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/*

 *  drivers/mtd/nand/rtc_from4.c

 *

 *  Copyright (C) 2004  Red Hat, Inc.

 *

 *  Derived from drivers/mtd/nand/spia.c

 *       Copyright (C) 2000 Steven J. Hill (sjhill@realitydiluted.com)

 *

 * $Id: rtc_from4.c,v 1.10 2005/11/07 11:14:31 gleixner 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.

 *

 * Overview:

 *   This is a device driver for the AG-AND flash device found on the

 *   Renesas Technology Corp. Flash ROM 4-slot interface board (FROM_BOARD4),

 *   which utilizes the Renesas HN29V1G91T-30 part.

 *   This chip is a 1 GBibit (128MiB x 8 bits) AG-AND flash device.

 */

#include <linux/delay.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/rslib.h>

#include <linux/bitrev.h>

#include <linux/module.h>

#include <linux/mtd/compatmac.h>

#include <linux/mtd/mtd.h>

#include <linux/mtd/nand.h>

#include <linux/mtd/partitions.h>

#include <asm/io.h>

/*

 * MTD structure for Renesas board

 */

static struct mtd_info *rtc_from4_mtd = NULL;

#define RTC_FROM4_MAX_CHIPS     2

/* HS77x9 processor register defines */

#define SH77X9_BCR1     ((volatile unsigned short *)(0xFFFFFF60))

#define SH77X9_BCR2     ((volatile unsigned short *)(0xFFFFFF62))

#define SH77X9_WCR1     ((volatile unsigned short *)(0xFFFFFF64))

#define SH77X9_WCR2     ((volatile unsigned short *)(0xFFFFFF66))

#define SH77X9_MCR      ((volatile unsigned short *)(0xFFFFFF68))

#define SH77X9_PCR      ((volatile unsigned short *)(0xFFFFFF6C))

#define SH77X9_FRQCR    ((volatile unsigned short *)(0xFFFFFF80))

/*

 * Values specific to the Renesas Technology Corp. FROM_BOARD4 (used with HS77x9 processor)

 */

/* Address where flash is mapped */

#define RTC_FROM4_FIO_BASE      0x14000000

/* CLE and ALE are tied to address lines 5 & 4, respectively */

#define RTC_FROM4_CLE           (1 << 5)

#define RTC_FROM4_ALE           (1 << 4)

/* address lines A24-A22 used for chip selection */

#define RTC_FROM4_NAND_ADDR_SLOT3       (0x00800000)

#define RTC_FROM4_NAND_ADDR_SLOT4       (0x00C00000)

#define RTC_FROM4_NAND_ADDR_FPGA        (0x01000000)

/* mask address lines A24-A22 used for chip selection */

#define RTC_FROM4_NAND_ADDR_MASK        (RTC_FROM4_NAND_ADDR_SLOT3 | RTC_FROM4_NAND_ADDR_SLOT4 | RTC_FROM4_NAND_ADDR_FPGA)

/* FPGA status register for checking device ready (bit zero) */

#define RTC_FROM4_FPGA_SR               (RTC_FROM4_NAND_ADDR_FPGA | 0x00000002)

#define RTC_FROM4_DEVICE_READY          0x0001

/* FPGA Reed-Solomon ECC Control register */

#define RTC_FROM4_RS_ECC_CTL            (RTC_FROM4_NAND_ADDR_FPGA | 0x00000050)

#define RTC_FROM4_RS_ECC_CTL_CLR        (1 << 7)

#define RTC_FROM4_RS_ECC_CTL_GEN        (1 << 6)

#define RTC_FROM4_RS_ECC_CTL_FD_E       (1 << 5)

/* FPGA Reed-Solomon ECC code base */

#define RTC_FROM4_RS_ECC                (RTC_FROM4_NAND_ADDR_FPGA | 0x00000060)

#define RTC_FROM4_RS_ECCN               (RTC_FROM4_NAND_ADDR_FPGA | 0x00000080)

/* FPGA Reed-Solomon ECC check register */

#define RTC_FROM4_RS_ECC_CHK            (RTC_FROM4_NAND_ADDR_FPGA | 0x00000070)

#define RTC_FROM4_RS_ECC_CHK_ERROR      (1 << 7)

#define ERR_STAT_ECC_AVAILABLE          0x20

/* Undefine for software ECC */

#define RTC_FROM4_HWECC 1

/* Define as 1 for no virtual erase blocks (in JFFS2) */

#define RTC_FROM4_NO_VIRTBLOCKS 0

/*

 * Module stuff

 */

static void __iomem *rtc_from4_fio_base = (void *)P2SEGADDR(RTC_FROM4_FIO_BASE);

static const struct mtd_partition partition_info[] = {

        {

         .name = "Renesas flash partition 1",

         .offset = 0,

         .size = MTDPART_SIZ_FULL},

};

#define NUM_PARTITIONS 1

/*

 *      hardware specific flash bbt decriptors

 *      Note: this is to allow debugging by disabling

 *              NAND_BBT_CREATE and/or NAND_BBT_WRITE

 *

 */

static uint8_t bbt_pattern[] = { 'B', 'b', 't', '0' };

static uint8_t mirror_pattern[] = { '1', 't', 'b', 'B' };

static struct nand_bbt_descr rtc_from4_bbt_main_descr = {

        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE

                | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,

        .offs = 40,

        .len = 4,

        .veroffs = 44,

        .maxblocks = 4,

        .pattern = bbt_pattern

};

static struct nand_bbt_descr rtc_from4_bbt_mirror_descr = {

        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE

                | NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,

        .offs = 40,

        .len = 4,

        .veroffs = 44,

        .maxblocks = 4,

        .pattern = mirror_pattern

};

#ifdef RTC_FROM4_HWECC

/* the Reed Solomon control structure */

static struct rs_control *rs_decoder;

/*

 *      hardware specific Out Of Band information

 */

static struct nand_ecclayout rtc_from4_nand_oobinfo = {

        .eccbytes = 32,

        .eccpos = {

                   0, 1, 2, 3, 4, 5, 6, 7,

                   8, 9, 10, 11, 12, 13, 14, 15,

                   16, 17, 18, 19, 20, 21, 22, 23,

                   24, 25, 26, 27, 28, 29, 30, 31},

        .oobfree = {{32, 32}}

};

#endif

/*

 * rtc_from4_hwcontrol - hardware specific access to control-lines

 * @mtd:        MTD device structure

 * @cmd:        hardware control command

 *

 * Address lines (A5 and A4) are used to control Command and Address Latch

 * Enable on this board, so set the read/write address appropriately.

 *

 * Chip Enable is also controlled by the Chip Select (CS5) and

 * Address lines (A24-A22), so no action is required here.

 *

 */

static void rtc_from4_hwcontrol(struct mtd_info *mtd, int cmd,

                                unsigned int ctrl)

{

        struct nand_chip *chip = (mtd->priv);

        if (cmd == NAND_CMD_NONE)

                return;

        if (ctrl & NAND_CLE)

                writeb(cmd, chip->IO_ADDR_W | RTC_FROM4_CLE);

        else

                writeb(cmd, chip->IO_ADDR_W | RTC_FROM4_ALE);

}

/*

 * rtc_from4_nand_select_chip - hardware specific chip select

 * @mtd:        MTD device structure

 * @chip:       Chip to select (0 == slot 3, 1 == slot 4)

 *

 * The chip select is based on address lines A24-A22.

 * This driver uses flash slots 3 and 4 (A23-A22).

 *

 */

static void rtc_from4_nand_select_chip(struct mtd_info *mtd, int chip)

{

        struct nand_chip *this = mtd->priv;

        this->IO_ADDR_R = (void __iomem *)((unsigned long)this->IO_ADDR_R & ~RTC_FROM4_NAND_ADDR_MASK);

        this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W & ~RTC_FROM4_NAND_ADDR_MASK);

        switch (chip) {

        case 0:          /* select slot 3 chip */

                this->IO_ADDR_R = (void __iomem *)((unsigned long)this->IO_ADDR_R | RTC_FROM4_NAND_ADDR_SLOT3);

                this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W | RTC_FROM4_NAND_ADDR_SLOT3);

                break;

        case 1:         /* select slot 4 chip */

                this->IO_ADDR_R = (void __iomem *)((unsigned long)this->IO_ADDR_R | RTC_FROM4_NAND_ADDR_SLOT4);

                this->IO_ADDR_W = (void __iomem *)((unsigned long)this->IO_ADDR_W | RTC_FROM4_NAND_ADDR_SLOT4);

                break;

        }

}

/*

 * rtc_from4_nand_device_ready - hardware specific ready/busy check

 * @mtd:        MTD device structure

 *

 * This board provides the Ready/Busy state in the status register

 * of the FPGA.  Bit zero indicates the RDY(1)/BSY(0) signal.

 *

 */

static int rtc_from4_nand_device_ready(struct mtd_info *mtd)

{

        unsigned short status;

        status = *((volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_FPGA_SR));

        return (status & RTC_FROM4_DEVICE_READY);

}

/*

 * deplete - code to perform device recovery in case there was a power loss

 * @mtd:        MTD device structure

 * @chip:       Chip to select (0 == slot 3, 1 == slot 4)

 *

 * If there was a sudden loss of power during an erase operation, a

 * "device recovery" operation must be performed when power is restored

 * to ensure correct operation.  This routine performs the required steps

 * for the requested chip.

 *

 * See page 86 of the data sheet for details.

 *

 */

static void deplete(struct mtd_info *mtd, int chip)

{

        struct nand_chip *this = mtd->priv;

        /* wait until device is ready */

        while (!this->dev_ready(mtd)) ;

        this->select_chip(mtd, chip);

        /* Send the commands for device recovery, phase 1 */

        this->cmdfunc(mtd, NAND_CMD_DEPLETE1, 0x0000, 0x0000);

        this->cmdfunc(mtd, NAND_CMD_DEPLETE2, -1, -1);

        /* Send the commands for device recovery, phase 2 */

        this->cmdfunc(mtd, NAND_CMD_DEPLETE1, 0x0000, 0x0004);

        this->cmdfunc(mtd, NAND_CMD_DEPLETE2, -1, -1);

}

#ifdef RTC_FROM4_HWECC

/*

 * rtc_from4_enable_hwecc - hardware specific hardware ECC enable function

 * @mtd:        MTD device structure

 * @mode:       I/O mode; read or write

 *

 * enable hardware ECC for data read or write

 *

 */

static void rtc_from4_enable_hwecc(struct mtd_info *mtd, int mode)

{

        volatile unsigned short *rs_ecc_ctl = (volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_RS_ECC_CTL);

        unsigned short status;

        switch (mode) {

        case NAND_ECC_READ:

                status = RTC_FROM4_RS_ECC_CTL_CLR | RTC_FROM4_RS_ECC_CTL_FD_E;

                *rs_ecc_ctl = status;

                break;

        case NAND_ECC_READSYN:

                status = 0x00;

                *rs_ecc_ctl = status;

                break;

        case NAND_ECC_WRITE:

                status = RTC_FROM4_RS_ECC_CTL_CLR | RTC_FROM4_RS_ECC_CTL_GEN | RTC_FROM4_RS_ECC_CTL_FD_E;

                *rs_ecc_ctl = status;

                break;

        default:

                BUG();

                break;

        }

}

/*

 * rtc_from4_calculate_ecc - hardware specific code to read ECC code

 * @mtd:        MTD device structure

 * @dat:        buffer containing the data to generate ECC codes

 * @ecc_code    ECC codes calculated

 *

 * The ECC code is calculated by the FPGA.  All we have to do is read the values

 * from the FPGA registers.

 *

 * Note: We read from the inverted registers, since data is inverted before

 * the code is calculated. So all 0xff data (blank page) results in all 0xff rs code

 *

 */

static void rtc_from4_calculate_ecc(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code)

{

        volatile unsigned short *rs_eccn = (volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_RS_ECCN);

        unsigned short value;

        int i;

        for (i = 0; i < 8; i++) {

                value = *rs_eccn;

                ecc_code[i] = (unsigned char)value;

                rs_eccn++;

        }

        ecc_code[7] |= 0x0f;    /* set the last four bits (not used) */

}

/*

 * rtc_from4_correct_data - hardware specific code to correct data using ECC code

 * @mtd:        MTD device structure

 * @buf:        buffer containing the data to generate ECC codes

 * @ecc1        ECC codes read

 * @ecc2        ECC codes calculated

 *

 * The FPGA tells us fast, if there's an error or not. If no, we go back happy

 * else we read the ecc results from the fpga and call the rs library to decode

 * and hopefully correct the error.

 *

 */

static int rtc_from4_correct_data(struct mtd_info *mtd, const u_char *buf, u_char *ecc1, u_char *ecc2)

{

        int i, j, res;

        unsigned short status;

        uint16_t par[6], syn[6];

        uint8_t ecc[8];

        volatile unsigned short *rs_ecc;

        status = *((volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_RS_ECC_CHK));

        if (!(status & RTC_FROM4_RS_ECC_CHK_ERROR)) {

                return 0;

        }

        /* Read the syndrom pattern from the FPGA and correct the bitorder */

        rs_ecc = (volatile unsigned short *)(rtc_from4_fio_base + RTC_FROM4_RS_ECC);

        for (i = 0; i < 8; i++) {

                ecc[i] = bitrev8(*rs_ecc);

                rs_ecc++;

        }

        /* convert into 6 10bit syndrome fields */

        par[5] = rs_decoder->index_of[(((uint16_t) ecc[0] >> 0) & 0x0ff) | (((uint16_t) ecc[1] << 8) & 0x300)];

        par[4] = rs_decoder->index_of[(((uint16_t) ecc[1] >> 2) & 0x03f) | (((uint16_t) ecc[2] << 6) & 0x3c0)];

        par[3] = rs_decoder->index_of[(((uint16_t) ecc[2] >> 4) & 0x00f) | (((uint16_t) ecc[3] << 4) & 0x3f0)];

        par[2] = rs_decoder->index_of[(((uint16_t) ecc[3] >> 6) & 0x003) | (((uint16_t) ecc[4] << 2) & 0x3fc)];

        par[1] = rs_decoder->index_of[(((uint16_t) ecc[5] >> 0) & 0x0ff) | (((uint16_t) ecc[6] << 8) & 0x300)];

        par[0] = (((uint16_t) ecc[6] >> 2) & 0x03f) | (((uint16_t) ecc[7] << 6) & 0x3c0);

        /* Convert to computable syndrome */

        for (i = 0; i < 6; i++) {

                syn[i] = par[0];

                for (j = 1; j < 6; j++)

                        if (par[j] != rs_decoder->nn)

                                syn[i] ^= rs_decoder->alpha_to[rs_modnn(rs_decoder, par[j] + i * j)];

                /* Convert to index form */

                syn[i] = rs_decoder->index_of[syn[i]];

        }

        /* Let the library code do its magic. */

        res = decode_rs8(rs_decoder, (uint8_t *) buf, par, 512, syn, 0, NULL, 0xff, NULL);

        if (res > 0) {

                DEBUG(MTD_DEBUG_LEVEL0, "rtc_from4_correct_data: " "ECC corrected %d errors on read\n", res);

        }

        return res;

}

/**

 * rtc_from4_errstat - perform additional error status checks

 * @mtd:        MTD device structure

 * @this:       NAND chip structure

 * @state:      state or the operation

 * @status:     status code returned from read status

 * @page:       startpage inside the chip, must be called with (page & this->pagemask)

 *

 * Perform additional error status checks on erase and write failures

 * to determine if errors are correctable.  For this device, correctable

 * 1-bit errors on erase and write are considered acceptable.

 *

 * note: see pages 34..37 of data sheet for details.

 *

 */

static int rtc_from4_errstat(struct mtd_info *mtd, struct nand_chip *this,

                             int state, int status, int page)

{

        int er_stat = 0;

        int rtn, retlen;

        size_t len;

        uint8_t *buf;

        int i;

        this->cmdfunc(mtd, NAND_CMD_STATUS_CLEAR, -1, -1);

        if (state == FL_ERASING) {

                for (i = 0; i < 4; i++) {

                        if (!(status & 1 << (i + 1)))

                                continue;

                        this->cmdfunc(mtd, (NAND_CMD_STATUS_ERROR + i + 1),

                                      -1, -1);

                        rtn = this->read_byte(mtd);

                        this->cmdfunc(mtd, NAND_CMD_STATUS_RESET, -1, -1);

                        /* err_ecc_not_avail */

                        if (!(rtn & ERR_STAT_ECC_AVAILABLE))

                                er_stat |= 1 << (i + 1);

                }

        } else if (state == FL_WRITING) {

                unsigned long corrected = mtd->ecc_stats.corrected;

                /* single bank write logic */

                this->cmdfunc(mtd, NAND_CMD_STATUS_ERROR, -1, -1);

                rtn = this->read_byte(mtd);

                this->cmdfunc(mtd, NAND_CMD_STATUS_RESET, -1, -1);

                if (!(rtn & ERR_STAT_ECC_AVAILABLE)) {

                        /* err_ecc_not_avail */

                        er_stat |= 1 << 1;

                        goto out;

                }

                len = mtd->writesize;

                buf = kmalloc(len, GFP_KERNEL);

                if (!buf) {

                        printk(KERN_ERR "rtc_from4_errstat: Out of memory!\n");

                        er_stat = 1;

                        goto out;

                }

                /* recovery read */

                rtn = nand_do_read(mtd, page, len, &retlen, buf);

                /* if read failed or > 1-bit error corrected */

                if (rtn || (mtd->ecc_stats.corrected - corrected) > 1)

                        er_stat |= 1 << 1;

                kfree(buf);

        }

        rtn = status;

        if (er_stat == 0) {      /* if ECC is available   */

                rtn = (status & ~NAND_STATUS_FAIL);     /*   clear the error bit */

        }

        return rtn;

}

#endif

/*

 * Main initialization routine

 */

static int __init rtc_from4_init(void)

{

        struct nand_chip *this;

        unsigned short bcr1, bcr2, wcr2;

        int i;

        /* Allocate memory for MTD device structure and private data */

        rtc_from4_mtd = kmalloc(sizeof(struct mtd_info) + sizeof(struct nand_chip), GFP_KERNEL);

        if (!rtc_from4_mtd) {

                printk("Unable to allocate Renesas NAND MTD device structure.\n");

                return -ENOMEM;

        }

        /* Get pointer to private data */

        this = (struct nand_chip *)(&rtc_from4_mtd[1]);

        /* Initialize structures */

        memset(rtc_from4_mtd, 0, sizeof(struct mtd_info));

        memset(this, 0, sizeof(struct nand_chip));

        /* Link the private data with the MTD structure */

        rtc_from4_mtd->priv = this;

        rtc_from4_mtd->owner = THIS_MODULE;

        /* set area 5 as PCMCIA mode to clear the spec of tDH(Data hold time;9ns min) */

        bcr1 = *SH77X9_BCR1 & ~0x0002;

        bcr1 |= 0x0002;

        *SH77X9_BCR1 = bcr1;

        /* set */

        bcr2 = *SH77X9_BCR2 & ~0x0c00;

        bcr2 |= 0x0800;

        *SH77X9_BCR2 = bcr2;

        /* set area 5 wait states */

        wcr2 = *SH77X9_WCR2 & ~0x1c00;

        wcr2 |= 0x1c00;

        *SH77X9_WCR2 = wcr2;

        /* Set address of NAND IO lines */

        this->IO_ADDR_R = rtc_from4_fio_base;

        this->IO_ADDR_W = rtc_from4_fio_base;

        /* Set address of hardware control function */

        this->cmd_ctrl = rtc_from4_hwcontrol;

        /* Set address of chip select function */

        this->select_chip = rtc_from4_nand_select_chip;

        /* command delay time (in us) */

        this->chip_delay = 100;

        /* return the status of the Ready/Busy line */

        this->dev_ready = rtc_from4_nand_device_ready;

#ifdef RTC_FROM4_HWECC

        printk(KERN_INFO "rtc_from4_init: using hardware ECC detection.\n");

        this->ecc.mode = NAND_ECC_HW_SYNDROME;

        this->ecc.size = 512;

        this->ecc.bytes = 8;

        /* return the status of extra status and ECC checks */

        this->errstat = rtc_from4_errstat;

        /* set the nand_oobinfo to support FPGA H/W error detection */

        this->ecc.layout = &rtc_from4_nand_oobinfo;

        this->ecc.hwctl = rtc_from4_enable_hwecc;

        this->ecc.calculate = rtc_from4_calculate_ecc;

        this->ecc.correct = rtc_from4_correct_data;

#else

        printk(KERN_INFO "rtc_from4_init: using software ECC detection.\n");

        this->ecc.mode = NAND_ECC_SOFT;

#endif

        /* set the bad block tables to support debugging */

        this->bbt_td = &rtc_from4_bbt_main_descr;

        this->bbt_md = &rtc_from4_bbt_mirror_descr;

        /* Scan to find existence of the device */

        if (nand_scan(rtc_from4_mtd, RTC_FROM4_MAX_CHIPS)) {

                kfree(rtc_from4_mtd);

                return -ENXIO;

        }

        /* Perform 'device recovery' for each chip in case there was a power loss. */

        for (i = 0; i < this->numchips; i++) {

                deplete(rtc_from4_mtd, i);

        }

#if RTC_FROM4_NO_VIRTBLOCKS

        /* use a smaller erase block to minimize wasted space when a block is bad */

        /* note: this uses eight times as much RAM as using the default and makes */

        /*       mounts take four times as long. */

        rtc_from4_mtd->flags |= MTD_NO_VIRTBLOCKS;

#endif

        /* Register the partitions */

        add_mtd_partitions(rtc_from4_mtd, partition_info, NUM_PARTITIONS);

#ifdef RTC_FROM4_HWECC

        /* We could create the decoder on demand, if memory is a concern.

         * This way we have it handy, if an error happens

         *

         * Symbolsize is 10 (bits)

         * Primitve polynomial is x^10+x^3+1

         * first consecutive root is 0

         * primitve element to generate roots = 1

         * generator polinomial degree = 6

         */

        rs_decoder = init_rs(10, 0x409, 0, 1, 6);

        if (!rs_decoder) {

                printk(KERN_ERR "Could not create a RS decoder\n");

                nand_release(rtc_from4_mtd);

                kfree(rtc_from4_mtd);

                return -ENOMEM;

        }

#endif

        /* Return happy */

        return 0;

}

module_init(rtc_from4_init);

/*

 * Clean up routine

 */

static void __exit rtc_from4_cleanup(void)

{

        /* Release resource, unregister partitions */

        nand_release(rtc_from4_mtd);

        /* Free the MTD device structure */

        kfree(rtc_from4_mtd);

#ifdef RTC_FROM4_HWECC

        /* Free the reed solomon resources */

        if (rs_decoder) {

                free_rs(rs_decoder);

        }

#endif

}

module_exit(rtc_from4_cleanup);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("d.marlin <dmarlin@redhat.com");

MODULE_DESCRIPTION("Board-specific glue layer for AG-AND flash on Renesas FROM_BOARD4");