path: root/drivers/mtd/devices/m25p80.c

/*
 * MTD SPI driver for ST M25Pxx (and similar) serial flash chips
 *
 * Author: Mike Lavender, mike@steroidmicros.com
 *
 * Copyright (c) 2005, Intec Automation Inc.
 *
 * Some parts are based on lart.c by Abraham Van Der Merwe
 *
 * Cleaned up and generalized based on mtd_dataflash.c
 *
 * This code is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/init.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/math64.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/mod_devicetable.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>

#include <linux/spi/spi.h>
#include <linux/spi/flash.h>

/* Flash opcodes. */
#define	OPCODE_WREN		0x06	/* Write enable */
#define	OPCODE_RDSR		0x05	/* Read status register */
#define	OPCODE_WRSR		0x01	/* Write status register 1 byte */
#define	OPCODE_NORM_READ	0x03	/* Read data bytes (low frequency) */
#define	OPCODE_FAST_READ	0x0b	/* Read data bytes (high frequency) */
#define	OPCODE_PP		0x02	/* Page program (up to 256 bytes) */
#define	OPCODE_BE_4K		0x20	/* Erase 4KiB block */
#define	OPCODE_BE_32K		0x52	/* Erase 32KiB block */
#define	OPCODE_CHIP_ERASE	0xc7	/* Erase whole flash chip */
#define	OPCODE_SE		0xd8	/* Sector erase (usually 64KiB) */
#define	OPCODE_RDID		0x9f	/* Read JEDEC ID */

/* Used for SST flashes only. */
#define	OPCODE_BP		0x02	/* Byte program */
#define	OPCODE_WRDI		0x04	/* Write disable */
#define	OPCODE_AAI_WP		0xad	/* Auto address increment word program */

/* Used for Macronix flashes only. */
#define	OPCODE_EN4B		0xb7	/* Enter 4-byte mode */
#define	OPCODE_EX4B		0xe9	/* Exit 4-byte mode */

/* Status Register bits. */
#define	SR_WIP			1	/* Write in progress */
#define	SR_WEL			2	/* Write enable latch */
/* meaning of other SR_* bits may differ between vendors */
#define	SR_BP0			4	/* Block protect 0 */
#define	SR_BP1			8	/* Block protect 1 */
#define	SR_BP2			0x10	/* Block protect 2 */
#define	SR_SRWD			0x80	/* SR write protect */

/* Define max times to check status register before we give up. */
#define	MAX_READY_WAIT_JIFFIES	(40 * HZ)	/* M25P16 specs 40s max chip erase */
#define	MAX_CMD_SIZE		5

#ifdef CONFIG_M25PXX_USE_FAST_READ
#define OPCODE_READ 	OPCODE_FAST_READ
#define FAST_READ_DUMMY_BYTE 1
#else
#define OPCODE_READ 	OPCODE_NORM_READ
#define FAST_READ_DUMMY_BYTE 0
#endif

/****************************************************************************/

struct m25p {
	struct spi_device	*spi;
	struct mutex		lock;
	struct mtd_info		mtd;
	unsigned		partitioned:1;
	u16			page_size;
	u16			addr_width;
	u8			erase_opcode;
	u8			*command;
};

static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
{
	return container_of(mtd, struct m25p, mtd);
}

/****************************************************************************/

/*
 * Internal helper functions
 */

/*
 * Read the status register, returning its value in the location
 * Return the status register value.
 * Returns negative if error occurred.
 */
static int read_sr(struct m25p *flash)
{
	ssize_t retval;
	u8 code = OPCODE_RDSR;
	u8 val;

	retval = spi_write_then_read(flash->spi, &code, 1, &val, 1);

	if (retval < 0) {
		dev_err(&flash->spi->dev, "error %d reading SR\n",
				(int) retval);
		return retval;
	}

	return val;
}

/*
 * Write status register 1 byte
 * Returns negative if error occurred.
 */
static int write_sr(struct m25p *flash, u8 val)
{
	flash->command[0] = OPCODE_WRSR;
	flash->command[1] = val;

	return spi_write(flash->spi, flash->command, 2);
}

/*
 * Set write enable latch with Write Enable command.
 * Returns negative if error occurred.
 */
static inline int write_enable(struct m25p *flash)
{
	u8	code = OPCODE_WREN;

	return spi_write_then_read(flash->spi, &code, 1, NULL, 0);
}

/*
 * Send write disble instruction to the chip.
 */
static inline int write_disable(struct m25p *flash)
{
	u8	code = OPCODE_WRDI;

	return spi_write_then_read(flash->spi, &code, 1, NULL, 0);
}

/*
 * Enable/disable 4-byte addressing mode.
 */
static inline int set_4byte(struct m25p *flash, int enable)
{
	u8	code = enable ? OPCODE_EN4B : OPCODE_EX4B;

	return spi_write_then_read(flash->spi, &code, 1, NULL, 0);
}

/*
 * Service routine to read status register until ready, or timeout occurs.
 * Returns non-zero if error.
 */
static int wait_till_ready(struct m25p *flash)
{
	unsigned long deadline;
	int sr;

	deadline = jiffies + MAX_READY_WAIT_JIFFIES;

	do {
		if ((sr = read_sr(flash)) < 0)
			break;
		else if (!(sr & SR_WIP))
			return 0;

		cond_resched();

	} while (!time_after_eq(jiffies, deadline));

	return 1;
}

/*
 * Erase the whole flash memory
 *
 * Returns 0 if successful, non-zero otherwise.
 */
static int erase_chip(struct m25p *flash)
{
	DEBUG(MTD_DEBUG_LEVEL3, "%s: %s %lldKiB\n",
	      dev_name(&flash->spi->dev),<