// SPDX-License-Identifier: GPL-2.0-or-later
/* drivers/mtd/maps/plat-ram.c
 *
 * (c) 2004-2005 Simtec Electronics
 *      http://www.simtec.co.uk/products/SWLINUX/
 *      Ben Dooks <ben@simtec.co.uk>
 *
 * Generic platform device based RAM map
*/

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/platform_device.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/plat-ram.h>

#include <asm/io.h>

/* private structure for each mtd platform ram device created */

struct platram_info {
        struct device           *dev;
        struct mtd_info         *mtd;
        struct map_info          map;
        struct platdata_mtd_ram *pdata;
};

/* to_platram_info()
 *
 * device private data to struct platram_info conversion
*/

static inline struct platram_info *to_platram_info(struct platform_device *dev)
{
        return platform_get_drvdata(dev);
}

/* platram_setrw
 *
 * call the platform device's set rw/ro control
 *
 * to = 0 => read-only
 *    = 1 => read-write
*/

static inline void platram_setrw(struct platram_info *info, int to)
{
        if (info->pdata == NULL)
                return;

        if (info->pdata->set_rw != NULL)
                (info->pdata->set_rw)(info->dev, to);
}

/* platram_remove
 *
 * called to remove the device from the driver's control
*/

static int platram_remove(struct platform_device *pdev)
{
        struct platram_info *info = to_platram_info(pdev);

        dev_dbg(&pdev->dev, "removing device\n");

        if (info == NULL)
                return 0;

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

        /* ensure ram is left read-only */

        platram_setrw(info, PLATRAM_RO);

        kfree(info);

        return 0;
}

/* platram_probe
 *
 * called from device drive system when a device matching our
 * driver is found.
*/

static int platram_probe(struct platform_device *pdev)
{
        struct platdata_mtd_ram *pdata;
        struct platram_info *info;
        struct resource *res;
        int err = 0;

        dev_dbg(&pdev->dev, "probe entered\n");

        if (dev_get_platdata(&pdev->dev) == NULL) {
                dev_err(&pdev->dev, "no platform data supplied\n");
                err = -ENOENT;
                goto exit_error;
        }

        pdata = dev_get_platdata(&pdev->dev);

        info = kzalloc(sizeof(*info), GFP_KERNEL);
        if (info == NULL) {
                err = -ENOMEM;
                goto exit_error;
        }

        platform_set_drvdata(pdev, info);

        info->dev = &pdev->dev;
        info->pdata = pdata;

        /* get the resource for the memory mapping */
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        info->map.virt = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(info->map.virt)) {
                err = PTR_ERR(info->map.virt);
                goto exit_free;
        }

        dev_dbg(&pdev->dev, "got platform resource %p (0x%llx)\n", res,
                (unsigned long long)res->start);

        /* setup map parameters */

        info->map.phys = res->start;
        info->map.size = resource_size(res);
        info->map.name = pdata->mapname != NULL ?
                        (char *)pdata->mapname : (char *)pdev->name;
        info->map.bankwidth = pdata->bankwidth;

        dev_dbg(&pdev->dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);

        simple_map_init(&info->map);

        dev_dbg(&pdev->dev, "initialised map, probing for mtd\n");

        /* probe for the right mtd map driver
         * supplied by the platform_data struct */

        if (pdata->map_probes) {
                const char * const *map_probes = pdata->map_probes;

                for ( ; !info->mtd && *map_probes; map_probes++)
                        info->mtd = do_map_probe(*map_probes , &info->map);
        }
        /* fallback to map_ram */
        else
                info->mtd = do_map_probe("map_ram", &info->map);

        if (info->mtd == NULL) {
                dev_err(&pdev->dev, "failed to probe for map_ram\n");
                err = -ENOMEM;
                goto exit_free;
        }

        info->mtd->dev.parent = &pdev->dev;

        platram_setrw(info, PLATRAM_RW);

        /* check to see if there are any available partitions, or whether
         * to add this device whole */

        err = mtd_device_parse_register(info->mtd, pdata->probes, NULL,
                                        pdata->partitions,
                                        pdata->nr_partitions);
        if (err) {
                dev_err(&pdev->dev, "failed to register mtd device\n");
                goto exit_free;
        }

        dev_info(&pdev->dev, "registered mtd device\n");

        if (pdata->nr_partitions) {
                /* add the whole device. */
                err = mtd_device_register(info->mtd, NULL, 0);
                if (err) {
                        dev_err(&pdev->dev,
                                "failed to register the entire device\n");
                        goto exit_free;
                }
        }

        return 0;

 exit_free:
        platram_remove(pdev);
 exit_error:
        return err;
}

/* device driver info */

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:mtd-ram");

static struct platform_driver platram_driver = {
        .probe          = platram_probe,
        .remove         = platram_remove,
        .driver         = {
                .name   = "mtd-ram",
        },
};

module_platform_driver(platram_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_DESCRIPTION("MTD platform RAM map driver");