autcpu12-nvram.c

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/*
 * NV-RAM memory access on autcpu12
 * (C) 2002 Thomas Gleixner ([email protected])
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/sizes.h>

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

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

struct autcpu12_nvram_priv {
    struct mtd_info *mtd;
    struct map_info map;
};

static int __devinit autcpu12_nvram_probe(struct platform_device *pdev)
{
    map_word tmp, save0, save1;
    struct resource *res;
    struct autcpu12_nvram_priv *priv;

    priv = devm_kzalloc(&pdev->dev,
                sizeof(struct autcpu12_nvram_priv), GFP_KERNEL);
    if (!priv)
        return -ENOMEM;

    platform_set_drvdata(pdev, priv);

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        dev_err(&pdev->dev, "failed to get memory resource\n");
        return -ENOENT;
    }

    priv->map.bankwidth = 4;
    priv->map.phys      = res->start;
    priv->map.size      = resource_size(res);
    priv->map.virt      = devm_request_and_ioremap(&pdev->dev, res);
    strcpy((char *)priv->map.name, res->name);
    if (!priv->map.virt) {
        dev_err(&pdev->dev, "failed to remap mem resource\n");
        return -EBUSY;
    }

    simple_map_init(&priv->map);

    /*
     * Check for 32K/128K
     * read ofs 0
     * read ofs 0x10000
     * Write complement to ofs 0x100000
     * Read and check result on ofs 0x0
     * Restore contents
     */
    save0 = map_read(&priv->map, 0);
    save1 = map_read(&priv->map, 0x10000);
    tmp.x[0] = ~save0.x[0];
    map_write(&priv->map, tmp, 0x10000);
    tmp = map_read(&priv->map, 0);
    /* if we find this pattern on 0x0, we have 32K size */
    if (!map_word_equal(&priv->map, tmp, save0)) {
        map_write(&priv->map, save0, 0x0);
        priv->map.size = SZ_32K;
    } else
        map_write(&priv->map, save1, 0x10000);

    priv->mtd = do_map_probe("map_ram", &priv->map);
    if (!priv->mtd) {
        dev_err(&pdev->dev, "probing failed\n");
        return -ENXIO;
    }

    priv->mtd->owner    = THIS_MODULE;
    priv->mtd->erasesize    = 16;
    priv->mtd->dev.parent   = &pdev->dev;
    if (!mtd_device_register(priv->mtd, NULL, 0)) {
        dev_info(&pdev->dev,
             "NV-RAM device size %ldKiB registered on AUTCPU12\n",
             priv->map.size / SZ_1K);
        return 0;
    }

    map_destroy(priv->mtd);
    dev_err(&pdev->dev, "NV-RAM device addition failed\n");
    return -ENOMEM;
}

static int __devexit autcpu12_nvram_remove(struct platform_device *pdev)
{
    struct autcpu12_nvram_priv *priv = platform_get_drvdata(pdev);

    mtd_device_unregister(priv->mtd);
    map_destroy(priv->mtd);

    return 0;
}

static struct platform_driver autcpu12_nvram_driver = {
    .driver     = {
        .name   = "autcpu12_nvram",
        .owner  = THIS_MODULE,
    },
    .probe      = autcpu12_nvram_probe,
    .remove     = __devexit_p(autcpu12_nvram_remove),
};
module_platform_driver(autcpu12_nvram_driver);

MODULE_AUTHOR("Thomas Gleixner");
MODULE_DESCRIPTION("autcpu12 NVRAM map driver");
MODULE_LICENSE("GPL");