toto.c

linux下的MTD设备驱动源代码,配合jffs2 yaffss2文件系统.

/*
 *  drivers/mtd/nand/toto.c
 *
 *  Copyright (c) 2003 Texas Instruments
 *
 *  Derived from drivers/mtd/autcpu12.c
 *
 *  Copyright (c) 2002 Thomas Gleixner <[e-mail]>
 *
 * This program 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.
 *
 *  Overview:
 *   This is a device driver for the NAND flash device found on the
 *   TI fido board. It supports 32MiB and 64MiB cards
 *
 * $Id: toto.c,v 1.2 2003/10/21 10:04:58 dwmw2 Exp $
 */

#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>
#include <asm/sizes.h>
#include <asm/arch/toto.h>
#include <asm/arch-omap1510/hardware.h>
#include <asm/arch/gpio.h>

/*
 * MTD structure for TOTO board
 */
static struct mtd_info *toto_mtd = NULL;

static int toto_io_base = OMAP_FLASH_1_BASE;

#define CONFIG_NAND_WORKAROUND 1

#define NAND_NCE 0x4000
#define NAND_CLE 0x1000
#define NAND_ALE 0x0002
#define NAND_MASK (NAND_CLE | NAND_ALE | NAND_NCE)

#define T_NAND_CTL_CLRALE(iob)  gpiosetout(NAND_ALE, 0)
#define T_NAND_CTL_SETALE(iob)  gpiosetout(NAND_ALE, NAND_ALE)
#ifdef CONFIG_NAND_WORKAROUND     /* "some" dev boards busted, blue wired to rts2 :( */
#define T_NAND_CTL_CLRCLE(iob)  gpiosetout(NAND_CLE, 0); rts2setout(2, 2)
#define T_NAND_CTL_SETCLE(iob)  gpiosetout(NAND_CLE, NAND_CLE); rts2setout(2, 0)
#else
#define T_NAND_CTL_CLRCLE(iob)  gpiosetout(NAND_CLE, 0)
#define T_NAND_CTL_SETCLE(iob)  gpiosetout(NAND_CLE, NAND_CLE)
#endif
#define T_NAND_CTL_SETNCE(iob)  gpiosetout(NAND_NCE, 0)
#define T_NAND_CTL_CLRNCE(iob)  gpiosetout(NAND_NCE, NAND_NCE)
                
/*
 * Define partitions for flash devices
 */

static struct mtd_partition partition_info64M[] = {
	{ .name =	"toto kernel partition 1",
	  .offset =	0,
	  .size	=	2 * SZ_1M },
	{ .name =	"toto file sys partition 2",
	  .offset =	2 * SZ_1M,
	  .size =	14 * SZ_1M },
	{ .name =	"toto user partition 3",
	  .offset =	16 * SZ_1M,
	  .size =	16 * SZ_1M },
	{ .name =	"toto devboard extra partition 4",
	  .offset =	32 * SZ_1M,
	  .size =	32 * SZ_1M },
};

static struct mtd_partition partition_info32M[] = {
	{ .name =	"toto kernel partition 1",
	  .offset =	0,
	  .size =	2 * SZ_1M },
	{ .name =	"toto file sys partition 2",
	  .offset =	2 * SZ_1M,
	  .size =	14 * SZ_1M },
	{ .name =	"toto user partition 3",
	  .offset =	16 * SZ_1M,
	  .size =	16 * SZ_1M },
};

#define NUM_PARTITIONS32M 3
#define NUM_PARTITIONS64M 4
/* 
 *	hardware specific access to control-lines
*/

static void toto_hwcontrol(struct mtd_info *mtd, int cmd)
{

	udelay(1); /* hopefully enough time for tc make proceding write to clear */
	switch(cmd){

		case NAND_CTL_SETCLE: T_NAND_CTL_SETCLE(cmd); break;
		case NAND_CTL_CLRCLE: T_NAND_CTL_CLRCLE(cmd); break;

		case NAND_CTL_SETALE: T_NAND_CTL_SETALE(cmd); break;
		case NAND_CTL_CLRALE: T_NAND_CTL_CLRALE(cmd); break;

		case NAND_CTL_SETNCE: T_NAND_CTL_SETNCE(cmd); break;
		case NAND_CTL_CLRNCE: T_NAND_CTL_CLRNCE(cmd); break;
	}
	udelay(1); /* allow time to ensure gpio state to over take memory write */
}

/*
 * Main initialization routine
 */
int __init toto_init (void)
{
	struct nand_chip *this;
	int err = 0;

	/* Allocate memory for MTD device structure and private data */
	toto_mtd = kmalloc (sizeof(struct mtd_info) + sizeof (struct nand_chip),
				GFP_KERNEL);
	if (!toto_mtd) {
		printk (KERN_WARNING "Unable to allocate toto NAND MTD device structure.\n");
		err = -ENOMEM;
		goto out;
	}

	/* Get pointer to private data */
	this = (struct nand_chip *) (&toto_mtd[1]);

	/* Initialize structures */
	memset((char *) toto_mtd, 0, sizeof(struct mtd_info));
	memset((char *) this, 0, sizeof(struct nand_chip));

	/* Link the private data with the MTD structure */
	toto_mtd->priv = this;

	/* Set address of NAND IO lines */
	this->IO_ADDR_R = toto_io_base;
	this->IO_ADDR_W = toto_io_base;
	this->hwcontrol = toto_hwcontrol;
	this->dev_ready = NULL;
	/* 25 us command delay time */
	this->chip_delay = 30;		
	this->eccmode = NAND_ECC_SOFT;

        /* Scan to find existance of the device */
	if (nand_scan (toto_mtd, 1)) {
		err = -ENXIO;
		goto out_mtd;
	}

	/* Allocate memory for internal data buffer */
	this->data_buf = kmalloc (sizeof(u_char) * (toto_mtd->oobblock + toto_mtd->oobsize), GFP_KERNEL);
	if (!this->data_buf) {
		printk (KERN_WARNING "Unable to allocate NAND data buffer for toto.\n");
		err = -ENOMEM;
		goto out_mtd;
	}

	/* Register the partitions */
	switch(toto_mtd->size){
		case SZ_64M: add_mtd_partitions(toto_mtd, partition_info64M, NUM_PARTITIONS64M); break; 
		case SZ_32M: add_mtd_partitions(toto_mtd, partition_info32M, NUM_PARTITIONS32M); break; 
		default: {
			printk (KERN_WARNING "Unsupported Nand device\n"); 
			err = -ENXIO;
			goto out_buf;
		}
	}

    	gpioreserve(NAND_MASK);  /* claim our gpios */
    	archflashwp(0,0);	 /* open up flash for writing */

	goto out;
    
out_buf:
	kfree (this->data_buf);    
out_mtd:
	kfree (toto_mtd);
out:
	return err;
}

module_init(toto_init);

/*
 * Clean up routine
 */
static void __exit toto_cleanup (void)
{
	struct nand_chip *this = (struct nand_chip *) &toto_mtd[1];

	/* Unregister partitions */
	del_mtd_partitions(toto_mtd);
	
	/* Unregister the device */
	del_mtd_device (toto_mtd);

	/* Free internal data buffers */
	kfree (this->data_buf);

	/* Free the MTD device structure */
	kfree (toto_mtd);

	/* stop flash writes */
	 archflashwp(0,1);
	
	/* release gpios to system */
	 gpiorelease(NAND_MASK);
}
module_exit(toto_cleanup);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Richard Woodruff <[e-mail]>");
MODULE_DESCRIPTION("Glue layer for NAND flash on toto board");