->read_dummy *
+			 spi_nor_get_protocol_addr_nbits(nor->read_proto)) /
+			NUM_BITS_IN_BYTE;
+		uma_cfg |= dummy_bytes << NPCM_FIU_UMA_CFG_DBSIZ_SHIFT;
+		uma_cfg |= (nor->addr_width << NPCM_FIU_UMA_CFG_ADDSIZ_SHIFT);
+	}
+
+	uma_cfg |= data_size << NPCM_FIU_UMA_CFG_RDATSIZ_SHIFT;
+	regmap_write(host->regmap, NPCM_FIU_UMA_CFG, uma_cfg);
+
+	regmap_write_bits(host->regmap, NPCM_FIU_UMA_CTS,
+			  NPCM_FIU_UMA_CTS_EXEC_DONE,
+			  NPCM_FIU_UMA_CTS_EXEC_DONE);
+
+	ret = regmap_read_poll_timeout(host->regmap, NPCM_FIU_UMA_CTS, val,
+				       (!(val & NPCM_FIU_UMA_CTS_EXEC_DONE)), 0,
+				       UMA_MICRO_SEC_TIMEOUT);
+	if (ret)
+		return ret;
+
+	if (data_size) {
+		for (i = 0; i <= data_size / 4; i++)
+			regmap_read(host->regmap, NPCM_FIU_UMA_DR0 + (i * 4),
+				    &data_reg[i]);
+		memcpy(data, data_reg, data_size);
+	}
+
+	return 0;
+}
+
+static int npcm_fiu_uma_write(struct spi_nor *nor, u8 transaction_code,
+			      u32 address, bool is_address_size, u8 *data,
+			      u32 data_size)
+{
+	struct npcm_chip *chip = nor->priv;
+	struct npcm_fiu_bus *host = chip->host;
+	u32 uma_cfg = BIT(10);
+	u32 data_reg[4] = {0};
+	u32 val;
+	u32 i;
+
+	regmap_update_bits(host->regmap, NPCM_FIU_UMA_CTS,
+			   NPCM_FIU_UMA_CTS_DEV_NUM,
+			   (chip->chipselect <<
+			    NPCM_FIU_UMA_CTS_DEV_NUM_SHIFT));
+
+	regmap_update_bits(host->regmap, NPCM_FIU_UMA_CMD,
+			   NPCM_FIU_UMA_CMD_CMD, transaction_code);
+	regmap_write(host->regmap, NPCM_FIU_UMA_ADDR, address);
+
+	if (data_size) {
+		memcpy(data_reg, data, data_size);
+		for (i = 0; i <= data_size / 4; i++)
+			regmap_write(host->regmap, NPCM_FIU_UMA_DW0 + (i * 4),
+				     data_reg[i]);
+	}
+
+	if (is_address_size) {
+		uma_cfg |=
+			ilog2(spi_nor_get_protocol_inst_nbits
+			      (nor->write_proto));
+		uma_cfg |=
+			ilog2(spi_nor_get_protocol_addr_nbits(nor->write_proto))
+		<< NPCM_FIU_UMA_CFG_ADBPCK_SHIFT;
+		uma_cfg |=
+			ilog2(spi_nor_get_protocol_data_nbits(nor->write_proto))
+		<< NPCM_FIU_UMA_CFG_WDBPCK_SHIFT;
+		uma_cfg |= (nor->addr_width << NPCM_FIU_UMA_CFG_ADDSIZ_SHIFT);
+	}
+
+	uma_cfg |= (data_size << NPCM_FIU_UMA_CFG_WDATSIZ_SHIFT);
+	regmap_write(host->regmap, NPCM_FIU_UMA_CFG, uma_cfg);
+
+	regmap_write_bits(host->regmap, NPCM_FIU_UMA_CTS,
+			  NPCM_FIU_UMA_CTS_EXEC_DONE,
+			  NPCM_FIU_UMA_CTS_EXEC_DONE);
+
+	return regmap_read_poll_timeout(host->regmap, NPCM_FIU_UMA_CTS, val,
+				       (!(val & NPCM_FIU_UMA_CTS_EXEC_DONE)), 0,
+					UMA_MICRO_SEC_TIMEOUT);
+}
+
+static int npcm_fiu_manualwrite(struct spi_nor *nor, u8 transaction_code,
+				u32 address, u8 *data, u32 data_size)
+{
+	u32 num_data_chunks;
+	u32 remain_data;
+	u32 idx = 0;
+	int ret;
+
+	struct npcm_chip *chip = nor->priv;
+	struct npcm_fiu_bus *host = chip->host;
+
+	num_data_chunks  = data_size / CHUNK_SIZE;
+	remain_data  = data_size % CHUNK_SIZE;
+
+	regmap_update_bits(host->regmap, NPCM_FIU_UMA_CTS,
+			   NPCM_FIU_UMA_CTS_DEV_NUM,
+			   (chip->chipselect <<
+			    NPCM_FIU_UMA_CTS_DEV_NUM_SHIFT));
+	regmap_update_bits(host->regmap, NPCM_FIU_UMA_CTS,
+			   NPCM_FIU_UMA_CTS_SW_CS, 0);
+
+	ret = npcm_fiu_uma_write(nor, transaction_code, address, true,
+				 NULL, 0);
+	if (ret)
+		return ret;
+
+	/* Starting the data writing loop in multiples of 8 */
+	for (idx = 0; idx < num_data_chunks; ++idx) {
+		ret = npcm_fiu_uma_write(nor, data[0], (u32)NULL, false,
+					 &data[1], CHUNK_SIZE - 1);
+		if (ret)
+			return ret;
+
+		data += CHUNK_SIZE;
+	}
+
+	/* Handling chunk remains */
+	if (remain_data > 0) {
+		ret = npcm_fiu_uma_write(nor, data[0], (u32)NULL, false,
+					 &data[1], remain_data - 1);
+		if (ret)
+			return ret;
+	}
+
+	regmap_update_bits(host->regmap, NPCM_FIU_UMA_CTS,
+			   NPCM_FIU_UMA_CTS_SW_CS, NPCM_FIU_UMA_CTS_SW_CS);
+
+	return 0;
+}
+
+static ssize_t npcm_fiu_write(struct spi_nor *nor, loff_t to,
+			      size_t len, const u_char *write_buf)
+{
+	u32 local_addr = (u32)to;
+	struct mtd_info *mtd;
+	u32 actual_size = 0;
+	u32 cnt = (u32)len;
+	int ret;
+
+	mtd = &nor->mtd;
+
+	if (cnt != 0) {
+		while (cnt) {
+			actual_size = ((((local_addr) / nor->page_size) + 1)
+				       * nor->page_size) - (local_addr);
+			if (actual_size > cnt)
+				actual_size = cnt;
+
+			ret = npcm_fiu_manualwrite(nor, nor->program_opcode,
+						   local_addr,
+						   (u_char *)write_buf,
+						   actual_size);
+			if (ret)
+				return ret;
+
+			write_buf += actual_size;
+			local_addr += actual_size;
+			cnt -= actual_size;
+		}
+	}
+
+	return (len - cnt);
+}
+
+static void npcm_fiu_set_drd(struct spi_nor *nor, struct npcm_fiu_bus *host)
+{
+	regmap_update_bits(host->regmap, NPCM_FIU_DRD_CFG,
+			   NPCM_FIU_DRD_CFG_ACCTYPE,
+			   ilog2(spi_nor_get_protocol_addr_nbits
+				 (nor->read_proto)) <<
+			   NPCM_FIU_DRD_ACCTYPE_SHIFT);
+	regmap_update_bits(host->regmap, NPCM_FIU_DRD_CFG,
+			   NPCM_FIU_DRD_CFG_DBW,
+			   ((nor->read_dummy *
+			     spi_nor_get_protocol_addr_nbits(nor->read_proto))
+			    / NUM_BITS_IN_BYTE) << NPCM_FIU_DRD_DBW_SHIFT);
+	regmap_update_bits(host->regmap, NPCM_FIU_DRD_CFG,
+			   NPCM_FIU_DRD_CFG_RDCMD, nor->read_opcode);
+	regmap_update_bits(host->regmap, NPCM_FIU_DRD_CFG,
+			   NPCM_FIU_DRD_CFG_ADDSIZ,
+			   (nor->addr_width - 3) << NPCM_FIU_DRD_ADDSIZ_SHIFT);
+}
+
+static ssize_t npcm_fiu_read(struct spi_nor *nor, loff_t from, size_t len,
+			     u_char *read_buf)
+{
+	struct npcm_chip *chip = nor->priv;
+	struct npcm_fiu_bus *host = chip->host;
+	int i, readlen, currlen;
+	struct mtd_info *mtd;
+	size_t retlen = 0;
+	u8 *buf_ptr;
+	u32 addr;
+	int ret;
+
+	mtd = &nor->mtd;
+
+	if (chip->direct_read) {
+		regmap_read(host->regmap, NPCM_FIU_DRD_CFG, &addr);
+		if (host->direct_rd_proto != chip->direct_rd_proto) {
+			npcm_fiu_set_drd(nor, host);
+			host->direct_rd_proto = chip->direct_rd_proto;
+		}
+		npcm_fiu_direct_read(mtd, from, len, &retlen, read_buf);
+	} else {
+		i = 0;
+		currlen = (int)len;
+
+		do {
+			addr = ((u32)from + i);
+			if (currlen < 4)
+				readlen = currlen;
+			else
+				readlen = 4;
+
+			buf_ptr = read_buf + i;
+			ret = npcm_fiu_uma_read(nor, nor->read_opcode, addr,
+						true, buf_ptr, readlen);
+			if (ret)
+				return ret;
+
+			i += readlen;
+			currlen -= 4;
+		} while (currlen > 0);
+
+		retlen = i;
+	}
+
+	return retlen;
+}
+
+static int npcm_fiu_erase(struct spi_nor *nor, loff_t offs)
+{
+	return npcm_fiu_uma_write(nor, nor->erase_opcode, (u32)offs, true,
+				  NULL, 0);
+}
+
+static int npcm_fiu_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf,
+			     int len)
+{
+	return npcm_fiu_uma_read(nor, opcode, 0, false, buf, len);
+}
+
+static int npcm_fiu_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf,
+			      int len)
+{
+	return npcm_fiu_uma_write(nor, opcode, 0, false, buf, len);
+}
+
+static int npcm_fiu_nor_prep(struct spi_nor *nor, enum spi_nor_ops ops)
+{
+	struct npcm_chip *chip = nor->priv;
+	struct npcm_fiu_bus *host = chip->host;
+
+	mutex_lock(&host->lock);
+
+	return 0;
+}
+
+static void npcm_fiu_nor_unprep(struct spi_nor *nor, enum spi_nor_ops ops)
+{
+	struct npcm_chip *chip = nor->priv;
+	struct npcm_fiu_bus *host = chip->host;
+
+	mutex_unlock(&host->lock);
+}
+
+/* Expansion bus registers as mtd_ram device */
+static int npcm_mtd_ram_register(struct device_node *np,
+				 struct npcm_fiu_bus *host)
+{
+	struct device *dev = host->dev;
+	struct npcm_chip *chip;
+	struct mtd_info *mtd;
+	struct spi_nor *nor;
+	u32 chipselect;
+	u32 rx_dummy = 0;
+	int ret;
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	ret = of_property_read_u32(np, "reg", &chipselect);
+	if (ret) {
+		dev_err(dev, "There's no reg property for %s\n",
+			dev->of_node->full_name);
+		return ret;
+	}
+
+	of_property_read_u32(np, "npcm,fiu-spix-rx-dummy-num", &rx_dummy);
+	if (rx_dummy > FIU_DRD_MAX_DUMMY_NUMBER) {
+		dev_warn(dev, "npcm,fiu-spix-rx-dummy-num %d not supported\n",
+			 rx_dummy);
+		rx_dummy = 0;
+	}
+
+	chip->host = host;
+	chip->chipselect = chipselect;
+	nor = &chip->nor;
+	nor->dev = dev;
+	nor->priv = chip;
+	mtd = &nor->mtd;
+
+	chip->flash_region_mapped_ptr =
+		devm_ioremap(dev, (host->res_mem->start +
+				   (host->info->max_map_size *
+				    chip->chipselect)), MAP_SIZE_8MB);
+	if (!chip->flash_region_mapped_ptr) {
+		dev_err(dev, "Error mapping memory region!\n");
+		return -ENOMEM;
+	}
+
+	/* Populate mtd_info data structure */
+	*mtd = (struct mtd_info) {
+		.dev		= { .parent = dev },
+		.name		= "exp-bus",
+		.type		= MTD_RAM,
+		.priv		= nor,
+		.size		= MAP_SIZE_8MB,
+		.writesize	= 1,
+		.writebufsize	= 1,
+		.flags		= MTD_CAP_RAM,
+		._read		= npcm_fiu_direct_read,
+		._write		= npcm_fiu_direct_write,
+	};
+
+	/* set read and write direct to configuration to SPI-X mode */
+	regmap_write(host->regmap, NPCM_FIU_DRD_CFG,
+		     NPCM_FIU_DRD_16_BYTE_BURST);
+	regmap_update_bits(host->regmap, NPCM_FIU_DRD_CFG,
+			   NPCM_FIU_DRD_CFG_ACCTYPE,
+			   DRD_SPI_X_MODE << NPCM_FIU_DRD_ACCTYPE_SHIFT);
+	regmap_update_bits(host->regmap, NPCM_FIU_DRD_CFG,
+			   NPCM_FIU_DRD_CFG_DBW,
+			   rx_dummy << NPCM_FIU_DRD_DBW_SHIFT);
+	regmap_write(host->regmap, NPCM_FIU_DWR_CFG,
+		     NPCM_FIU_DWR_16_BYTE_BURST);
+	regmap_update_bits(host->regmap, NPCM_FIU_DWR_CFG,
+			   NPCM_FIU_DWR_CFG_ABPCK,
+			   DWR_ABPCK_4_BIT_PER_CLK << NPCM_FIU_DWR_ABPCK_SHIFT);
+	regmap_update_bits(host->regmap, NPCM_FIU_DWR_CFG,
+			   NPCM_FIU_DWR_CFG_DBPCK,
+			   DWR_DBPCK_4_BIT_PER_CLK << NPCM_FIU_DWR_DBPCK_SHIFT);
+
+	ret = mtd_device_parse_register(mtd, NULL, NULL, NULL, 0);
+	if (ret)
+		return ret;
+
+	host->chip[chip->chipselect] = chip;
+
+	return 0;
+}
+
+static void npcm_fiu_enable_direct_rd(struct spi_nor *nor,
+				      struct npcm_fiu_bus *host,
+				      struct npcm_chip *chip)
+{
+	struct device *dev = host->dev;
+	u32 flashsize;
+
+	if (!host->res_mem) {
+		dev_warn(dev, "Reserved memory not defined, direct read disabled\n");
+		return;
+	}
+
+	/* direct read supports only I/O read mode */
+	if (nor->read_proto != SNOR_PROTO_1_1_1 &&
+	    nor->read_proto != SNOR_PROTO_1_2_2 &&
+	    nor->read_proto != SNOR_PROTO_1_4_4) {
+		dev_warn(dev, "Only Read I/O commands supported, direct read disabled\n");
+		return;
+	}
+
+	flashsize = (u32)(nor->mtd.size >> 10) * 1024;
+	if (flashsize == 0 || flashsize > host->info->max_map_size) {
+		dev_warn(dev, "Flash size ecxeed(0x%x) map size(0x%x), direct read disabled\n"
+			 , flashsize, host->info->max_map_size);
+		return;
+	}
+
+	chip->flash_region_mapped_ptr =
+		devm_ioremap(dev, (host->res_mem->start +
+				   (host->info->max_map_size *
+				    chip->chipselect)), flashsize);
+	if (!chip->flash_region_mapped_ptr) {
+		dev_warn(dev, "Error mapping memory region, direct read disabled\n");
+		return;
+	}
+
+	npcm_fiu_set_drd(nor, host);
+
+	host->direct_rd_proto = nor->read_proto;
+	chip->direct_rd_proto = nor->read_proto;
+	chip->direct_read = true;
+}
+
+/* Get spi flash device information and register it as a mtd device. */
+static int npcm_fiu_nor_register(struct device_node *np,
+				 struct npcm_fiu_bus *host)
+{
+	struct device *dev = host->dev;
+	struct npcm_chip *chip;
+	struct mtd_info *mtd;
+	struct spi_nor *nor;
+	u32 chipselect;
+	int ret;
+	u32 val;
+	struct spi_nor_hwcaps hwcaps = {
+		.mask = SNOR_HWCAPS_READ |
+			SNOR_HWCAPS_READ_FAST |
+			SNOR_HWCAPS_PP |
+			SNOR_HWCAPS_PP_1_1_4 |
+			SNOR_HWCAPS_PP_1_4_4 |
+			SNOR_HWCAPS_PP_4_4_4,
+	};
+
+	/* This driver mode supports only NOR flash devices. */
+	if (!of_device_is_compatible(np, "jedec,spi-nor")) {
+		dev_err(dev, "The device is no compatible to jedec,spi-nor\n");
+		return -ENOMEM;
+	}
+
+	ret = of_property_read_u32(np, "reg", &chipselect);
+	if (ret) {
+		dev_err(dev, "There's no reg property for %s\n", np->full_name);
+		return ret;
+	}
+
+	if (chipselect >= host->info->max_cs) {
+		dev_err(dev, "Flash device number exceeds the maximum chipselect number\n");
+		return -ENOMEM;
+	}
+
+	if (!of_property_read_u32(np, "spi-rx-bus-width", &val)) {
+		switch (val) {
+		case 1:
+			break;
+		case 2:
+			hwcaps.mask |= SNOR_HWCAPS_READ_1_1_2
+				| SNOR_HWCAPS_READ_1_2_2
+				| SNOR_HWCAPS_READ_2_2_2;
+			break;
+		case 4:
+			hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4
+				 | SNOR_HWCAPS_READ_1_4_4
+				 | SNOR_HWCAPS_READ_4_4_4;
+				break;
+		default:
+			dev_warn(dev, "spi-rx-bus-width %d not supported\n", val);
+			break;
+		}
+	}
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->host = host;
+	chip->chipselect = chipselect;
+
+	nor = &chip->nor;
+	mtd = &nor->mtd;
+
+	nor->dev = dev;
+	nor->priv = chip;
+
+	spi_nor_set_flash_node(nor, np);
+
+	nor->prepare = npcm_fiu_nor_prep;
+	nor->unprepare = npcm_fiu_nor_unprep;
+	nor->read_reg = npcm_fiu_read_reg;
+	nor->write_reg = npcm_fiu_write_reg;
+	nor->read = npcm_fiu_read;
+	nor->write = npcm_fiu_write;
+	nor->erase = npcm_fiu_erase;
+
+	ret = spi_nor_scan(nor, NULL, &hwcaps);
+	if (ret)
+		return ret;
+
+	npcm_fiu_enable_direct_rd(nor, host, chip);
+	ret = mtd_device_register(mtd, NULL, 0);
+	if (ret) {
+		dev_err(dev, "MTD NOR device register failed\n");
+		return ret;
+	}
+
+	host->chip[chip->chipselect] = chip;
+	return 0;
+}
+
+static void npcm_fiu_unregister_all(struct npcm_fiu_bus *host)
+{
+	struct npcm_chip *chip;
+	int n;
+
+	for (n = 0; n < host->info->max_cs; n++) {
+		chip = host->chip[n];
+		if (chip)
+			mtd_device_unregister(&chip->nor.mtd);
+	}
+}
+
+static void npcm_fiu_register_all(struct npcm_fiu_bus *host)
+{
+	struct device *dev = host->dev;
+	struct device_node *np;
+	int ret;
+
+	for_each_available_child_of_node(dev->of_node, np) {
+		if (host->spix_mode)
+			ret = npcm_mtd_ram_register(np, host);
+		else
+			ret = npcm_fiu_nor_register(np, host);
+		if (ret)
+			dev_warn(dev, "npcm fiu %s registration failed\n", np->full_name);
+	}
+}
+
+static const struct of_device_id npcm_fiu_dt_ids[] = {
+	{ .compatible = "nuvoton,npcm750-fiu", .data = &npxm7xx_fiu_data  },
+	{ /* sentinel */ }
+};
+
+static int npcm_fiu_probe(struct platform_device *pdev)
+{
+	const struct fiu_data *fiu_data_match;
+	const struct of_device_id *match;
+	struct device *dev = &pdev->dev;
+	struct npcm_fiu_bus *host;
+	struct resource *res;
+
+	host = devm_kzalloc(dev, sizeof(*host), GFP_KERNEL);
+	if (!host)
+		return -ENOMEM;
+
+	match = of_match_device(npcm_fiu_dt_ids, dev);
+	if (!match || !match->data) {
+		dev_err(dev, "No compatible OF match\n");
+		return -ENODEV;
+	}
+
+	fiu_data_match = match->data;
+
+	host->id = of_alias_get_id(dev->of_node, "fiu");
+	if (host->id < 0 || host->id >= fiu_data_match->fiu_max) {
+		dev_err(dev, "Invalid platform device id: %d\n", host->id);
+		return -EINVAL;
+	}
+
+	host->info = &fiu_data_match->npcm_fiu_data_info[host->id];
+
+	platform_set_drvdata(pdev, host);
+	host->dev = dev;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "control");
+	host->regbase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(host->regbase))
+		return PTR_ERR(host->regbase);
+
+	host->regmap = devm_regmap_init_mmio(dev, host->regbase,
+					     &npcm_mtd_regmap_config);
+	if (IS_ERR(host->regmap)) {
+		dev_err(dev, "Failed to create regmap\n");
+		return PTR_ERR(host->regmap);
+	}
+
+	host->res_mem = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+						     "memory");
+	host->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(host->clk))
+		return PTR_ERR(host->clk);
+
+	host->spix_mode = of_property_read_bool(dev->of_node, "spix-mode");
+
+	mutex_init(&host->lock);
+	clk_prepare_enable(host->clk);
+
+	npcm_fiu_register_all(host);
+
+	dev_info(dev, "NPCM %s probe succeed\n", host->info->name);
+
+	return 0;
+}
+
+static int npcm_fiu_remove(struct platform_device *pdev)
+{
+	struct npcm_fiu_bus *host = platform_get_drvdata(pdev);
+
+	npcm_fiu_unregister_all(host);
+	mutex_destroy(&host->lock);
+	clk_disable_unprepare(host->clk);
+	return 0;
+}
+
+MODULE_DEVICE_TABLE(of, npcm_fiu_dt_ids);
+
+static struct platform_driver npcm_fiu_driver = {
+	.driver = {
+		.name	= "NPCM-FIU",
+		.bus	= &platform_bus_type,
+		.of_match_table = npcm_fiu_dt_ids,
+	},
+	.probe      = npcm_fiu_probe,
+	.remove	    = npcm_fiu_remove,
+};
+module_platform_driver(npcm_fiu_driver);
+
+MODULE_DESCRIPTION("Nuvoton FLASH Interface Unit SPI Controller Driver");
+MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
+MODULE_LICENSE("GPL v2");
-- 
2.14.1