latch-addr-flash.c

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/*
 * Interface for NOR flash driver whose high address lines are latched
 *
 * Copyright © 2000 Nicolas Pitre <[email protected]>
 * Copyright © 2005-2008 Analog Devices Inc.
 * Copyright © 2008 MontaVista Software, Inc. <[email protected]>
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#include <linux/platform_device.h>
#include <linux/mtd/latch-addr-flash.h>
#include <linux/slab.h>

#define DRIVER_NAME "latch-addr-flash"

struct latch_addr_flash_info {
    struct mtd_info     *mtd;
    struct map_info     map;
    struct resource     *res;

    void            (*set_window)(unsigned long offset, void *data);
    void            *data;

    /* cache; could be found out of res */
    unsigned long       win_mask;

    spinlock_t      lock;
};

static map_word lf_read(struct map_info *map, unsigned long ofs)
{
    struct latch_addr_flash_info *info;
    map_word datum;

    info = (struct latch_addr_flash_info *)map->map_priv_1;

    spin_lock(&info->lock);

    info->set_window(ofs, info->data);
    datum = inline_map_read(map, info->win_mask & ofs);

    spin_unlock(&info->lock);

    return datum;
}

static void lf_write(struct map_info *map, map_word datum, unsigned long ofs)
{
    struct latch_addr_flash_info *info;

    info = (struct latch_addr_flash_info *)map->map_priv_1;

    spin_lock(&info->lock);

    info->set_window(ofs, info->data);
    inline_map_write(map, datum, info->win_mask & ofs);

    spin_unlock(&info->lock);
}

static void lf_copy_from(struct map_info *map, void *to,
        unsigned long from, ssize_t len)
{
    struct latch_addr_flash_info *info =
        (struct latch_addr_flash_info *) map->map_priv_1;
    unsigned n;

    while (len > 0) {
        n = info->win_mask + 1 - (from & info->win_mask);
        if (n > len)
            n = len;

        spin_lock(&info->lock);

        info->set_window(from, info->data);
        memcpy_fromio(to, map->virt + (from & info->win_mask), n);

        spin_unlock(&info->lock);

        to += n;
        from += n;
        len -= n;
    }
}

static char *rom_probe_types[] = { "cfi_probe", NULL };

static int latch_addr_flash_remove(struct platform_device *dev)
{
    struct latch_addr_flash_info *info;
    struct latch_addr_flash_data *latch_addr_data;

    info = platform_get_drvdata(dev);
    if (info == NULL)
        return 0;
    platform_set_drvdata(dev, NULL);

    latch_addr_data = dev->dev.platform_data;

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

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

    if (info->res != NULL)
        release_mem_region(info->res->start, resource_size(info->res));

    kfree(info);

    if (latch_addr_data->done)
        latch_addr_data->done(latch_addr_data->data);

    return 0;
}

static int __devinit latch_addr_flash_probe(struct platform_device *dev)
{
    struct latch_addr_flash_data *latch_addr_data;
    struct latch_addr_flash_info *info;
    resource_size_t win_base = dev->resource->start;
    resource_size_t win_size = resource_size(dev->resource);
    char **probe_type;
    int chipsel;
    int err;

    latch_addr_data = dev->dev.platform_data;
    if (latch_addr_data == NULL)
        return -ENODEV;

    pr_notice("latch-addr platform flash device: %#llx byte "
          "window at %#.8llx\n",
          (unsigned long long)win_size, (unsigned long long)win_base);

    chipsel = dev->id;

    if (latch_addr_data->init) {
        err = latch_addr_data->init(latch_addr_data->data, chipsel);
        if (err != 0)
            return err;
    }

    info = kzalloc(sizeof(struct latch_addr_flash_info), GFP_KERNEL);
    if (info == NULL) {
        err = -ENOMEM;
        goto done;
    }

    platform_set_drvdata(dev, info);

    info->res = request_mem_region(win_base, win_size, DRIVER_NAME);
    if (info->res == NULL) {
        dev_err(&dev->dev, "Could not reserve memory region\n");
        err = -EBUSY;
        goto free_info;
    }

    info->map.name      = DRIVER_NAME;
    info->map.size      = latch_addr_data->size;
    info->map.bankwidth = latch_addr_data->width;

    info->map.phys      = NO_XIP;
    info->map.virt      = ioremap(win_base, win_size);
    if (!info->map.virt) {
        err = -ENOMEM;
        goto free_res;
    }

    info->map.map_priv_1    = (unsigned long)info;

    info->map.read      = lf_read;
    info->map.copy_from = lf_copy_from;
    info->map.write     = lf_write;
    info->set_window    = latch_addr_data->set_window;
    info->data      = latch_addr_data->data;
    info->win_mask      = win_size - 1;

    spin_lock_init(&info->lock);

    for (probe_type = rom_probe_types; !info->mtd && *probe_type;
        probe_type++)
        info->mtd = do_map_probe(*probe_type, &info->map);

    if (info->mtd == NULL) {
        dev_err(&dev->dev, "map_probe failed\n");
        err = -ENODEV;
        goto iounmap;
    }
    info->mtd->owner = THIS_MODULE;

    mtd_device_parse_register(info->mtd, NULL, NULL,
                  latch_addr_data->parts,
                  latch_addr_data->nr_parts);
    return 0;

iounmap:
    iounmap(info->map.virt);
free_res:
    release_mem_region(info->res->start, resource_size(info->res));
free_info:
    kfree(info);
done:
    if (latch_addr_data->done)
        latch_addr_data->done(latch_addr_data->data);
    return err;
}

static struct platform_driver latch_addr_flash_driver = {
    .probe      = latch_addr_flash_probe,
    .remove     = __devexit_p(latch_addr_flash_remove),
    .driver     = {
        .name   = DRIVER_NAME,
    },
};

module_platform_driver(latch_addr_flash_driver);

MODULE_AUTHOR("David Griego <[email protected]>");
MODULE_DESCRIPTION("MTD map driver for flashes addressed physically with upper "
        "address lines being set board specifically");
MODULE_LICENSE("GPL v2");