path: root/drivers/mtd/nand/docg4.c

/*
 *  Copyright © 2012 Mike Dunn <mikedunn@newsguy.com>
 *
 * mtd nand driver for M-Systems DiskOnChip G4
 *
 * 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.
 *
 * Tested on the Palm Treo 680.  The G4 is also present on Toshiba Portege, Asus
 * P526, some HTC smartphones (Wizard, Prophet, ...), O2 XDA Zinc, maybe others.
 * Should work on these as well.  Let me know!
 *
 * TODO:
 *
 *  Mechanism for management of password-protected areas
 *
 *  Hamming ecc when reading oob only
 *
 *  According to the M-Sys documentation, this device is also available in a
 *  "dual-die" configuration having a 256MB capacity, but no mechanism for
 *  detecting this variant is documented.  Currently this driver assumes 128MB
 *  capacity.
 *
 *  Support for multiple cascaded devices ("floors").  Not sure which gadgets
 *  contain multiple G4s in a cascaded configuration, if any.
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/export.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/bitops.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/bch.h>
#include <linux/bitrev.h>

/*
 * You'll want to ignore badblocks if you're reading a partition that contains
 * data written by the TrueFFS library (i.e., by PalmOS, Windows, etc), since
 * it does not use mtd nand's method for marking bad blocks (using oob area).
 * This will also skip the check of the "page written" flag.
 */
static bool ignore_badblocks;
module_param(ignore_badblocks, bool, 0);
MODULE_PARM_DESC(ignore_badblocks, "no badblock checking performed");

struct docg4_priv {
	struct mtd_info	*mtd;
	struct device *dev;
	void __iomem *virtadr;
	int status;
	struct {
		unsigned int command;
		int column;
		int page;
	} last_command;
	uint8_t oob_buf[16];
	uint8_t ecc_buf[7];
	int oob_page;
	struct bch_control *bch;
};

/*
 * Defines prefixed with DOCG4 are unique to the diskonchip G4.  All others are
 * shared with other diskonchip devices (P3, G3 at least).
 *
 * Functions with names prefixed with docg4_ are mtd / nand interface functions
 * (though they may also be called internally).  All others are internal.
 */

#define DOC_IOSPACE_DATA		0x0800

/* register offsets */
#define DOC_CHIPID			0x1000
#define DOC_DEVICESELECT		0x100a
#define DOC_ASICMODE			0x100c
#define DOC_DATAEND			0x101e
#define DOC_NOP				0x103e

#define DOC_FLASHSEQUENCE		0x1032
#define DOC_FLASHCOMMAND		0x1034
#define DOC_FLASHADDRESS		0x1036
#define DOC_FLASHCONTROL		0x1038
#define DOC_ECCCONF0			0x1040
#define DOC_ECCCONF1			0x1042
#define DOC_HAMMINGPARITY		0x1046
#define DOC_BCH_SYNDROM(idx)		(0x1048 + idx)

#define DOC_ASICMODECONFIRM		0x1072
#define DOC_CHIPID_INV			0x1074
#define DOC_POWERMODE			0x107c

#define DOCG4_MYSTERY_REG		0x1050

/* apparently used only to write oob bytes 6 and 7 */
#define DOCG4_OOB_6_7			0x1052

/* DOC_FLASHSEQUENCE register commands */
#define DOC_SEQ_RESET			0x00
#define DOCG4_SEQ_PAGE_READ		0x03
#define DOCG4_SEQ_FLUSH			0x29
#define DOCG4_SEQ_PAGEWRITE		0x16
#define DOCG4_SEQ_PAGEPROG		0x1e
#define DOCG4_SEQ_BLOCKERASE		0x24

/* DOC_FLASHCOMMAND register commands */
#define DOCG4_CMD_PAGE_READ             0x00
#define DOC_CMD_ERASECYCLE2		0xd0
#define DOCG4_CMD_FLUSH                 0x70
#define DOCG4_CMD_READ2                 0x30
#define DOC_CMD_PROG_BLOCK_ADDR		0x60
#define DOCG4_CMD_PAGEWRITE		0x80
#define DOC_CMD_PROG_CYCLE2		0x10
#define DOC_CMD_RESET			0xff

/* DOC_POWERMODE register bits */
#define DOC_POWERDOWN_READY		0x80

/* DOC_FLASHCONTROL register bits */
#define DOC_CTRL_CE			0x10
#define DOC_CTRL_UNKNOWN		0x40