/*
 *  drivers/mtd/nand/au1550nd.c
 *
 *  Copyright (C) 2004 Embedded Edge, LLC
 *
 * $Id: au1550nd.c,v 1.12 2005/09/23 01:44:55 ppopov 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.
 *
 */

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

/* fixme: this is ugly */
#if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 0)
#include <asm/mach-au1x00/au1xxx.h>
#else
#include <asm/au1000.h>
#ifdef CONFIG_MIPS_PB1550
#include <asm/pb1550.h> 
#endif
#ifdef CONFIG_MIPS_DB1550
#include <asm/db1x00.h> 
#endif
#endif

/*
 * MTD structure for NAND controller
 */
static struct mtd_info *au1550_mtd = NULL;
static void __iomem *p_nand;
static int nand_width = 1; /* default x8*/

/*
 * Define partitions for flash device
 */
const static struct mtd_partition partition_info[] = {
	{ 
		.name 	= "NAND FS 0",
	  	.offset = 0,
	  	.size 	= 8*1024*1024 
	},
	{ 
		.name 	= "NAND FS 1",
		.offset =  MTDPART_OFS_APPEND,
 		.size 	=    MTDPART_SIZ_FULL
	}
};
#define NB_OF(x)  (sizeof(x)/sizeof(x[0]))


/**
 * au_read_byte -  read one byte from the chip
 * @mtd:	MTD device structure
 *
 *  read function for 8bit buswith
 */
static u_char au_read_byte(struct mtd_info *mtd)
{
	struct nand_chip *this = mtd->priv;
	u_char ret = readb(this->IO_ADDR_R);
	au_sync();
	return ret;
}

/**
 * au_write_byte -  write one byte to the chip
 * @mtd:	MTD device structure
 * @byte:	pointer to data byte to write
 *
 *  write function for 8it buswith
 */
static void au_write_byte(struct mtd_info *mtd, u_char byte)
{
	struct nand_chip *this = mtd->priv;
	writeb(byte, this->IO_ADDR_W);
	au_sync();
}

/**
 * au_read_byte16 -  read one byte endianess aware from the chip
 * @mtd:	MTD device structure
 *
 *  read function for 16bit buswith with 
 * endianess conversion
 */
static u_char au_read_byte16(struct mtd_info *mtd)
{
	struct nand_chip *this = mtd->priv;
	u_char ret = (u_char) cpu_to_le16(readw(this->IO_ADDR_R));
	au_sync();
	return ret;
}

/**
 * au_write_byte16 -  write one byte endianess aware to the chip
 * @mtd:	MTD device structure
 * @byte:	pointer to data byte to write
 *
 *  write function for 16bit buswith with
 * endianess conversion
 */
static void au_write_byte16(struct mtd_info *mtd, u_char byte)
{
	struct nand_chip *this = mtd->priv;
	writew(le16_to_cpu((u16) byte), this->IO_ADDR_W);
	au_sync();
}

/**
 * au_read_word -  read one word from the chip
 * @mtd:	MTD device structure
 *
 *  read function for 16bit buswith without 
 * endianess conversion
 */
static u16 au_read_word(struct mtd_info *mtd)
{
	struct nand_chip *this = mtd->priv;
	u16 ret = readw(this->IO_ADDR_R);
	au_sync();
	return ret;
}

/**
 * au_write_word -  write one word to the chip
 * @mtd:	MTD device structure
 * @word:	data word to write
 *
 *  write function for 16bit buswith without 
 * endianess conversion
 */
static void au_write_word(struct mtd_info *mtd, u16 word)
{
	struct nand_chip *this = mtd->priv;
	writew(word, this->IO_ADDR_W);
	au_sync();
}

/**
 * au_write_buf -  write buffer to chip
 * @mtd:	MTD device structure
 * @buf:	data buffer
 * @len:	number of bytes to write
 *
 *  write function for 8bit buswith
 */
static void au_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
{
	int i;
	struct nand_chip *this = mtd->priv;

	for (i=0; i<len; i++) {
		writeb(buf[i], this->IO_ADDR_W);
		au_sync();
	}
}

/**
 * au_read_buf -  read chip data into buffer 
 * @mtd:	MTD device structure
 * @buf:	buffer to store date
 * @len:	number of bytes to read
 *
 *  read function for 8bit buswith
 */
static void au_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
	int i;
	struct nand_chip *this = mtd->priv;

	for (i=0; i<len; i++) {
		buf[i] = readb(this->IO_ADDR_R);
		au_sync();	
	}
}

/**
 * au_verify_buf -  Verify chip data against buffer 
 * @mtd:	MTD device structure
 * @buf:	buffer containing the data to compare
 * @len:	number of bytes to compare
 *
 *  verify function for 8bit buswith
 */
static int au_verify_buf(struct mtd_info *mtd, const u_char *buf, int len)
{
	int i;
	struct nand_chip *this = mtd->priv;

	for (i=0; i<len; i++) {
		if (buf[i] != readb(this->IO_ADDR_R))
			return -EFAULT;
		au_sync();
	}

	return 0;
}

/**
 * au_write_buf16 -  write buffer to chip
 * @mtd:	MTD device structure
 * @buf:	data buffer
 * @len:	number of bytes to write
 *
 *  write function for 16bit buswith
 */
static void au_write_buf16(struct mtd_info *mtd, const u_char *buf, int len)
{
	int i;
	struct nand_chip *this = mtd->priv;
	u16 *p = (u16 *) buf;
	len >>= 1;
	
	for (i=0; i<len; i++) {
		writew(p[i], this->IO_ADDR_W);
		au_sync();
	}
		
}

/**
 * au_read_buf16 -  read chip data into buffer 
 * @mtd:	MTD device structure
 * @buf:	buffer to store date
 * @len:	number of bytes to read
 *
 *  read function for 16bit buswith
 */
static void au_read_buf16(struct mtd_info *mtd, u_char *buf, int len)
{
	int i;
	struct nand_chip *this = mtd->priv;
	u16 *p = (u16 *) buf;
	len >>= 1;

	for (i=0; i<len; i++) {
		p[i] = readw(this->IO_ADDR_R);
		au_sync();
	}
}

/**
 * au_verify_buf16 -  Verify chip data against buffer 
 * @mtd:	MTD device structure
 * @buf:	buffer containing the data to compare
 * @len:	number of bytes to compare
 *
 *  verify function for 16bit buswith
 */
static int au_verify_buf16(struct mtd_info *mtd, const u_char *buf, int len)
{
	int i;
	struct nand_chip *this = mtd->priv;
	u16 *p = (u16 *) buf;
	len >>= 1;

	for (i=0; i<len; i++) {
		if (p[i] != readw(this->IO_ADDR_R))
			return -EFAULT;
		au_sync();
	}
	return 0;
}


static void au1550_hwcontrol(struct mtd_info *mtd, int cmd)
{
	register struct nand_chip *this = mtd->priv;

	switch(cmd){

	case NAND_CTL_SETCLE: this->IO_ADDR_W = p_nand + MEM_STNAND_CMD; break;
	case NAND_CTL_CLRCLE: this->IO_ADDR_W = p_nand + MEM_STNAND_DATA; break;

	case NAND_CTL_SETALE: this->IO_ADDR_W = p_nand + MEM_STNAND_ADDR; break;
	case NAND_CTL_CLRALE: 
		this->IO_ADDR_W = p_nand + MEM_STNAND_DATA; 
		/* FIXME: Nobody knows why this is neccecary, 
		 * but it works only that way */
		udelay(1); 
		break;

	case NAND_CTL_SETNCE: 
		/* assert (force assert) chip enable */
		au_writel((1<<(4+NAND_CS)) , MEM_STNDCTL); break;
		break;

	case NAND_CTL_CLRNCE: 
 		/* deassert chip enable */
		au_writel(0, MEM_STNDCTL); break;
		break;
	}

	this->IO_ADDR_R = this->IO_ADDR_W;
	
	/* Drain the writebuffer */
	au_sync();
}

int au1550_device_ready(struct mtd_info *mtd)
{
	int ret = (au_readl(MEM_STSTAT) & 0x1) ? 1 : 0;
	au_sync();
	return ret;
}

/*
 * Main initialization routine
 */
int __init au1xxx_nand_init (void)
{
	struct nand_chip *this;
	u16 boot_swapboot = 0; /* default value */
	int retval;
	u32 mem_staddr;
	u32 nand_phys;

	/* Allocate memory for MTD device structure and private data */
	au1550_mtd = kmalloc (sizeof(struct mtd_info) + 
			sizeof (struct nand_chip), GFP_KERNEL);
	if (!au1550_mtd) {
		printk ("Unable to allocate NAND MTD dev structure.\n");
		return -ENOMEM;
	}

	/* Get pointer to private data */
	this = (struct nand_chip *) (&au1550_mtd[1]);

	/* Initialize structures */
	memset((char *) au1550_mtd, 0, sizeof(struct mtd_info));
	memset((char *) this, 0, sizeof(struct nand_chip));

	/* Link the private data with the MTD structure */
	au1550_mtd->priv = this;


	/* disable interrupts */
	au_writel(au_readl(MEM_STNDCTL) & ~(1<<8), MEM_STNDCTL);
 
	/* disable NAND boot */
	au_writel(au_readl(MEM_STNDCTL) & ~(1<<0), MEM_STNDCTL);

#ifdef CONFIG_MIPS_PB1550
	/* set gpio206 high */
	au_writel(au_readl(GPIO2_DIR) & ~(1<<6), GPIO2_DIR);

	boot_swapboot = (au_readl(MEM_STSTAT) & (0x7<<1)) | 
		((bcsr->status >> 6)  & 0x1);
	switch (boot_swapboot) {
		case 0:
		case 2:
		case 8:
		case 0xC:
		case 0xD:
			/* x16 NAND Flash */
			nand_width = 0;
			break;
		case 1:
		case 9:
		case 3:
		case 0xE:
		case 0xF:
			/* x8 NAND Flash */
			nand_width = 1;
			break;
		default:
			printk("Pb1550 NAND: bad boot:swap\n");
			retval = -EINVAL;
			goto outmem;
	}
#endif

	/* Configure chip-select; normally done by boot code, e.g. YAMON */
#ifdef NAND_STCFG
	if (NAND_CS == 0) {
		au_writel(NAND_STCFG,  MEM_STCFG0);
		au_writel(NAND_STTIME, MEM_STTIME0);
		au_writel(NAND_STADDR, MEM_STADDR0);
	}
	if (NAND_CS == 1) {
		au_writel(NAND_STCFG,  MEM_STCFG1);
		au_writel(NAND_STTIME, MEM_STTIME1);
		au_writel(NAND_STADDR, MEM_STADDR1);
	}
	if (NAND_CS == 2) {
		au_writel(NAND_STCFG,  MEM_STCFG2);
		au_writel(NAND_STTIME, MEM_STTIME2);
		au_writel(NAND_STADDR, MEM_STADDR2);
	}
	if (NAND_CS == 3) {
		au_writel(NAND_STCFG,  MEM_STCFG3);
		au_writel(NAND_STTIME, MEM_STTIME3);
		au_writel(NAND_STADDR, MEM_STADDR3);
	}
#endif
 
	/* Locate NAND chip-select in order to determine NAND phys address */
	mem_staddr = 0x00000000;
	if (((au_readl(MEM_STCFG0) & 0x7) == 0x5) && (NAND_CS == 0))
		mem_staddr = au_readl(MEM_STADDR0);
	else if (((au_readl(MEM_STCFG1) & 0x7) == 0x5) && (NAND_CS == 1))
		mem_staddr = au_readl(MEM_STADDR1);
	else if (((au_readl(MEM_STCFG2) & 0x7) == 0x5) && (NAND_CS == 2))
		mem_staddr = au_readl(MEM_STADDR2);
	else if (((au_readl(MEM_STCFG3) & 0x7) == 0x5) && (NAND_CS == 3))
		mem_staddr = au_readl(MEM_STADDR3);

	if (mem_staddr == 0x00000000) {
		printk("Au1xxx NAND: ERROR WITH NAND CHIP-SELECT\n");
		kfree(au1550_mtd);
		return 1;
	}
	nand_phys = (mem_staddr << 4) & 0xFFFC0000;

	p_nand = (void __iomem *)ioremap(nand_phys, 0x1000);

	/* make controller and MTD agree */
	if (NAND_CS == 0)
		nand_width = au_readl(MEM_STCFG0) & (1<<22);
	if (NAND_CS == 1)
		nand_width = au_readl(MEM_STCFG1) & (1<<22);
	if (NAND_CS == 2)
		nand_width = au_readl(MEM_STCFG2) & (1<<22);
	if (NAND_CS == 3)
		nand_width = au_readl(MEM_STCFG3) & (1<<22);


	/* Set address of hardware control function */
	this->hwcontrol = au1550_hwcontrol;
	this->dev_ready = au1550_device_ready;
	/* 30 us command delay time */
	this->chip_delay = 30;		
	this->eccmode = NAND_ECC_SOFT;

	this->options = NAND_NO_AUTOINCR;

	if (!nand_width)
		this->options |= NAND_BUSWIDTH_16;

	this->read_byte = (!nand_width) ? au_read_byte16 : au_read_byte;
	this->write_byte = (!nand_width) ? au_write_byte16 : au_write_byte;
	this->write_word = au_write_word;
	this->read_word = au_read_word;
	this->write_buf = (!nand_width) ? au_write_buf16 : au_write_buf;
	this->read_buf = (!nand_width) ? au_read_buf16 : au_read_buf;
	this->verify_buf = (!nand_width) ? au_verify_buf16 : au_verify_buf;

	/* Scan to find existence of the device */
	if (nand_scan (au1550_mtd, 1)) {
		retval = -ENXIO;
		goto outio;
	}

	/* Register the partitions */
	add_mtd_partitions(au1550_mtd, partition_info, NB_OF(partition_info));

	return 0;

 outio:
	iounmap ((void *)p_nand);
	
 outmem:
	kfree (au1550_mtd);
	return retval;
}

module_init(au1xxx_nand_init);

/*
 * Clean up routine
 */
#ifdef MODULE
static void __exit au1550_cleanup (void)
{
	struct nand_chip *this = (struct nand_chip *) &au1550_mtd[1];

	/* Release resources, unregister device */
	nand_release (au1550_mtd);

	/* Free the MTD device structure */
	kfree (au1550_mtd);

	/* Unmap */
	iounmap ((void *)p_nand);
}
module_exit(au1550_cleanup);
#endif

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Embedded Edge, LLC");
MODULE_DESCRIPTION("Board-specific glue layer for NAND flash on Pb1550 board");