drivers/mtd/nand/bcm47xxnflash/ops_bcm4706.c - linux - Git at Google

 /*
  * BCM47XX NAND flash driver
  *
  * Copyright (C) 2012 Rafał Miłecki <zajec5@gmail.com>
  *
  * 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 "bcm47xxnflash.h"

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/bcma/bcma.h>

 /* Broadcom uses 1'000'000 but it seems to be too many. Tests on WNDR4500 has
  * shown ~1000 retries as maxiumum. */
 #define NFLASH_READY_RETRIES		10000

 #define NFLASH_SECTOR_SIZE		512

 #define NCTL_CMD0			0x00010000
 #define NCTL_CMD1W			0x00080000
 #define NCTL_READ			0x00100000
 #define NCTL_WRITE			0x00200000
 #define NCTL_SPECADDR			0x01000000
 #define NCTL_READY			0x04000000
 #define NCTL_ERR			0x08000000
 #define NCTL_CSA			0x40000000
 #define NCTL_START			0x80000000

 /**************************************************
  * Various helpers
  **************************************************/

 static inline u8 bcm47xxnflash_ops_bcm4706_ns_to_cycle(u16 ns, u16 clock)
 {
 	return ((ns * 1000 * clock) / 1000000) + 1;
 }

 static int bcm47xxnflash_ops_bcm4706_ctl_cmd(struct bcma_drv_cc *cc, u32 code)
 {
 	int i = 0;

 	bcma_cc_write32(cc, BCMA_CC_NFLASH_CTL, NCTL_START | code);
 	for (i = 0; i < NFLASH_READY_RETRIES; i++) {
 		if (!(bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) & NCTL_START)) {
 			i = 0;
 			break;
 		}
 	}
 	if (i) {
 		pr_err("NFLASH control command not ready!\n");
 		return -EBUSY;
 	}
 	return 0;
 }

 static int bcm47xxnflash_ops_bcm4706_poll(struct bcma_drv_cc *cc)
 {
 	int i;

 	for (i = 0; i < NFLASH_READY_RETRIES; i++) {
 		if (bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) & NCTL_READY) {
 			if (bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) &
 			    BCMA_CC_NFLASH_CTL_ERR) {
 				pr_err("Error on polling\n");
 				return -EBUSY;
 			} else {
 				return 0;
 			}
 		}
 	}

 	pr_err("Polling timeout!\n");
 	return -EBUSY;
 }

 /**************************************************
  * R/W
  **************************************************/

 static void bcm47xxnflash_ops_bcm4706_read(struct mtd_info *mtd, uint8_t *buf,
 					   int len)
 {
 	struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
 	struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;

 	u32 ctlcode;
 	u32 *dest = (u32 *)buf;
 	int i;
 	int toread;

 	BUG_ON(b47n->curr_page_addr & ~nand_chip->pagemask);
 	/* Don't validate column using nand_chip->page_shift, it may be bigger
 	 * when accessing OOB */

 	while (len) {
 		/* We can read maximum of 0x200 bytes at once */
 		toread = min(len, 0x200);

 		/* Set page and column */
 		bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_COL_ADDR,
 				b47n->curr_column);
 		bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_ROW_ADDR,
 				b47n->curr_page_addr);

 		/* Prepare to read */
 		ctlcode = NCTL_CSA | NCTL_CMD1W | 0x00040000 | 0x00020000 |
 			  NCTL_CMD0;
 		ctlcode |= NAND_CMD_READSTART << 8;
 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc, ctlcode))
 			return;
 		if (bcm47xxnflash_ops_bcm4706_poll(b47n->cc))
 			return;

 		/* Eventually read some data :) */
 		for (i = 0; i < toread; i += 4, dest++) {
 			ctlcode = NCTL_CSA | 0x30000000 | NCTL_READ;
 			if (i == toread - 4) /* Last read goes without that */
 				ctlcode &= ~NCTL_CSA;
 			if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc,
 							      ctlcode))
 				return;
 			*dest = bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_DATA);
 		}

 		b47n->curr_column += toread;
 		len -= toread;
 	}
 }

 static void bcm47xxnflash_ops_bcm4706_write(struct mtd_info *mtd,
 					    const uint8_t *buf, int len)
 {
 	struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
 	struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;
 	struct bcma_drv_cc *cc = b47n->cc;

 	u32 ctlcode;
 	const u32 *data = (u32 *)buf;
 	int i;

 	BUG_ON(b47n->curr_page_addr & ~nand_chip->pagemask);
 	/* Don't validate column using nand_chip->page_shift, it may be bigger
 	 * when accessing OOB */

 	for (i = 0; i < len; i += 4, data++) {
 		bcma_cc_write32(cc, BCMA_CC_NFLASH_DATA, *data);

 		ctlcode = NCTL_CSA | 0x30000000 | NCTL_WRITE;
 		if (i == len - 4) /* Last read goes without that */
 			ctlcode &= ~NCTL_CSA;
 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode)) {
 			pr_err("%s ctl_cmd didn't work!\n", __func__);
 			return;
 		}
 	}

 	b47n->curr_column += len;
 }

 /**************************************************
  * NAND chip ops
  **************************************************/

 /* Default nand_select_chip calls cmd_ctrl, which is not used in BCM4706 */
 static void bcm47xxnflash_ops_bcm4706_select_chip(struct mtd_info *mtd,
 						  int chip)
 {
 	return;
 }

 static int bcm47xxnflash_ops_bcm4706_dev_ready(struct mtd_info *mtd)
 {
 	struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
 	struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;

 	return !!(bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_CTL) & NCTL_READY);
 }

 /*
  * Default nand_command and nand_command_lp don't match BCM4706 hardware layout.
  * For example, reading chip id is performed in a non-standard way.
  * Setting column and page is also handled differently, we use a special
  * registers of ChipCommon core. Hacking cmd_ctrl to understand and convert
  * standard commands would be much more complicated.
  */
 static void bcm47xxnflash_ops_bcm4706_cmdfunc(struct mtd_info *mtd,
 					      unsigned command, int column,
 					      int page_addr)
 {
 	struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
 	struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;
 	struct bcma_drv_cc *cc = b47n->cc;
 	u32 ctlcode;
 	int i;

 	if (column != -1)
 		b47n->curr_column = column;
 	if (page_addr != -1)
 		b47n->curr_page_addr = page_addr;

 	switch (command) {
 	case NAND_CMD_RESET:
 		pr_warn("Chip reset not implemented yet\n");
 		break;
 	case NAND_CMD_READID:
 		ctlcode = NCTL_CSA | 0x01000000 | NCTL_CMD1W | NCTL_CMD0;
 		ctlcode |= NAND_CMD_READID;
 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc, ctlcode)) {
 			pr_err("READID error\n");
 			break;
 		}

 		/*
 		 * Reading is specific, last one has to go without NCTL_CSA
 		 * bit. We don't know how many reads NAND subsystem is going
 		 * to perform, so cache everything.
 		 */
 		for (i = 0; i < ARRAY_SIZE(b47n->id_data); i++) {
 			ctlcode = NCTL_CSA | NCTL_READ;
 			if (i == ARRAY_SIZE(b47n->id_data) - 1)
 				ctlcode &= ~NCTL_CSA;
 			if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc,
 							      ctlcode)) {
 				pr_err("READID error\n");
 				break;
 			}
 			b47n->id_data[i] =
 				bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_DATA)
 				& 0xFF;
 		}

 		break;
 	case NAND_CMD_STATUS:
 		ctlcode = NCTL_CSA | NCTL_CMD0 | NAND_CMD_STATUS;
 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
 			pr_err("STATUS command error\n");
 		break;
 	case NAND_CMD_READ0:
 		break;
 	case NAND_CMD_READOOB:
 		if (page_addr != -1)
 			b47n->curr_column += mtd->writesize;
 		break;
 	case NAND_CMD_ERASE1:
 		bcma_cc_write32(cc, BCMA_CC_NFLASH_ROW_ADDR,
 				b47n->curr_page_addr);
 		ctlcode = 0x00040000 | NCTL_CMD1W | NCTL_CMD0 |
 			  NAND_CMD_ERASE1 | (NAND_CMD_ERASE2 << 8);
 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
 			pr_err("ERASE1 failed\n");
 		break;
 	case NAND_CMD_ERASE2:
 		break;
 	case NAND_CMD_SEQIN:
 		/* Set page and column */
 		bcma_cc_write32(cc, BCMA_CC_NFLASH_COL_ADDR,
 				b47n->curr_column);
 		bcma_cc_write32(cc, BCMA_CC_NFLASH_ROW_ADDR,
 				b47n->curr_page_addr);

 		/* Prepare to write */
 		ctlcode = 0x40000000 | 0x00040000 | 0x00020000 | 0x00010000;
 		ctlcode |= NAND_CMD_SEQIN;
 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
 			pr_err("SEQIN failed\n");
 		break;
 	case NAND_CMD_PAGEPROG:
 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, 0x00010000 |
 							  NAND_CMD_PAGEPROG))
 			pr_err("PAGEPROG failed\n");
 		if (bcm47xxnflash_ops_bcm4706_poll(cc))
 			pr_err("PAGEPROG not ready\n");
 		break;
 	default:
 		pr_err("Command 0x%X unsupported\n", command);
 		break;
 	}
 	b47n->curr_command = command;
 }

 static u8 bcm47xxnflash_ops_bcm4706_read_byte(struct mtd_info *mtd)
 {
 	struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
 	struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;
 	struct bcma_drv_cc *cc = b47n->cc;
 	u32 tmp = 0;

 	switch (b47n->curr_command) {
 	case NAND_CMD_READID:
 		if (b47n->curr_column >= ARRAY_SIZE(b47n->id_data)) {
 			pr_err("Requested invalid id_data: %d\n",
 			       b47n->curr_column);
 			return 0;
 		}
 		return b47n->id_data[b47n->curr_column++];
 	case NAND_CMD_STATUS:
 		if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, NCTL_READ))
 			return 0;
 		return bcma_cc_read32(cc, BCMA_CC_NFLASH_DATA) & 0xff;
 	case NAND_CMD_READOOB:
 		bcm47xxnflash_ops_bcm4706_read(mtd, (u8 *)&tmp, 4);
 		return tmp & 0xFF;
 	}

 	pr_err("Invalid command for byte read: 0x%X\n", b47n->curr_command);
 	return 0;
 }

 static void bcm47xxnflash_ops_bcm4706_read_buf(struct mtd_info *mtd,
 					       uint8_t *buf, int len)
 {
 	struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
 	struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;

 	switch (b47n->curr_command) {
 	case NAND_CMD_READ0:
 	case NAND_CMD_READOOB:
 		bcm47xxnflash_ops_bcm4706_read(mtd, buf, len);
 		return;
 	}

 	pr_err("Invalid command for buf read: 0x%X\n", b47n->curr_command);
 }

 static void bcm47xxnflash_ops_bcm4706_write_buf(struct mtd_info *mtd,
 						const uint8_t *buf, int len)
 {
 	struct nand_chip *nand_chip = (struct nand_chip *)mtd->priv;
 	struct bcm47xxnflash *b47n = (struct bcm47xxnflash *)nand_chip->priv;

 	switch (b47n->curr_command) {
 	case NAND_CMD_SEQIN:
 		bcm47xxnflash_ops_bcm4706_write(mtd, buf, len);
 		return;
 	}

 	pr_err("Invalid command for buf write: 0x%X\n", b47n->curr_command);
 }

 /**************************************************
  * Init
  **************************************************/

 int bcm47xxnflash_ops_bcm4706_init(struct bcm47xxnflash *b47n)
 {
 	struct nand_chip *nand_chip = (struct nand_chip *)&b47n->nand_chip;
 	int err;
 	u32 freq;
 	u16 clock;
 	u8 w0, w1, w2, w3, w4;

 	unsigned long chipsize; /* MiB */
 	u8 tbits, col_bits, col_size, row_bits, row_bsize;
 	u32 val;

 	b47n->nand_chip.select_chip = bcm47xxnflash_ops_bcm4706_select_chip;
 	nand_chip->dev_ready = bcm47xxnflash_ops_bcm4706_dev_ready;
 	b47n->nand_chip.cmdfunc = bcm47xxnflash_ops_bcm4706_cmdfunc;
 	b47n->nand_chip.read_byte = bcm47xxnflash_ops_bcm4706_read_byte;
 	b47n->nand_chip.read_buf = bcm47xxnflash_ops_bcm4706_read_buf;
 	b47n->nand_chip.write_buf = bcm47xxnflash_ops_bcm4706_write_buf;

 	nand_chip->chip_delay = 50;
 	b47n->nand_chip.bbt_options = NAND_BBT_USE_FLASH;
 	b47n->nand_chip.ecc.mode = NAND_ECC_NONE; /* TODO: implement ECC */

 	/* Enable NAND flash access */
 	bcma_cc_set32(b47n->cc, BCMA_CC_4706_FLASHSCFG,
 		      BCMA_CC_4706_FLASHSCFG_NF1);

 	/* Configure wait counters */
 	if (b47n->cc->status & BCMA_CC_CHIPST_4706_PKG_OPTION) {
 		/* 400 MHz */
 		freq = 400000000 / 4;
 	} else {
 		freq = bcma_chipco_pll_read(b47n->cc, 4);
 		freq = (freq & 0xFFF) >> 3;
 		/* Fixed reference clock 25 MHz and m = 2 */
 		freq = (freq * 25000000 / 2) / 4;
 	}
 	clock = freq / 1000000;
 	w0 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(15, clock);
 	w1 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(20, clock);
 	w2 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(10, clock);
 	w3 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(10, clock);
 	w4 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(100, clock);
 	bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_WAITCNT0,
 			(w4 << 24 | w3 << 18 | w2 << 12 | w1 << 6 | w0));

 	/* Scan NAND */
 	err = nand_scan(&b47n->mtd, 1);
 	if (err) {
 		pr_err("Could not scan NAND flash: %d\n", err);
 		goto exit;
 	}

 	/* Configure FLASH */
 	chipsize = b47n->nand_chip.chipsize >> 20;
 	tbits = ffs(chipsize); /* find first bit set */
 	if (!tbits || tbits != fls(chipsize)) {
 		pr_err("Invalid flash size: 0x%lX\n", chipsize);
 		err = -ENOTSUPP;
 		goto exit;
 	}
 	tbits += 19; /* Broadcom increases *index* by 20, we increase *pos* */

 	col_bits = b47n->nand_chip.page_shift + 1;
 	col_size = (col_bits + 7) / 8;

 	row_bits = tbits - col_bits + 1;
 	row_bsize = (row_bits + 7) / 8;

 	val = ((row_bsize - 1) << 6) | ((col_size - 1) << 4) | 2;
 	bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_CONF, val);

 exit:
 	if (err)
 		bcma_cc_mask32(b47n->cc, BCMA_CC_4706_FLASHSCFG,
 			       ~BCMA_CC_4706_FLASHSCFG_NF1);
 	return err;
 }
	/*
	* BCM47XX NAND flash driver
	*
	* Copyright (C) 2012 Rafał Miłecki <zajec5@gmail.com>
	*
	* 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 "bcm47xxnflash.h"

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/slab.h>
	#include <linux/bcma/bcma.h>

	/* Broadcom uses 1'000'000 but it seems to be too many. Tests on WNDR4500 has
	* shown ~1000 retries as maxiumum. */
	#define NFLASH_READY_RETRIES 10000

	#define NFLASH_SECTOR_SIZE 512

	#define NCTL_CMD0 0x00010000
	#define NCTL_CMD1W 0x00080000
	#define NCTL_READ 0x00100000
	#define NCTL_WRITE 0x00200000
	#define NCTL_SPECADDR 0x01000000
	#define NCTL_READY 0x04000000
	#define NCTL_ERR 0x08000000
	#define NCTL_CSA 0x40000000
	#define NCTL_START 0x80000000

	/**************************************************
	* Various helpers
	**************************************************/

	static inline u8 bcm47xxnflash_ops_bcm4706_ns_to_cycle(u16 ns, u16 clock)
	{
	return ((ns * 1000 * clock) / 1000000) + 1;
	}

	static int bcm47xxnflash_ops_bcm4706_ctl_cmd(struct bcma_drv_cc *cc, u32 code)
	{
	int i = 0;

	bcma_cc_write32(cc, BCMA_CC_NFLASH_CTL, NCTL_START \| code);
	for (i = 0; i < NFLASH_READY_RETRIES; i++) {
	if (!(bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) & NCTL_START)) {
	i = 0;
	break;
	}
	}
	if (i) {
	pr_err("NFLASH control command not ready!\n");
	return -EBUSY;
	}
	return 0;
	}

	static int bcm47xxnflash_ops_bcm4706_poll(struct bcma_drv_cc *cc)
	{
	int i;

	for (i = 0; i < NFLASH_READY_RETRIES; i++) {
	if (bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) & NCTL_READY) {
	if (bcma_cc_read32(cc, BCMA_CC_NFLASH_CTL) &
	BCMA_CC_NFLASH_CTL_ERR) {
	pr_err("Error on polling\n");
	return -EBUSY;
	} else {
	return 0;
	}
	}
	}

	pr_err("Polling timeout!\n");
	return -EBUSY;
	}

	/**************************************************
	* R/W
	**************************************************/

	static void bcm47xxnflash_ops_bcm4706_read(struct mtd_info mtd, uint8_t buf,
	int len)
	{
	struct nand_chip nand_chip = (struct nand_chip )mtd->priv;
	struct bcm47xxnflash b47n = (struct bcm47xxnflash )nand_chip->priv;

	u32 ctlcode;
	u32 dest = (u32 )buf;
	int i;
	int toread;

	BUG_ON(b47n->curr_page_addr & ~nand_chip->pagemask);
	/* Don't validate column using nand_chip->page_shift, it may be bigger
	* when accessing OOB */

	while (len) {
	/* We can read maximum of 0x200 bytes at once */
	toread = min(len, 0x200);

	/* Set page and column */
	bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_COL_ADDR,
	b47n->curr_column);
	bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_ROW_ADDR,
	b47n->curr_page_addr);

	/* Prepare to read */
	ctlcode = NCTL_CSA \| NCTL_CMD1W \| 0x00040000 \| 0x00020000 \|
	NCTL_CMD0;
	ctlcode \|= NAND_CMD_READSTART << 8;
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc, ctlcode))
	return;
	if (bcm47xxnflash_ops_bcm4706_poll(b47n->cc))
	return;

	/* Eventually read some data :) */
	for (i = 0; i < toread; i += 4, dest++) {
	ctlcode = NCTL_CSA \| 0x30000000 \| NCTL_READ;
	if (i == toread - 4) /* Last read goes without that */
	ctlcode &= ~NCTL_CSA;
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc,
	ctlcode))
	return;
	*dest = bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_DATA);
	}

	b47n->curr_column += toread;
	len -= toread;
	}
	}

	static void bcm47xxnflash_ops_bcm4706_write(struct mtd_info *mtd,
	const uint8_t *buf, int len)
	{
	struct nand_chip nand_chip = (struct nand_chip )mtd->priv;
	struct bcm47xxnflash b47n = (struct bcm47xxnflash )nand_chip->priv;
	struct bcma_drv_cc *cc = b47n->cc;

	u32 ctlcode;
	const u32 data = (u32 )buf;
	int i;

	BUG_ON(b47n->curr_page_addr & ~nand_chip->pagemask);
	/* Don't validate column using nand_chip->page_shift, it may be bigger
	* when accessing OOB */

	for (i = 0; i < len; i += 4, data++) {
	bcma_cc_write32(cc, BCMA_CC_NFLASH_DATA, *data);

	ctlcode = NCTL_CSA \| 0x30000000 \| NCTL_WRITE;
	if (i == len - 4) /* Last read goes without that */
	ctlcode &= ~NCTL_CSA;
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode)) {
	pr_err("%s ctl_cmd didn't work!\n", __func__);
	return;
	}
	}

	b47n->curr_column += len;
	}

	/**************************************************
	* NAND chip ops
	**************************************************/

	/* Default nand_select_chip calls cmd_ctrl, which is not used in BCM4706 */
	static void bcm47xxnflash_ops_bcm4706_select_chip(struct mtd_info *mtd,
	int chip)
	{
	return;
	}

	static int bcm47xxnflash_ops_bcm4706_dev_ready(struct mtd_info *mtd)
	{
	struct nand_chip nand_chip = (struct nand_chip )mtd->priv;
	struct bcm47xxnflash b47n = (struct bcm47xxnflash )nand_chip->priv;

	return !!(bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_CTL) & NCTL_READY);
	}

	/*
	* Default nand_command and nand_command_lp don't match BCM4706 hardware layout.
	* For example, reading chip id is performed in a non-standard way.
	* Setting column and page is also handled differently, we use a special
	* registers of ChipCommon core. Hacking cmd_ctrl to understand and convert
	* standard commands would be much more complicated.
	*/
	static void bcm47xxnflash_ops_bcm4706_cmdfunc(struct mtd_info *mtd,
	unsigned command, int column,
	int page_addr)
	{
	struct nand_chip nand_chip = (struct nand_chip )mtd->priv;
	struct bcm47xxnflash b47n = (struct bcm47xxnflash )nand_chip->priv;
	struct bcma_drv_cc *cc = b47n->cc;
	u32 ctlcode;
	int i;

	if (column != -1)
	b47n->curr_column = column;
	if (page_addr != -1)
	b47n->curr_page_addr = page_addr;

	switch (command) {
	case NAND_CMD_RESET:
	pr_warn("Chip reset not implemented yet\n");
	break;
	case NAND_CMD_READID:
	ctlcode = NCTL_CSA \| 0x01000000 \| NCTL_CMD1W \| NCTL_CMD0;
	ctlcode \|= NAND_CMD_READID;
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc, ctlcode)) {
	pr_err("READID error\n");
	break;
	}

	/*
	* Reading is specific, last one has to go without NCTL_CSA
	* bit. We don't know how many reads NAND subsystem is going
	* to perform, so cache everything.
	*/
	for (i = 0; i < ARRAY_SIZE(b47n->id_data); i++) {
	ctlcode = NCTL_CSA \| NCTL_READ;
	if (i == ARRAY_SIZE(b47n->id_data) - 1)
	ctlcode &= ~NCTL_CSA;
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(b47n->cc,
	ctlcode)) {
	pr_err("READID error\n");
	break;
	}
	b47n->id_data[i] =
	bcma_cc_read32(b47n->cc, BCMA_CC_NFLASH_DATA)
	& 0xFF;
	}

	break;
	case NAND_CMD_STATUS:
	ctlcode = NCTL_CSA \| NCTL_CMD0 \| NAND_CMD_STATUS;
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
	pr_err("STATUS command error\n");
	break;
	case NAND_CMD_READ0:
	break;
	case NAND_CMD_READOOB:
	if (page_addr != -1)
	b47n->curr_column += mtd->writesize;
	break;
	case NAND_CMD_ERASE1:
	bcma_cc_write32(cc, BCMA_CC_NFLASH_ROW_ADDR,
	b47n->curr_page_addr);
	ctlcode = 0x00040000 \| NCTL_CMD1W \| NCTL_CMD0 \|
	NAND_CMD_ERASE1 \| (NAND_CMD_ERASE2 << 8);
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
	pr_err("ERASE1 failed\n");
	break;
	case NAND_CMD_ERASE2:
	break;
	case NAND_CMD_SEQIN:
	/* Set page and column */
	bcma_cc_write32(cc, BCMA_CC_NFLASH_COL_ADDR,
	b47n->curr_column);
	bcma_cc_write32(cc, BCMA_CC_NFLASH_ROW_ADDR,
	b47n->curr_page_addr);

	/* Prepare to write */
	ctlcode = 0x40000000 \| 0x00040000 \| 0x00020000 \| 0x00010000;
	ctlcode \|= NAND_CMD_SEQIN;
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, ctlcode))
	pr_err("SEQIN failed\n");
	break;
	case NAND_CMD_PAGEPROG:
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, 0x00010000 \|
	NAND_CMD_PAGEPROG))
	pr_err("PAGEPROG failed\n");
	if (bcm47xxnflash_ops_bcm4706_poll(cc))
	pr_err("PAGEPROG not ready\n");
	break;
	default:
	pr_err("Command 0x%X unsupported\n", command);
	break;
	}
	b47n->curr_command = command;
	}

	static u8 bcm47xxnflash_ops_bcm4706_read_byte(struct mtd_info *mtd)
	{
	struct nand_chip nand_chip = (struct nand_chip )mtd->priv;
	struct bcm47xxnflash b47n = (struct bcm47xxnflash )nand_chip->priv;
	struct bcma_drv_cc *cc = b47n->cc;
	u32 tmp = 0;

	switch (b47n->curr_command) {
	case NAND_CMD_READID:
	if (b47n->curr_column >= ARRAY_SIZE(b47n->id_data)) {
	pr_err("Requested invalid id_data: %d\n",
	b47n->curr_column);
	return 0;
	}
	return b47n->id_data[b47n->curr_column++];
	case NAND_CMD_STATUS:
	if (bcm47xxnflash_ops_bcm4706_ctl_cmd(cc, NCTL_READ))
	return 0;
	return bcma_cc_read32(cc, BCMA_CC_NFLASH_DATA) & 0xff;
	case NAND_CMD_READOOB:
	bcm47xxnflash_ops_bcm4706_read(mtd, (u8 *)&tmp, 4);
	return tmp & 0xFF;
	}

	pr_err("Invalid command for byte read: 0x%X\n", b47n->curr_command);
	return 0;
	}

	static void bcm47xxnflash_ops_bcm4706_read_buf(struct mtd_info *mtd,
	uint8_t *buf, int len)
	{
	struct nand_chip nand_chip = (struct nand_chip )mtd->priv;
	struct bcm47xxnflash b47n = (struct bcm47xxnflash )nand_chip->priv;

	switch (b47n->curr_command) {
	case NAND_CMD_READ0:
	case NAND_CMD_READOOB:
	bcm47xxnflash_ops_bcm4706_read(mtd, buf, len);
	return;
	}

	pr_err("Invalid command for buf read: 0x%X\n", b47n->curr_command);
	}

	static void bcm47xxnflash_ops_bcm4706_write_buf(struct mtd_info *mtd,
	const uint8_t *buf, int len)
	{
	struct nand_chip nand_chip = (struct nand_chip )mtd->priv;
	struct bcm47xxnflash b47n = (struct bcm47xxnflash )nand_chip->priv;

	switch (b47n->curr_command) {
	case NAND_CMD_SEQIN:
	bcm47xxnflash_ops_bcm4706_write(mtd, buf, len);
	return;
	}

	pr_err("Invalid command for buf write: 0x%X\n", b47n->curr_command);
	}

	/**************************************************
	* Init
	**************************************************/

	int bcm47xxnflash_ops_bcm4706_init(struct bcm47xxnflash *b47n)
	{
	struct nand_chip nand_chip = (struct nand_chip )&b47n->nand_chip;
	int err;
	u32 freq;
	u16 clock;
	u8 w0, w1, w2, w3, w4;

	unsigned long chipsize; /* MiB */
	u8 tbits, col_bits, col_size, row_bits, row_bsize;
	u32 val;

	b47n->nand_chip.select_chip = bcm47xxnflash_ops_bcm4706_select_chip;
	nand_chip->dev_ready = bcm47xxnflash_ops_bcm4706_dev_ready;
	b47n->nand_chip.cmdfunc = bcm47xxnflash_ops_bcm4706_cmdfunc;
	b47n->nand_chip.read_byte = bcm47xxnflash_ops_bcm4706_read_byte;
	b47n->nand_chip.read_buf = bcm47xxnflash_ops_bcm4706_read_buf;
	b47n->nand_chip.write_buf = bcm47xxnflash_ops_bcm4706_write_buf;

	nand_chip->chip_delay = 50;
	b47n->nand_chip.bbt_options = NAND_BBT_USE_FLASH;
	b47n->nand_chip.ecc.mode = NAND_ECC_NONE; /* TODO: implement ECC */

	/* Enable NAND flash access */
	bcma_cc_set32(b47n->cc, BCMA_CC_4706_FLASHSCFG,
	BCMA_CC_4706_FLASHSCFG_NF1);

	/* Configure wait counters */
	if (b47n->cc->status & BCMA_CC_CHIPST_4706_PKG_OPTION) {
	/* 400 MHz */
	freq = 400000000 / 4;
	} else {
	freq = bcma_chipco_pll_read(b47n->cc, 4);
	freq = (freq & 0xFFF) >> 3;
	/* Fixed reference clock 25 MHz and m = 2 */
	freq = (freq * 25000000 / 2) / 4;
	}
	clock = freq / 1000000;
	w0 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(15, clock);
	w1 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(20, clock);
	w2 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(10, clock);
	w3 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(10, clock);
	w4 = bcm47xxnflash_ops_bcm4706_ns_to_cycle(100, clock);
	bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_WAITCNT0,
	(w4 << 24 \| w3 << 18 \| w2 << 12 \| w1 << 6 \| w0));

	/* Scan NAND */
	err = nand_scan(&b47n->mtd, 1);
	if (err) {
	pr_err("Could not scan NAND flash: %d\n", err);
	goto exit;
	}

	/* Configure FLASH */
	chipsize = b47n->nand_chip.chipsize >> 20;
	tbits = ffs(chipsize); /* find first bit set */
	if (!tbits \|\| tbits != fls(chipsize)) {
	pr_err("Invalid flash size: 0x%lX\n", chipsize);
	err = -ENOTSUPP;
	goto exit;
	}
	tbits += 19; /* Broadcom increases index by 20, we increase pos */

	col_bits = b47n->nand_chip.page_shift + 1;
	col_size = (col_bits + 7) / 8;

	row_bits = tbits - col_bits + 1;
	row_bsize = (row_bits + 7) / 8;

	val = ((row_bsize - 1) << 6) \| ((col_size - 1) << 4) \| 2;
	bcma_cc_write32(b47n->cc, BCMA_CC_NFLASH_CONF, val);

	exit:
	if (err)
	bcma_cc_mask32(b47n->cc, BCMA_CC_4706_FLASHSCFG,
	~BCMA_CC_4706_FLASHSCFG_NF1);
	return err;
	}