/*
 * Interface for NOR flash driver whose high address lines are latched
 *
 * Copyright © 2000 Nicolas Pitre <nico@cam.org>
 * Copyright © 2005-2008 Analog Devices Inc.
 * Copyright © 2008 MontaVista Software, Inc. <source@mvista.com>
 *
 * 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;

        latch_addr_data = dev_get_platdata(&dev->dev);

        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 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_get_platdata(&dev->dev);
        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         = latch_addr_flash_remove,
        .driver         = {
                .name   = DRIVER_NAME,
        },
};

module_platform_driver(latch_addr_flash_driver);

MODULE_AUTHOR("David Griego <dgriego@mvista.com>");
MODULE_DESCRIPTION("MTD map driver for flashes addressed physically with upper "
                "address lines being set board specifically");
MODULE_LICENSE("GPL v2");