axisflashmap.c

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/*
 * 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 <linux/cramfs_fs.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);