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/*

 * Flash mappings described by the OF (or flattened) device tree

 *

 * Copyright (C) 2006 MontaVista Software Inc.

 * Author: Vitaly Wool <vwool@ru.mvista.com>

 *

 * Revised to handle newer style flash binding by:

 *   Copyright (C) 2007 David Gibson, IBM Corporation.

 *

 * 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.

 */

#include <linux/module.h>

#include <linux/types.h>

#include <linux/init.h>

#include <linux/device.h>

#include <linux/mtd/mtd.h>

#include <linux/mtd/map.h>

#include <linux/mtd/partitions.h>

#include <linux/of.h>

#include <linux/of_platform.h>

struct of_flash {

        struct mtd_info         *mtd;

        struct map_info         map;

        struct resource         *res;

#ifdef CONFIG_MTD_PARTITIONS

        struct mtd_partition    *parts;

#endif

};

#ifdef CONFIG_MTD_PARTITIONS

#define OF_FLASH_PARTS(info)    ((info)->parts)

static int parse_obsolete_partitions(struct of_device *dev,

                                     struct of_flash *info,

                                     struct device_node *dp)

{

        int i, plen, nr_parts;

        const struct {

                u32 offset, len;

        } *part;

        const char *names;

        part = of_get_property(dp, "partitions", &plen);

        if (!part)

                return 0; /* No partitions found */

        dev_warn(&dev->dev, "Device tree uses obsolete partition map binding\n");

        nr_parts = plen / sizeof(part[0]);

        info->parts = kzalloc(nr_parts * sizeof(*info->parts), GFP_KERNEL);

        if (!info->parts)

                return -ENOMEM;

        names = of_get_property(dp, "partition-names", &plen);

        for (i = 0; i < nr_parts; i++) {

                info->parts[i].offset = part->offset;

                info->parts[i].size   = part->len & ~1;

                if (part->len & 1) /* bit 0 set signifies read only partition */

                        info->parts[i].mask_flags = MTD_WRITEABLE;

                if (names && (plen > 0)) {

                        int len = strlen(names) + 1;

                        info->parts[i].name = (char *)names;

                        plen -= len;

                        names += len;

                } else {

                        info->parts[i].name = "unnamed";

                }

                part++;

        }

        return nr_parts;

}

static int __devinit parse_partitions(struct of_flash *info,

                                      struct of_device *dev)

{

        const char *partname;

        static const char *part_probe_types[]

                = { "cmdlinepart", "RedBoot", NULL };

        struct device_node *dp = dev->node, *pp;

        int nr_parts, i;

        /* First look for RedBoot table or partitions on the command

         * line, these take precedence over device tree information */

        nr_parts = parse_mtd_partitions(info->mtd, part_probe_types,

                                        &info->parts, 0);

        if (nr_parts > 0) {

                add_mtd_partitions(info->mtd, info->parts, nr_parts);

                return 0;

        }

        /* First count the subnodes */

        nr_parts = 0;

        for (pp = dp->child; pp; pp = pp->sibling)

                nr_parts++;

        if (nr_parts == 0)

                return parse_obsolete_partitions(dev, info, dp);

        info->parts = kzalloc(nr_parts * sizeof(*info->parts),

                              GFP_KERNEL);

        if (!info->parts)

                return -ENOMEM;

        for (pp = dp->child, i = 0; pp; pp = pp->sibling, i++) {

                const u32 *reg;

                int len;

                reg = of_get_property(pp, "reg", &len);

                if (!reg || (len != 2*sizeof(u32))) {

                        dev_err(&dev->dev, "Invalid 'reg' on %s\n",

                                dp->full_name);

                        kfree(info->parts);

                        info->parts = NULL;

                        return -EINVAL;

                }

                info->parts[i].offset = reg[0];

                info->parts[i].size = reg[1];

                partname = of_get_property(pp, "label", &len);

                if (!partname)

                        partname = of_get_property(pp, "name", &len);

                info->parts[i].name = (char *)partname;

                if (of_get_property(pp, "read-only", &len))

                        info->parts[i].mask_flags = MTD_WRITEABLE;

        }

        return nr_parts;

}

#else /* MTD_PARTITIONS */

#define OF_FLASH_PARTS(info)            (0)

#define parse_partitions(info, dev)     (0)

#endif /* MTD_PARTITIONS */

static int of_flash_remove(struct of_device *dev)

{

        struct of_flash *info;

        info = dev_get_drvdata(&dev->dev);

        if (!info)

                return 0;

        dev_set_drvdata(&dev->dev, NULL);

        if (info->mtd) {

                if (OF_FLASH_PARTS(info)) {

                        del_mtd_partitions(info->mtd);

                        kfree(OF_FLASH_PARTS(info));

                } else {

                        del_mtd_device(info->mtd);

                }

                map_destroy(info->mtd);

        }

        if (info->map.virt)

                iounmap(info->map.virt);

        if (info->res) {

                release_resource(info->res);

                kfree(info->res);

        }

        return 0;

}

/* Helper function to handle probing of the obsolete "direct-mapped"

 * compatible binding, which has an extra "probe-type" property

 * describing the type of flash probe necessary. */

static struct mtd_info * __devinit obsolete_probe(struct of_device *dev,

                                                  struct map_info *map)

{

        struct device_node *dp = dev->node;

        const char *of_probe;

        struct mtd_info *mtd;

        static const char *rom_probe_types[]

                = { "cfi_probe", "jedec_probe", "map_rom"};

        int i;

        dev_warn(&dev->dev, "Device tree uses obsolete \"direct-mapped\" "

                 "flash binding\n");

        of_probe = of_get_property(dp, "probe-type", NULL);

        if (!of_probe) {

                for (i = 0; i < ARRAY_SIZE(rom_probe_types); i++) {

                        mtd = do_map_probe(rom_probe_types[i], map);

                        if (mtd)

                                return mtd;

                }

                return NULL;

        } else if (strcmp(of_probe, "CFI") == 0) {

                return do_map_probe("cfi_probe", map);

        } else if (strcmp(of_probe, "JEDEC") == 0) {

                return do_map_probe("jedec_probe", map);

        } else {

                if (strcmp(of_probe, "ROM") != 0)

                        dev_warn(&dev->dev, "obsolete_probe: don't know probe "

                                 "type '%s', mapping as rom\n", of_probe);

                return do_map_probe("mtd_rom", map);

        }

}

static int __devinit of_flash_probe(struct of_device *dev,

                                    const struct of_device_id *match)

{

        struct device_node *dp = dev->node;

        struct resource res;

        struct of_flash *info;

        const char *probe_type = match->data;

        const u32 *width;

        int err;

        err = -ENXIO;

        if (of_address_to_resource(dp, 0, &res)) {

                dev_err(&dev->dev, "Can't get IO address from device tree\n");

                goto err_out;

        }

        dev_dbg(&dev->dev, "of_flash device: %.8llx-%.8llx\n",

                (unsigned long long)res.start, (unsigned long long)res.end);

        err = -ENOMEM;

        info = kzalloc(sizeof(*info), GFP_KERNEL);

        if (!info)

                goto err_out;

        dev_set_drvdata(&dev->dev, info);

        err = -EBUSY;

        info->res = request_mem_region(res.start, res.end - res.start + 1,

                                       dev->dev.bus_id);

        if (!info->res)

                goto err_out;

        err = -ENXIO;

        width = of_get_property(dp, "bank-width", NULL);

        if (!width) {

                dev_err(&dev->dev, "Can't get bank width from device tree\n");

                goto err_out;

        }

        info->map.name = dev->dev.bus_id;

        info->map.phys = res.start;

        info->map.size = res.end - res.start + 1;

        info->map.bankwidth = *width;

        err = -ENOMEM;

        info->map.virt = ioremap(info->map.phys, info->map.size);

        if (!info->map.virt) {

                dev_err(&dev->dev, "Failed to ioremap() flash region\n");

                goto err_out;

        }

        simple_map_init(&info->map);

        if (probe_type)

                info->mtd = do_map_probe(probe_type, &info->map);

        else

                info->mtd = obsolete_probe(dev, &info->map);

        err = -ENXIO;

        if (!info->mtd) {

                dev_err(&dev->dev, "do_map_probe() failed\n");

                goto err_out;

        }

        info->mtd->owner = THIS_MODULE;

        err = parse_partitions(info, dev);

        if (err < 0)

                goto err_out;

        if (err > 0)

                add_mtd_partitions(info->mtd, OF_FLASH_PARTS(info), err);

        else

                add_mtd_device(info->mtd);

        return 0;

err_out:

        of_flash_remove(dev);

        return err;

}

static struct of_device_id of_flash_match[] = {

        {

                .compatible     = "cfi-flash",

                .data           = (void *)"cfi_probe",

        },

        {

                /* FIXME: JEDEC chips can't be safely and reliably

                 * probed, although the mtd code gets it right in

                 * practice most of the time.  We should use the

                 * vendor and device ids specified by the binding to

                 * bypass the heuristic probe code, but the mtd layer

                 * provides, at present, no interface for doing so

                 * :(. */

                .compatible     = "jedec-flash",

                .data           = (void *)"jedec_probe",

        },

        {

                .type           = "rom",

                .compatible     = "direct-mapped"

        },

        { },

};

MODULE_DEVICE_TABLE(of, of_flash_match);

static struct of_platform_driver of_flash_driver = {

        .name           = "of-flash",

        .match_table    = of_flash_match,

        .probe          = of_flash_probe,

        .remove         = of_flash_remove,

};

static int __init of_flash_init(void)

{

        return of_register_platform_driver(&of_flash_driver);

}

static void __exit of_flash_exit(void)

{

        of_unregister_platform_driver(&of_flash_driver);

}

module_init(of_flash_init);

module_exit(of_flash_exit);

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Vitaly Wool <vwool@ru.mvista.com>");

MODULE_DESCRIPTION("Device tree based MTD map driver");