Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1104 insertions, 0 deletions

diff --git a/drivers/mtd/devices/spear_smi.c b/drivers/mtd/devices/spear_smi.c
new file mode 100644
index 0000000000..0a35e5236a
--- /dev/null
+++ b/drivers/mtd/devices/spear_smi.c
@@ -0,0 +1,1104 @@
+/*
+ * SMI (Serial Memory Controller) device driver for Serial NOR Flash on
+ * SPEAr platform
+ * The serial nor interface is largely based on m25p80.c, however the SPI
+ * interface has been replaced by SMI.
+ *
+ * Copyright © 2010 STMicroelectronics.
+ * Ashish Priyadarshi
+ * Shiraz Hashim <shiraz.linux.kernel@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/param.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/spear_smi.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+/* SMI clock rate */
+#define SMI_MAX_CLOCK_FREQ	50000000 /* 50 MHz */
+
+/* MAX time out to safely come out of a erase or write busy conditions */
+#define SMI_PROBE_TIMEOUT	(HZ / 10)
+#define SMI_MAX_TIME_OUT	(3 * HZ)
+
+/* timeout for command completion */
+#define SMI_CMD_TIMEOUT		(HZ / 10)
+
+/* registers of smi */
+#define SMI_CR1		0x0	/* SMI control register 1 */
+#define SMI_CR2		0x4	/* SMI control register 2 */
+#define SMI_SR		0x8	/* SMI status register */
+#define SMI_TR		0xC	/* SMI transmit register */
+#define SMI_RR		0x10	/* SMI receive register */
+
+/* defines for control_reg 1 */
+#define BANK_EN		(0xF << 0)	/* enables all banks */
+#define DSEL_TIME	(0x6 << 4)	/* Deselect time 6 + 1 SMI_CK periods */
+#define SW_MODE		(0x1 << 28)	/* enables SW Mode */
+#define WB_MODE		(0x1 << 29)	/* Write Burst Mode */
+#define FAST_MODE	(0x1 << 15)	/* Fast Mode */
+#define HOLD1		(0x1 << 16)	/* Clock Hold period selection */
+
+/* defines for control_reg 2 */
+#define SEND		(0x1 << 7)	/* Send data */
+#define TFIE		(0x1 << 8)	/* Transmission Flag Interrupt Enable */
+#define WCIE		(0x1 << 9)	/* Write Complete Interrupt Enable */
+#define RD_STATUS_REG	(0x1 << 10)	/* reads status reg */
+#define WE		(0x1 << 11)	/* Write Enable */
+
+#define TX_LEN_SHIFT	0
+#define RX_LEN_SHIFT	4
+#define BANK_SHIFT	12
+
+/* defines for status register */
+#define SR_WIP		0x1	/* Write in progress */
+#define SR_WEL		0x2	/* Write enable latch */
+#define SR_BP0		0x4	/* Block protect 0 */
+#define SR_BP1		0x8	/* Block protect 1 */
+#define SR_BP2		0x10	/* Block protect 2 */
+#define SR_SRWD		0x80	/* SR write protect */
+#define TFF		0x100	/* Transfer Finished Flag */
+#define WCF		0x200	/* Transfer Finished Flag */
+#define ERF1		0x400	/* Forbidden Write Request */
+#define ERF2		0x800	/* Forbidden Access */
+
+#define WM_SHIFT	12
+
+/* flash opcodes */
+#define OPCODE_RDID	0x9f	/* Read JEDEC ID */
+
+/* Flash Device Ids maintenance section */
+
+/* data structure to maintain flash ids from different vendors */
+struct flash_device {
+	char *name;
+	u8 erase_cmd;
+	u32 device_id;
+	u32 pagesize;
+	unsigned long sectorsize;
+	unsigned long size_in_bytes;
+};
+
+#define FLASH_ID(n, es, id, psize, ssize, size)	\
+{				\
+	.name = n,		\
+	.erase_cmd = es,	\
+	.device_id = id,	\
+	.pagesize = psize,	\
+	.sectorsize = ssize,	\
+	.size_in_bytes = size	\
+}
+
+static struct flash_device flash_devices[] = {
+	FLASH_ID("st m25p16"     , 0xd8, 0x00152020, 0x100, 0x10000, 0x200000),
+	FLASH_ID("st m25p32"     , 0xd8, 0x00162020, 0x100, 0x10000, 0x400000),
+	FLASH_ID("st m25p64"     , 0xd8, 0x00172020, 0x100, 0x10000, 0x800000),
+	FLASH_ID("st m25p128"    , 0xd8, 0x00182020, 0x100, 0x40000, 0x1000000),
+	FLASH_ID("st m25p05"     , 0xd8, 0x00102020, 0x80 , 0x8000 , 0x10000),
+	FLASH_ID("st m25p10"     , 0xd8, 0x00112020, 0x80 , 0x8000 , 0x20000),
+	FLASH_ID("st m25p20"     , 0xd8, 0x00122020, 0x100, 0x10000, 0x40000),
+	FLASH_ID("st m25p40"     , 0xd8, 0x00132020, 0x100, 0x10000, 0x80000),
+	FLASH_ID("st m25p80"     , 0xd8, 0x00142020, 0x100, 0x10000, 0x100000),
+	FLASH_ID("st m45pe10"    , 0xd8, 0x00114020, 0x100, 0x10000, 0x20000),
+	FLASH_ID("st m45pe20"    , 0xd8, 0x00124020, 0x100, 0x10000, 0x40000),
+	FLASH_ID("st m45pe40"    , 0xd8, 0x00134020, 0x100, 0x10000, 0x80000),
+	FLASH_ID("st m45pe80"    , 0xd8, 0x00144020, 0x100, 0x10000, 0x100000),
+	FLASH_ID("sp s25fl004"   , 0xd8, 0x00120201, 0x100, 0x10000, 0x80000),
+	FLASH_ID("sp s25fl008"   , 0xd8, 0x00130201, 0x100, 0x10000, 0x100000),
+	FLASH_ID("sp s25fl016"   , 0xd8, 0x00140201, 0x100, 0x10000, 0x200000),
+	FLASH_ID("sp s25fl032"   , 0xd8, 0x00150201, 0x100, 0x10000, 0x400000),
+	FLASH_ID("sp s25fl064"   , 0xd8, 0x00160201, 0x100, 0x10000, 0x800000),
+	FLASH_ID("atmel 25f512"  , 0x52, 0x0065001F, 0x80 , 0x8000 , 0x10000),
+	FLASH_ID("atmel 25f1024" , 0x52, 0x0060001F, 0x100, 0x8000 , 0x20000),
+	FLASH_ID("atmel 25f2048" , 0x52, 0x0063001F, 0x100, 0x10000, 0x40000),
+	FLASH_ID("atmel 25f4096" , 0x52, 0x0064001F, 0x100, 0x10000, 0x80000),
+	FLASH_ID("atmel 25fs040" , 0xd7, 0x0004661F, 0x100, 0x10000, 0x80000),
+	FLASH_ID("mac 25l512"    , 0xd8, 0x001020C2, 0x010, 0x10000, 0x10000),
+	FLASH_ID("mac 25l1005"   , 0xd8, 0x001120C2, 0x010, 0x10000, 0x20000),
+	FLASH_ID("mac 25l2005"   , 0xd8, 0x001220C2, 0x010, 0x10000, 0x40000),
+	FLASH_ID("mac 25l4005"   , 0xd8, 0x001320C2, 0x010, 0x10000, 0x80000),
+	FLASH_ID("mac 25l4005a"  , 0xd8, 0x001320C2, 0x010, 0x10000, 0x80000),
+	FLASH_ID("mac 25l8005"   , 0xd8, 0x001420C2, 0x010, 0x10000, 0x100000),
+	FLASH_ID("mac 25l1605"   , 0xd8, 0x001520C2, 0x100, 0x10000, 0x200000),
+	FLASH_ID("mac 25l1605a"  , 0xd8, 0x001520C2, 0x010, 0x10000, 0x200000),
+	FLASH_ID("mac 25l3205"   , 0xd8, 0x001620C2, 0x100, 0x10000, 0x400000),
+	FLASH_ID("mac 25l3205a"  , 0xd8, 0x001620C2, 0x100, 0x10000, 0x400000),
+	FLASH_ID("mac 25l6405"   , 0xd8, 0x001720C2, 0x100, 0x10000, 0x800000),
+};
+
+/* Define spear specific structures */
+
+struct spear_snor_flash;
+
+/**
+ * struct spear_smi - Structure for SMI Device
+ *
+ * @clk: functional clock
+ * @status: current status register of SMI.
+ * @clk_rate: functional clock rate of SMI (default: SMI_MAX_CLOCK_FREQ)
+ * @lock: lock to prevent parallel access of SMI.
+ * @io_base: base address for registers of SMI.
+ * @pdev: platform device
+ * @cmd_complete: queue to wait for command completion of NOR-flash.
+ * @num_flashes: number of flashes actually present on board.
+ * @flash: separate structure for each Serial NOR-flash attached to SMI.
+ */
+struct spear_smi {
+	struct clk *clk;
+	u32 status;
+	unsigned long clk_rate;
+	struct mutex lock;
+	void __iomem *io_base;
+	struct platform_device *pdev;
+	wait_queue_head_t cmd_complete;
+	u32 num_flashes;
+	struct spear_snor_flash *flash[MAX_NUM_FLASH_CHIP];
+};
+
+/**
+ * struct spear_snor_flash - Structure for Serial NOR Flash
+ *
+ * @bank: Bank number(0, 1, 2, 3) for each NOR-flash.
+ * @dev_id: Device ID of NOR-flash.
+ * @lock: lock to manage flash read, write and erase operations
+ * @mtd: MTD info for each NOR-flash.
+ * @num_parts: Total number of partition in each bank of NOR-flash.
+ * @parts: Partition info for each bank of NOR-flash.
+ * @page_size: Page size of NOR-flash.
+ * @base_addr: Base address of NOR-flash.
+ * @erase_cmd: erase command may vary on different flash types
+ * @fast_mode: flash supports read in fast mode
+ */
+struct spear_snor_flash {
+	u32 bank;
+	u32 dev_id;
+	struct mutex lock;
+	struct mtd_info mtd;
+	u32 num_parts;
+	struct mtd_partition *parts;
+	u32 page_size;
+	void __iomem *base_addr;
+	u8 erase_cmd;
+	u8 fast_mode;
+};
+
+static inline struct spear_snor_flash *get_flash_data(struct mtd_info *mtd)
+{
+	return container_of(mtd, struct spear_snor_flash, mtd);
+}
+
+/**
+ * spear_smi_read_sr - Read status register of flash through SMI
+ * @dev: structure of SMI information.
+ * @bank: bank to which flash is connected
+ *
+ * This routine will return the status register of the flash chip present at the
+ * given bank.
+ */
+static int spear_smi_read_sr(struct spear_smi *dev, u32 bank)
+{
+	int ret;
+	u32 ctrlreg1;
+
+	mutex_lock(&dev->lock);
+	dev->status = 0; /* Will be set in interrupt handler */
+
+	ctrlreg1 = readl(dev->io_base + SMI_CR1);
+	/* program smi in hw mode */
+	writel(ctrlreg1 & ~(SW_MODE | WB_MODE), dev->io_base + SMI_CR1);
+
+	/* performing a rsr instruction in hw mode */
+	writel((bank << BANK_SHIFT) | RD_STATUS_REG | TFIE,
+			dev->io_base + SMI_CR2);
+
+	/* wait for tff */
+	ret = wait_event_interruptible_timeout(dev->cmd_complete,
+			dev->status & TFF, SMI_CMD_TIMEOUT);
+
+	/* copy dev->status (lower 16 bits) in order to release lock */
+	if (ret > 0)
+		ret = dev->status & 0xffff;
+	else if (ret == 0)
+		ret = -ETIMEDOUT;
+
+	/* restore the ctrl regs state */
+	writel(ctrlreg1, dev->io_base + SMI_CR1);
+	writel(0, dev->io_base + SMI_CR2);
+	mutex_unlock(&dev->lock);
+
+	return ret;
+}
+
+/**
+ * spear_smi_wait_till_ready - wait till flash is ready
+ * @dev: structure of SMI information.
+ * @bank: flash corresponding to this bank
+ * @timeout: timeout for busy wait condition
+ *
+ * This routine checks for WIP (write in progress) bit in Status register
+ * If successful the routine returns 0 else -EBUSY
+ */
+static int spear_smi_wait_till_ready(struct spear_smi *dev, u32 bank,
+		unsigned long timeout)
+{
+	unsigned long finish;
+	int status;
+
+	finish = jiffies + timeout;
+	do {
+		status = spear_smi_read_sr(dev, bank);
+		if (status < 0) {
+			if (status == -ETIMEDOUT)
+				continue; /* try till finish */
+			return status;
+		} else if (!(status & SR_WIP)) {
+			return 0;
+		}
+
+		cond_resched();
+	} while (!time_after_eq(jiffies, finish));
+
+	dev_err(&dev->pdev->dev, "smi controller is busy, timeout\n");
+	return -EBUSY;
+}
+
+/**
+ * spear_smi_int_handler - SMI Interrupt Handler.
+ * @irq: irq number
+ * @dev_id: structure of SMI device, embedded in dev_id.
+ *
+ * The handler clears all interrupt conditions and records the status in
+ * dev->status which is used by the driver later.
+ */
+static irqreturn_t spear_smi_int_handler(int irq, void *dev_id)
+{
+	u32 status = 0;
+	struct spear_smi *dev = dev_id;
+
+	status = readl(dev->io_base + SMI_SR);
+
+	if (unlikely(!status))
+		return IRQ_NONE;
+
+	/* clear all interrupt conditions */
+	writel(0, dev->io_base + SMI_SR);
+
+	/* copy the status register in dev->status */
+	dev->status |= status;
+
+	/* send the completion */
+	wake_up_interruptible(&dev->cmd_complete);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * spear_smi_hw_init - initializes the smi controller.
+ * @dev: structure of smi device
+ *
+ * this routine initializes the smi controller wit the default values
+ */
+static void spear_smi_hw_init(struct spear_smi *dev)
+{
+	unsigned long rate = 0;
+	u32 prescale = 0;
+	u32 val;
+
+	rate = clk_get_rate(dev->clk);
+
+	/* functional clock of smi */
+	prescale = DIV_ROUND_UP(rate, dev->clk_rate);
+
+	/*
+	 * setting the standard values, fast mode, prescaler for
+	 * SMI_MAX_CLOCK_FREQ (50MHz) operation and bank enable
+	 */
+	val = HOLD1 | BANK_EN | DSEL_TIME | (prescale << 8);
+
+	mutex_lock(&dev->lock);
+	/* clear all interrupt conditions */
+	writel(0, dev->io_base + SMI_SR);
+
+	writel(val, dev->io_base + SMI_CR1);
+	mutex_unlock(&dev->lock);
+}
+
+/**
+ * get_flash_index - match chip id from a flash list.
+ * @flash_id: a valid nor flash chip id obtained from board.
+ *
+ * try to validate the chip id by matching from a list, if not found then simply
+ * returns negative. In case of success returns index in to the flash devices
+ * array.
+ */
+static int get_flash_index(u32 flash_id)
+{
+	int index;
+
+	/* Matches chip-id to entire list of 'serial-nor flash' ids */
+	for (index = 0; index < ARRAY_SIZE(flash_devices); index++) {
+		if (flash_devices[index].device_id == flash_id)
+			return index;
+	}
+
+	/* Memory chip is not listed and not supported */
+	return -ENODEV;
+}
+
+/**
+ * spear_smi_write_enable - Enable the flash to do write operation
+ * @dev: structure of SMI device
+ * @bank: enable write for flash connected to this bank
+ *
+ * Set write enable latch with Write Enable command.
+ * Returns 0 on success.
+ */
+static int spear_smi_write_enable(struct spear_smi *dev, u32 bank)
+{
+	int ret;
+	u32 ctrlreg1;
+
+	mutex_lock(&dev->lock);
+	dev->status = 0; /* Will be set in interrupt handler */
+
+	ctrlreg1 = readl(dev->io_base + SMI_CR1);
+	/* program smi in h/w mode */
+	writel(ctrlreg1 & ~SW_MODE, dev->io_base + SMI_CR1);
+
+	/* give the flash, write enable command */
+	writel((bank << BANK_SHIFT) | WE | TFIE, dev->io_base + SMI_CR2);
+
+	ret = wait_event_interruptible_timeout(dev->cmd_complete,
+			dev->status & TFF, SMI_CMD_TIMEOUT);
+
+	/* restore the ctrl regs state */
+	writel(ctrlreg1, dev->io_base + SMI_CR1);
+	writel(0, dev->io_base + SMI_CR2);
+
+	if (ret == 0) {
+		ret = -EIO;
+		dev_err(&dev->pdev->dev,
+			"smi controller failed on write enable\n");
+	} else if (ret > 0) {
+		/* check whether write mode status is set for required bank */
+		if (dev->status & (1 << (bank + WM_SHIFT)))
+			ret = 0;
+		else {
+			dev_err(&dev->pdev->dev, "couldn't enable write\n");
+			ret = -EIO;
+		}
+	}
+
+	mutex_unlock(&dev->lock);
+	return ret;
+}
+
+static inline u32
+get_sector_erase_cmd(struct spear_snor_flash *flash, u32 offset)
+{
+	u32 cmd;
+	u8 *x = (u8 *)&cmd;
+
+	x[0] = flash->erase_cmd;
+	x[1] = offset >> 16;
+	x[2] = offset >> 8;
+	x[3] = offset;
+
+	return cmd;
+}
+
+/**
+ * spear_smi_erase_sector - erase one sector of flash
+ * @dev: structure of SMI information
+ * @command: erase command to be send
+ * @bank: bank to which this command needs to be send
+ * @bytes: size of command
+ *
+ * Erase one sector of flash memory at offset ``offset'' which is any
+ * address within the sector which should be erased.
+ * Returns 0 if successful, non-zero otherwise.
+ */
+static int spear_smi_erase_sector(struct spear_smi *dev,
+		u32 bank, u32 command, u32 bytes)
+{
+	u32 ctrlreg1 = 0;
+	int ret;
+
+	ret = spear_smi_wait_till_ready(dev, bank, SMI_MAX_TIME_OUT);
+	if (ret)
+		return ret;
+
+	ret = spear_smi_write_enable(dev, bank);
+	if (ret)
+		return ret;
+
+	mutex_lock(&dev->lock);
+
+	ctrlreg1 = readl(dev->io_base + SMI_CR1);
+	writel((ctrlreg1 | SW_MODE) & ~WB_MODE, dev->io_base + SMI_CR1);
+
+	/* send command in sw mode */
+	writel(command, dev->io_base + SMI_TR);
+
+	writel((bank << BANK_SHIFT) | SEND | TFIE | (bytes << TX_LEN_SHIFT),
+			dev->io_base + SMI_CR2);
+
+	ret = wait_event_interruptible_timeout(dev->cmd_complete,
+			dev->status & TFF, SMI_CMD_TIMEOUT);
+
+	if (ret == 0) {
+		ret = -EIO;
+		dev_err(&dev->pdev->dev, "sector erase failed\n");
+	} else if (ret > 0)
+		ret = 0; /* success */
+
+	/* restore ctrl regs */
+	writel(ctrlreg1, dev->io_base + SMI_CR1);
+	writel(0, dev->io_base + SMI_CR2);
+
+	mutex_unlock(&dev->lock);
+	return ret;
+}
+
+/**
+ * spear_mtd_erase - perform flash erase operation as requested by user
+ * @mtd: Provides the memory characteristics
+ * @e_info: Provides the erase information
+ *
+ * Erase an address range on the flash chip. The address range may extend
+ * one or more erase sectors. Return an error is there is a problem erasing.
+ */
+static int spear_mtd_erase(struct mtd_info *mtd, struct erase_info *e_info)
+{
+	struct spear_snor_flash *flash = get_flash_data(mtd);
+	struct spear_smi *dev = mtd->priv;
+	u32 addr, command, bank;
+	int len, ret;
+
+	if (!flash || !dev)
+		return -ENODEV;
+
+	bank = flash->bank;
+	if (bank > dev->num_flashes - 1) {
+		dev_err(&dev->pdev->dev, "Invalid Bank Num");
+		return -EINVAL;
+	}
+
+	addr = e_info->addr;
+	len = e_info->len;
+
+	mutex_lock(&flash->lock);
+
+	/* now erase sectors in loop */
+	while (len) {
+		command = get_sector_erase_cmd(flash, addr);
+		/* preparing the command for flash */
+		ret = spear_smi_erase_sector(dev, bank, command, 4);
+		if (ret) {
+			mutex_unlock(&flash->lock);
+			return ret;
+		}
+		addr += mtd->erasesize;
+		len -= mtd->erasesize;
+	}
+
+	mutex_unlock(&flash->lock);
+
+	return 0;
+}
+
+/**
+ * spear_mtd_read - performs flash read operation as requested by the user
+ * @mtd: MTD information of the memory bank
+ * @from: Address from which to start read
+ * @len: Number of bytes to be read
+ * @retlen: Fills the Number of bytes actually read
+ * @buf: Fills this after reading
+ *
+ * Read an address range from the flash chip. The address range
+ * may be any size provided it is within the physical boundaries.
+ * Returns 0 on success, non zero otherwise
+ */
+static int spear_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
+		size_t *retlen, u8 *buf)
+{
+	struct spear_snor_flash *flash = get_flash_data(mtd);
+	struct spear_smi *dev = mtd->priv;
+	void __iomem *src;
+	u32 ctrlreg1, val;
+	int ret;
+
+	if (!flash || !dev)
+		return -ENODEV;
+
+	if (flash->bank > dev->num_flashes - 1) {
+		dev_err(&dev->pdev->dev, "Invalid Bank Num");
+		return -EINVAL;
+	}
+
+	/* select address as per bank number */
+	src = flash->base_addr + from;
+
+	mutex_lock(&flash->lock);
+
+	/* wait till previous write/erase is done. */
+	ret = spear_smi_wait_till_ready(dev, flash->bank, SMI_MAX_TIME_OUT);
+	if (ret) {
+		mutex_unlock(&flash->lock);
+		return ret;
+	}
+
+	mutex_lock(&dev->lock);
+	/* put smi in hw mode not wbt mode */
+	ctrlreg1 = val = readl(dev->io_base + SMI_CR1);
+	val &= ~(SW_MODE | WB_MODE);
+	if (flash->fast_mode)
+		val |= FAST_MODE;
+
+	writel(val, dev->io_base + SMI_CR1);
+
+	memcpy_fromio(buf, src, len);
+
+	/* restore ctrl reg1 */
+	writel(ctrlreg1, dev->io_base + SMI_CR1);
+	mutex_unlock(&dev->lock);
+
+	*retlen = len;
+	mutex_unlock(&flash->lock);
+
+	return 0;
+}
+
+/*
+ * The purpose of this function is to ensure a memcpy_toio() with byte writes
+ * only. Its structure is inspired from the ARM implementation of _memcpy_toio()
+ * which also does single byte writes but cannot be used here as this is just an
+ * implementation detail and not part of the API. Not mentioning the comment
+ * stating that _memcpy_toio() should be optimized.
+ */
+static void spear_smi_memcpy_toio_b(volatile void __iomem *dest,
+				    const void *src, size_t len)
+{
+	const unsigned char *from = src;
+
+	while (len) {
+		len--;
+		writeb(*from, dest);
+		from++;
+		dest++;
+	}
+}
+
+static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank,
+		void __iomem *dest, const void *src, size_t len)
+{
+	int ret;
+	u32 ctrlreg1;
+
+	/* wait until finished previous write command. */
+	ret = spear_smi_wait_till_ready(dev, bank, SMI_MAX_TIME_OUT);
+	if (ret)
+		return ret;
+
+	/* put smi in write enable */
+	ret = spear_smi_write_enable(dev, bank);
+	if (ret)
+		return ret;
+
+	/* put smi in hw, write burst mode */
+	mutex_lock(&dev->lock);
+
+	ctrlreg1 = readl(dev->io_base + SMI_CR1);
+	writel((ctrlreg1 | WB_MODE) & ~SW_MODE, dev->io_base + SMI_CR1);
+
+	/*
+	 * In Write Burst mode (WB_MODE), the specs states that writes must be:
+	 * - incremental
+	 * - of the same size
+	 * The ARM implementation of memcpy_toio() will optimize the number of
+	 * I/O by using as much 4-byte writes as possible, surrounded by
+	 * 2-byte/1-byte access if:
+	 * - the destination is not 4-byte aligned
+	 * - the length is not a multiple of 4-byte.
+	 * Avoid this alternance of write access size by using our own 'byte
+	 * access' helper if at least one of the two conditions above is true.
+	 */
+	if (IS_ALIGNED(len, sizeof(u32)) &&
+	    IS_ALIGNED((uintptr_t)dest, sizeof(u32)))
+		memcpy_toio(dest, src, len);
+	else
+		spear_smi_memcpy_toio_b(dest, src, len);
+
+	writel(ctrlreg1, dev->io_base + SMI_CR1);
+
+	mutex_unlock(&dev->lock);
+	return 0;
+}
+
+/**
+ * spear_mtd_write - performs write operation as requested by the user.
+ * @mtd: MTD information of the memory bank.
+ * @to:	Address to write.
+ * @len: Number of bytes to be written.
+ * @retlen: Number of bytes actually wrote.
+ * @buf: Buffer from which the data to be taken.
+ *
+ * Write an address range to the flash chip. Data must be written in
+ * flash_page_size chunks. The address range may be any size provided
+ * it is within the physical boundaries.
+ * Returns 0 on success, non zero otherwise
+ */
+static int spear_mtd_write(struct mtd_info *mtd, loff_t to, size_t len,
+		size_t *retlen, const u8 *buf)
+{
+	struct spear_snor_flash *flash = get_flash_data(mtd);
+	struct spear_smi *dev = mtd->priv;
+	void __iomem *dest;
+	u32 page_offset, page_size;
+	int ret;
+
+	if (!flash || !dev)
+		return -ENODEV;
+
+	if (flash->bank > dev->num_flashes - 1) {
+		dev_err(&dev->pdev->dev, "Invalid Bank Num");
+		return -EINVAL;
+	}
+
+	/* select address as per bank number */
+	dest = flash->base_addr + to;
+	mutex_lock(&flash->lock);
+
+	page_offset = (u32)to % flash->page_size;
+
+	/* do if all the bytes fit onto one page */
+	if (page_offset + len <= flash->page_size) {
+		ret = spear_smi_cpy_toio(dev, flash->bank, dest, buf, len);
+		if (!ret)
+			*retlen += len;
+	} else {
+		u32 i;
+
+		/* the size of data remaining on the first page */
+		page_size = flash->page_size - page_offset;
+
+		ret = spear_smi_cpy_toio(dev, flash->bank, dest, buf,
+				page_size);
+		if (ret)
+			goto err_write;
+		else
+			*retlen += page_size;
+
+		/* write everything in pagesize chunks */
+		for (i = page_size; i < len; i += page_size) {
+			page_size = len - i;
+			if (page_size > flash->page_size)
+				page_size = flash->page_size;
+
+			ret = spear_smi_cpy_toio(dev, flash->bank, dest + i,
+					buf + i, page_size);
+			if (ret)
+				break;
+			else
+				*retlen += page_size;
+		}
+	}
+
+err_write:
+	mutex_unlock(&flash->lock);
+
+	return ret;
+}
+
+/**
+ * spear_smi_probe_flash - Detects the NOR Flash chip.
+ * @dev: structure of SMI information.
+ * @bank: bank on which flash must be probed
+ *
+ * This routine will check whether there exists a flash chip on a given memory
+ * bank ID.
+ * Return index of the probed flash in flash devices structure
+ */
+static int spear_smi_probe_flash(struct spear_smi *dev, u32 bank)
+{
+	int ret;
+	u32 val = 0;
+
+	ret = spear_smi_wait_till_ready(dev, bank, SMI_PROBE_TIMEOUT);
+	if (ret)
+		return ret;
+
+	mutex_lock(&dev->lock);
+
+	dev->status = 0; /* Will be set in interrupt handler */
+	/* put smi in sw mode */
+	val = readl(dev->io_base + SMI_CR1);
+	writel(val | SW_MODE, dev->io_base + SMI_CR1);
+
+	/* send readid command in sw mode */
+	writel(OPCODE_RDID, dev->io_base + SMI_TR);
+
+	val = (bank << BANK_SHIFT) | SEND | (1 << TX_LEN_SHIFT) |
+		(3 << RX_LEN_SHIFT) | TFIE;
+	writel(val, dev->io_base + SMI_CR2);
+
+	/* wait for TFF */
+	ret = wait_event_interruptible_timeout(dev->cmd_complete,
+			dev->status & TFF, SMI_CMD_TIMEOUT);
+	if (ret <= 0) {
+		ret = -ENODEV;
+		goto err_probe;
+	}
+
+	/* get memory chip id */
+	val = readl(dev->io_base + SMI_RR);
+	val &= 0x00ffffff;
+	ret = get_flash_index(val);
+
+err_probe:
+	/* clear sw mode */
+	val = readl(dev->io_base + SMI_CR1);
+	writel(val & ~SW_MODE, dev->io_base + SMI_CR1);
+
+	mutex_unlock(&dev->lock);
+	return ret;
+}
+
+
+#ifdef CONFIG_OF
+static int spear_smi_probe_config_dt(struct platform_device *pdev,
+				     struct device_node *np)
+{
+	struct spear_smi_plat_data *pdata = dev_get_platdata(&pdev->dev);
+	struct device_node *pp;
+	const __be32 *addr;
+	u32 val;
+	int len;
+	int i = 0;
+
+	if (!np)
+		return -ENODEV;
+
+	of_property_read_u32(np, "clock-rate", &val);
+	pdata->clk_rate = val;
+
+	pdata->board_flash_info = devm_kzalloc(&pdev->dev,
+					       sizeof(*pdata->board_flash_info),
+					       GFP_KERNEL);
+	if (!pdata->board_flash_info)
+		return -ENOMEM;
+
+	/* Fill structs for each subnode (flash device) */
+	for_each_child_of_node(np, pp) {
+		pdata->np[i] = pp;
+
+		/* Read base-addr and size from DT */
+		addr = of_get_property(pp, "reg", &len);
+		pdata->board_flash_info->mem_base = be32_to_cpup(&addr[0]);
+		pdata->board_flash_info->size = be32_to_cpup(&addr[1]);
+
+		pdata->board_flash_info->fast_mode =
+			of_property_read_bool(pp, "st,smi-fast-mode");
+
+		i++;
+	}
+
+	pdata->num_flashes = i;
+
+	return 0;
+}
+#else
+static int spear_smi_probe_config_dt(struct platform_device *pdev,
+				     struct device_node *np)
+{
+	return -ENOSYS;
+}
+#endif
+
+static int spear_smi_setup_banks(struct platform_device *pdev,
+				 u32 bank, struct device_node *np)
+{
+	struct spear_smi *dev = platform_get_drvdata(pdev);
+	struct spear_smi_flash_info *flash_info;
+	struct spear_smi_plat_data *pdata;
+	struct spear_snor_flash *flash;
+	struct mtd_partition *parts = NULL;
+	int count = 0;
+	int flash_index;
+	int ret = 0;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (bank > pdata->num_flashes - 1)
+		return -EINVAL;
+
+	flash_info = &pdata->board_flash_info[bank];
+	if (!flash_info)
+		return -ENODEV;
+
+	flash = devm_kzalloc(&pdev->dev, sizeof(*flash), GFP_ATOMIC);
+	if (!flash)
+		return -ENOMEM;
+	flash->bank = bank;
+	flash->fast_mode = flash_info->fast_mode ? 1 : 0;
+	mutex_init(&flash->lock);
+
+	/* verify whether nor flash is really present on board */
+	flash_index = spear_smi_probe_flash(dev, bank);
+	if (flash_index < 0) {
+		dev_info(&dev->pdev->dev, "smi-nor%d not found\n", bank);
+		return flash_index;
+	}
+	/* map the memory for nor flash chip */
+	flash->base_addr = devm_ioremap(&pdev->dev, flash_info->mem_base,
+					flash_info->size);
+	if (!flash->base_addr)
+		return -EIO;
+
+	dev->flash[bank] = flash;
+	flash->mtd.priv = dev;
+
+	if (flash_info->name)
+		flash->mtd.name = flash_info->name;
+	else
+		flash->mtd.name = flash_devices[flash_index].name;
+
+	flash->mtd.dev.parent = &pdev->dev;
+	mtd_set_of_node(&flash->mtd, np);
+	flash->mtd.type = MTD_NORFLASH;
+	flash->mtd.writesize = 1;
+	flash->mtd.flags = MTD_CAP_NORFLASH;
+	flash->mtd.size = flash_info->size;
+	flash->mtd.erasesize = flash_devices[flash_index].sectorsize;
+	flash->page_size = flash_devices[flash_index].pagesize;
+	flash->mtd.writebufsize = flash->page_size;
+	flash->erase_cmd = flash_devices[flash_index].erase_cmd;
+	flash->mtd._erase = spear_mtd_erase;
+	flash->mtd._read = spear_mtd_read;
+	flash->mtd._write = spear_mtd_write;
+	flash->dev_id = flash_devices[flash_index].device_id;
+
+	dev_info(&dev->pdev->dev, "mtd .name=%s .size=%llx(%lluM)\n",
+			flash->mtd.name, flash->mtd.size,
+			flash->mtd.size / (1024 * 1024));
+
+	dev_info(&dev->pdev->dev, ".erasesize = 0x%x(%uK)\n",
+			flash->mtd.erasesize, flash->mtd.erasesize / 1024);
+
+#ifndef CONFIG_OF
+	if (flash_info->partitions) {
+		parts = flash_info->partitions;
+		count = flash_info->nr_partitions;
+	}
+#endif
+
+	ret = mtd_device_register(&flash->mtd, parts, count);
+	if (ret) {
+		dev_err(&dev->pdev->dev, "Err MTD partition=%d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * spear_smi_probe - Entry routine
+ * @pdev: platform device structure
+ *
+ * This is the first routine which gets invoked during booting and does all
+ * initialization/allocation work. The routine looks for available memory banks,
+ * and do proper init for any found one.
+ * Returns 0 on success, non zero otherwise
+ */
+static int spear_smi_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct spear_smi_plat_data *pdata = NULL;
+	struct spear_smi *dev;
+	int irq, ret = 0;
+	int i;
+
+	if (np) {
+		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+		if (!pdata) {
+			ret = -ENOMEM;
+			goto err;
+		}
+		pdev->dev.platform_data = pdata;
+		ret = spear_smi_probe_config_dt(pdev, np);
+		if (ret) {
+			ret = -ENODEV;
+			dev_err(&pdev->dev, "no platform data\n");
+			goto err;
+		}
+	} else {
+		pdata = dev_get_platdata(&pdev->dev);
+		if (!pdata) {
+			ret = -ENODEV;
+			dev_err(&pdev->dev, "no platform data\n");
+			goto err;
+		}
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		ret = -ENODEV;
+		goto err;
+	}
+
+	dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	dev->io_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(dev->io_base)) {
+		ret = PTR_ERR(dev->io_base);
+		goto err;
+	}
+
+	dev->pdev = pdev;
+	dev->clk_rate = pdata->clk_rate;
+
+	if (dev->clk_rate > SMI_MAX_CLOCK_FREQ)
+		dev->clk_rate = SMI_MAX_CLOCK_FREQ;
+
+	dev->num_flashes = pdata->num_flashes;
+
+	if (dev->num_flashes > MAX_NUM_FLASH_CHIP) {
+		dev_err(&pdev->dev, "exceeding max number of flashes\n");
+		dev->num_flashes = MAX_NUM_FLASH_CHIP;
+	}
+
+	dev->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+	if (IS_ERR(dev->clk)) {
+		ret = PTR_ERR(dev->clk);
+		goto err;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq, spear_smi_int_handler, 0,
+			       pdev->name, dev);
+	if (ret) {
+		dev_err(&dev->pdev->dev, "SMI IRQ allocation failed\n");
+		goto err;
+	}
+
+	mutex_init(&dev->lock);
+	init_waitqueue_head(&dev->cmd_complete);
+	spear_smi_hw_init(dev);
+	platform_set_drvdata(pdev, dev);
+
+	/* loop for each serial nor-flash which is connected to smi */
+	for (i = 0; i < dev->num_flashes; i++) {
+		ret = spear_smi_setup_banks(pdev, i, pdata->np[i]);
+		if (ret) {
+			dev_err(&dev->pdev->dev, "bank setup failed\n");
+			goto err;
+		}
+	}
+
+	return 0;
+err:
+	return ret;
+}
+
+/**
+ * spear_smi_remove - Exit routine
+ * @pdev: platform device structure
+ *
+ * free all allocations and delete the partitions.
+ */
+static int spear_smi_remove(struct platform_device *pdev)
+{
+	struct spear_smi *dev;
+	struct spear_snor_flash *flash;
+	int i;
+
+	dev = platform_get_drvdata(pdev);
+
+	/* clean up for all nor flash */
+	for (i = 0; i < dev->num_flashes; i++) {
+		flash = dev->flash[i];
+		if (!flash)
+			continue;
+
+		/* clean up mtd stuff */
+		WARN_ON(mtd_device_unregister(&flash->mtd));
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int spear_smi_suspend(struct device *dev)
+{
+	struct spear_smi *sdev = dev_get_drvdata(dev);
+
+	if (sdev && sdev->clk)
+		clk_disable_unprepare(sdev->clk);
+
+	return 0;
+}
+
+static int spear_smi_resume(struct device *dev)
+{
+	struct spear_smi *sdev = dev_get_drvdata(dev);
+	int ret = -EPERM;
+
+	if (sdev && sdev->clk)
+		ret = clk_prepare_enable(sdev->clk);
+
+	if (!ret)
+		spear_smi_hw_init(sdev);
+	return ret;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(spear_smi_pm_ops, spear_smi_suspend, spear_smi_resume);
+
+#ifdef CONFIG_OF
+static const struct of_device_id spear_smi_id_table[] = {
+	{ .compatible = "st,spear600-smi" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, spear_smi_id_table);
+#endif
+
+static struct platform_driver spear_smi_driver = {
+	.driver = {
+		.name = "smi",
+		.bus = &platform_bus_type,
+		.of_match_table = of_match_ptr(spear_smi_id_table),
+		.pm = &spear_smi_pm_ops,
+	},
+	.probe = spear_smi_probe,
+	.remove = spear_smi_remove,
+};
+module_platform_driver(spear_smi_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ashish Priyadarshi, Shiraz Hashim <shiraz.linux.kernel@gmail.com>");
+MODULE_DESCRIPTION("MTD SMI driver for serial nor flash chips");