/*
 * Handle mapping of the flash memory access routines
 * on TQM8xxL based devices.
 *
 * based on rpxlite.c
 *
 * Copyright(C) 2001 Kirk Lee <kirk@hpc.ee.ntu.edu.tw>
 *
 * This code is GPLed
 *
 */

/*
 * According to TQM8xxL hardware manual, TQM8xxL series have
 * following flash memory organisations:
 *      | capacity |    | chip type |   | bank0 |       | bank1 |
 *          2MiB           512Kx16        2MiB             0
 *          4MiB           1Mx16          4MiB             0
 *          8MiB           1Mx16          4MiB             4MiB
 * Thus, we choose CONFIG_MTD_CFI_I2 & CONFIG_MTD_CFI_B4 at
 * kernel configuration.
 */
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>

#include <asm/io.h>

#define FLASH_ADDR 0x40000000
#define FLASH_SIZE 0x00800000
#define FLASH_BANK_MAX 4

// trivial struct to describe partition information
struct mtd_part_def
{
        int nums;
        unsigned char *type;
        struct mtd_partition* mtd_part;
};

//static struct mtd_info *mymtd;
static struct mtd_info* mtd_banks[FLASH_BANK_MAX];
static struct map_info* map_banks[FLASH_BANK_MAX];
static struct mtd_part_def part_banks[FLASH_BANK_MAX];
static unsigned long num_banks;
static void __iomem *start_scan_addr;

/*
 * Here are partition information for all known TQM8xxL series devices.
 * See include/linux/mtd/partitions.h for definition of the mtd_partition
 * structure.
 *
 * The *_max_flash_size is the maximum possible mapped flash size which
 * is not necessarily the actual flash size.  It must correspond to the
 * value specified in the mapping definition defined by the
 * "struct map_desc *_io_desc" for the corresponding machine.
 */

/* Currently, TQM8xxL has up to 8MiB flash */
static unsigned long tqm8xxl_max_flash_size = 0x00800000;

/* partition definition for first flash bank
 * (cf. "drivers/char/flash_config.c")
 */
static struct mtd_partition tqm8xxl_partitions[] = {
        {
          .name = "ppcboot",
          .offset = 0x00000000,
          .size = 0x00020000,           /* 128KB           */
          .mask_flags = MTD_WRITEABLE,  /* force read-only */
        },
        {
          .name = "kernel",             /* default kernel image */
          .offset = 0x00020000,
          .size = 0x000e0000,
          .mask_flags = MTD_WRITEABLE,  /* force read-only */
        },
        {
          .name = "user",
          .offset = 0x00100000,
          .size = 0x00100000,
        },
        {
          .name = "initrd",
          .offset = 0x00200000,
          .size = 0x00200000,
        }
};
/* partition definition for second flash bank */
static struct mtd_partition tqm8xxl_fs_partitions[] = {
        {
          .name = "cramfs",
          .offset = 0x00000000,
          .size = 0x00200000,
        },
        {
          .name = "jffs",
          .offset = 0x00200000,
          .size = 0x00200000,
          //.size = MTDPART_SIZ_FULL,
        }
};

static int __init init_tqm_mtd(void)
{
        int idx = 0, ret = 0;
        unsigned long flash_addr, flash_size, mtd_size = 0;
        /* pointer to TQM8xxL board info data */
        bd_t *bd = (bd_t *)__res;

        flash_addr = bd->bi_flashstart;
        flash_size = bd->bi_flashsize;

        //request maximum flash size address space
        start_scan_addr = ioremap(flash_addr, flash_size);
        if (!start_scan_addr) {
                printk(KERN_WARNING "%s:Failed to ioremap address:0x%x\n", __func__, flash_addr);
                return -EIO;
        }

        for (idx = 0 ; idx < FLASH_BANK_MAX ; idx++) {
                if(mtd_size >= flash_size)
                        break;

                printk(KERN_INFO "%s: chip probing count %d\n", __func__, idx);

                map_banks[idx] = kzalloc(sizeof(struct map_info), GFP_KERNEL);
                if(map_banks[idx] == NULL) {
                        ret = -ENOMEM;
                        /* FIXME: What if some MTD devices were probed already? */
                        goto error_mem;
                }

                map_banks[idx]->name = kmalloc(16, GFP_KERNEL);

                if (!map_banks[idx]->name) {
                        ret = -ENOMEM;
                        /* FIXME: What if some MTD devices were probed already? */
                        goto error_mem;
                }
                sprintf(map_banks[idx]->name, "TQM8xxL%d", idx);

                map_banks[idx]->size = flash_size;
                map_banks[idx]->bankwidth = 4;

                simple_map_init(map_banks[idx]);

                map_banks[idx]->virt = start_scan_addr;
                map_banks[idx]->phys = flash_addr;
                /* FIXME: This looks utterly bogus, but I'm trying to
                   preserve the behaviour of the original (shown here)...

                map_banks[idx]->map_priv_1 =
                start_scan_addr + ((idx > 0) ?
                (mtd_banks[idx-1] ? mtd_banks[idx-1]->size : 0) : 0);
                */

                if (idx && mtd_banks[idx-1]) {
                        map_banks[idx]->virt += mtd_banks[idx-1]->size;
                        map_banks[idx]->phys += mtd_banks[idx-1]->size;
                }

                //start to probe flash chips
                mtd_banks[idx] = do_map_probe("cfi_probe", map_banks[idx]);

                if (mtd_banks[idx]) {
                        mtd_banks[idx]->owner = THIS_MODULE;
                        mtd_size += mtd_banks[idx]->size;
                        num_banks++;

                        printk(KERN_INFO "%s: bank%d, name:%s, size:%dbytes \n", __func__, num_banks,
                        mtd_banks[idx]->name, mtd_banks[idx]->size);
                }
        }

        /* no supported flash chips found */
        if (!num_banks) {
                printk(KERN_NOTICE "TQM8xxL: No support flash chips found!\n");
                ret = -ENXIO;
                goto error_mem;
        }

        /*
         * Select Static partition definitions
         */
        part_banks[0].mtd_part = tqm8xxl_partitions;
        part_banks[0].type = "Static image";
        part_banks[0].nums = ARRAY_SIZE(tqm8xxl_partitions);

        part_banks[1].mtd_part = tqm8xxl_fs_partitions;
        part_banks[1].type = "Static file system";
        part_banks[1].nums = ARRAY_SIZE(tqm8xxl_fs_partitions);

        for(idx = 0; idx < num_banks ; idx++) {
                if (part_banks[idx].nums == 0)
                        printk(KERN_NOTICE "TQM flash%d: no partition info available, registering whole flash at once\n", idx);
                else
                        printk(KERN_NOTICE "TQM flash%d: Using %s partition definition\n",
                                        idx, part_banks[idx].type);
                mtd_device_register(mtd_banks[idx], part_banks[idx].mtd_part,
                part_banks[idx].nums);
        }
        return 0;
error_mem:
        for(idx = 0 ; idx < FLASH_BANK_MAX ; idx++) {
                if(map_banks[idx] != NULL) {
                        kfree(map_banks[idx]->name);
                        map_banks[idx]->name = NULL;
                        kfree(map_banks[idx]);
                        map_banks[idx] = NULL;
                }
        }
error:
        iounmap(start_scan_addr);
        return ret;
}

static void __exit cleanup_tqm_mtd(void)
{
        unsigned int idx = 0;
        for(idx = 0 ; idx < num_banks ; idx++) {
                /* destroy mtd_info previously allocated */
                if (mtd_banks[idx]) {
                        mtd_device_unregister(mtd_banks[idx]);
                        map_destroy(mtd_banks[idx]);
                }
                /* release map_info not used anymore */
                kfree(map_banks[idx]->name);
                kfree(map_banks[idx]);
        }

        if (start_scan_addr) {
                iounmap(start_scan_addr);
                start_scan_addr = 0;
        }
}

module_init(init_tqm_mtd);
module_exit(cleanup_tqm_mtd);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kirk Lee <kirk@hpc.ee.ntu.edu.tw>");
MODULE_DESCRIPTION("MTD map driver for TQM8xxL boards");