lantiq-flash.c

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/*
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License version 2 as published
 *  by the Free Software Foundation.
 *
 *  Copyright (C) 2004 Liu Peng Infineon IFAP DC COM CPE
 *  Copyright (C) 2010 John Crispin <[email protected]>
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/cfi.h>
#include <linux/platform_device.h>
#include <linux/mtd/physmap.h>
#include <linux/of.h>

#include <lantiq_soc.h>

/*
 * The NOR flash is connected to the same external bus unit (EBU) as PCI.
 * To make PCI work we need to enable the endianness swapping for the address
 * written to the EBU. This endianness swapping works for PCI correctly but
 * fails for attached NOR devices. To workaround this we need to use a complex
 * map. The workaround involves swapping all addresses whilst probing the chip.
 * Once probing is complete we stop swapping the addresses but swizzle the
 * unlock addresses to ensure that access to the NOR device works correctly.
 */

enum {
    LTQ_NOR_PROBING,
    LTQ_NOR_NORMAL
};

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

static const char ltq_map_name[] = "ltq_nor";
static const char *ltq_probe_types[] __devinitconst = {
                    "cmdlinepart", "ofpart", NULL };

static map_word
ltq_read16(struct map_info *map, unsigned long adr)
{
    unsigned long flags;
    map_word temp;

    if (map->map_priv_1 == LTQ_NOR_PROBING)
        adr ^= 2;
    spin_lock_irqsave(&ebu_lock, flags);
    temp.x[0] = *(u16 *)(map->virt + adr);
    spin_unlock_irqrestore(&ebu_lock, flags);
    return temp;
}

static void
ltq_write16(struct map_info *map, map_word d, unsigned long adr)
{
    unsigned long flags;

    if (map->map_priv_1 == LTQ_NOR_PROBING)
        adr ^= 2;
    spin_lock_irqsave(&ebu_lock, flags);
    *(u16 *)(map->virt + adr) = d.x[0];
    spin_unlock_irqrestore(&ebu_lock, flags);
}

/*
 * The following 2 functions copy data between iomem and a cached memory
 * section. As memcpy() makes use of pre-fetching we cannot use it here.
 * The normal alternative of using memcpy_{to,from}io also makes use of
 * memcpy() on MIPS so it is not applicable either. We are therefore stuck
 * with having to use our own loop.
 */
static void
ltq_copy_from(struct map_info *map, void *to,
    unsigned long from, ssize_t len)
{
    unsigned char *f = (unsigned char *)map->virt + from;
    unsigned char *t = (unsigned char *)to;
    unsigned long flags;

    spin_lock_irqsave(&ebu_lock, flags);
    while (len--)
        *t++ = *f++;
    spin_unlock_irqrestore(&ebu_lock, flags);
}

static void
ltq_copy_to(struct map_info *map, unsigned long to,
    const void *from, ssize_t len)
{
    unsigned char *f = (unsigned char *)from;
    unsigned char *t = (unsigned char *)map->virt + to;
    unsigned long flags;

    spin_lock_irqsave(&ebu_lock, flags);
    while (len--)
        *t++ = *f++;
    spin_unlock_irqrestore(&ebu_lock, flags);
}

static int __devinit
ltq_mtd_probe(struct platform_device *pdev)
{
    struct mtd_part_parser_data ppdata;
    struct ltq_mtd *ltq_mtd;
    struct cfi_private *cfi;
    int err;

    if (of_machine_is_compatible("lantiq,falcon") &&
            (ltq_boot_select() != BS_FLASH)) {
        dev_err(&pdev->dev, "invalid bootstrap options\n");
        return -ENODEV;
    }

    ltq_mtd = kzalloc(sizeof(struct ltq_mtd), GFP_KERNEL);
    platform_set_drvdata(pdev, ltq_mtd);

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

    ltq_mtd->map = kzalloc(sizeof(struct map_info), GFP_KERNEL);
    ltq_mtd->map->phys = ltq_mtd->res->start;
    ltq_mtd->map->size = resource_size(ltq_mtd->res);
    ltq_mtd->map->virt = devm_request_and_ioremap(&pdev->dev, ltq_mtd->res);
    if (!ltq_mtd->map->virt) {
        dev_err(&pdev->dev, "failed to remap mem resource\n");
        err = -EBUSY;
        goto err_out;
    }

    ltq_mtd->map->name = ltq_map_name;
    ltq_mtd->map->bankwidth = 2;
    ltq_mtd->map->read = ltq_read16;
    ltq_mtd->map->write = ltq_write16;
    ltq_mtd->map->copy_from = ltq_copy_from;
    ltq_mtd->map->copy_to = ltq_copy_to;

    ltq_mtd->map->map_priv_1 = LTQ_NOR_PROBING;
    ltq_mtd->mtd = do_map_probe("cfi_probe", ltq_mtd->map);
    ltq_mtd->map->map_priv_1 = LTQ_NOR_NORMAL;

    if (!ltq_mtd->mtd) {
        dev_err(&pdev->dev, "probing failed\n");
        err = -ENXIO;
        goto err_free;
    }

    ltq_mtd->mtd->owner = THIS_MODULE;

    cfi = ltq_mtd->map->fldrv_priv;
    cfi->addr_unlock1 ^= 1;
    cfi->addr_unlock2 ^= 1;

    ppdata.of_node = pdev->dev.of_node;
    err = mtd_device_parse_register(ltq_mtd->mtd, ltq_probe_types,
                    &ppdata, NULL, 0);
    if (err) {
        dev_err(&pdev->dev, "failed to add partitions\n");
        goto err_destroy;
    }

    return 0;

err_destroy:
    map_destroy(ltq_mtd->mtd);
err_free:
    kfree(ltq_mtd->map);
err_out:
    kfree(ltq_mtd);
    return err;
}

static int __devexit
ltq_mtd_remove(struct platform_device *pdev)
{
    struct ltq_mtd *ltq_mtd = platform_get_drvdata(pdev);

    if (ltq_mtd) {
        if (ltq_mtd->mtd) {
            mtd_device_unregister(ltq_mtd->mtd);
            map_destroy(ltq_mtd->mtd);
        }
        kfree(ltq_mtd->map);
        kfree(ltq_mtd);
    }
    return 0;
}

static const struct of_device_id ltq_mtd_match[] = {
    { .compatible = "lantiq,nor" },
    {},
};
MODULE_DEVICE_TABLE(of, ltq_mtd_match);

static struct platform_driver ltq_mtd_driver = {
    .probe = ltq_mtd_probe,
    .remove = __devexit_p(ltq_mtd_remove),
    .driver = {
        .name = "ltq-nor",
        .owner = THIS_MODULE,
        .of_match_table = ltq_mtd_match,
    },
};

module_platform_driver(ltq_mtd_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("John Crispin <[email protected]>");
MODULE_DESCRIPTION("Lantiq SoC NOR");