[PATCH 24/74] ST SPEAr: Add smi driver for serial NOR flash

[Viresh KUMAR <viresh.kumar@st.com>]

From: Shiraz Hashim <shiraz.hashim@st.com>

SPEAr platforms(spear3xx/spear6xx/spear13xx) provide SMI(Serial Memory
Interface) controller to access serial NOR flash. SMI provides a simple
interface for SPI/serial NOR flashes and has certain inbuilt commands
and features to support these flashes easily. It also makes it possible
to map an address range in order to directly access (read/write) the SNOR
over address bus. This patch intends to provide serial nor driver support
for spear platforms which are accessed through SMI.

Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
---
 arch/arm/plat-spear/include/plat/smi.h |   68 ++
 drivers/mtd/devices/Kconfig            |    7 +
 drivers/mtd/devices/Makefile           |    1 +
 drivers/mtd/devices/spear_smi.c        | 1122 ++++++++++++++++++++++++++++++++
 4 files changed, 1198 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/plat-spear/include/plat/smi.h
 create mode 100644 drivers/mtd/devices/spear_smi.c

diff --git a/arch/arm/plat-spear/include/plat/smi.h b/arch/arm/plat-spear/include/plat/smi.h
new file mode 100644
index 0000000..4c74df7
--- /dev/null
+++ b/arch/arm/plat-spear/include/plat/smi.h
@@ -0,0 +1,68 @@
+/*
+ * arch/arm/plat-spear/include/plat/smi.h
+ *
+ * Copyright (C) 2010 ST Microelectronics
+ * Shiraz Hashim <shiraz.hashim@st.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.
+ */
+
+#ifndef __PLAT_SMI_H
+#define __PLAT_SMI_H
+
+#include <linux/types.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/platform_device.h>
+
+/* macro to define partitions for flash devices */
+#define DEFINE_PARTS(n, of, s)		\
+{					\
+	.name = n,			\
+	.offset = of,			\
+	.size = s,			\
+}
+
+/**
+ * struct spear_smi_flash_info - platform structure for passing flash
+ * information
+ *
+ * name: name of the serial nor flash for identification
+ * mem_base: the memory base on which the flash is mapped
+ * size: size of the flash in bytes
+ * num_parts: number of partitions
+ * parts: parition details
+ * fast_mode: whether flash supports fast mode
+ */
+
+struct spear_smi_flash_info {
+	char *name;
+	unsigned long mem_base;
+	unsigned long size;
+	int num_parts;
+	struct mtd_partition *parts;
+	u8 fast_mode;
+};
+
+/**
+ * struct spear_smi_plat_data - platform structure for configuring smi
+ *
+ * clk_rate: clk rate at which SMI must operate
+ * num_flashes: number of flashes present on board
+ * board_flash_info: specific details of each flash present on board
+ */
+struct spear_smi_plat_data {
+	unsigned long clk_rate;
+	int num_flashes;
+	struct spear_smi_flash_info *board_flash_info;
+};
+
+static inline void smi_set_plat_data(struct platform_device *pdev,
+		struct spear_smi_plat_data *pdata)
+{
+	pdev->dev.platform_data = pdata;
+}
+
+#endif /* __PLAT_SMI_H */
diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 35081ce..83daf23 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/drivers/mtd/devices/Kconfig
@@ -102,6 +102,13 @@ config M25PXX_USE_FAST_READ
 	help
 	  This option enables FAST_READ access supported by ST M25Pxx.
 
+config MTD_SPEAR_SMI
+	tristate "SPEAR MTD NOR Support through SMI controller"
+	depends on PLAT_SPEAR
+	default y
+	help
+	  This enable SNOR support on SPEAR platforms using SMI controller
+
 config MTD_SST25L
 	tristate "Support SST25L (non JEDEC) SPI Flash chips"
 	depends on SPI_MASTER
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
index f3226b1..6e9063b 100644
--- a/drivers/mtd/devices/Makefile
+++ b/drivers/mtd/devices/Makefile
@@ -16,4 +16,5 @@ obj-$(CONFIG_MTD_LART)		+= lart.o
 obj-$(CONFIG_MTD_BLOCK2MTD)	+= block2mtd.o
 obj-$(CONFIG_MTD_DATAFLASH)	+= mtd_dataflash.o
 obj-$(CONFIG_MTD_M25P80)	+= m25p80.o
+obj-$(CONFIG_MTD_SPEAR_SMI)	+= spear_smi.o
 obj-$(CONFIG_MTD_SST25L)	+= sst25l.o
diff --git a/drivers/mtd/devices/spear_smi.c b/drivers/mtd/devices/spear_smi.c
new file mode 100644
index 0000000..6dd7de1
--- /dev/null
+++ b/drivers/mtd/devices/spear_smi.c
@@ -0,0 +1,1122 @@
+/*
+ * linux/drivers/mtd/devices/spear_smi.c
+ *
+ * SMI (Serial Memory Controller) device driver for Serial NOR Flash on
+ * SPEAr platform
+ * The serial nor interface is largely based on drivers/mtd/m25p80.c,
+ * however the SPI interface has been replaced by SMI.
+ *
+ * Copyright (C) 2010 STMicroelectronics.
+ * Ashish Priyadarshi
+ * Shiraz Hashim <shiraz.hashim@st.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/param.h>
+#include <linux/platform_device.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <plat/smi.h>
+
+/* max possible slots for serial-nor flash chip in the SMI controller */
+#define MAX_NUM_FLASH_CHIP	4
+
+/* 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),
+};
+
+/* These partitions would be used if platform doesn't pass one */
+static struct mtd_partition part_info_8M[] = {
+	DEFINE_PARTS("Xloader", 0x00, 0x10000),
+	DEFINE_PARTS("UBoot", 0x10000, 0x40000),
+	DEFINE_PARTS("Kernel", 0x50000, 0x2C0000),
+	DEFINE_PARTS("Root File System", 0x310000, 0x4F0000),
+};
+
+static struct mtd_partition part_info_16M[] = {
+	DEFINE_PARTS("Xloader", 0x00, 0x40000),
+	DEFINE_PARTS("UBoot", 0x40000, 0x100000),
+	DEFINE_PARTS("Kernel", 0x140000, 0x300000),
+	DEFINE_PARTS("Root File System", 0x440000, 0xBC0000),
+};
+
+/* 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
+		ret = -EIO;
+
+	/* 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)
+			continue; /* try till timeout */
+		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 status;
+}
+
+/**
+ * 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);
+	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 {
+		/* 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
+		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;
+
+	/* do not allow erase past end of device */
+	if (e_info->addr + e_info->len > flash->mtd.size)
+		return -EINVAL;
+
+	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) {
+			e_info->state = MTD_ERASE_FAILED;
+			mutex_unlock(&flash->lock);
+			return ret;
+		}
+		addr += mtd->erasesize;
+		len -= mtd->erasesize;
+	}
+
+	mutex_unlock(&flash->lock);
+	e_info->state = MTD_ERASE_DONE;
+	mtd_erase_callback(e_info);
+
+	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 *src;
+	u32 ctrlreg1, val;
+	int ret;
+
+	if (!len)
+		return 0;
+
+	if (!flash || !dev)
+		return -ENODEV;
+
+	/* do not allow reads past end of device */
+	if (from + len > flash->mtd.size)
+		return -EINVAL;
+
+	if (flash->bank > dev->num_flashes - 1) {
+		dev_err(&dev->pdev->dev, "Invalid Bank Num");
+		return -EINVAL;
+	}
+
+	if (!retlen)
+		return -EINVAL;
+	else
+		*retlen = 0;
+
+	/* 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, (u8 *)src, len);
+
+	/* restore ctrl reg1 */
+	writel(ctrlreg1, dev->io_base + SMI_CR1);
+	mutex_unlock(&dev->lock);
+
+	*retlen = len;
+	mutex_unlock(&flash->lock);
+
+	return 0;
+}
+
+static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank,
+		void *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);
+
+	memcpy_toio(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 *dest;
+	u32 page_offset, page_size;
+	int ret;
+
+	if (!flash || !dev)
+		return -ENODEV;
+
+	if (!len)
+		return 0;
+
+	/* do not allow write past end of page */
+	if (to + len > flash->mtd.size)
+		return -EINVAL;
+
+	if (flash->bank > dev->num_flashes - 1) {
+		dev_err(&dev->pdev->dev, "Invalid Bank Num");
+		return -EINVAL;
+	}
+
+	if (!retlen)
+		return -EINVAL;
+	else
+		*retlen = 0;
+
+	/* 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;
+}
+
+static int spear_smi_setup_banks(struct platform_device *pdev, u32 bank)
+{
+	const char *part_probes[] = {"cmdlinepart", NULL};
+	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;
+	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 = kzalloc(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);
+		kfree(flash);
+		return flash_index;
+	}
+	/* map the memory for nor flash chip */
+	flash->base_addr = ioremap(flash_info->mem_base, flash_info->size);
+	if (!flash->base_addr) {
+		kfree(flash);
+		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.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->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);
+
+	if (!mtd_has_partitions()) {
+		ret = add_mtd_device(&flash->mtd);
+		return ret;
+	}
+
+	flash->num_parts = 0;
+	if (mtd_has_cmdlinepart()) {
+		flash->num_parts = parse_mtd_partitions(&flash->mtd,
+				part_probes, &flash->parts, 0);
+	}
+
+	if (flash->num_parts <= 0) {
+		if (flash_info->parts) {
+			flash->parts = flash_info->parts;
+			flash->num_parts = flash_info->num_parts;
+		} else {
+			/* choose from default ones */
+			switch (flash->mtd.size) {
+			case 0x800000:/* 8MB */
+				flash->parts = part_info_8M;
+				flash->num_parts =
+					ARRAY_SIZE(part_info_8M);
+				break;
+			case 0x1000000:/* 16MB */
+				flash->parts = part_info_16M;
+				flash->num_parts =
+					ARRAY_SIZE(part_info_16M);
+				break;
+			default:
+				dev_err(&pdev->dev, "undefined partition\n");
+			}
+		}
+	}
+
+	/* Register the partitions */
+	ret = add_mtd_partitions(&flash->mtd, flash->parts, flash->num_parts);
+	if (ret)
+		dev_err(&dev->pdev->dev, "Err MTD partition=%d\n", ret);
+
+	return ret;
+}
+
+/**
+ * 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 __devinit spear_smi_probe(struct platform_device *pdev)
+{
+	struct spear_smi_plat_data *pdata;
+	struct spear_smi *dev;
+	struct resource *smi_base;
+	int irq, ret = 0;
+	int i;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (pdata < 0) {
+		ret = -ENODEV;
+		dev_err(&pdev->dev, "no platform data\n");
+		goto err;
+	}
+
+	smi_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!smi_base) {
+		ret = -ENODEV;
+		dev_err(&pdev->dev, "invalid smi base address\n");
+		goto err;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		ret = -ENODEV;
+		dev_err(&pdev->dev, "invalid smi irq\n");
+		goto err;
+	}
+
+	dev = kzalloc(sizeof(*dev), GFP_ATOMIC);
+	if (!dev) {
+		ret = -ENOMEM;
+		dev_err(&pdev->dev, "mem alloc fail\n");
+		goto err;
+	}
+
+	smi_base = request_mem_region(smi_base->start, resource_size(smi_base),
+			pdev->name);
+	if (!smi_base) {
+		ret = -EBUSY;
+		dev_err(&pdev->dev, "request mem region fail\n");
+		goto err_mem;
+	}
+
+	dev->io_base = ioremap(smi_base->start, resource_size(smi_base));
+	if (!dev->io_base) {
+		ret = -EIO;
+		dev_err(&pdev->dev, "ioremap fail\n");
+		goto err_ioremap;
+	}
+
+	dev->pdev = pdev;
+	dev->clk_rate = pdata->clk_rate;
+
+	if (dev->clk_rate < 0 || 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 = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dev->clk)) {
+		ret = PTR_ERR(dev->clk);
+		goto err_clk;
+	}
+
+	ret = clk_enable(dev->clk);
+	if (ret)
+		goto err_clk_enable;
+
+	ret = request_irq(irq, spear_smi_int_handler, 0, pdev->name, dev);
+	if (ret) {
+		dev_err(&dev->pdev->dev, "SMI IRQ allocation failed\n");
+		goto err_irq;
+	}
+
+	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);
+		if (ret) {
+			dev_err(&dev->pdev->dev, "bank setup failed\n");
+			goto err_bank_setup;
+		}
+	}
+
+	return 0;
+
+err_bank_setup:
+	free_irq(irq, dev);
+	platform_set_drvdata(pdev, NULL);
+err_irq:
+	clk_disable(dev->clk);
+err_clk_enable:
+	clk_put(dev->clk);
+err_clk:
+	iounmap(dev->io_base);
+err_ioremap:
+	release_mem_region(smi_base->start, resource_size(smi_base));
+err_mem:
+	kfree(dev);
+err:
+	return ret;
+}
+
+/**
+ * spear_smi_remove - Exit routine
+ * @pdev: platform device structure
+ *
+ * free all allocations and delete the partitions.
+ */
+static int __devexit spear_smi_remove(struct platform_device *pdev)
+{
+	struct spear_smi *dev;
+	struct spear_snor_flash *flash;
+	int ret;
+	int i, irq;
+
+	dev = platform_get_drvdata(pdev);
+	if (!dev) {
+		dev_err(&pdev->dev, "dev is null\n");
+		return -ENODEV;
+	}
+
+	/* 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 */
+		if (mtd_has_partitions())
+			ret = del_mtd_partitions(&flash->mtd);
+		else
+			ret = del_mtd_device(&flash->mtd);
+
+		if (ret)
+			dev_err(&pdev->dev, "error removing mtd\n");
+
+		iounmap(flash->base_addr);
+		kfree(flash);
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	free_irq(irq, dev);
+
+	clk_disable(dev->clk);
+	clk_put(dev->clk);
+	iounmap(dev->io_base);
+	kfree(dev);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+int spear_smi_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct spear_smi *dev = platform_get_drvdata(pdev);
+
+	if (dev && dev->clk)
+		clk_disable(dev->clk);
+
+	return 0;
+}
+
+int spear_smi_resume(struct platform_device *pdev)
+{
+	struct spear_smi *dev = platform_get_drvdata(pdev);
+	int ret = -EPERM;
+
+	if (dev && dev->clk)
+		ret = clk_enable(dev->clk);
+
+	return ret;
+}
+
+static struct platform_driver spear_smi_driver = {
+	.driver = {
+		.name = "smi",
+		.bus = &platform_bus_type,
+		.owner = THIS_MODULE,
+	},
+	.probe = spear_smi_probe,
+	.remove = __devexit_p(spear_smi_remove),
+	.suspend = spear_smi_suspend,
+	.resume = spear_smi_resume,
+};
+
+static int spear_smi_init(void)
+{
+	return platform_driver_register(&spear_smi_driver);
+}
+module_init(spear_smi_init);
+
+static void spear_smi_exit(void)
+{
+	platform_driver_unregister(&spear_smi_driver);
+}
+module_exit(spear_smi_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ashish Priyadarshi, Shiraz Hashim <shiraz.hashim@st.com>");
+MODULE_DESCRIPTION("MTD SMI driver for serial nor flash chips");
-- 
1.7.2.2