Committer: Michael Beasley <mike@snafu.setup>

[mikesnafu-overlay.git] / drivers / mtd / nand / bf5xx_nand.c

/* linux/drivers/mtd/nand/bf5xx_nand.c
 *
 * Copyright 2006-2007 Analog Devices Inc.
 *      http://blackfin.uclinux.org/
 *      Bryan Wu <bryan.wu@analog.com>
 *
 * Blackfin BF5xx on-chip NAND flash controller driver
 *
 * Derived from drivers/mtd/nand/s3c2410.c
 * Copyright (c) 2007 Ben Dooks <ben@simtec.co.uk>
 *
 * Derived from drivers/mtd/nand/cafe.c
 * Copyright © 2006 Red Hat, Inc.
 * Copyright © 2006 David Woodhouse <dwmw2@infradead.org>
 *
 * Changelog:
 *      12-Jun-2007  Bryan Wu:  Initial version
 *      18-Jul-2007  Bryan Wu:
 *              - ECC_HW and ECC_SW supported
 *              - DMA supported in ECC_HW
 *              - YAFFS tested as rootfs in both ECC_HW and ECC_SW
 *
 * TODO:
 *      Enable JFFS2 over NAND as rootfs
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/bitops.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/nand_ecc.h>
#include <linux/mtd/partitions.h>

#include <asm/blackfin.h>
#include <asm/dma.h>
#include <asm/cacheflush.h>
#include <asm/nand.h>
#include <asm/portmux.h>

#define DRV_NAME        "bf5xx-nand"
#define DRV_VERSION     "1.2"
#define DRV_AUTHOR      "Bryan Wu <bryan.wu@analog.com>"
#define DRV_DESC        "BF5xx on-chip NAND FLash Controller Driver"

#ifdef CONFIG_MTD_NAND_BF5XX_HWECC
static int hardware_ecc = 1;
#else
static int hardware_ecc;
#endif

static unsigned short bfin_nfc_pin_req[] =
        {P_NAND_CE,
         P_NAND_RB,
         P_NAND_D0,
         P_NAND_D1,
         P_NAND_D2,
         P_NAND_D3,
         P_NAND_D4,
         P_NAND_D5,
         P_NAND_D6,
         P_NAND_D7,
         P_NAND_WE,
         P_NAND_RE,
         P_NAND_CLE,
         P_NAND_ALE,
         0};

/*
 * Data structures for bf5xx nand flash controller driver
 */

/* bf5xx nand info */
struct bf5xx_nand_info {
        /* mtd info */
        struct nand_hw_control          controller;
        struct mtd_info                 mtd;
        struct nand_chip                chip;

        /* platform info */
        struct bf5xx_nand_platform      *platform;

        /* device info */
        struct device                   *device;

        /* DMA stuff */
        struct completion               dma_completion;
};

/*
 * Conversion functions
 */
static struct bf5xx_nand_info *mtd_to_nand_info(struct mtd_info *mtd)
{
        return container_of(mtd, struct bf5xx_nand_info, mtd);
}

static struct bf5xx_nand_info *to_nand_info(struct platform_device *pdev)
{
        return platform_get_drvdata(pdev);
}

static struct bf5xx_nand_platform *to_nand_plat(struct platform_device *pdev)
{
        return pdev->dev.platform_data;
}

/*
 * struct nand_chip interface function pointers
 */

/*
 * bf5xx_nand_hwcontrol
 *
 * Issue command and address cycles to the chip
 */
static void bf5xx_nand_hwcontrol(struct mtd_info *mtd, int cmd,
                                   unsigned int ctrl)
{
        if (cmd == NAND_CMD_NONE)
                return;

        while (bfin_read_NFC_STAT() & WB_FULL)
                cpu_relax();

        if (ctrl & NAND_CLE)
                bfin_write_NFC_CMD(cmd);
        else
                bfin_write_NFC_ADDR(cmd);
        SSYNC();
}

/*
 * bf5xx_nand_devready()
 *
 * returns 0 if the nand is busy, 1 if it is ready
 */
static int bf5xx_nand_devready(struct mtd_info *mtd)
{
        unsigned short val = bfin_read_NFC_IRQSTAT();

        if ((val & NBUSYIRQ) == NBUSYIRQ)
                return 1;
        else
                return 0;
}

/*
 * ECC functions
 * These allow the bf5xx to use the controller's ECC
 * generator block to ECC the data as it passes through
 */

/*
 * ECC error correction function
 */
static int bf5xx_nand_correct_data_256(struct mtd_info *mtd, u_char *dat,
                                        u_char *read_ecc, u_char *calc_ecc)
{
        struct bf5xx_nand_info *info = mtd_to_nand_info(mtd);
        u32 syndrome[5];
        u32 calced, stored;
        int i;
        unsigned short failing_bit, failing_byte;
        u_char data;

        calced = calc_ecc[0] | (calc_ecc[1] << 8) | (calc_ecc[2] << 16);
        stored = read_ecc[0] | (read_ecc[1] << 8) | (read_ecc[2] << 16);

        syndrome[0] = (calced ^ stored);

        /*
         * syndrome 0: all zero
         * No error in data
         * No action
         */
        if (!syndrome[0] || !calced || !stored)
                return 0;

        /*
         * sysdrome 0: only one bit is one
         * ECC data was incorrect
         * No action
         */
        if (hweight32(syndrome[0]) == 1) {
                dev_err(info->device, "ECC data was incorrect!\n");
                return 1;
        }

        syndrome[1] = (calced & 0x7FF) ^ (stored & 0x7FF);
        syndrome[2] = (calced & 0x7FF) ^ ((calced >> 11) & 0x7FF);
        syndrome[3] = (stored & 0x7FF) ^ ((stored >> 11) & 0x7FF);
        syndrome[4] = syndrome[2] ^ syndrome[3];

        for (i = 0; i < 5; i++)
                dev_info(info->device, "syndrome[%d] 0x%08x\n", i, syndrome[i]);

        dev_info(info->device,
                "calced[0x%08x], stored[0x%08x]\n",
                calced, stored);

        /*
         * sysdrome 0: exactly 11 bits are one, each parity
         * and parity' pair is 1 & 0 or 0 & 1.
         * 1-bit correctable error
         * Correct the error
         */
        if (hweight32(syndrome[0]) == 11 && syndrome[4] == 0x7FF) {
                dev_info(info->device,
                        "1-bit correctable error, correct it.\n");
                dev_info(info->device,
                        "syndrome[1] 0x%08x\n", syndrome[1]);

                failing_bit = syndrome[1] & 0x7;
                failing_byte = syndrome[1] >> 0x3;
                data = *(dat + failing_byte);
                data = data ^ (0x1 << failing_bit);
                *(dat + failing_byte) = data;

                return 0;
        }

        /*
         * sysdrome 0: random data
         * More than 1-bit error, non-correctable error
         * Discard data, mark bad block
         */
        dev_err(info->device,
                "More than 1-bit error, non-correctable error.\n");
        dev_err(info->device,
                "Please discard data, mark bad block\n");

        return 1;
}

static int bf5xx_nand_correct_data(struct mtd_info *mtd, u_char *dat,
                                        u_char *read_ecc, u_char *calc_ecc)
{
        struct bf5xx_nand_info *info = mtd_to_nand_info(mtd);
        struct bf5xx_nand_platform *plat = info->platform;
        unsigned short page_size = (plat->page_size ? 512 : 256);
        int ret;

        ret = bf5xx_nand_correct_data_256(mtd, dat, read_ecc, calc_ecc);

        /* If page size is 512, correct second 256 bytes */
        if (page_size == 512) {
                dat += 256;
                read_ecc += 8;
                calc_ecc += 8;
                ret = bf5xx_nand_correct_data_256(mtd, dat, read_ecc, calc_ecc);
        }

        return ret;
}

static void bf5xx_nand_enable_hwecc(struct mtd_info *mtd, int mode)
{
        return;
}

static int bf5xx_nand_calculate_ecc(struct mtd_info *mtd,
                const u_char *dat, u_char *ecc_code)
{
        struct bf5xx_nand_info *info = mtd_to_nand_info(mtd);
        struct bf5xx_nand_platform *plat = info->platform;
        u16 page_size = (plat->page_size ? 512 : 256);
        u16 ecc0, ecc1;
        u32 code[2];
        u8 *p;

        /* first 4 bytes ECC code for 256 page size */
        ecc0 = bfin_read_NFC_ECC0();
        ecc1 = bfin_read_NFC_ECC1();

        code[0] = (ecc0 & 0x3FF) | ((ecc1 & 0x3FF) << 11);

        dev_dbg(info->device, "returning ecc 0x%08x\n", code[0]);

        /* first 3 bytes in ecc_code for 256 page size */
        p = (u8 *) code;
        memcpy(ecc_code, p, 3);

        /* second 4 bytes ECC code for 512 page size */
        if (page_size == 512) {
                ecc0 = bfin_read_NFC_ECC2();
                ecc1 = bfin_read_NFC_ECC3();
                code[1] = (ecc0 & 0x3FF) | ((ecc1 & 0x3FF) << 11);

                /* second 3 bytes in ecc_code for second 256
                 * bytes of 512 page size
                 */
                p = (u8 *) (code + 1);
                memcpy((ecc_code + 3), p, 3);
                dev_dbg(info->device, "returning ecc 0x%08x\n", code[1]);
        }

        return 0;
}

/*
 * PIO mode for buffer writing and reading
 */
static void bf5xx_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
        int i;
        unsigned short val;

        /*
         * Data reads are requested by first writing to NFC_DATA_RD
         * and then reading back from NFC_READ.
         */
        for (i = 0; i < len; i++) {
                while (bfin_read_NFC_STAT() & WB_FULL)
                        cpu_relax();

                /* Contents do not matter */
                bfin_write_NFC_DATA_RD(0x0000);
                SSYNC();

                while ((bfin_read_NFC_IRQSTAT() & RD_RDY) != RD_RDY)
                        cpu_relax();

                buf[i] = bfin_read_NFC_READ();

                val = bfin_read_NFC_IRQSTAT();
                val |= RD_RDY;
                bfin_write_NFC_IRQSTAT(val);
                SSYNC();
        }
}

static uint8_t bf5xx_nand_read_byte(struct mtd_info *mtd)
{
        uint8_t val;

        bf5xx_nand_read_buf(mtd, &val, 1);

        return val;
}

static void bf5xx_nand_write_buf(struct mtd_info *mtd,
                                const uint8_t *buf, int len)
{
        int i;

        for (i = 0; i < len; i++) {
                while (bfin_read_NFC_STAT() & WB_FULL)
                        cpu_relax();

                bfin_write_NFC_DATA_WR(buf[i]);
                SSYNC();
        }
}

static void bf5xx_nand_read_buf16(struct mtd_info *mtd, uint8_t *buf, int len)
{
        int i;
        u16 *p = (u16 *) buf;
        len >>= 1;

        /*
         * Data reads are requested by first writing to NFC_DATA_RD
         * and then reading back from NFC_READ.
         */
        bfin_write_NFC_DATA_RD(0x5555);

        SSYNC();

        for (i = 0; i < len; i++)
                p[i] = bfin_read_NFC_READ();
}

static void bf5xx_nand_write_buf16(struct mtd_info *mtd,
                                const uint8_t *buf, int len)
{
        int i;
        u16 *p = (u16 *) buf;
        len >>= 1;

        for (i = 0; i < len; i++)
                bfin_write_NFC_DATA_WR(p[i]);

        SSYNC();
}

/*
 * DMA functions for buffer writing and reading
 */
static irqreturn_t bf5xx_nand_dma_irq(int irq, void *dev_id)
{
        struct bf5xx_nand_info *info = dev_id;

        clear_dma_irqstat(CH_NFC);
        disable_dma(CH_NFC);
        complete(&info->dma_completion);

        return IRQ_HANDLED;
}

static int bf5xx_nand_dma_rw(struct mtd_info *mtd,
                                uint8_t *buf, int is_read)
{
        struct bf5xx_nand_info *info = mtd_to_nand_info(mtd);
        struct bf5xx_nand_platform *plat = info->platform;
        unsigned short page_size = (plat->page_size ? 512 : 256);
        unsigned short val;

        dev_dbg(info->device, " mtd->%p, buf->%p, is_read %d\n",
                        mtd, buf, is_read);

        /*
         * Before starting a dma transfer, be sure to invalidate/flush
         * the cache over the address range of your DMA buffer to
         * prevent cache coherency problems. Otherwise very subtle bugs
         * can be introduced to your driver.
         */
        if (is_read)
                invalidate_dcache_range((unsigned int)buf,
                                (unsigned int)(buf + page_size));
        else
                flush_dcache_range((unsigned int)buf,
                                (unsigned int)(buf + page_size));

        /*
         * This register must be written before each page is
         * transferred to generate the correct ECC register
         * values.
         */
        bfin_write_NFC_RST(0x1);
        SSYNC();

        disable_dma(CH_NFC);
        clear_dma_irqstat(CH_NFC);

        /* setup DMA register with Blackfin DMA API */
        set_dma_config(CH_NFC, 0x0);
        set_dma_start_addr(CH_NFC, (unsigned long) buf);
        set_dma_x_count(CH_NFC, (page_size >> 2));
        set_dma_x_modify(CH_NFC, 4);

        /* setup write or read operation */
        val = DI_EN | WDSIZE_32;
        if (is_read)
                val |= WNR;
        set_dma_config(CH_NFC, val);
        enable_dma(CH_NFC);

        /* Start PAGE read/write operation */
        if (is_read)
                bfin_write_NFC_PGCTL(0x1);
        else
                bfin_write_NFC_PGCTL(0x2);
        wait_for_completion(&info->dma_completion);

        return 0;
}

static void bf5xx_nand_dma_read_buf(struct mtd_info *mtd,
                                        uint8_t *buf, int len)
{
        struct bf5xx_nand_info *info = mtd_to_nand_info(mtd);
        struct bf5xx_nand_platform *plat = info->platform;
        unsigned short page_size = (plat->page_size ? 512 : 256);

        dev_dbg(info->device, "mtd->%p, buf->%p, int %d\n", mtd, buf, len);

        if (len == page_size)
                bf5xx_nand_dma_rw(mtd, buf, 1);
        else
                bf5xx_nand_read_buf(mtd, buf, len);
}

static void bf5xx_nand_dma_write_buf(struct mtd_info *mtd,
                                const uint8_t *buf, int len)
{
        struct bf5xx_nand_info *info = mtd_to_nand_info(mtd);
        struct bf5xx_nand_platform *plat = info->platform;
        unsigned short page_size = (plat->page_size ? 512 : 256);

        dev_dbg(info->device, "mtd->%p, buf->%p, len %d\n", mtd, buf, len);

        if (len == page_size)
                bf5xx_nand_dma_rw(mtd, (uint8_t *)buf, 0);
        else
                bf5xx_nand_write_buf(mtd, buf, len);
}

/*
 * System initialization functions
 */

static int bf5xx_nand_dma_init(struct bf5xx_nand_info *info)
{
        int ret;
        unsigned short val;

        /* Do not use dma */
        if (!hardware_ecc)
                return 0;

        init_completion(&info->dma_completion);

#ifdef CONFIG_BF54x
        /* Setup DMAC1 channel mux for NFC which shared with SDH */
        val = bfin_read_DMAC1_PERIMUX();
        val &= 0xFFFE;
        bfin_write_DMAC1_PERIMUX(val);
        SSYNC();
#endif
        /* Request NFC DMA channel */
        ret = request_dma(CH_NFC, "BF5XX NFC driver");
        if (ret < 0) {
                dev_err(info->device, " unable to get DMA channel\n");
                return ret;
        }

        set_dma_callback(CH_NFC, (void *) bf5xx_nand_dma_irq, (void *) info);

        /* Turn off the DMA channel first */
        disable_dma(CH_NFC);
        return 0;
}

/*
 * BF5XX NFC hardware initialization
 *  - pin mux setup
 *  - clear interrupt status
 */
static int bf5xx_nand_hw_init(struct bf5xx_nand_info *info)
{
        int err = 0;
        unsigned short val;
        struct bf5xx_nand_platform *plat = info->platform;

        /* setup NFC_CTL register */
        dev_info(info->device,
                "page_size=%d, data_width=%d, wr_dly=%d, rd_dly=%d\n",
                (plat->page_size ? 512 : 256),
                (plat->data_width ? 16 : 8),
                plat->wr_dly, plat->rd_dly);

        val = (plat->page_size << NFC_PG_SIZE_OFFSET) |
                (plat->data_width << NFC_NWIDTH_OFFSET) |
                (plat->rd_dly << NFC_RDDLY_OFFSET) |
                (plat->rd_dly << NFC_WRDLY_OFFSET);
        dev_dbg(info->device, "NFC_CTL is 0x%04x\n", val);

        bfin_write_NFC_CTL(val);
        SSYNC();

        /* clear interrupt status */
        bfin_write_NFC_IRQMASK(0x0);
        SSYNC();
        val = bfin_read_NFC_IRQSTAT();
        bfin_write_NFC_IRQSTAT(val);
        SSYNC();

        if (peripheral_request_list(bfin_nfc_pin_req, DRV_NAME)) {
                printk(KERN_ERR DRV_NAME
                ": Requesting Peripherals failed\n");
                return -EFAULT;
        }

        /* DMA initialization  */
        if (bf5xx_nand_dma_init(info))
                err = -ENXIO;

        return err;
}

/*
 * Device management interface
 */
static int bf5xx_nand_add_partition(struct bf5xx_nand_info *info)
{
        struct mtd_info *mtd = &info->mtd;

#ifdef CONFIG_MTD_PARTITIONS
        struct mtd_partition *parts = info->platform->partitions;
        int nr = info->platform->nr_partitions;

        return add_mtd_partitions(mtd, parts, nr);
#else
        return add_mtd_device(mtd);
#endif
}

static int bf5xx_nand_remove(struct platform_device *pdev)
{
        struct bf5xx_nand_info *info = to_nand_info(pdev);
        struct mtd_info *mtd = NULL;

        platform_set_drvdata(pdev, NULL);

        /* first thing we need to do is release all our mtds
         * and their partitions, then go through freeing the
         * resources used
         */
        mtd = &info->mtd;
        if (mtd) {
                nand_release(mtd);
                kfree(mtd);
        }

        peripheral_free_list(bfin_nfc_pin_req);

        /* free the common resources */
        kfree(info);

        return 0;
}

/*
 * bf5xx_nand_probe
 *
 * called by device layer when it finds a device matching
 * one our driver can handled. This code checks to see if
 * it can allocate all necessary resources then calls the
 * nand layer to look for devices
 */
static int bf5xx_nand_probe(struct platform_device *pdev)
{
        struct bf5xx_nand_platform *plat = to_nand_plat(pdev);
        struct bf5xx_nand_info *info = NULL;
        struct nand_chip *chip = NULL;
        struct mtd_info *mtd = NULL;
        int err = 0;

        dev_dbg(&pdev->dev, "(%p)\n", pdev);

        if (!plat) {
                dev_err(&pdev->dev, "no platform specific information\n");
                goto exit_error;
        }

        info = kzalloc(sizeof(*info), GFP_KERNEL);
        if (info == NULL) {
                dev_err(&pdev->dev, "no memory for flash info\n");
                err = -ENOMEM;
                goto exit_error;
        }

        platform_set_drvdata(pdev, info);

        spin_lock_init(&info->controller.lock);
        init_waitqueue_head(&info->controller.wq);

        info->device     = &pdev->dev;
        info->platform   = plat;

        /* initialise chip data struct */
        chip = &info->chip;

        if (plat->data_width)
                chip->options |= NAND_BUSWIDTH_16;

        chip->options |= NAND_CACHEPRG | NAND_SKIP_BBTSCAN;

        chip->read_buf = (plat->data_width) ?
                bf5xx_nand_read_buf16 : bf5xx_nand_read_buf;
        chip->write_buf = (plat->data_width) ?
                bf5xx_nand_write_buf16 : bf5xx_nand_write_buf;

        chip->read_byte    = bf5xx_nand_read_byte;

        chip->cmd_ctrl     = bf5xx_nand_hwcontrol;
        chip->dev_ready    = bf5xx_nand_devready;

        chip->priv         = &info->mtd;
        chip->controller   = &info->controller;

        chip->IO_ADDR_R    = (void __iomem *) NFC_READ;
        chip->IO_ADDR_W    = (void __iomem *) NFC_DATA_WR;

        chip->chip_delay   = 0;

        /* initialise mtd info data struct */
        mtd             = &info->mtd;
        mtd->priv       = chip;
        mtd->owner      = THIS_MODULE;

        /* initialise the hardware */
        err = bf5xx_nand_hw_init(info);
        if (err != 0)
                goto exit_error;

        /* setup hardware ECC data struct */
        if (hardware_ecc) {
                if (plat->page_size == NFC_PG_SIZE_256) {
                        chip->ecc.bytes = 3;
                        chip->ecc.size = 256;
                } else if (plat->page_size == NFC_PG_SIZE_512) {
                        chip->ecc.bytes = 6;
                        chip->ecc.size = 512;
                }

                chip->read_buf      = bf5xx_nand_dma_read_buf;
                chip->write_buf     = bf5xx_nand_dma_write_buf;
                chip->ecc.calculate = bf5xx_nand_calculate_ecc;
                chip->ecc.correct   = bf5xx_nand_correct_data;
                chip->ecc.mode      = NAND_ECC_HW;
                chip->ecc.hwctl     = bf5xx_nand_enable_hwecc;
        } else {
                chip->ecc.mode      = NAND_ECC_SOFT;
        }

        /* scan hardware nand chip and setup mtd info data struct */
        if (nand_scan(mtd, 1)) {
                err = -ENXIO;
                goto exit_error;
        }

        /* add NAND partition */
        bf5xx_nand_add_partition(info);

        dev_dbg(&pdev->dev, "initialised ok\n");
        return 0;

exit_error:
        bf5xx_nand_remove(pdev);

        if (err == 0)
                err = -EINVAL;
        return err;
}

/* PM Support */
#ifdef CONFIG_PM

static int bf5xx_nand_suspend(struct platform_device *dev, pm_message_t pm)
{
        struct bf5xx_nand_info *info = platform_get_drvdata(dev);

        return 0;
}

static int bf5xx_nand_resume(struct platform_device *dev)
{
        struct bf5xx_nand_info *info = platform_get_drvdata(dev);

        return 0;
}

#else
#define bf5xx_nand_suspend NULL
#define bf5xx_nand_resume NULL
#endif

/* driver device registration */
static struct platform_driver bf5xx_nand_driver = {
        .probe          = bf5xx_nand_probe,
        .remove         = bf5xx_nand_remove,
        .suspend        = bf5xx_nand_suspend,
        .resume         = bf5xx_nand_resume,
        .driver         = {
                .name   = DRV_NAME,
                .owner  = THIS_MODULE,
        },
};

static int __init bf5xx_nand_init(void)
{
        printk(KERN_INFO "%s, Version %s (c) 2007 Analog Devices, Inc.\n",
                DRV_DESC, DRV_VERSION);

        return platform_driver_register(&bf5xx_nand_driver);
}

static void __exit bf5xx_nand_exit(void)
{
        platform_driver_unregister(&bf5xx_nand_driver);
}

module_init(bf5xx_nand_init);
module_exit(bf5xx_nand_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR(DRV_AUTHOR);
MODULE_DESCRIPTION(DRV_DESC);