/*
** z2ram - Amiga pseudo-driver to access 16bit-RAM in ZorroII space
**         as a block device, to be used as a RAM disk or swap space
** 
** Copyright (C) 1994 by Ingo Wilken (Ingo.Wilken@informatik.uni-oldenburg.de)
**
** ++Geert: support for zorro_unused_z2ram, better range checking
** ++roman: translate accesses via an array
** ++Milan: support for ChipRAM usage
** ++yambo: converted to 2.0 kernel
** ++yambo: modularized and support added for 3 minor devices including:
**          MAJOR  MINOR  DESCRIPTION
**          -----  -----  ----------------------------------------------
**          37     0       Use Zorro II and Chip ram
**          37     1       Use only Zorro II ram
**          37     2       Use only Chip ram
**          37     4-7     Use memory list entry 1-4 (first is 0)
** ++jskov: support for 1-4th memory list entry.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation.  This software is provided "as is" without express or
** implied warranty.
*/

#define DEVICE_NAME "Z2RAM"

#include <linux/major.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/blk-mq.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/pgtable.h>

#include <asm/setup.h>
#include <asm/amigahw.h>

#include <linux/zorro.h>

#define Z2MINOR_COMBINED      (0)
#define Z2MINOR_Z2ONLY        (1)
#define Z2MINOR_CHIPONLY      (2)
#define Z2MINOR_MEMLIST1      (4)
#define Z2MINOR_MEMLIST2      (5)
#define Z2MINOR_MEMLIST3      (6)
#define Z2MINOR_MEMLIST4      (7)
#define Z2MINOR_COUNT         (8)       /* Move this down when adding a new minor */

#define Z2RAM_CHUNK1024       ( Z2RAM_CHUNKSIZE >> 10 )

static DEFINE_MUTEX(z2ram_mutex);
static u_long *z2ram_map = NULL;
static u_long z2ram_size = 0;
static int z2_count = 0;
static int chip_count = 0;
static int list_count = 0;
static int current_device = -1;

static DEFINE_SPINLOCK(z2ram_lock);

static struct gendisk *z2ram_gendisk[Z2MINOR_COUNT];

static blk_status_t z2_queue_rq(struct blk_mq_hw_ctx *hctx,
                                const struct blk_mq_queue_data *bd)
{
        struct request *req = bd->rq;
        unsigned long start = blk_rq_pos(req) << 9;
        unsigned long len = blk_rq_cur_bytes(req);

        blk_mq_start_request(req);

        if (start + len > z2ram_size) {
                pr_err(DEVICE_NAME ": bad access: block=%llu, "
                       "count=%u\n",
                       (unsigned long long)blk_rq_pos(req),
                       blk_rq_cur_sectors(req));
                return BLK_STS_IOERR;
        }

        spin_lock_irq(&z2ram_lock);

        while (len) {
                unsigned long addr = start & Z2RAM_CHUNKMASK;
                unsigned long size = Z2RAM_CHUNKSIZE - addr;
                void *buffer = bio_data(req->bio);

                if (len < size)
                        size = len;
                addr += z2ram_map[start >> Z2RAM_CHUNKSHIFT];
                if (rq_data_dir(req) == READ)
                        memcpy(buffer, (char *)addr, size);
                else
                        memcpy((char *)addr, buffer, size);
                start += size;
                len -= size;
        }

        spin_unlock_irq(&z2ram_lock);
        blk_mq_end_request(req, BLK_STS_OK);
        return BLK_STS_OK;
}

static void get_z2ram(void)
{
        int i;

        for (i = 0; i < Z2RAM_SIZE / Z2RAM_CHUNKSIZE; i++) {
                if (test_bit(i, zorro_unused_z2ram)) {
                        z2_count++;
                        z2ram_map[z2ram_size++] =
                            (unsigned long)ZTWO_VADDR(Z2RAM_START) +
                            (i << Z2RAM_CHUNKSHIFT);
                        clear_bit(i, zorro_unused_z2ram);
                }
        }

        return;
}

static void get_chipram(void)
{

        while (amiga_chip_avail() > (Z2RAM_CHUNKSIZE * 4)) {
                chip_count++;
                z2ram_map[z2ram_size] =
                    (u_long) amiga_chip_alloc(Z2RAM_CHUNKSIZE, "z2ram");

                if (z2ram_map[z2ram_size] == 0) {
                        break;
                }

                z2ram_size++;
        }

        return;
}

static int z2_open(struct gendisk *disk, blk_mode_t mode)
{
        int device = disk->first_minor;
        int max_z2_map = (Z2RAM_SIZE / Z2RAM_CHUNKSIZE) * sizeof(z2ram_map[0]);
        int max_chip_map = (amiga_chip_size / Z2RAM_CHUNKSIZE) *
            sizeof(z2ram_map[0]);
        int rc = -ENOMEM;

        mutex_lock(&z2ram_mutex);
        if (current_device != -1 && current_device != device) {
                rc = -EBUSY;
                goto err_out;
        }

        if (current_device == -1) {
                z2_count = 0;
                chip_count = 0;
                list_count = 0;
                z2ram_size = 0;

                /* Use a specific list entry. */
                if (device >= Z2MINOR_MEMLIST1 && device <= Z2MINOR_MEMLIST4) {
                        int index = device - Z2MINOR_MEMLIST1 + 1;
                        unsigned long size, paddr, vaddr;

                        if (index >= m68k_realnum_memory) {
                                printk(KERN_ERR DEVICE_NAME
                                       ": no such entry in z2ram_map\n");
                                goto err_out;
                        }

                        paddr = m68k_memory[index].addr;
                        size = m68k_memory[index].size & ~(Z2RAM_CHUNKSIZE - 1);

#ifdef __powerpc__
                        /* FIXME: ioremap doesn't build correct memory tables. */
                        {
                                vfree(vmalloc(size));
                        }

                        vaddr = (unsigned long)ioremap_wt(paddr, size);

#else
                        vaddr =
                            (unsigned long)z_remap_nocache_nonser(paddr, size);
#endif
                        z2ram_map =
                            kmalloc_objs(z2ram_map[0], size / Z2RAM_CHUNKSIZE);
                        if (z2ram_map == NULL) {
                                printk(KERN_ERR DEVICE_NAME
                                       ": cannot get mem for z2ram_map\n");
                                goto err_out;
                        }

                        while (size) {
                                z2ram_map[z2ram_size++] = vaddr;
                                size -= Z2RAM_CHUNKSIZE;
                                vaddr += Z2RAM_CHUNKSIZE;
                                list_count++;
                        }

                        if (z2ram_size != 0)
                                printk(KERN_INFO DEVICE_NAME
                                       ": using %iK List Entry %d Memory\n",
                                       list_count * Z2RAM_CHUNK1024, index);
                } else
                        switch (device) {
                        case Z2MINOR_COMBINED:

                                z2ram_map =
                                    kmalloc(max_z2_map + max_chip_map,
                                            GFP_KERNEL);
                                if (z2ram_map == NULL) {
                                        printk(KERN_ERR DEVICE_NAME
                                               ": cannot get mem for z2ram_map\n");
                                        goto err_out;
                                }

                                get_z2ram();
                                get_chipram();

                                if (z2ram_size != 0)
                                        printk(KERN_INFO DEVICE_NAME
                                               ": using %iK Zorro II RAM and %iK Chip RAM (Total %dK)\n",
                                               z2_count * Z2RAM_CHUNK1024,
                                               chip_count * Z2RAM_CHUNK1024,
                                               (z2_count +
                                                chip_count) * Z2RAM_CHUNK1024);

                                break;

                        case Z2MINOR_Z2ONLY:
                                z2ram_map = kmalloc(max_z2_map, GFP_KERNEL);
                                if (!z2ram_map)
                                        goto err_out;

                                get_z2ram();

                                if (z2ram_size != 0)
                                        printk(KERN_INFO DEVICE_NAME
                                               ": using %iK of Zorro II RAM\n",
                                               z2_count * Z2RAM_CHUNK1024);

                                break;

                        case Z2MINOR_CHIPONLY:
                                z2ram_map = kmalloc(max_chip_map, GFP_KERNEL);
                                if (!z2ram_map)
                                        goto err_out;

                                get_chipram();

                                if (z2ram_size != 0)
                                        printk(KERN_INFO DEVICE_NAME
                                               ": using %iK Chip RAM\n",
                                               chip_count * Z2RAM_CHUNK1024);

                                break;

                        default:
                                rc = -ENODEV;
                                goto err_out;

                                break;
                        }

                if (z2ram_size == 0) {
                        printk(KERN_NOTICE DEVICE_NAME
                               ": no unused ZII/Chip RAM found\n");
                        goto err_out_kfree;
                }

                current_device = device;
                z2ram_size <<= Z2RAM_CHUNKSHIFT;
                set_capacity(z2ram_gendisk[device], z2ram_size >> 9);
        }

        mutex_unlock(&z2ram_mutex);
        return 0;

err_out_kfree:
        kfree(z2ram_map);
err_out:
        mutex_unlock(&z2ram_mutex);
        return rc;
}

static void z2_release(struct gendisk *disk)
{
        mutex_lock(&z2ram_mutex);
        if (current_device == -1) {
                mutex_unlock(&z2ram_mutex);
                return;
        }
        mutex_unlock(&z2ram_mutex);
        /*
         * FIXME: unmap memory
         */
}

static const struct block_device_operations z2_fops = {
        .owner = THIS_MODULE,
        .open = z2_open,
        .release = z2_release,
};

static struct blk_mq_tag_set tag_set;

static const struct blk_mq_ops z2_mq_ops = {
        .queue_rq = z2_queue_rq,
};

static int z2ram_register_disk(int minor)
{
        struct gendisk *disk;
        int err;

        disk = blk_mq_alloc_disk(&tag_set, NULL, NULL);
        if (IS_ERR(disk))
                return PTR_ERR(disk);

        disk->major = Z2RAM_MAJOR;
        disk->first_minor = minor;
        disk->minors = 1;
        disk->flags |= GENHD_FL_NO_PART;
        disk->fops = &z2_fops;
        if (minor)
                sprintf(disk->disk_name, "z2ram%d", minor);
        else
                sprintf(disk->disk_name, "z2ram");

        z2ram_gendisk[minor] = disk;
        err = add_disk(disk);
        if (err)
                put_disk(disk);
        return err;
}

static int __init z2_init(void)
{
        int ret, i;

        if (!MACH_IS_AMIGA)
                return -ENODEV;

        if (register_blkdev(Z2RAM_MAJOR, DEVICE_NAME))
                return -EBUSY;

        tag_set.ops = &z2_mq_ops;
        tag_set.nr_hw_queues = 1;
        tag_set.nr_maps = 1;
        tag_set.queue_depth = 16;
        tag_set.numa_node = NUMA_NO_NODE;
        ret = blk_mq_alloc_tag_set(&tag_set);
        if (ret)
                goto out_unregister_blkdev;

        for (i = 0; i < Z2MINOR_COUNT; i++) {
                ret = z2ram_register_disk(i);
                if (ret && i == 0)
                        goto out_free_tagset;
        }

        return 0;

out_free_tagset:
        blk_mq_free_tag_set(&tag_set);
out_unregister_blkdev:
        unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);
        return ret;
}

static void __exit z2_exit(void)
{
        int i, j;

        unregister_blkdev(Z2RAM_MAJOR, DEVICE_NAME);

        for (i = 0; i < Z2MINOR_COUNT; i++) {
                del_gendisk(z2ram_gendisk[i]);
                put_disk(z2ram_gendisk[i]);
        }
        blk_mq_free_tag_set(&tag_set);

        if (current_device != -1) {
                i = 0;

                for (j = 0; j < z2_count; j++) {
                        set_bit(i++, zorro_unused_z2ram);
                }

                for (j = 0; j < chip_count; j++) {
                        if (z2ram_map[i]) {
                                amiga_chip_free((void *)z2ram_map[i++]);
                        }
                }

                if (z2ram_map != NULL) {
                        kfree(z2ram_map);
                }
        }

        return;
}

module_init(z2_init);
module_exit(z2_exit);
MODULE_DESCRIPTION("Amiga Zorro II ramdisk driver");
MODULE_LICENSE("GPL");