sa1100-flash.c

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/*
 * Flash memory access on SA11x0 based devices
 *
 * (C) 2000 Nicolas Pitre <[email protected]>
 */
#include <linux/module.h>
#include <linux/types.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/io.h>

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

#include <mach/hardware.h>
#include <asm/sizes.h>
#include <asm/mach/flash.h>

struct sa_subdev_info {
    char name[16];
    struct map_info map;
    struct mtd_info *mtd;
    struct flash_platform_data *plat;
};

struct sa_info {
    struct mtd_info     *mtd;
    int         num_subdev;
    struct sa_subdev_info   subdev[0];
};

static DEFINE_SPINLOCK(sa1100_vpp_lock);
static int sa1100_vpp_refcnt;
static void sa1100_set_vpp(struct map_info *map, int on)
{
    struct sa_subdev_info *subdev = container_of(map, struct sa_subdev_info, map);
    unsigned long flags;

    spin_lock_irqsave(&sa1100_vpp_lock, flags);
    if (on) {
        if (++sa1100_vpp_refcnt == 1)   /* first nested 'on' */
            subdev->plat->set_vpp(1);
    } else {
        if (--sa1100_vpp_refcnt == 0)   /* last nested 'off' */
            subdev->plat->set_vpp(0);
    }
    spin_unlock_irqrestore(&sa1100_vpp_lock, flags);
}

static void sa1100_destroy_subdev(struct sa_subdev_info *subdev)
{
    if (subdev->mtd)
        map_destroy(subdev->mtd);
    if (subdev->map.virt)
        iounmap(subdev->map.virt);
    release_mem_region(subdev->map.phys, subdev->map.size);
}

static int sa1100_probe_subdev(struct sa_subdev_info *subdev, struct resource *res)
{
    unsigned long phys;
    unsigned int size;
    int ret;

    phys = res->start;
    size = res->end - phys + 1;

    /*
     * Retrieve the bankwidth from the MSC registers.
     * We currently only implement CS0 and CS1 here.
     */
    switch (phys) {
    default:
        printk(KERN_WARNING "SA1100 flash: unknown base address "
               "0x%08lx, assuming CS0\n", phys);

    case SA1100_CS0_PHYS:
        subdev->map.bankwidth = (MSC0 & MSC_RBW) ? 2 : 4;
        break;

    case SA1100_CS1_PHYS:
        subdev->map.bankwidth = ((MSC0 >> 16) & MSC_RBW) ? 2 : 4;
        break;
    }

    if (!request_mem_region(phys, size, subdev->name)) {
        ret = -EBUSY;
        goto out;
    }

    if (subdev->plat->set_vpp)
        subdev->map.set_vpp = sa1100_set_vpp;

    subdev->map.phys = phys;
    subdev->map.size = size;
    subdev->map.virt = ioremap(phys, size);
    if (!subdev->map.virt) {
        ret = -ENOMEM;
        goto err;
    }

    simple_map_init(&subdev->map);

    /*
     * Now let's probe for the actual flash.  Do it here since
     * specific machine settings might have been set above.
     */
    subdev->mtd = do_map_probe(subdev->plat->map_name, &subdev->map);
    if (subdev->mtd == NULL) {
        ret = -ENXIO;
        goto err;
    }
    subdev->mtd->owner = THIS_MODULE;

    printk(KERN_INFO "SA1100 flash: CFI device at 0x%08lx, %uMiB, %d-bit\n",
        phys, (unsigned)(subdev->mtd->size >> 20),
        subdev->map.bankwidth * 8);

    return 0;

 err:
    sa1100_destroy_subdev(subdev);
 out:
    return ret;
}

static void sa1100_destroy(struct sa_info *info, struct flash_platform_data *plat)
{
    int i;

    if (info->mtd) {
        mtd_device_unregister(info->mtd);
        if (info->mtd != info->subdev[0].mtd)
            mtd_concat_destroy(info->mtd);
    }

    for (i = info->num_subdev - 1; i >= 0; i--)
        sa1100_destroy_subdev(&info->subdev[i]);
    kfree(info);

    if (plat->exit)
        plat->exit();
}

static struct sa_info *__devinit
sa1100_setup_mtd(struct platform_device *pdev, struct flash_platform_data *plat)
{
    struct sa_info *info;
    int nr, size, i, ret = 0;

    /*
     * Count number of devices.
     */
    for (nr = 0; ; nr++)
        if (!platform_get_resource(pdev, IORESOURCE_MEM, nr))
            break;

    if (nr == 0) {
        ret = -ENODEV;
        goto out;
    }

    size = sizeof(struct sa_info) + sizeof(struct sa_subdev_info) * nr;

    /*
     * Allocate the map_info structs in one go.
     */
    info = kzalloc(size, GFP_KERNEL);
    if (!info) {
        ret = -ENOMEM;
        goto out;
    }

    if (plat->init) {
        ret = plat->init();
        if (ret)
            goto err;
    }

    /*
     * Claim and then map the memory regions.
     */
    for (i = 0; i < nr; i++) {
        struct sa_subdev_info *subdev = &info->subdev[i];
        struct resource *res;

        res = platform_get_resource(pdev, IORESOURCE_MEM, i);
        if (!res)
            break;

        subdev->map.name = subdev->name;
        sprintf(subdev->name, "%s-%d", plat->name, i);
        subdev->plat = plat;

        ret = sa1100_probe_subdev(subdev, res);
        if (ret)
            break;
    }

    info->num_subdev = i;

    /*
     * ENXIO is special.  It means we didn't find a chip when we probed.
     */
    if (ret != 0 && !(ret == -ENXIO && info->num_subdev > 0))
        goto err;

    /*
     * If we found one device, don't bother with concat support.  If
     * we found multiple devices, use concat if we have it available,
     * otherwise fail.  Either way, it'll be called "sa1100".
     */
    if (info->num_subdev == 1) {
        strcpy(info->subdev[0].name, plat->name);
        info->mtd = info->subdev[0].mtd;
        ret = 0;
    } else if (info->num_subdev > 1) {
        struct mtd_info *cdev[nr];
        /*
         * We detected multiple devices.  Concatenate them together.
         */
        for (i = 0; i < info->num_subdev; i++)
            cdev[i] = info->subdev[i].mtd;

        info->mtd = mtd_concat_create(cdev, info->num_subdev,
                          plat->name);
        if (info->mtd == NULL)
            ret = -ENXIO;
    }

    if (ret == 0)
        return info;

 err:
    sa1100_destroy(info, plat);
 out:
    return ERR_PTR(ret);
}

static const char *part_probes[] = { "cmdlinepart", "RedBoot", NULL };

static int __devinit sa1100_mtd_probe(struct platform_device *pdev)
{
    struct flash_platform_data *plat = pdev->dev.platform_data;
    struct sa_info *info;
    int err;

    if (!plat)
        return -ENODEV;

    info = sa1100_setup_mtd(pdev, plat);
    if (IS_ERR(info)) {
        err = PTR_ERR(info);
        goto out;
    }

    /*
     * Partition selection stuff.
     */
    mtd_device_parse_register(info->mtd, part_probes, NULL, plat->parts,
                  plat->nr_parts);

    platform_set_drvdata(pdev, info);
    err = 0;

 out:
    return err;
}

static int __exit sa1100_mtd_remove(struct platform_device *pdev)
{
    struct sa_info *info = platform_get_drvdata(pdev);
    struct flash_platform_data *plat = pdev->dev.platform_data;

    platform_set_drvdata(pdev, NULL);
    sa1100_destroy(info, plat);

    return 0;
}

static struct platform_driver sa1100_mtd_driver = {
    .probe      = sa1100_mtd_probe,
    .remove     = __exit_p(sa1100_mtd_remove),
    .driver     = {
        .name   = "sa1100-mtd",
        .owner  = THIS_MODULE,
    },
};

module_platform_driver(sa1100_mtd_driver);

MODULE_AUTHOR("Nicolas Pitre");
MODULE_DESCRIPTION("SA1100 CFI map driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sa1100-mtd");