plat-ram.c

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/* drivers/mtd/maps/plat-ram.c
 *
 * (c) 2004-2005 Simtec Electronics
 *  http://www.simtec.co.uk/products/SWLINUX/
 *  Ben Dooks <[email protected]>
 *
 * Generic platform device based RAM map
 *
 * 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/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/platform_device.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/plat-ram.h>

#include <asm/io.h>

/* private structure for each mtd platform ram device created */

struct platram_info {
    struct device       *dev;
    struct mtd_info     *mtd;
    struct map_info      map;
    struct resource     *area;
    struct platdata_mtd_ram *pdata;
};

/* to_platram_info()
 *
 * device private data to struct platram_info conversion
*/

static inline struct platram_info *to_platram_info(struct platform_device *dev)
{
    return (struct platram_info *)platform_get_drvdata(dev);
}

/* platram_setrw
 *
 * call the platform device's set rw/ro control
 *
 * to = 0 => read-only
 *    = 1 => read-write
*/

static inline void platram_setrw(struct platram_info *info, int to)
{
    if (info->pdata == NULL)
        return;

    if (info->pdata->set_rw != NULL)
        (info->pdata->set_rw)(info->dev, to);
}

/* platram_remove
 *
 * called to remove the device from the driver's control
*/

static int platram_remove(struct platform_device *pdev)
{
    struct platram_info *info = to_platram_info(pdev);

    platform_set_drvdata(pdev, NULL);

    dev_dbg(&pdev->dev, "removing device\n");

    if (info == NULL)
        return 0;

    if (info->mtd) {
        mtd_device_unregister(info->mtd);
        map_destroy(info->mtd);
    }

    /* ensure ram is left read-only */

    platram_setrw(info, PLATRAM_RO);

    /* release resources */

    if (info->area) {
        release_resource(info->area);
        kfree(info->area);
    }

    if (info->map.virt != NULL)
        iounmap(info->map.virt);

    kfree(info);

    return 0;
}

/* platram_probe
 *
 * called from device drive system when a device matching our
 * driver is found.
*/

static int platram_probe(struct platform_device *pdev)
{
    struct platdata_mtd_ram *pdata;
    struct platram_info *info;
    struct resource *res;
    int err = 0;

    dev_dbg(&pdev->dev, "probe entered\n");

    if (pdev->dev.platform_data == NULL) {
        dev_err(&pdev->dev, "no platform data supplied\n");
        err = -ENOENT;
        goto exit_error;
    }

    pdata = pdev->dev.platform_data;

    info = kzalloc(sizeof(*info), GFP_KERNEL);
    if (info == NULL) {
        dev_err(&pdev->dev, "no memory for flash info\n");
        err = -ENOMEM;
        goto exit_error;
    }

    platform_set_drvdata(pdev, info);

    info->dev = &pdev->dev;
    info->pdata = pdata;

    /* get the resource for the memory mapping */

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

    if (res == NULL) {
        dev_err(&pdev->dev, "no memory resource specified\n");
        err = -ENOENT;
        goto exit_free;
    }

    dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
        (unsigned long long)res->start);

    /* setup map parameters */

    info->map.phys = res->start;
    info->map.size = resource_size(res);
    info->map.name = pdata->mapname != NULL ?
            (char *)pdata->mapname : (char *)pdev->name;
    info->map.bankwidth = pdata->bankwidth;

    /* register our usage of the memory area */

    info->area = request_mem_region(res->start, info->map.size, pdev->name);
    if (info->area == NULL) {
        dev_err(&pdev->dev, "failed to request memory region\n");
        err = -EIO;
        goto exit_free;
    }

    /* remap the memory area */

    info->map.virt = ioremap(res->start, info->map.size);
    dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);

    if (info->map.virt == NULL) {
        dev_err(&pdev->dev, "failed to ioremap() region\n");
        err = -EIO;
        goto exit_free;
    }

    simple_map_init(&info->map);

    dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");

    /* probe for the right mtd map driver
     * supplied by the platform_data struct */

    if (pdata->map_probes) {
        const char **map_probes = pdata->map_probes;

        for ( ; !info->mtd && *map_probes; map_probes++)
            info->mtd = do_map_probe(*map_probes , &info->map);
    }
    /* fallback to map_ram */
    else
        info->mtd = do_map_probe("map_ram", &info->map);

    if (info->mtd == NULL) {
        dev_err(&pdev->dev, "failed to probe for map_ram\n");
        err = -ENOMEM;
        goto exit_free;
    }

    info->mtd->owner = THIS_MODULE;
    info->mtd->dev.parent = &pdev->dev;

    platram_setrw(info, PLATRAM_RW);

    /* check to see if there are any available partitions, or wether
     * to add this device whole */

    err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
                    pdata->partitions,
                    pdata->nr_partitions);
    if (!err)
        dev_info(&pdev->dev, "registered mtd device\n");

    if (pdata->nr_partitions) {
        /* add the whole device. */
        err = mtd_device_register(info->mtd, NULL, 0);
        if (err) {
            dev_err(&pdev->dev,
                "failed to register the entire device\n");
        }
    }

    return err;

 exit_free:
    platram_remove(pdev);
 exit_error:
    return err;
}

/* device driver info */

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:mtd-ram");

static struct platform_driver platram_driver = {
    .probe      = platram_probe,
    .remove     = platram_remove,
    .driver     = {
        .name   = "mtd-ram",
        .owner  = THIS_MODULE,
    },
};

/* module init/exit */

static int __init platram_init(void)
{
    printk("Generic platform RAM MTD, (c) 2004 Simtec Electronics\n");
    return platform_driver_register(&platram_driver);
}

static void __exit platram_exit(void)
{
    platform_driver_unregister(&platram_driver);
}

module_init(platram_init);
module_exit(platram_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ben Dooks <[email protected]>");
MODULE_DESCRIPTION("MTD platform RAM map driver");