/*
 * (C) Copyright 2009
 * Magnus Lilja <lilja.magnus@gmail.com>
 *
 * (C) Copyright 2008
 * Maxim Artamonov, <scn1874 at yandex.ru>
 *
 * (C) Copyright 2006-2008
 * Stefan Roese, DENX Software Engineering, sr at denx.de.
 *
 * 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 <common.h>
#include <nand.h>
#include <asm-arm/arch/mx31-regs.h>
#include <asm/io.h>
#include <fsl_nfc.h>

static struct fsl_nfc_regs *nfc;

static void nfc_wait_ready(void)
{
        uint32_t tmp;

        while (!(readw(&nfc->nand_flash_config2) & NFC_INT))
                ;

        /* Reset interrupt flag */
        tmp = readw(&nfc->nand_flash_config2);
        tmp &= ~NFC_INT;
        writew(tmp, &nfc->nand_flash_config2);
}

static void nfc_nand_init(void)
{
        /* unlocking RAM Buff */
        writew(0x2, &nfc->configuration);

        /* hardware ECC checking and correct */
        writew(NFC_ECC_EN, &nfc->nand_flash_config1);
}

static void nfc_nand_command(unsigned short command)
{
        writew(command, &nfc->flash_cmd);
        writew(NFC_CMD, &nfc->nand_flash_config2);
        nfc_wait_ready();
}

static void nfc_nand_page_address(unsigned int page_address)
{
        unsigned int page_count;

        writew(0x00, &nfc->flash_cmd);
        writew(NFC_ADDR, &nfc->nand_flash_config2);
        nfc_wait_ready();

        /* code only for 2kb flash */
        if (CONFIG_SYS_NAND_PAGE_SIZE == 0x800) {
                writew(0x00, &nfc->flash_add);
                writew(NFC_ADDR, &nfc->nand_flash_config2);
                nfc_wait_ready();
        }

        page_count = CONFIG_SYS_NAND_SIZE / CONFIG_SYS_NAND_PAGE_SIZE;

        if (page_address <= page_count) {
                page_count--; /* transform 0x01000000 to 0x00ffffff */
                do {
                        writew(page_address & 0xff, &nfc->flash_add);
                        writew(NFC_ADDR, &nfc->nand_flash_config2);
                        nfc_wait_ready();
                        page_address = page_address >> 8;
                        page_count = page_count >> 8;
                } while (page_count);
        }
}

static void nfc_nand_data_output(void)
{
        int i;

        /*
         * The NAND controller requires four output commands for
         * large page devices.
         */
        for (i = 0; i < (CONFIG_SYS_NAND_PAGE_SIZE / 512); i++) {
                writew(NFC_ECC_EN, &nfc->nand_flash_config1);
                writew(i, &nfc->buffer_address); /* read in i:th buffer */
                writew(NFC_OUTPUT, &nfc->nand_flash_config2);
                nfc_wait_ready();
        }
}

static int nfc_nand_check_ecc(void)
{
        return readw(&nfc->ecc_status_result);
}

static int nfc_read_page(unsigned int page_address, unsigned char *buf)
{
        int i;
        u32 *src;
        u32 *dst;

        writew(0, &nfc->buffer_address); /* read in first 0 buffer */
        nfc_nand_command(NAND_CMD_READ0);
        nfc_nand_page_address(page_address);

        if (CONFIG_SYS_NAND_PAGE_SIZE == 0x800)
                nfc_nand_command(NAND_CMD_READSTART);

        nfc_nand_data_output(); /* fill the main buffer 0 */

        if (nfc_nand_check_ecc())
                return -1;

        src = &nfc->main_area0[0];
        dst = (u32 *)buf;

        /* main copy loop from NAND-buffer to SDRAM memory */
        for (i = 0; i < (CONFIG_SYS_NAND_PAGE_SIZE / 4); i++) {
                writel(readl(src), dst);
                src++;
                dst++;
        }

        return 0;
}

static int is_badblock(int pagenumber)
{
        int page = pagenumber;
        u32 badblock;
        u32 *src;

        /* Check the first two pages for bad block markers */
        for (page = pagenumber; page < pagenumber + 2; page++) {
                writew(0, &nfc->buffer_address); /* read in first 0 buffer */
                nfc_nand_command(NAND_CMD_READ0);
                nfc_nand_page_address(page);

                if (CONFIG_SYS_NAND_PAGE_SIZE == 0x800)
                        nfc_nand_command(NAND_CMD_READSTART);

                nfc_nand_data_output(); /* fill the main buffer 0 */

                src = &nfc->spare_area0[0];

                /*
                 * IMPORTANT NOTE: The nand flash controller uses a non-
                 * standard layout for large page devices. This can
                 * affect the position of the bad block marker.
                 */
                /* Get the bad block marker */
                badblock = readl(&src[CONFIG_SYS_NAND_BAD_BLOCK_POS / 4]);
                badblock >>= 8 * (CONFIG_SYS_NAND_BAD_BLOCK_POS % 4);
                badblock &= 0xff;

                /* bad block marker verify */
                if (badblock != 0xff)
                        return 1; /* potential bad block */
        }

        return 0;
}

static int nand_load(unsigned int from, unsigned int size, unsigned char *buf)
{
        int i;
        unsigned int page;
        unsigned int maxpages = CONFIG_SYS_NAND_SIZE /
                                CONFIG_SYS_NAND_PAGE_SIZE;

        nfc = (void *)NFC_BASE_ADDR;

        nfc_nand_init();

        /* Convert to page number */
        page = from / CONFIG_SYS_NAND_PAGE_SIZE;
        i = 0;

        while (i < (size / CONFIG_SYS_NAND_PAGE_SIZE)) {
                if (nfc_read_page(page, buf) < 0)
                        return -1;

                page++;
                i++;
                buf = buf + CONFIG_SYS_NAND_PAGE_SIZE;

                /*
                 * Check if we have crossed a block boundary, and if so
                 * check for bad block.
                 */
                if (!(page % CONFIG_SYS_NAND_PAGE_COUNT)) {
                        /*
                         * Yes, new block. See if this block is good. If not,
                         * loop until we find i good block.
                         */
                        while (is_badblock(page)) {
                                page = page + CONFIG_SYS_NAND_PAGE_COUNT;
                                /* Check i we've reached the end of flash. */
                                if (page >= maxpages)
                                        return -1;
                        }
                }
        }

        return 0;
}

/*
 * The main entry for NAND booting. It's necessary that SDRAM is already
 * configured and available since this code loads the main U-Boot image
 * from NAND into SDRAM and starts it from there.
 */
void nand_boot(void)
{
        __attribute__((noreturn)) void (*uboot)(void);

        nfc = (void *)NFC_BASE_ADDR;

        /*
         * CONFIG_SYS_NAND_U_BOOT_OFFS and CONFIG_SYS_NAND_U_BOOT_SIZE must
         * be aligned to full pages
         */
        if (!nand_load(CONFIG_SYS_NAND_U_BOOT_OFFS, CONFIG_SYS_NAND_U_BOOT_SIZE,
                       (uchar *)CONFIG_SYS_NAND_U_BOOT_DST)) {
                /* Copy from NAND successful, start U-boot */
                uboot = (void *)CONFIG_SYS_NAND_U_BOOT_START;
                uboot();
        } else {
                /* Unrecoverable error when copying from NAND */
                hang();
        }
}

/*
 * Called in case of an exception.
 */
void hang(void)
{
        /* Loop forever */
        while (1) ;
}