mtd: OneNAND OTP support rework

What is OTP in OneNAND?
The device includes,
1. one block-sized OTP (One Time Programmable) area and
2. user-controlled 1st block OTP(Block 0)
that can be used to increase system security or to provide
identification capabilities.

What is done?
In OneNAND, one block of the NAND Array is set aside as an OTP
memory area, and 1st Block (Block 0) can be used as OTP area.
This area, available to the user, can be configured and locked
with secured user information. The OTP block can be read,
programmed and locked using the same operations as any other NAND
Flash Array memory block. After issuing an OTP-Lock, OTP block
cannot be erased. OTP block is fully-guaranteed to be a good
block.

Why it is done?
Locking the 1st Block OTP has the effect of a 'Write-protect' to
guard against accidental re-programming of data stored in the 1st
block and OTP Block.

Which problem it solves?
OTP support is provided in the existing implementation of
OneNAND/Flex-OneNAND driver, but it is not working with OneNAND
devices. Have observed the following in current OTP OneNAND Implmentation,
1. DataSheet specific sequence to lock the OTP Area is not followed.
2. Certain functions are quiet generic to cope with OTP specific activity.
This patch re-implements OTP support for OneNAND device.

How it is done?
For all blocks, 8th word is available to the user.
However, in case of OTP Block, 8th word of sector 0, page 0 is reserved as
OTP Locking Bit area. Therefore, in case of OTP Block, user usage on this
area is prohibited. Condition specific values are entered in the 8th word,
sector0, page 0 of the OTP block during the process of issuing an OTP-Lock.
The possible conditions are:
1. Only 1st Block Lock
2. Only OTP Block Lock
3. Lock both the 1st Block and the OTP Block

What Other feature additions have been done in this patch?
This patch adds feature for:
1. Only 1st Block Lock
2. Lock both the 1st Block and the OTP Blocks

Re-implemented OTP support for OneNAND
Added following features to OneNAND
1. Lock only 1st Block in OneNAND
2. Lock BOTH 1st Block and OTP Block in OneNAND

[comments were slightly tweaked by Artem]

Signed-off-by: Amul Kumar Saha <[e-mail]>
Reviewed-by: Adrian Hunter <[e-mail]>
Signed-off-by: Artem Bityutskiy <[e-mail]>
Signed-off-by: David Woodhouse <[e-mail]>

drivers/mtd/onenand/onenand_base.c

···
 /*
  *  linux/drivers/mtd/onenand/onenand_base.c
  *
- *  Copyright (C) 2005-2007 Samsung Electronics
+ *  Copyright © 2005-2009 Samsung Electronics
+ *  Copyright © 2007 Nokia Corporation
+ *
  *  Kyungmin Park <[e-mail]>
  *
  *  Credits:
  *	Adrian Hunter <[e-mail]>:
  *	auto-placement support, read-while load support, various fixes
- *	Copyright (C) Nokia Corporation, 2007
  *
  *	Vishak G <vishak.g at samsung.com>, Rohit Hagargundgi <h.rohit at samsung.com>
  *	Flex-OneNAND support
- *	Copyright (C) Samsung Electronics, 2008
+ *	Amul Kumar Saha <amul.saha at samsung.com>
+ *	OTP support
  *
  * 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
···
 				"LOCK: Locking information for SLC boundary"
 				"    : 0->Set boundary in unlocked status"
 				"    : 1->Set boundary in locked status");
+
+/* Default OneNAND/Flex-OneNAND OTP options*/
+static int otp;
+
+module_param(otp, int, 0400);
+MODULE_PARM_DESC(otp,	"Corresponding behaviour of OneNAND in OTP"
+			"Syntax : otp=LOCK_TYPE"
+			"LOCK_TYPE : Keys issued, for specific OTP Lock type"
+			"	   : 0 -> Default (No Blocks Locked)"
+			"	   : 1 -> OTP Block lock"
+			"	   : 2 -> 1st Block lock"
+			"	   : 3 -> BOTH OTP Block and 1st Block lock");
 
 /**
  *  onenand_oob_128 - oob info for Flex-Onenand with 4KB page
···
 
 #ifdef CONFIG_MTD_ONENAND_OTP
 
+/**
+ * onenand_otp_command - Send OTP specific command to OneNAND device
+ * @param mtd	 MTD device structure
+ * @param cmd	 the command to be sent
+ * @param addr	 offset to read from or write to
+ * @param len	 number of bytes to read or write
+ */
+static int onenand_otp_command(struct mtd_info *mtd, int cmd, loff_t addr,
+				size_t len)
+{
+	struct onenand_chip *this = mtd->priv;
+	int value, block, page;
+
+	/* Address translation */
+	switch (cmd) {
+	case ONENAND_CMD_OTP_ACCESS:
+		block = (int) (addr >> this->erase_shift);
+		page = -1;
+		break;
+
+	default:
+		block = (int) (addr >> this->erase_shift);
+		page = (int) (addr >> this->page_shift);
+
+		if (ONENAND_IS_2PLANE(this)) {
+			/* Make the even block number */
+			block &= ~1;
+			/* Is it the odd plane? */
+			if (addr & this->writesize)
+				block++;
+			page >>= 1;
+		}
+		page &= this->page_mask;
+		break;
+	}
+
+	if (block != -1) {
+		/* Write 'DFS, FBA' of Flash */
+		value = onenand_block_address(this, block);
+		this->write_word(value, this->base +
+				ONENAND_REG_START_ADDRESS1);
+	}
+
+	if (page != -1) {
+		/* Now we use page size operation */
+		int sectors = 4, count = 4;
+		int dataram;
+
+		switch (cmd) {
+		default:
+			if (ONENAND_IS_2PLANE(this) && cmd == ONENAND_CMD_PROG)
+				cmd = ONENAND_CMD_2X_PROG;
+			dataram = ONENAND_CURRENT_BUFFERRAM(this);
+			break;
+		}
+
+		/* Write 'FPA, FSA' of Flash */
+		value = onenand_page_address(page, sectors);
+		this->write_word(value, this->base +
+				ONENAND_REG_START_ADDRESS8);
+
+		/* Write 'BSA, BSC' of DataRAM */
+		value = onenand_buffer_address(dataram, sectors, count);
+		this->write_word(value, this->base + ONENAND_REG_START_BUFFER);
+	}
+
+	/* Interrupt clear */
+	this->write_word(ONENAND_INT_CLEAR, this->base + ONENAND_REG_INTERRUPT);
+
+	/* Write command */
+	this->write_word(cmd, this->base + ONENAND_REG_COMMAND);
+
+	return 0;
+}
+
+/**
+ * onenand_otp_write_oob_nolock - [Internal] OneNAND write out-of-band, specific to OTP
+ * @param mtd		MTD device structure
+ * @param to		offset to write to
+ * @param len		number of bytes to write
+ * @param retlen	pointer to variable to store the number of written bytes
+ * @param buf		the data to write
+ *
+ * OneNAND write out-of-band only for OTP
+ */
+static int onenand_otp_write_oob_nolock(struct mtd_info *mtd, loff_t to,
+				    struct mtd_oob_ops *ops)
+{
+	struct onenand_chip *this = mtd->priv;
+	int column, ret = 0, oobsize;
+	int written = 0;
+	u_char *oobbuf;
+	size_t len = ops->ooblen;
+	const u_char *buf = ops->oobbuf;
+	int block, value, status;
+
+	to += ops->ooboffs;
+
+	/* Initialize retlen, in case of early exit */
+	ops->oobretlen = 0;
+
+	oobsize = mtd->oobsize;
+
+	column = to & (mtd->oobsize - 1);
+
+	oobbuf = this->oob_buf;
+
+	/* Loop until all data write */
+	while (written < len) {
+		int thislen = min_t(int, oobsize, len - written);
+
+		cond_resched();
+
+		block = (int) (to >> this->erase_shift);
+		/*
+		 * Write 'DFS, FBA' of Flash
+		 * Add: F100h DQ=DFS, FBA
+		 */
+
+		value = onenand_block_address(this, block);
+		this->write_word(value, this->base +
+				ONENAND_REG_START_ADDRESS1);
+
+		/*
+		 * Select DataRAM for DDP
+		 * Add: F101h DQ=DBS
+		 */
+
+		value = onenand_bufferram_address(this, block);
+		this->write_word(value, this->base +
+				ONENAND_REG_START_ADDRESS2);
+		ONENAND_SET_NEXT_BUFFERRAM(this);
+
+		/*
+		 * Enter OTP access mode
+		 */
+		this->command(mtd, ONENAND_CMD_OTP_ACCESS, 0, 0);
+		this->wait(mtd, FL_OTPING);
+
+		/* We send data to spare ram with oobsize
+		 * to prevent byte access */
+		memcpy(oobbuf + column, buf, thislen);
+
+		/*
+		 * Write Data into DataRAM
+		 * Add: 8th Word
+		 * in sector0/spare/page0
+		 * DQ=XXFCh
+		 */
+		this->write_bufferram(mtd, ONENAND_SPARERAM,
+					oobbuf, 0, mtd->oobsize);
+
+		onenand_otp_command(mtd, ONENAND_CMD_PROGOOB, to, mtd->oobsize);
+		onenand_update_bufferram(mtd, to, 0);
+		if (ONENAND_IS_2PLANE(this)) {
+			ONENAND_SET_BUFFERRAM1(this);
+			onenand_update_bufferram(mtd, to + this->writesize, 0);
+		}
+
+		ret = this->wait(mtd, FL_WRITING);
+		if (ret) {
+			printk(KERN_ERR "%s: write failed %d\n", __func__, ret);
+			break;
+		}
+
+		/* Exit OTP access mode */
+		this->command(mtd, ONENAND_CMD_RESET, 0, 0);
+		this->wait(mtd, FL_RESETING);
+
+		status = this->read_word(this->base + ONENAND_REG_CTRL_STATUS);
+		status &= 0x60;
+
+		if (status == 0x60) {
+			printk(KERN_DEBUG "\nBLOCK\tSTATUS\n");
+			printk(KERN_DEBUG "1st Block\tLOCKED\n");
+			printk(KERN_DEBUG "OTP Block\tLOCKED\n");
+		} else if (status == 0x20) {
+			printk(KERN_DEBUG "\nBLOCK\tSTATUS\n");
+			printk(KERN_DEBUG "1st Block\tLOCKED\n");
+			printk(KERN_DEBUG "OTP Block\tUN-LOCKED\n");
+		} else if (status == 0x40) {
+			printk(KERN_DEBUG "\nBLOCK\tSTATUS\n");
+			printk(KERN_DEBUG "1st Block\tUN-LOCKED\n");
+			printk(KERN_DEBUG "OTP Block\tLOCKED\n");
+		} else {
+			printk(KERN_DEBUG "Reboot to check\n");
+		}
+
+		written += thislen;
+		if (written == len)
+			break;
+
+		to += mtd->writesize;
+		buf += thislen;
+		column = 0;
+	}
+
+	ops->oobretlen = written;
+
+	return ret;
+}
+
 /* Internal OTP operation */
 typedef int (*otp_op_t)(struct mtd_info *mtd, loff_t form, size_t len,
 		size_t *retlen, u_char *buf);
···
 	struct mtd_oob_ops ops;
 	int ret;
 
-	/* Enter OTP access mode */
-	this->command(mtd, ONENAND_CMD_OTP_ACCESS, 0, 0);
-	this->wait(mtd, FL_OTPING);
-
 	if (FLEXONENAND(this)) {
+
+		/* Enter OTP access mode */
+		this->command(mtd, ONENAND_CMD_OTP_ACCESS, 0, 0);
+		this->wait(mtd, FL_OTPING);
 		/*
 		 * For Flex-OneNAND, we write lock mark to 1st word of sector 4 of
 		 * main area of page 49.
···
 		ops.oobbuf = NULL;
 		ret = onenand_write_ops_nolock(mtd, mtd->writesize * 49, &ops);
 		*retlen = ops.retlen;
+
+		/* Exit OTP access mode */
+		this->command(mtd, ONENAND_CMD_RESET, 0, 0);
+		this->wait(mtd, FL_RESETING);
 	} else {
 		ops.mode = MTD_OOB_PLACE;
 		ops.ooblen = len;
 		ops.oobbuf = buf;
 		ops.ooboffs = 0;
-		ret = onenand_write_oob_nolock(mtd, from, &ops);
+		ret = onenand_otp_write_oob_nolock(mtd, from, &ops);
 		*retlen = ops.oobretlen;
 	}
-
-	/* Exit OTP access mode */
-	this->command(mtd, ONENAND_CMD_RESET, 0, 0);
-	this->wait(mtd, FL_RESETING);
 
 	return ret;
 }
···
 	if (density < ONENAND_DEVICE_DENSITY_512Mb)
 		otp_pages = 20;
 	else
-		otp_pages = 10;
+		otp_pages = 50;
 
 	if (mode == MTD_OTP_FACTORY) {
 		from += mtd->writesize * otp_pages;
-		otp_pages = 64 - otp_pages;
+		otp_pages = ONENAND_PAGES_PER_BLOCK - otp_pages;
 	}
 
 	/* Check User/Factory boundary */
-	if (((mtd->writesize * otp_pages) - (from + len)) < 0)
-		return 0;
+	if (mode == MTD_OTP_USER) {
+		if (((mtd->writesize * otp_pages) - (from + len)) < 0)
+			return 0;
+	} else {
+		if (((mtd->writesize * otp_pages) - len) < 0)
+			return 0;
+	}
 
 	onenand_get_device(mtd, FL_OTPING);
 	while (len > 0 && otp_pages > 0) {
···
 			*retlen += sizeof(struct otp_info);
 		} else {
 			size_t tmp_retlen;
-			int size = len;
 
 			ret = action(mtd, from, len, &tmp_retlen, buf);
 
-			buf += size;
-			len -= size;
-			*retlen += size;
+			buf += tmp_retlen;
+			len -= tmp_retlen;
+			*retlen += tmp_retlen;
 
 			if (ret)
 				break;
···
 	u_char *buf = FLEXONENAND(this) ? this->page_buf : this->oob_buf;
 	size_t retlen;
 	int ret;
+	unsigned int otp_lock_offset = ONENAND_OTP_LOCK_OFFSET;
 
 	memset(buf, 0xff, FLEXONENAND(this) ? this->writesize
 						 : mtd->oobsize);
-	/*
-	 * Note: OTP lock operation
-	 *       OTP block : 0xXXFC
-	 *       1st block : 0xXXF3 (If chip support)
-	 *       Both      : 0xXXF0 (If chip support)
-	 */
-	if (FLEXONENAND(this))
-		buf[FLEXONENAND_OTP_LOCK_OFFSET] = 0xFC;
-	else
-		buf[ONENAND_OTP_LOCK_OFFSET] = 0xFC;
-
 	/*
 	 * Write lock mark to 8th word of sector0 of page0 of the spare0.
 	 * We write 16 bytes spare area instead of 2 bytes.
···
 	from = 0;
 	len = FLEXONENAND(this) ? mtd->writesize : 16;
 
+	/*
+	 * Note: OTP lock operation
+	 *       OTP block : 0xXXFC			XX 1111 1100
+	 *       1st block : 0xXXF3 (If chip support)	XX 1111 0011
+	 *       Both      : 0xXXF0 (If chip support)	XX 1111 0000
+	 */
+	if (FLEXONENAND(this))
+		otp_lock_offset = FLEXONENAND_OTP_LOCK_OFFSET;
+
+	/* ONENAND_OTP_AREA | ONENAND_OTP_BLOCK0 | ONENAND_OTP_AREA_BLOCK0 */
+	if (otp == 1)
+		buf[otp_lock_offset] = 0xFC;
+	else if (otp == 2)
+		buf[otp_lock_offset] = 0xF3;
+	else if (otp == 3)
+		buf[otp_lock_offset] = 0xF0;
+	else if (otp != 0)
+		printk(KERN_DEBUG "[OneNAND] Invalid option selected for OTP\n");
+
 	ret = onenand_otp_walk(mtd, from, len, &retlen, buf, do_otp_lock, MTD_OTP_USER);
 
 	return ret ? : retlen;
 }
+
 #endif	/* CONFIG_MTD_ONENAND_OTP */
 
 /**

include/linux/mtd/onenand.h

···
 /*
  *  linux/include/linux/mtd/onenand.h
  *
- *  Copyright (C) 2005-2007 Samsung Electronics
+ *  Copyright © 2005-2009 Samsung Electronics
  *  Kyungmin Park <[e-mail]>
  *
  * This program is free software; you can redistribute it and/or modify
···
 /*
  * Helper macros
  */
+#define ONENAND_PAGES_PER_BLOCK        (1<<6)
+
 #define ONENAND_CURRENT_BUFFERRAM(this)		(this->bufferram_index)
 #define ONENAND_NEXT_BUFFERRAM(this)		(this->bufferram_index ^ 1)
 #define ONENAND_SET_NEXT_BUFFERRAM(this)	(this->bufferram_index ^= 1)