/*
 * File...........: linux/fs/partitions/ibm.c      
 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
 *                  Volker Sameske <sameske@de.ibm.com>
 * Bugreports.to..: <Linux390@de.ibm.com>
 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999,2000

 * History of changes (starts July 2000)
 * 07/10/00 Fixed detection of CMS formatted disks     
 * 02/13/00 VTOC partition support added
 * 12/27/01 fixed PL030593 (CMS reserved minidisk not detected on 64 bit)
 * 07/24/03 no longer using contents of freed page for CMS label recognition (BZ3611)
 */

#include <linux/config.h>
#include <linux/fs.h>
#include <linux/genhd.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/blk.h>
#include <linux/slab.h>
#include <linux/hdreg.h>
#include <linux/ioctl.h>
#include <linux/version.h>
#include <asm/ebcdic.h>
#include <asm/uaccess.h>
#include <asm/dasd.h>

#include "ibm.h"
#include "check.h"
#include <asm/vtoc.h>

/*
 * compute the block number from a 
 * cyl-cyl-head-head structure
 */
static inline int
cchh2blk (cchh_t *ptr, struct hd_geometry *geo) {
        return ptr->cc * geo->heads * geo->sectors +
               ptr->hh * geo->sectors;
}


/*
 * compute the block number from a 
 * cyl-cyl-head-head-block structure
 */
static inline int
cchhb2blk (cchhb_t *ptr, struct hd_geometry *geo) {
        return ptr->cc * geo->heads * geo->sectors +
                ptr->hh * geo->sectors +
                ptr->b;
}

/*
 * We used to use ioctl_by_bdev in early 2.4, but it broke
 * between 2.4.9 and 2.4.18 somewhere.
 */
extern int (*genhd_dasd_ioctl)(struct inode *inp, struct file *filp,
                            unsigned int no, unsigned long data);

static int
ibm_ioctl_unopened(struct block_device *bdev, unsigned cmd, unsigned long arg)
{
        int res;
        mm_segment_t old_fs = get_fs();

        if (genhd_dasd_ioctl == NULL)
                return -ENODEV;
#if 0
        lock_kernel();
        if (bd_ops->owner)
                __MOD_INC_USE_COUNT(bdev->bd_op->owner);
        unlock_kernel();
#endif
        set_fs(KERNEL_DS);
        res = (*genhd_dasd_ioctl)(bdev->bd_inode, NULL, cmd, arg);
        set_fs(old_fs);
#if 0
        lock_kernel();
        if (bd_ops->owner)
                __MOD_DEV_USE_COUNT(bd_ops->owner);
        unlock_kernel();
#endif
        return res;
}

/*
 */
int 
ibm_partition(struct gendisk *hd, struct block_device *bdev,
              unsigned long first_sector, int first_part_minor)
{
        int blocksize, offset, size;
        dasd_information_t *info;
        struct hd_geometry *geo;
        char type[5] = {0,};
        char name[7] = {0,};
        volume_label_t *vlabel;
        unsigned char *data;
        Sector sect;

        if ( first_sector != 0 )
                BUG();

        if ((info = kmalloc(sizeof(dasd_information_t), GFP_KERNEL)) == NULL)
                goto out_noinfo;
        if ((geo = kmalloc(sizeof(struct hd_geometry), GFP_KERNEL)) == NULL)
                goto out_nogeo;
        if ((vlabel = kmalloc(sizeof(volume_label_t), GFP_KERNEL)) == NULL)
                goto out_novlab;

        if (ibm_ioctl_unopened(bdev, BIODASDINFO, (unsigned long)info) != 0 ||
            ibm_ioctl_unopened(bdev, HDIO_GETGEO, (unsigned long)geo) != 0)
                goto out_noioctl;

        if ((blocksize = get_hardsect_size(to_kdev_t(bdev->bd_dev))) <= 0)
                goto out_badsect;

        /*
         * Get volume label, extract name and type.
         */
        data = read_dev_sector(bdev, info->label_block*(blocksize/512), &sect);
        if (data == NULL)
                goto out_readerr;
        strncpy (type, data, 4);
        if ((!info->FBA_layout) && (!strcmp(info->type, "ECKD")))
                strncpy(name, data + 8, 6);
        else
                strncpy(name, data + 4, 6);
        memcpy (vlabel, data, sizeof(volume_label_t));
        put_dev_sector(sect);

        EBCASC(type, 4);
        EBCASC(name, 6);

        /*
         * Three different types: CMS1, VOL1 and LNX1/unlabeled
         */
        if (strncmp(type, "CMS1", 4) == 0) {
                /*
                 * VM style CMS1 labeled disk
                 */
                int *label = (int *) vlabel;

                if (label[13] != 0) {
                        printk("CMS1/%8s(MDSK):", name);
                        /* disk is reserved minidisk */
                        blocksize = label[3];
                        offset = label[13];
                        size = (label[7] - 1)*(blocksize >> 9);
                } else {
                        printk("CMS1/%8s:", name);
                        offset = (info->label_block + 1);
                        size = bdev->bd_inode->i_size >> 9;
                }
                // add_gd_partition(hd, first_part_minor - 1, 0, size);
                add_gd_partition(hd, first_part_minor,
                                 offset*(blocksize >> 9),
                                 size-offset*(blocksize >> 9));
        } else if ((strncmp(type, "VOL1", 4) == 0) &&
                (!info->FBA_layout) && (!strcmp(info->type, "ECKD"))) {
                /*
                 * New style VOL1 labeled disk
                 */
                unsigned int blk;
                int counter;

                printk("VOL1/%8s:", name);

                /* get block number and read then go through format1 labels */
                blk = cchhb2blk(&vlabel->vtoc, geo) + 1;
                counter = 0;
                while ((data = read_dev_sector(bdev, blk*(blocksize/512),
                                               &sect)) != NULL) {
                        format1_label_t f1;

                        memcpy(&f1, data, sizeof(format1_label_t));
                        put_dev_sector(sect);

                        /* skip FMT4 / FMT5 / FMT7 labels */
                        if (f1.DS1FMTID == _ascebc['4']
                            || f1.DS1FMTID == _ascebc['5']
                            || f1.DS1FMTID == _ascebc['7']) {
                                blk++;
                                continue;
                        }

                        /* only FMT1 valid at this point */
                        if (f1.DS1FMTID != _ascebc['1'])
                                break;

                        /* OK, we got valid partition data */
                        offset = cchh2blk(&f1.DS1EXT1.llimit, geo);
                        size  = cchh2blk(&f1.DS1EXT1.ulimit, geo) - 
                                offset + geo->sectors;
                        if (counter >= hd->max_p)
                                break;
                        add_gd_partition(hd, first_part_minor + counter, 
                                         offset * (blocksize >> 9),
                                         size * (blocksize >> 9));
                        counter++;
                        blk++;
                }
        } else {
                /*
                 * Old style LNX1 or unlabeled disk
                 */
                if (strncmp(type, "LNX1", 4) == 0)
                        printk ("LNX1/%8s:", name);
                else
                        printk("(nonl)/%8s:", name);
                offset = (info->label_block + 1);
                size = (bdev->bd_inode->i_size >> 9);
                // add_gd_partition(hd, first_part_minor - 1, 0, size);
                add_gd_partition(hd, first_part_minor,
                                 offset*(blocksize >> 9),
                                  size-offset*(blocksize >> 9));
        }

        printk("\n");
        kfree(vlabel);
        kfree(geo);
        kfree(info);
        return 1;

out_readerr:
out_badsect:
out_noioctl:
        kfree(vlabel);
out_novlab:
        kfree(geo);
out_nogeo:
        kfree(info);
out_noinfo:
        return 0;
}