// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Cobalt NOR flash functions
 *
 *  Copyright 2012-2015 Cisco Systems, Inc. and/or its affiliates.
 *  All rights reserved.
 */

#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/cfi.h>
#include <linux/time.h>

#include "cobalt-flash.h"

#define ADRS(offset) (COBALT_BUS_FLASH_BASE + offset)

static struct map_info cobalt_flash_map = {
        .name =         "cobalt-flash",
        .bankwidth =    2,         /* 16 bits */
        .size =         0x4000000, /* 64MB */
        .phys =         0,         /* offset  */
};

static map_word flash_read16(struct map_info *map, unsigned long offset)
{
        map_word r;

        r.x[0] = cobalt_bus_read32(map->virt, ADRS(offset));
        if (offset & 0x2)
                r.x[0] >>= 16;
        else
                r.x[0] &= 0x0000ffff;

        return r;
}

static void flash_write16(struct map_info *map, const map_word datum,
                          unsigned long offset)
{
        u16 data = (u16)datum.x[0];

        cobalt_bus_write16(map->virt, ADRS(offset), data);
}

static void flash_copy_from(struct map_info *map, void *to,
                            unsigned long from, ssize_t len)
{
        u32 src = from;
        u8 *dest = to;
        u32 data;

        while (len) {
                data = cobalt_bus_read32(map->virt, ADRS(src));
                do {
                        *dest = data >> (8 * (src & 3));
                        src++;
                        dest++;
                        len--;
                } while (len && (src % 4));
        }
}

static void flash_copy_to(struct map_info *map, unsigned long to,
                          const void *from, ssize_t len)
{
        const u8 *src = from;
        u32 dest = to;

        pr_info("%s: offset 0x%x: length %zu\n", __func__, dest, len);
        while (len) {
                u16 data;

                do {
                        data = *src << (8 * (dest & 1));
                        src++;
                        dest++;
                        len--;
                } while (len && (dest % 2));

                cobalt_bus_write16(map->virt, ADRS(dest - 2), data);
        }
}

int cobalt_flash_probe(struct cobalt *cobalt)
{
        struct map_info *map = &cobalt_flash_map;
        struct mtd_info *mtd;

        BUG_ON(!map_bankwidth_supported(map->bankwidth));
        map->virt = cobalt->bar1;
        map->read = flash_read16;
        map->write = flash_write16;
        map->copy_from = flash_copy_from;
        map->copy_to = flash_copy_to;

        mtd = do_map_probe("cfi_probe", map);
        cobalt->mtd = mtd;
        if (!mtd) {
                cobalt_err("Probe CFI flash failed!\n");
                return -1;
        }

        mtd->owner = THIS_MODULE;
        mtd->dev.parent = &cobalt->pci_dev->dev;
        mtd_device_register(mtd, NULL, 0);
        return 0;
}

void cobalt_flash_remove(struct cobalt *cobalt)
{
        if (cobalt->mtd) {
                mtd_device_unregister(cobalt->mtd);
                map_destroy(cobalt->mtd);
        }
}