/*
 * Physical mapping layer for MTD using the Axis partitiontable format
 *
 * Copyright (c) 2001-2007 Axis Communications AB
 *
 * This file is under the GPL.
 *
 * First partition is always sector 0 regardless of if we find a partitiontable
 * or not. In the start of the next sector, there can be a partitiontable that
 * tells us what other partitions to define. If there isn't, we use a default
 * partition split defined below.
 *
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>

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

#include <asm/axisflashmap.h>
#include <asm/mmu.h>

#define MEM_CSE0_SIZE (0x04000000)
#define MEM_CSE1_SIZE (0x04000000)

#define FLASH_UNCACHED_ADDR  KSEG_E
#define FLASH_CACHED_ADDR    KSEG_F

#define PAGESIZE (512)

#if CONFIG_ETRAX_FLASH_BUSWIDTH==1
#define flash_data __u8
#elif CONFIG_ETRAX_FLASH_BUSWIDTH==2
#define flash_data __u16
#elif CONFIG_ETRAX_FLASH_BUSWIDTH==4
#define flash_data __u32
#endif

/* From head.S */
extern unsigned long romfs_in_flash; /* 1 when romfs_start, _length in flash */
extern unsigned long romfs_start, romfs_length;
extern unsigned long nand_boot; /* 1 when booted from nand flash */

struct partition_name {
        char name[6];
};

/* The master mtd for the entire flash. */
struct mtd_info* axisflash_mtd = NULL;

/* Map driver functions. */

static map_word flash_read(struct map_info *map, unsigned long ofs)
{
        map_word tmp;
        tmp.x[0] = *(flash_data *)(map->map_priv_1 + ofs);
        return tmp;
}

static void flash_copy_from(struct map_info *map, void *to,
                            unsigned long from, ssize_t len)
{
        memcpy(to, (void *)(map->map_priv_1 + from), len);
}

static void flash_write(struct map_info *map, map_word d, unsigned long adr)
{
        *(flash_data *)(map->map_priv_1 + adr) = (flash_data)d.x[0];
}

/*
 * The map for chip select e0.
 *
 * We run into tricky coherence situations if we mix cached with uncached
 * accesses to we only use the uncached version here.
 *
 * The size field is the total size where the flash chips may be mapped on the
 * chip select. MTD probes should find all devices there and it does not matter
 * if there are unmapped gaps or aliases (mirrors of flash devices). The MTD
 * probes will ignore them.
 *
 * The start address in map_priv_1 is in virtual memory so we cannot use
 * MEM_CSE0_START but must rely on that FLASH_UNCACHED_ADDR is the start
 * address of cse0.
 */
static struct map_info map_cse0 = {
        .name = "cse0",
        .size = MEM_CSE0_SIZE,
        .bankwidth = CONFIG_ETRAX_FLASH_BUSWIDTH,
        .read = flash_read,
        .copy_from = flash_copy_from,
        .write = flash_write,
        .map_priv_1 = FLASH_UNCACHED_ADDR
};

/*
 * The map for chip select e1.
 *
 * If there was a gap between cse0 and cse1, map_priv_1 would get the wrong
 * address, but there isn't.
 */
static struct map_info map_cse1 = {
        .name = "cse1",
        .size = MEM_CSE1_SIZE,
        .bankwidth = CONFIG_ETRAX_FLASH_BUSWIDTH,
        .read = flash_read,
        .copy_from = flash_copy_from,
        .write = flash_write,
        .map_priv_1 = FLASH_UNCACHED_ADDR + MEM_CSE0_SIZE
};

#define MAX_PARTITIONS                  7
#ifdef CONFIG_ETRAX_NANDBOOT
#define NUM_DEFAULT_PARTITIONS          4
#define DEFAULT_ROOTFS_PARTITION_NO     2
#define DEFAULT_MEDIA_SIZE              0x2000000 /* 32 megs */
#else
#define NUM_DEFAULT_PARTITIONS          3
#define DEFAULT_ROOTFS_PARTITION_NO     (-1)
#define DEFAULT_MEDIA_SIZE              0x800000 /* 8 megs */
#endif

#if (MAX_PARTITIONS < NUM_DEFAULT_PARTITIONS)
#error MAX_PARTITIONS must be >= than NUM_DEFAULT_PARTITIONS
#endif

/* Initialize the ones normally used. */
static struct mtd_partition axis_partitions[MAX_PARTITIONS] = {
        {
                .name = "part0",
                .size = CONFIG_ETRAX_PTABLE_SECTOR,
                .offset = 0
        },
        {
                .name = "part1",
                .size = 0,
                .offset = 0
        },
        {
                .name = "part2",
                .size = 0,
                .offset = 0
        },
        {
                .name = "part3",
                .size = 0,
                .offset = 0
        },
        {
                .name = "part4",
                .size = 0,
                .offset = 0
        },
        {
                .name = "part5",
                .size = 0,
                .offset = 0
        },
        {
                .name = "part6",
                .size = 0,
                .offset = 0
        },
};


/* If no partition-table was found, we use this default-set.
 * Default flash size is 8MB (NOR). CONFIG_ETRAX_PTABLE_SECTOR is most
 * likely the size of one flash block and "filesystem"-partition needs
 * to be >=5 blocks to be able to use JFFS.
 */
static struct mtd_partition axis_default_partitions[NUM_DEFAULT_PARTITIONS] = {
        {
                .name = "boot firmware",
                .size = CONFIG_ETRAX_PTABLE_SECTOR,
                .offset = 0
        },
        {
                .name = "kernel",
                .size = 10 * CONFIG_ETRAX_PTABLE_SECTOR,
                .offset = CONFIG_ETRAX_PTABLE_SECTOR
        },
#define FILESYSTEM_SECTOR (11 * CONFIG_ETRAX_PTABLE_SECTOR)
#ifdef CONFIG_ETRAX_NANDBOOT
        {
                .name = "rootfs",
                .size = 10 * CONFIG_ETRAX_PTABLE_SECTOR,
                .offset = FILESYSTEM_SECTOR
        },
#undef FILESYSTEM_SECTOR
#define FILESYSTEM_SECTOR (21 * CONFIG_ETRAX_PTABLE_SECTOR)
#endif
        {
                .name = "rwfs",
                .size = DEFAULT_MEDIA_SIZE - FILESYSTEM_SECTOR,
                .offset = FILESYSTEM_SECTOR
        }
};

#ifdef CONFIG_ETRAX_AXISFLASHMAP_MTD0WHOLE
/* Main flash device */
static struct mtd_partition main_partition = {
        .name = "main",
        .size = 0,
        .offset = 0
};
#endif

/* Auxiliary partition if we find another flash */
static struct mtd_partition aux_partition = {
        .name = "aux",
        .size = 0,
        .offset = 0
};

/*
 * Probe a chip select for AMD-compatible (JEDEC) or CFI-compatible flash
 * chips in that order (because the amd_flash-driver is faster).
 */
static struct mtd_info *probe_cs(struct map_info *map_cs)
{
        struct mtd_info *mtd_cs = NULL;

        printk(KERN_INFO
               "%s: Probing a 0x%08lx bytes large window at 0x%08lx.\n",
               map_cs->name, map_cs->size, map_cs->map_priv_1);

#ifdef CONFIG_MTD_CFI
        mtd_cs = do_map_probe("cfi_probe", map_cs);
#endif
#ifdef CONFIG_MTD_JEDECPROBE
        if (!mtd_cs)
                mtd_cs = do_map_probe("jedec_probe", map_cs);
#endif

        return mtd_cs;
}

/*
 * Probe each chip select individually for flash chips. If there are chips on
 * both cse0 and cse1, the mtd_info structs will be concatenated to one struct
 * so that MTD partitions can cross chip boundries.
 *
 * The only known restriction to how you can mount your chips is that each
 * chip select must hold similar flash chips. But you need external hardware
 * to do that anyway and you can put totally different chips on cse0 and cse1
 * so it isn't really much of a restriction.
 */
extern struct mtd_info* __init crisv32_nand_flash_probe (void);
static struct mtd_info *flash_probe(void)
{
        struct mtd_info *mtd_cse0;
        struct mtd_info *mtd_cse1;
        struct mtd_info *mtd_total;
        struct mtd_info *mtds[2];
        int count = 0;

        if ((mtd_cse0 = probe_cs(&map_cse0)) != NULL)
                mtds[count++] = mtd_cse0;
        if ((mtd_cse1 = probe_cs(&map_cse1)) != NULL)
                mtds[count++] = mtd_cse1;

        if (!mtd_cse0 && !mtd_cse1) {
                /* No chip found. */
                return NULL;
        }

        if (count > 1) {
                /* Since the concatenation layer adds a small overhead we
                 * could try to figure out if the chips in cse0 and cse1 are
                 * identical and reprobe the whole cse0+cse1 window. But since
                 * flash chips are slow, the overhead is relatively small.
                 * So we use the MTD concatenation layer instead of further
                 * complicating the probing procedure.
                 */
                mtd_total = mtd_concat_create(mtds, count, "cse0+cse1");
                if (!mtd_total) {
                        printk(KERN_ERR "%s and %s: Concatenation failed!\n",
                                map_cse0.name, map_cse1.name);

                        /* The best we can do now is to only use what we found
                         * at cse0. */
                        mtd_total = mtd_cse0;
                        map_destroy(mtd_cse1);
                }
        } else
                mtd_total = mtd_cse0 ? mtd_cse0 : mtd_cse1;

        return mtd_total;
}

/*
 * Probe the flash chip(s) and, if it succeeds, read the partition-table
 * and register the partitions with MTD.
 */
static int __init init_axis_flash(void)
{
        struct mtd_info *main_mtd;
        struct mtd_info *aux_mtd = NULL;
        int err = 0;
        int pidx = 0;
        struct partitiontable_head *ptable_head = NULL;
        struct partitiontable_entry *ptable;
        int ptable_ok = 0;
        static char page[PAGESIZE];
        size_t len;
        int ram_rootfs_partition = -1; /* -1 => no RAM rootfs partition */
        int part;

        /* We need a root fs. If it resides in RAM, we need to use an
         * MTDRAM device, so it must be enabled in the kernel config,
         * but its size must be configured as 0 so as not to conflict
         * with our usage.
         */
#if !defined(CONFIG_MTD_MTDRAM) || (CONFIG_MTDRAM_TOTAL_SIZE != 0) || (CONFIG_MTDRAM_ABS_POS != 0)
        if (!romfs_in_flash && !nand_boot) {
                printk(KERN_EMERG "axisflashmap: Cannot create an MTD RAM "
                       "device; configure CONFIG_MTD_MTDRAM with size = 0!\n");
                panic("This kernel cannot boot from RAM!\n");
        }
#endif

        main_mtd = flash_probe();
        if (main_mtd)
                printk(KERN_INFO "%s: 0x%08x bytes of NOR flash memory.\n",
                       main_mtd->name, main_mtd->size);

#ifdef CONFIG_ETRAX_NANDFLASH
        aux_mtd = crisv32_nand_flash_probe();
        if (aux_mtd)
                printk(KERN_INFO "%s: 0x%08x bytes of NAND flash memory.\n",
                        aux_mtd->name, aux_mtd->size);

#ifdef CONFIG_ETRAX_NANDBOOT
        {
                struct mtd_info *tmp_mtd;

                printk(KERN_INFO "axisflashmap: Set to boot from NAND flash, "
                       "making NAND flash primary device.\n");
                tmp_mtd = main_mtd;
                main_mtd = aux_mtd;
                aux_mtd = tmp_mtd;
        }
#endif /* CONFIG_ETRAX_NANDBOOT */
#endif /* CONFIG_ETRAX_NANDFLASH */

        if (!main_mtd && !aux_mtd) {
                /* There's no reason to use this module if no flash chip can
                 * be identified. Make sure that's understood.
                 */
                printk(KERN_INFO "axisflashmap: Found no flash chip.\n");
        }

#if 0 /* Dump flash memory so we can see what is going on */
        if (main_mtd) {
                int sectoraddr, i;
                for (sectoraddr = 0; sectoraddr < 2*65536+4096;
                                sectoraddr += PAGESIZE) {
                        main_mtd->read(main_mtd, sectoraddr, PAGESIZE, &len,
                                page);
                        printk(KERN_INFO
                               "Sector at %d (length %d):\n",
                               sectoraddr, len);
                        for (i = 0; i < PAGESIZE; i += 16) {
                                printk(KERN_INFO
                                       "%02x %02x %02x %02x "
                                       "%02x %02x %02x %02x "
                                       "%02x %02x %02x %02x "
                                       "%02x %02x %02x %02x\n",
                                       page[i] & 255, page[i+1] & 255,
                                       page[i+2] & 255, page[i+3] & 255,
                                       page[i+4] & 255, page[i+5] & 255,
                                       page[i+6] & 255, page[i+7] & 255,
                                       page[i+8] & 255, page[i+9] & 255,
                                       page[i+10] & 255, page[i+11] & 255,
                                       page[i+12] & 255, page[i+13] & 255,
                                       page[i+14] & 255, page[i+15] & 255);
                        }
                }
        }
#endif

        if (main_mtd) {
                main_mtd->owner = THIS_MODULE;
                axisflash_mtd = main_mtd;

                loff_t ptable_sector = CONFIG_ETRAX_PTABLE_SECTOR;

                /* First partition (rescue) is always set to the default. */
                pidx++;
#ifdef CONFIG_ETRAX_NANDBOOT
                /* We know where the partition table should be located,
                 * it will be in first good block after that.
                 */
                int blockstat;
                do {
                        blockstat = mtd_block_isbad(main_mtd, ptable_sector);
                        if (blockstat < 0)
                                ptable_sector = 0; /* read error */
                        else if (blockstat)
                                ptable_sector += main_mtd->erasesize;
                } while (blockstat && ptable_sector);
#endif
                if (ptable_sector) {
                        mtd_read(main_mtd, ptable_sector, PAGESIZE, &len,
                                 page);
                        ptable_head = &((struct partitiontable *) page)->head;
                }

#if 0 /* Dump partition table so we can see what is going on */
                printk(KERN_INFO
                       "axisflashmap: flash read %d bytes at 0x%08x, data: "
                       "%02x %02x %02x %02x %02x %02x %02x %02x\n",
                       len, CONFIG_ETRAX_PTABLE_SECTOR,
                       page[0] & 255, page[1] & 255,
                       page[2] & 255, page[3] & 255,
                       page[4] & 255, page[5] & 255,
                       page[6] & 255, page[7] & 255);
                printk(KERN_INFO
                       "axisflashmap: partition table offset %d, data: "
                       "%02x %02x %02x %02x %02x %02x %02x %02x\n",
                       PARTITION_TABLE_OFFSET,
                       page[PARTITION_TABLE_OFFSET+0] & 255,
                       page[PARTITION_TABLE_OFFSET+1] & 255,
                       page[PARTITION_TABLE_OFFSET+2] & 255,
                       page[PARTITION_TABLE_OFFSET+3] & 255,
                       page[PARTITION_TABLE_OFFSET+4] & 255,
                       page[PARTITION_TABLE_OFFSET+5] & 255,
                       page[PARTITION_TABLE_OFFSET+6] & 255,
                       page[PARTITION_TABLE_OFFSET+7] & 255);
#endif
        }

        if (ptable_head && (ptable_head->magic == PARTITION_TABLE_MAGIC)
            && (ptable_head->size <
                (MAX_PARTITIONS * sizeof(struct partitiontable_entry) +
                PARTITIONTABLE_END_MARKER_SIZE))
            && (*(unsigned long*)((void*)ptable_head + sizeof(*ptable_head) +
                                  ptable_head->size -
                                  PARTITIONTABLE_END_MARKER_SIZE)
                == PARTITIONTABLE_END_MARKER)) {
                /* Looks like a start, sane length and end of a
                 * partition table, lets check csum etc.
                 */
                struct partitiontable_entry *max_addr =
                        (struct partitiontable_entry *)
                        ((unsigned long)ptable_head + sizeof(*ptable_head) +
                         ptable_head->size);
                unsigned long offset = CONFIG_ETRAX_PTABLE_SECTOR;
                unsigned char *p;
                unsigned long csum = 0;

                ptable = (struct partitiontable_entry *)
                        ((unsigned long)ptable_head + sizeof(*ptable_head));

                /* Lets be PARANOID, and check the checksum. */
                p = (unsigned char*) ptable;

                while (p <= (unsigned char*)max_addr) {
                        csum += *p++;
                        csum += *p++;
                        csum += *p++;
                        csum += *p++;
                }
                ptable_ok = (csum == ptable_head->checksum);

                /* Read the entries and use/show the info.  */
                printk(KERN_INFO "axisflashmap: "
                       "Found a%s partition table at 0x%p-0x%p.\n",
                       (ptable_ok ? " valid" : "n invalid"), ptable_head,
                       max_addr);

                /* We have found a working bootblock.  Now read the
                 * partition table.  Scan the table.  It ends with 0xffffffff.
                 */
                while (ptable_ok
                       && ptable->offset != PARTITIONTABLE_END_MARKER
                       && ptable < max_addr
                       && pidx < MAX_PARTITIONS - 1) {

                        axis_partitions[pidx].offset = offset + ptable->offset;
#ifdef CONFIG_ETRAX_NANDFLASH
                        if (main_mtd->type == MTD_NANDFLASH) {
                                axis_partitions[pidx].size =
                                        (((ptable+1)->offset ==
                                          PARTITIONTABLE_END_MARKER) ?
                                          main_mtd->size :
                                          ((ptable+1)->offset + offset)) -
                                        (ptable->offset + offset);

                        } else
#endif /* CONFIG_ETRAX_NANDFLASH */
                                axis_partitions[pidx].size = ptable->size;
#ifdef CONFIG_ETRAX_NANDBOOT
                        /* Save partition number of jffs2 ro partition.
                         * Needed if RAM booting or root file system in RAM.
                         */
                        if (!nand_boot &&
                            ram_rootfs_partition < 0 && /* not already set */
                            ptable->type == PARTITION_TYPE_JFFS2 &&
                            (ptable->flags & PARTITION_FLAGS_READONLY_MASK) ==
                                PARTITION_FLAGS_READONLY)
                                ram_rootfs_partition = pidx;
#endif /* CONFIG_ETRAX_NANDBOOT */
                        pidx++;
                        ptable++;
                }
        }

        /* Decide whether to use default partition table. */
        /* Only use default table if we actually have a device (main_mtd) */

        struct mtd_partition *partition = &axis_partitions[0];
        if (main_mtd && !ptable_ok) {
                memcpy(axis_partitions, axis_default_partitions,
                       sizeof(axis_default_partitions));
                pidx = NUM_DEFAULT_PARTITIONS;
                ram_rootfs_partition = DEFAULT_ROOTFS_PARTITION_NO;
        }

        /* Add artificial partitions for rootfs if necessary */
        if (romfs_in_flash) {
                /* rootfs is in directly accessible flash memory = NOR flash.
                   Add an overlapping device for the rootfs partition. */
                printk(KERN_INFO "axisflashmap: Adding partition for "
                       "overlapping root file system image\n");
                axis_partitions[pidx].size = romfs_length;
                axis_partitions[pidx].offset = romfs_start - FLASH_CACHED_ADDR;
                axis_partitions[pidx].name = "romfs";
                axis_partitions[pidx].mask_flags |= MTD_WRITEABLE;
                ram_rootfs_partition = -1;
                pidx++;
        } else if (romfs_length && !nand_boot) {
                /* romfs exists in memory, but not in flash, so must be in RAM.
                 * Configure an MTDRAM partition. */
                if (ram_rootfs_partition < 0) {
                        /* None set yet, put it at the end */
                        ram_rootfs_partition = pidx;
                        pidx++;
                }
                printk(KERN_INFO "axisflashmap: Adding partition for "
                       "root file system image in RAM\n");
                axis_partitions[ram_rootfs_partition].size = romfs_length;
                axis_partitions[ram_rootfs_partition].offset = romfs_start;
                axis_partitions[ram_rootfs_partition].name = "romfs";
                axis_partitions[ram_rootfs_partition].mask_flags |=
                        MTD_WRITEABLE;
        }

#ifdef CONFIG_ETRAX_AXISFLASHMAP_MTD0WHOLE
        if (main_mtd) {
                main_partition.size = main_mtd->size;
                err = mtd_device_register(main_mtd, &main_partition, 1);
                if (err)
                        panic("axisflashmap: Could not initialize "
                              "partition for whole main mtd device!\n");
        }
#endif

        /* Now, register all partitions with mtd.
         * We do this one at a time so we can slip in an MTDRAM device
         * in the proper place if required. */

        for (part = 0; part < pidx; part++) {
                if (part == ram_rootfs_partition) {
                        /* add MTDRAM partition here */
                        struct mtd_info *mtd_ram;

                        mtd_ram = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
                        if (!mtd_ram)
                                panic("axisflashmap: Couldn't allocate memory "
                                      "for mtd_info!\n");
                        printk(KERN_INFO "axisflashmap: Adding RAM partition "
                               "for rootfs image.\n");
                        err = mtdram_init_device(mtd_ram,
                                                 (void *)partition[part].offset,
                                                 partition[part].size,
                                                 partition[part].name);
                        if (err)
                                panic("axisflashmap: Could not initialize "
                                      "MTD RAM device!\n");
                        /* JFFS2 likes to have an erasesize. Keep potential
                         * JFFS2 rootfs happy by providing one. Since image
                         * was most likely created for main mtd, use that
                         * erasesize, if available. Otherwise, make a guess. */
                        mtd_ram->erasesize = (main_mtd ? main_mtd->erasesize :
                                CONFIG_ETRAX_PTABLE_SECTOR);
                } else {
                        err = mtd_device_register(main_mtd, &partition[part],
                                                  1);
                        if (err)
                                panic("axisflashmap: Could not add mtd "
                                        "partition %d\n", part);
                }
        }

        if (aux_mtd) {
                aux_partition.size = aux_mtd->size;
                err = mtd_device_register(aux_mtd, &aux_partition, 1);
                if (err)
                        panic("axisflashmap: Could not initialize "
                              "aux mtd device!\n");

        }

        return err;
}

/* This adds the above to the kernels init-call chain. */
module_init(init_axis_flash);

EXPORT_SYMBOL(axisflash_mtd);