accessing NAND flash through an IDE interface

Hi Thomas,
I am not sure if you received the patch I sent you last month for accessing nand flash through an IDE interface so I am sending it again.

I think some people may find it useful.

Thank you.

William J Beksi                          <[email protected]>
GPG Key Fingerprint = ED4B 32C3 69E6 C2B7 705C  263F CB2F 3253 E7E1 DB3B

/* drivers/mtd/nand/ide.c
*
* Copyright (C) 2004 William J Beksi <[email protected]> *
* Overview:
* This device driver allows a NAND flash device to be accessed from
* an IDE interface.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <linux/delay.h>
#include <asm/io.h>

/*
* Values specific to the IDE
*/
#define IDE_IO_BASE_1 0x1F0 /* IDE1 NAND flash I/O base address */
#define IDE_IO_BASE_2 0x170 /* IDE2 NAND flash I/O base address */

#define IDE_IO_BASE IDE_IO_BASE_1

/*
* IDE MTD structure
*/
static struct mtd_info *ide_mtd = NULL;

/*
* Define partitions for flash device
*/

const static struct mtd_partition partition_info[] = {
	{ 
		.name   = "IDE flash partition 1", 
		.offset = 0,  
		.size   = 3*1024*1024 
	},
	{
		.name   = "IDE flash partition 2",
		.offset = 3*1024*1024,
		.size   = 3*1024*1024
	}
};

#define NUM_PARTITIONS 2

static void ide_hwcontrol(struct mtd_info *mtd, int cmd)

{
	struct nand_chip *this = (struct nand_chip *) mtd->priv;

	switch (cmd) {
		case NAND_CTL_SETCLE: this->IO_ADDR_W = (unsigned char *) IDE_IO_BASE+1; break;
		case NAND_CTL_CLRCLE: this->IO_ADDR_W = (unsigned char *) IDE_IO_BASE;   break;
		case NAND_CTL_SETALE: this->IO_ADDR_W = (unsigned char *) IDE_IO_BASE+2; break;	
		case NAND_CTL_CLRALE: this->IO_ADDR_W = (unsigned char *) IDE_IO_BASE;   break;
	}
}

/*
* Main initialization routine
*/
int __init ide_init(void)

{
	struct nand_chip *this;
	int err = 0;

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

	/* Initialize structures */
	memset((char *) ide_mtd, 0, sizeof(struct mtd_info) + sizeof(struct nand_chip));

	/* Get pointer to private data */
	this = (struct nand_chip *) (&ide_mtd[1]);
	/* Link the private data with the MTD structure */
	ide_mtd->priv = this;

	/* Set address of NAND IO lines */
	this->IO_ADDR_R  = (void __iomem *) IDE_IO_BASE;
	this->IO_ADDR_W  = (void __iomem *) IDE_IO_BASE;
	/* Reference hardware control function */
	this->hwcontrol = ide_hwcontrol;
	/* Set command delay time */
	this->chip_delay = 20;
	/* Assign the device ready function */
	this->dev_ready = NULL;
	/* Set the ECC generator mode */
	this->eccmode = NAND_ECC_SOFT;

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

	/* Register the partitions */
	add_mtd_partitions(ide_mtd, partition_info, NUM_PARTITIONS);
	goto out;

out_mtd:

	kfree(ide_mtd);
out:
	return err;
}

module_init(ide_init);

/*
* Clean up routine
*/
#ifdef MODULE
static void __exit ide_cleanup (void)

{
	/* Release resources, unregister the device */
	nand_release(ide_mtd);	

	/* Free the MTD device structure */
	kfree(ide_mtd);
}

module_exit(ide_cleanup);
#endif

MODULE_LICENSE("GPL");
MODULE_AUTHOR("William J Beksi <[email protected]>"); MODULE_DESCRIPTION("Glue layer for NAND flash through an IDE interface");

Index: drivers/mtd/nand/Kconfig
===================================================================
RCS file: /home/cvs/mtd/drivers/mtd/nand/Kconfig,v retrieving revision 1.26

diff -u -r1.26 Kconfig
@@ -204,4 +204,11 @@
 	  The simulator may simulate verious NAND flash chips for the
 	  MTD nand layer.
  
+config MTD_NAND_IDE
+	tristate "Support for NAND Flash through a PC's IDE interface"
+	depends on MTD_NAND && MTD_PARTITIONS
+	help
+	  This enables the driver for accessing NAND Flash through the
+	  IDE interface of a PC.
+	
 endmenu

Index: drivers/mtd/nand/Makefile.common
===================================================================
RCS file: /home/cvs/mtd/drivers/mtd/nand/Makefile.common,v retrieving revision 1.15

diff -u -r1.15 Makefile.common
@@ -20,5 +20,6 @@
 obj-$(CONFIG_MTD_NAND_RTC_FROM4)	+= rtc_from4.o
 obj-$(CONFIG_MTD_NAND_SHARPSL)		+= sharpsl.o
 obj-$(CONFIG_MTD_NAND_NANDSIM)		+= nandsim.o
+obj-$(CONFIG_MTD_NAND_IDE)		+= ide.o
 
 nand-objs = nand_base.o nand_bbt.o

Index: drivers/mtd/nand/nand_base.c
===================================================================
RCS file: /home/cvs/mtd/drivers/mtd/nand/nand_base.c,v retrieving revision 1.130

@@ -84,6 +84,8 @@
#include <linux/mtd/partitions.h>
#endif

+#define NAND_USE_IO_INSTR 0

As I said before, I'm not going to accept a change which needs to tweak a source file to make use of it.

tglx

I was not aware of this. I have made all the changes as per your suggestion and then you finally reject the patch, a little discouraging.

Is there any other way let people choose between using readb/inb and writeb/outb inside nand_base.c? Or should I just create my own separate patch to allow people to use the driver and make it available elsewhere?

Thank you,
William

I did not intend to discourage you and I'm sorry if I did not express myself clear enough. I guess my assumptions of what's obvious are wrong.

Sure, more than one.
The simplest is to convert your #define into a CONFIG_OPTION with the appropriate dependencies.

Another possibility is to make it runtime selectable via the nand options. Also here it should be compile time dependend on CPU architectures which have seperate I/O instructions.

Running away is not a solution. Stick your nose into LKML and watch how patches are dissected several times before acceptance. Whats wrong with that ? It's the way Open Source development works.

tglx