// SPDX-License-Identifier: GPL-2.0-only
/*
 * Flash memory access on SA11x0 based devices
 *
 * (C) 2000 Nicolas Pitre <nico@fluxnic.net>
 */
#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 <linux/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[];
};

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);
                fallthrough;
        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;
        }

        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 *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;

                cdev = kmalloc_array(nr, sizeof(*cdev), GFP_KERNEL);
                if (!cdev) {
                        ret = -ENOMEM;
                        goto err;
                }

                /*
                 * 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);
                kfree(cdev);
                if (info->mtd == NULL) {
                        ret = -ENXIO;
                        goto err;
                }
        }
        info->mtd->dev.parent = &pdev->dev;

        if (ret == 0)
                return info;

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

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

static int sa1100_mtd_probe(struct platform_device *pdev)
{
        struct flash_platform_data *plat = dev_get_platdata(&pdev->dev);
        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 sa1100_mtd_remove(struct platform_device *pdev)
{
        struct sa_info *info = platform_get_drvdata(pdev);
        struct flash_platform_data *plat = dev_get_platdata(&pdev->dev);

        sa1100_destroy(info, plat);

        return 0;
}

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

module_platform_driver(sa1100_mtd_driver);

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