physmap_of.c

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/*
 * Flash mappings described by the OF (or flattened) device tree
 *
 * Copyright (C) 2006 MontaVista Software Inc.
 * Author: Vitaly Wool <[email protected]>
 *
 * 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/mtd/concat.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/slab.h>

struct of_flash_list {
    struct mtd_info *mtd;
    struct map_info map;
    struct resource *res;
};

struct of_flash {
    struct mtd_info     *cmtd;
    int list_size; /* number of elements in of_flash_list */
    struct of_flash_list    list[0];
};

static int of_flash_remove(struct platform_device *dev)
{
    struct of_flash *info;
    int i;

    info = dev_get_drvdata(&dev->dev);
    if (!info)
        return 0;
    dev_set_drvdata(&dev->dev, NULL);

    if (info->cmtd != info->list[0].mtd) {
        mtd_device_unregister(info->cmtd);
        mtd_concat_destroy(info->cmtd);
    }

    if (info->cmtd)
        mtd_device_unregister(info->cmtd);

    for (i = 0; i < info->list_size; i++) {
        if (info->list[i].mtd)
            map_destroy(info->list[i].mtd);

        if (info->list[i].map.virt)
            iounmap(info->list[i].map.virt);

        if (info->list[i].res) {
            release_resource(info->list[i].res);
            kfree(info->list[i].res);
        }
    }

    kfree(info);

    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 platform_device *dev,
                          struct map_info *map)
{
    struct device_node *dp = dev->dev.of_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);
    }
}

/* When partitions are set we look for a linux,part-probe property which
   specifies the list of partition probers to use. If none is given then the
   default is use. These take precedence over other device tree
   information. */
static const char *part_probe_types_def[] = { "cmdlinepart", "RedBoot",
                    "ofpart", "ofoldpart", NULL };
static const char ** __devinit of_get_probes(struct device_node *dp)
{
    const char *cp;
    int cplen;
    unsigned int l;
    unsigned int count;
    const char **res;

    cp = of_get_property(dp, "linux,part-probe", &cplen);
    if (cp == NULL)
        return part_probe_types_def;

    count = 0;
    for (l = 0; l != cplen; l++)
        if (cp[l] == 0)
            count++;

    res = kzalloc((count + 1)*sizeof(*res), GFP_KERNEL);
    count = 0;
    while (cplen > 0) {
        res[count] = cp;
        l = strlen(cp) + 1;
        cp += l;
        cplen -= l;
        count++;
    }
    return res;
}

static void __devinit of_free_probes(const char **probes)
{
    if (probes != part_probe_types_def)
        kfree(probes);
}

static struct of_device_id of_flash_match[];
static int __devinit of_flash_probe(struct platform_device *dev)
{
    const char **part_probe_types;
    const struct of_device_id *match;
    struct device_node *dp = dev->dev.of_node;
    struct resource res;
    struct of_flash *info;
    const char *probe_type;
    const __be32 *width;
    int err;
    int i;
    int count;
    const __be32 *p;
    int reg_tuple_size;
    struct mtd_info **mtd_list = NULL;
    resource_size_t res_size;
    struct mtd_part_parser_data ppdata;
    bool map_indirect;

    match = of_match_device(of_flash_match, &dev->dev);
    if (!match)
        return -EINVAL;
    probe_type = match->data;

    reg_tuple_size = (of_n_addr_cells(dp) + of_n_size_cells(dp)) * sizeof(u32);

    /*
     * Get number of "reg" tuples. Scan for MTD devices on area's
     * described by each "reg" region. This makes it possible (including
     * the concat support) to support the Intel P30 48F4400 chips which
     * consists internally of 2 non-identical NOR chips on one die.
     */
    p = of_get_property(dp, "reg", &count);
    if (count % reg_tuple_size != 0) {
        dev_err(&dev->dev, "Malformed reg property on %s\n",
                dev->dev.of_node->full_name);
        err = -EINVAL;
        goto err_flash_remove;
    }
    count /= reg_tuple_size;

    map_indirect = of_property_read_bool(dp, "no-unaligned-direct-access");

    err = -ENOMEM;
    info = kzalloc(sizeof(struct of_flash) +
               sizeof(struct of_flash_list) * count, GFP_KERNEL);
    if (!info)
        goto err_flash_remove;

    dev_set_drvdata(&dev->dev, info);

    mtd_list = kzalloc(sizeof(*mtd_list) * count, GFP_KERNEL);
    if (!mtd_list)
        goto err_flash_remove;

    for (i = 0; i < count; i++) {
        err = -ENXIO;
        if (of_address_to_resource(dp, i, &res)) {
            /*
             * Continue with next register tuple if this
             * one is not mappable
             */
            continue;
        }

        dev_dbg(&dev->dev, "of_flash device: %pR\n", &res);

        err = -EBUSY;
        res_size = resource_size(&res);
        info->list[i].res = request_mem_region(res.start, res_size,
                               dev_name(&dev->dev));
        if (!info->list[i].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->list[i].map.name = dev_name(&dev->dev);
        info->list[i].map.phys = res.start;
        info->list[i].map.size = res_size;
        info->list[i].map.bankwidth = be32_to_cpup(width);

        err = -ENOMEM;
        info->list[i].map.virt = ioremap(info->list[i].map.phys,
                         info->list[i].map.size);
        if (!info->list[i].map.virt) {
            dev_err(&dev->dev, "Failed to ioremap() flash"
                " region\n");
            goto err_out;
        }

        simple_map_init(&info->list[i].map);

        /*
         * On some platforms (e.g. MPC5200) a direct 1:1 mapping
         * may cause problems with JFFS2 usage, as the local bus (LPB)
         * doesn't support unaligned accesses as implemented in the
         * JFFS2 code via memcpy(). By setting NO_XIP, the
         * flash will not be exposed directly to the MTD users
         * (e.g. JFFS2) any more.
         */
        if (map_indirect)
            info->list[i].map.phys = NO_XIP;

        if (probe_type) {
            info->list[i].mtd = do_map_probe(probe_type,
                             &info->list[i].map);
        } else {
            info->list[i].mtd = obsolete_probe(dev,
                               &info->list[i].map);
        }
        mtd_list[i] = info->list[i].mtd;

        err = -ENXIO;
        if (!info->list[i].mtd) {
            dev_err(&dev->dev, "do_map_probe() failed\n");
            goto err_out;
        } else {
            info->list_size++;
        }
        info->list[i].mtd->owner = THIS_MODULE;
        info->list[i].mtd->dev.parent = &dev->dev;
    }

    err = 0;
    if (info->list_size == 1) {
        info->cmtd = info->list[0].mtd;
    } else if (info->list_size > 1) {
        /*
         * We detected multiple devices. Concatenate them together.
         */
        info->cmtd = mtd_concat_create(mtd_list, info->list_size,
                           dev_name(&dev->dev));
        if (info->cmtd == NULL)
            err = -ENXIO;
    }
    if (err)
        goto err_out;

    ppdata.of_node = dp;
    part_probe_types = of_get_probes(dp);
    mtd_device_parse_register(info->cmtd, part_probe_types, &ppdata,
            NULL, 0);
    of_free_probes(part_probe_types);

    kfree(mtd_list);

    return 0;

err_out:
    kfree(mtd_list);
err_flash_remove:
    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",
    },
    {
        .compatible     = "mtd-ram",
        .data           = (void *)"map_ram",
    },
    {
        .type       = "rom",
        .compatible = "direct-mapped"
    },
    { },
};
MODULE_DEVICE_TABLE(of, of_flash_match);

static struct platform_driver of_flash_driver = {
    .driver = {
        .name = "of-flash",
        .owner = THIS_MODULE,
        .of_match_table = of_flash_match,
    },
    .probe      = of_flash_probe,
    .remove     = of_flash_remove,
};

module_platform_driver(of_flash_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Vitaly Wool <[email protected]>");
MODULE_DESCRIPTION("Device tree based MTD map driver");