nand.c

linux嵌入式课程实践中的一个关于声卡驱动程序 。

/*
 *  drivers/mtd/nand.c
 *
 *  Copyright (C) 2000 Steven J. Hill ([e-mail])
 *
 *  10-29-2001  Thomas Gleixner ([e-mail])
 * 		- Changed nand_chip structure for controlline function to
 *		support different hardware structures (Access to
 *		controllines ALE,CLE,NCE via hardware specific function. 
 *		- exit out of "failed erase block" changed, to avoid
 *		driver hangup
 *		- init_waitqueue_head added in function nand_scan !!
 *
 *  01-30-2002  Thomas Gleixner ([e-mail])
 *		change in nand_writev to block invalid vecs entries
 *
 *  02-11-2002  Thomas Gleixner ([e-mail])
 *		- major rewrite to avoid duplicated code
 *		  common nand_write_page function  
 *		  common get_chip function 
 *		- added oob_config structure for out of band layouts
 *		- write_oob changed for partial programming
 *		- read cache for faster access for subsequent reads
 *		from the same page.
 *		- support for different read/write address
 *		- support for device ready/busy line
 *		- read oob for more than one page enabled
 *
 *  02-27-2002	Thomas Gleixner ([e-mail])
 *		- command-delay can be programmed
 *		- fixed exit from erase with callback-function enabled
 *
 *  03-21-2002  Thomas Gleixner ([e-mail])
 *		- DEBUG improvements provided by Elizabeth Clarke 
 *		([e-mail])
 *		- added zero check for this->chip_delay
 *
 *  04-03-2002  Thomas Gleixner ([e-mail])
 *		- added added hw-driver supplied command and wait functions
 *		- changed blocking for erase (erase suspend enabled)
 *		- check pointers before accessing flash provided by
 *		John Hall ([e-mail])
 *
 *  04-09-2002  Thomas Gleixner ([e-mail])
 *		- nand_wait repaired
 *
 *  04-28-2002  Thomas Gleixner ([e-mail])	
 *		- OOB config defines moved to nand.h 
 *
 * $Id: nand.c,v 1.24 2002/04/28 13:39:48 gleixner Exp $
 *
 * 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 the generic MTD driver for NAND flash devices. It should be
 *   capable of working with almost all NAND chips currently available.
 */

#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/nand_ids.h>
#include <linux/interrupt.h>
#include <asm/io.h>

#ifdef CONFIG_MTD_NAND_ECC
#include <linux/mtd/nand_ecc.h>
#endif

/*
 * Macros for low-level register control
 */
#define nand_select()	this->hwcontrol(NAND_CTL_SETNCE); \
			this->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);

#define nand_deselect() this->hwcontrol(NAND_CTL_CLRNCE);

/*
 * Definition of the out of band configuration structure
 */
struct nand_oob_config {
	int ecc_pos[6];		/* position of ECC bytes inside oob */
	int badblock_pos;	/* position of bad block flag inside oob -1 = inactive */
	int eccvalid_pos;	/* position of ECC valid flag inside oob -1 = inactive */
};


static struct nand_oob_config oob_config;
/*
 * NAND low-level MTD interface functions
 */
static int nand_read (struct mtd_info *mtd, loff_t from, size_t len, size_t * retlen, u_char * buf);
static int nand_read_ecc (struct mtd_info *mtd, loff_t from, size_t len,
			  size_t * retlen, u_char * buf, u_char * ecc_code);
static int nand_read_oob (struct mtd_info *mtd, loff_t from, size_t len, size_t * retlen, u_char * buf);
static int nand_write (struct mtd_info *mtd, loff_t to, size_t len, size_t * retlen, const u_char * buf);
static int nand_write_ecc (struct mtd_info *mtd, loff_t to, size_t len,
			   size_t * retlen, const u_char * buf, u_char * ecc_code);
static int nand_write_oob (struct mtd_info *mtd, loff_t to, size_t len, size_t * retlen, const u_char * buf);
static int nand_writev (struct mtd_info *mtd, const struct iovec *vecs,
			unsigned long count, loff_t to, size_t * retlen);
static int nand_erase (struct mtd_info *mtd, struct erase_info *instr);
static void nand_sync (struct mtd_info *mtd);
static int nand_write_page (struct mtd_info *mtd, struct nand_chip *this,
			    int page, int col, int last, u_char * ecc_code);

/*
 * Send command to NAND device
 */
static void nand_command (struct mtd_info *mtd, unsigned command, int column, int page_addr)
{
	register struct nand_chip *this = mtd->priv;
	register unsigned long NAND_IO_ADDR = this->IO_ADDR_W;

	/* Begin command latch cycle */
	this->hwcontrol (NAND_CTL_SETCLE);

	/*
	 * Write out the command to the device.
	 */
	if (command != NAND_CMD_SEQIN)
		writeb (command, NAND_IO_ADDR);
	else {
		if (mtd->oobblock == 256 && column >= 256) {
			column -= 256;
			writeb (NAND_CMD_RESET, NAND_IO_ADDR);
			writeb (NAND_CMD_READOOB, NAND_IO_ADDR);
			writeb (NAND_CMD_SEQIN, NAND_IO_ADDR);
		} else if (mtd->oobblock == 512 && column >= 256) {
			if (column < 512) {
				column -= 256;
				writeb (NAND_CMD_READ1, NAND_IO_ADDR);
				writeb (NAND_CMD_SEQIN, NAND_IO_ADDR);
			} else {
				column -= 512;
				writeb (NAND_CMD_READOOB, NAND_IO_ADDR);
				writeb (NAND_CMD_SEQIN, NAND_IO_ADDR);
			}
		} else {
			writeb (NAND_CMD_READ0, NAND_IO_ADDR);
			writeb (NAND_CMD_SEQIN, NAND_IO_ADDR);
		}
	}

	/* Set ALE and clear CLE to start address cycle */
	this->hwcontrol (NAND_CTL_CLRCLE);

	if (column != -1 || page_addr != -1)
		this->hwcontrol (NAND_CTL_SETALE);

	/* Serially input address */
	if (column != -1)
		writeb (column, NAND_IO_ADDR);
	if (page_addr != -1) {
		writeb ((unsigned char) (page_addr & 0xff), NAND_IO_ADDR);
		writeb ((unsigned char) ((page_addr >> 8) & 0xff), NAND_IO_ADDR);
		/* One more address cycle for higher density devices */
		if (mtd->size & 0x0c000000) {
			writeb ((unsigned char) ((page_addr >> 16) & 0x0f), NAND_IO_ADDR);
		}
	}
	/* Latch in address */
	if (column != -1 || page_addr != -1)
		this->hwcontrol (NAND_CTL_CLRALE);

	/* 
	 * If we don't have access to the busy pin, we apply the given
	 * command delay
	*/
	if (!this->dev_ready) {
		udelay (this->chip_delay);
		return;
	}
	
	/* program and erase have their own busy handlers */
	switch (command) {
	case NAND_CMD_PAGEPROG:
	case NAND_CMD_ERASE1:
	case NAND_CMD_ERASE2:
		udelay (this->chip_delay);
		return;
	}
	/* wait until command is processed */
	while (!this->dev_ready());	
}

/*
 *	Get chip for selected access
 */
static inline void nand_get_chip (struct nand_chip *this, int new_state, int *erase_state)
{

	DECLARE_WAITQUEUE (wait, current);

	/* 
	 * Grab the lock and see if the device is available 
	 * For erasing, we keep the spinlock until the
	 * erase command is written. 
	*/
	
retry:
	spin_lock_bh (&this->chip_lock);

	if (this->state == FL_READY) {
		this->state = new_state;
		if (new_state != FL_ERASING)
			spin_unlock_bh (&this->chip_lock);
		return;
	}

	if (this->state == FL_ERASING) {
		if (new_state != FL_ERASING) {
			this->state = new_state;
			spin_unlock_bh (&this->chip_lock);
			return;
		}
	}

	set_current_state (TASK_UNINTERRUPTIBLE);
	add_wait_queue (&this->wq, &wait);
	spin_unlock_bh (&this->chip_lock);
	schedule ();
	remove_wait_queue (&this->wq, &wait);
	goto retry;
}

/*
 * Wait for command done. This applies to erase and program only
 * Erase can take up to 400ms and program up to 20ms according to 
 * general NAND and SmartMedia specs
 *
*/
static int nand_wait(struct mtd_info *mtd, struct nand_chip *this, int state)
{

	DECLARE_WAITQUEUE (wait, current);
	unsigned long	timeo = jiffies;
	int	status;
	
	if (state == FL_ERASING)
		 timeo += (HZ * 400) / 1000;
	else
		 timeo += (HZ * 20) / 1000;

	spin_lock_bh (&this->chip_lock);
	while (time_before(jiffies, timeo)) {		
		/* Check, if we were interrupted */
		if (this->state != state) {
			spin_unlock_bh (&this->chip_lock);
			return 0;
		}
		if (this->dev_ready) {
			if (this->dev_ready ())
				break;
		}
		this->cmdfunc (mtd, NAND_CMD_STATUS, -1, -1);
		if (readb (this->IO_ADDR_R) & 0x40)
			break;
						
		set_current_state (TASK_UNINTERRUPTIBLE);
		add_wait_queue (&this->wq, &wait);
		spin_unlock_bh (&this->chip_lock);
		schedule_timeout (1);
		remove_wait_queue (&this->wq, &wait);
		spin_lock_bh (&this->chip_lock);
	}
	this->cmdfunc (mtd, NAND_CMD_STATUS, -1, -1);
	status = (int) readb (this->IO_ADDR_R);
	spin_unlock_bh (&this->chip_lock);

	return status;
}

/*
 *	Nand_page_program function is used for write and writev !
 */
static int nand_write_page (struct mtd_info *mtd, struct nand_chip *this,
			    int page, int col, int last, u_char * ecc_code)
{

	int i, status;
#ifdef CONFIG_MTD_NAND_VERIFY_WRITE
#ifdef CONFIG_MTD_NAND_ECC
	int ecc_bytes = (mtd->oobblock == 512) ? 6 : 3;
#endif
#endif
	/* pad oob area */
	for (i = mtd->oobblock; i < mtd->oobblock + mtd->oobsize; i++)
		this->data_buf[i] = 0xff;

#ifdef CONFIG_MTD_NAND_ECC
	/* Zero out the ECC array */
	for (i = 0; i < 6; i++)
		ecc_code[i] = 0x00;

	/* Read back previous written data, if col > 0 */
	if (col) {
		this->cmdfunc (mtd, NAND_CMD_READ0, col, page);
		for (i = 0; i < col; i++)
			this->data_buf[i] = readb (this->IO_ADDR_R);
	}

	/* Calculate and write the ECC if we have enough data */
	if ((col < mtd->eccsize) && (last >= mtd->eccsize)) {
		nand_calculate_ecc (&this->data_buf[0], &(ecc_code[0]));
		for (i = 0; i < 3; i++)
			this->data_buf[(mtd->oobblock + oob_config.ecc_pos[i])] = ecc_code[i];
		if (oob_config.eccvalid_pos != -1)
			this->data_buf[mtd->oobblock + oob_config.eccvalid_pos] = 0xf0;
	}

	/* Calculate and write the second ECC if we have enough data */
	if ((mtd->oobblock == 512) && (last == mtd->oobblock)) {
		nand_calculate_ecc (&this->data_buf[256], &(ecc_code[3]));
		for (i = 3; i < 6; i++)
			this->data_buf[(mtd->oobblock + oob_config.ecc_pos[i])] = ecc_code[i];
		if (oob_config.eccvalid_pos != -1)
			this->data_buf[mtd->oobblock + oob_config.eccvalid_pos] &= 0x0f;
	}
#endif
	/* Prepad for partial page programming !!! */
	for (i = 0; i < col; i++)
		this->data_buf[i] = 0xff;

	/* Postpad for partial page programming !!! oob is already padded */
	for (i = last; i < mtd->oobblock; i++)
		this->data_buf[i] = 0xff;

	/* Send command to begin auto page programming */
	this->cmdfunc (mtd, NAND_CMD_SEQIN, 0x00, page);

	/* Write out complete page of data */
	for (i = 0; i < (mtd->oobblock + mtd->oobsize); i++)
		writeb (this->data_buf[i], this->IO_ADDR_W);

	/* Send command to actually program the data */
	this->cmdfunc (mtd, NAND_CMD_PAGEPROG, -1, -1);

	/* call wait ready function */
	status = this->waitfunc (mtd, this, FL_WRITING);

	/* See if device thinks it succeeded */
	if (status & 0x01) {
		DEBUG (MTD_DEBUG_LEVEL0, "nand_write_ecc: " "Failed write, page 0x%08x, ", page);
		return -EIO;
	}
#ifdef CONFIG_MTD_NAND_VERIFY_WRITE
	/*
	 * The NAND device assumes that it is always writing to
	 * a cleanly erased page. Hence, it performs its internal
	 * write verification only on bits that transitioned from
	 * 1 to 0. The device does NOT verify the whole page on a
	 * byte by byte basis. It is possible that the page was
	 * not completely erased or the page is becoming unusable
	 * due to wear. The read with ECC would catch the error
	 * later when the ECC page check fails, but we would rather
	 * catch it early in the page write stage. Better to write
	 * no data than invalid data.
	 */

	/* Send command to read back the page */
	if (col < mtd->eccsize)
		this->cmdfunc (mtd, NAND_CMD_READ0, col, page);
	else
		this->cmdfunc (mtd, NAND_CMD_READ1, col - 256, page);

	/* Loop through and verify the data */
	for (i = col; i < last; i++) {
		if (this->data_buf[i] != readb (this->IO_ADDR_R)) {
			DEBUG (MTD_DEBUG_LEVEL0, "nand_write_ecc: " "Failed write verify, page 0x%08x ", page);
			return -EIO;
		}
	}

#ifdef CONFIG_MTD_NAND_ECC
	/*
	 * We also want to check that the ECC bytes wrote
	 * correctly for the same reasons stated above.
	 */
	this->cmdfunc (mtd, NAND_CMD_READOOB, 0x00, page);
	for (i = 0; i < mtd->oobsize; i++)
		this->data_buf[i] = readb (this->IO_ADDR_R);
	for (i = 0; i < ecc_bytes; i++) {
		if ((this->data_buf[(oob_config.ecc_pos[i])] != ecc_code[i]) && ecc_code[i]) {
			DEBUG (MTD_DEBUG_LEVEL0,
			       "nand_write_ecc: Failed ECC write "
			       "verify, page 0x%08x, " "%6i bytes were succesful\n", page, i);
			return -EIO;
		}
	}
#endif
#endif
	return 0;
}

/*
 * NAND read
 */
static int nand_read (struct mtd_info *mtd, loff_t from, size_t len, size_t * retlen, u_char * buf)
{
#ifdef CONFIG_MTD_NAND_ECC
	struct nand_chip *this = mtd->priv;

	return nand_read_ecc (mtd, from, len, retlen, buf, this->ecc_code_buf);