dasd_diag.c

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/*
 * Author(s)......: Holger Smolinski <[email protected]>
 * Based on.......: linux/drivers/s390/block/mdisk.c
 * ...............: by Hartmunt Penner <[email protected]>
 * Bugreports.to..: <[email protected]>
 * Copyright IBM Corp. 1999, 2000
 *
 */

#define KMSG_COMPONENT "dasd"

#include <linux/kernel_stat.h>
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/hdreg.h>
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/jiffies.h>

#include <asm/dasd.h>
#include <asm/debug.h>
#include <asm/ebcdic.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/vtoc.h>
#include <asm/diag.h>

#include "dasd_int.h"
#include "dasd_diag.h"

#define PRINTK_HEADER "dasd(diag):"

MODULE_LICENSE("GPL");

/* The maximum number of blocks per request (max_blocks) is dependent on the
 * amount of storage that is available in the static I/O buffer for each
 * device. Currently each device gets 2 pages. We want to fit two requests
 * into the available memory so that we can immediately start the next if one
 * finishes. */
#define DIAG_MAX_BLOCKS (((2 * PAGE_SIZE - sizeof(struct dasd_ccw_req) - \
               sizeof(struct dasd_diag_req)) / \
                   sizeof(struct dasd_diag_bio)) / 2)
#define DIAG_MAX_RETRIES    32
#define DIAG_TIMEOUT        50

static struct dasd_discipline dasd_diag_discipline;

struct dasd_diag_private {
    struct dasd_diag_characteristics rdc_data;
    struct dasd_diag_rw_io iob;
    struct dasd_diag_init_io iib;
    blocknum_t pt_block;
    struct ccw_dev_id dev_id;
};

struct dasd_diag_req {
    unsigned int block_count;
    struct dasd_diag_bio bio[0];
};

static const u8 DASD_DIAG_CMS1[] = { 0xc3, 0xd4, 0xe2, 0xf1 };/* EBCDIC CMS1 */

/* Perform DIAG250 call with block I/O parameter list iob (input and output)
 * and function code cmd.
 * In case of an exception return 3. Otherwise return result of bitwise OR of
 * resulting condition code and DIAG return code. */
static inline int dia250(void *iob, int cmd)
{
    register unsigned long reg2 asm ("2") = (unsigned long) iob;
    typedef union {
        struct dasd_diag_init_io init_io;
        struct dasd_diag_rw_io rw_io;
    } addr_type;
    int rc;

    rc = 3;
    asm volatile(
        "   diag    2,%2,0x250\n"
        "0: ipm %0\n"
        "   srl %0,28\n"
        "   or  %0,3\n"
        "1:\n"
        EX_TABLE(0b,1b)
        : "+d" (rc), "=m" (*(addr_type *) iob)
        : "d" (cmd), "d" (reg2), "m" (*(addr_type *) iob)
        : "3", "cc");
    return rc;
}

/* Initialize block I/O to DIAG device using the specified blocksize and
 * block offset. On success, return zero and set end_block to contain the
 * number of blocks on the device minus the specified offset. Return non-zero
 * otherwise. */
static inline int
mdsk_init_io(struct dasd_device *device, unsigned int blocksize,
         blocknum_t offset, blocknum_t *end_block)
{
    struct dasd_diag_private *private;
    struct dasd_diag_init_io *iib;
    int rc;

    private = (struct dasd_diag_private *) device->private;
    iib = &private->iib;
    memset(iib, 0, sizeof (struct dasd_diag_init_io));

    iib->dev_nr = private->dev_id.devno;
    iib->block_size = blocksize;
    iib->offset = offset;
    iib->flaga = DASD_DIAG_FLAGA_DEFAULT;

    rc = dia250(iib, INIT_BIO);

    if ((rc & 3) == 0 && end_block)
        *end_block = iib->end_block;

    return rc;
}

/* Remove block I/O environment for device. Return zero on success, non-zero
 * otherwise. */
static inline int
mdsk_term_io(struct dasd_device * device)
{
    struct dasd_diag_private *private;
    struct dasd_diag_init_io *iib;
    int rc;

    private = (struct dasd_diag_private *) device->private;
    iib = &private->iib;
    memset(iib, 0, sizeof (struct dasd_diag_init_io));
    iib->dev_nr = private->dev_id.devno;
    rc = dia250(iib, TERM_BIO);
    return rc;
}

/* Error recovery for failed DIAG requests - try to reestablish the DIAG
 * environment. */
static void
dasd_diag_erp(struct dasd_device *device)
{
    int rc;

    mdsk_term_io(device);
    rc = mdsk_init_io(device, device->block->bp_block, 0, NULL);
    if (rc == 4) {
        if (!(test_and_set_bit(DASD_FLAG_DEVICE_RO, &device->flags)))
            pr_warning("%s: The access mode of a DIAG device "
                   "changed to read-only\n",
                   dev_name(&device->cdev->dev));
        rc = 0;
    }
    if (rc)
        pr_warning("%s: DIAG ERP failed with "
                "rc=%d\n", dev_name(&device->cdev->dev), rc);
}

/* Start a given request at the device. Return zero on success, non-zero
 * otherwise. */
static int
dasd_start_diag(struct dasd_ccw_req * cqr)
{
    struct dasd_device *device;
    struct dasd_diag_private *private;
    struct dasd_diag_req *dreq;
    int rc;

    device = cqr->startdev;
    if (cqr->retries < 0) {
        DBF_DEV_EVENT(DBF_ERR, device, "DIAG start_IO: request %p "
                "- no retry left)", cqr);
        cqr->status = DASD_CQR_ERROR;
        return -EIO;
    }
    private = (struct dasd_diag_private *) device->private;
    dreq = (struct dasd_diag_req *) cqr->data;

    private->iob.dev_nr = private->dev_id.devno;
    private->iob.key = 0;
    private->iob.flags = DASD_DIAG_RWFLAG_ASYNC;
    private->iob.block_count = dreq->block_count;
    private->iob.interrupt_params = (addr_t) cqr;
    private->iob.bio_list = dreq->bio;
    private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;

    cqr->startclk = get_clock();
    cqr->starttime = jiffies;
    cqr->retries--;

    rc = dia250(&private->iob, RW_BIO);
    switch (rc) {
    case 0: /* Synchronous I/O finished successfully */
        cqr->stopclk = get_clock();
        cqr->status = DASD_CQR_SUCCESS;
        /* Indicate to calling function that only a dasd_schedule_bh()
           and no timer is needed */
                rc = -EACCES;
        break;
    case 8: /* Asynchronous I/O was started */
        cqr->status = DASD_CQR_IN_IO;
        rc = 0;
        break;
    default: /* Error condition */
        cqr->status = DASD_CQR_QUEUED;
        DBF_DEV_EVENT(DBF_WARNING, device, "dia250 returned rc=%d", rc);
        dasd_diag_erp(device);
        rc = -EIO;
        break;
    }
    cqr->intrc = rc;
    return rc;
}

/* Terminate given request at the device. */
static int
dasd_diag_term_IO(struct dasd_ccw_req * cqr)
{
    struct dasd_device *device;

    device = cqr->startdev;
    mdsk_term_io(device);
    mdsk_init_io(device, device->block->bp_block, 0, NULL);
    cqr->status = DASD_CQR_CLEAR_PENDING;
    cqr->stopclk = get_clock();
    dasd_schedule_device_bh(device);
    return 0;
}

/* Handle external interruption. */
static void dasd_ext_handler(struct ext_code ext_code,
                 unsigned int param32, unsigned long param64)
{
    struct dasd_ccw_req *cqr, *next;
    struct dasd_device *device;
    unsigned long long expires;
    unsigned long flags;
    addr_t ip;
    int rc;

    switch (ext_code.subcode >> 8) {
    case DASD_DIAG_CODE_31BIT:
        ip = (addr_t) param32;
        break;
    case DASD_DIAG_CODE_64BIT:
        ip = (addr_t) param64;
        break;
    default:
        return;
    }
    kstat_cpu(smp_processor_id()).irqs[EXTINT_DSD]++;
    if (!ip) {      /* no intparm: unsolicited interrupt */
        DBF_EVENT(DBF_NOTICE, "%s", "caught unsolicited "
                  "interrupt");
        return;
    }
    cqr = (struct dasd_ccw_req *) ip;
    device = (struct dasd_device *) cqr->startdev;
    if (strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
        DBF_DEV_EVENT(DBF_WARNING, device,
                " magic number of dasd_ccw_req 0x%08X doesn't"
                " match discipline 0x%08X",
                cqr->magic, *(int *) (&device->discipline->name));
        return;
    }

    /* get irq lock to modify request queue */
    spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);

    /* Check for a pending clear operation */
    if (cqr->status == DASD_CQR_CLEAR_PENDING) {
        cqr->status = DASD_CQR_CLEARED;
        dasd_device_clear_timer(device);
        dasd_schedule_device_bh(device);
        spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
        return;
    }

    cqr->stopclk = get_clock();

    expires = 0;
    if ((ext_code.subcode & 0xff) == 0) {
        cqr->status = DASD_CQR_SUCCESS;
        /* Start first request on queue if possible -> fast_io. */
        if (!list_empty(&device->ccw_queue)) {
            next = list_entry(device->ccw_queue.next,
                      struct dasd_ccw_req, devlist);
            if (next->status == DASD_CQR_QUEUED) {
                rc = dasd_start_diag(next);
                if (rc == 0)
                    expires = next->expires;
            }
        }
    } else {
        cqr->status = DASD_CQR_QUEUED;
        DBF_DEV_EVENT(DBF_DEBUG, device, "interrupt status for "
                  "request %p was %d (%d retries left)", cqr,
                  ext_code.subcode & 0xff, cqr->retries);
        dasd_diag_erp(device);
    }

    if (expires != 0)
        dasd_device_set_timer(device, expires);
    else
        dasd_device_clear_timer(device);
    dasd_schedule_device_bh(device);

    spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
}

/* Check whether device can be controlled by DIAG discipline. Return zero on
 * success, non-zero otherwise. */
static int
dasd_diag_check_device(struct dasd_device *device)
{
    struct dasd_block *block;
    struct dasd_diag_private *private;
    struct dasd_diag_characteristics *rdc_data;
    struct dasd_diag_bio bio;
    struct vtoc_cms_label *label;
    blocknum_t end_block;
    unsigned int sb, bsize;
    int rc;

    private = (struct dasd_diag_private *) device->private;
    if (private == NULL) {
        private = kzalloc(sizeof(struct dasd_diag_private),GFP_KERNEL);
        if (private == NULL) {
            DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                "Allocating memory for private DASD data "
                      "failed\n");
            return -ENOMEM;
        }
        ccw_device_get_id(device->cdev, &private->dev_id);
        device->private = (void *) private;
    }
    block = dasd_alloc_block();
    if (IS_ERR(block)) {
        DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                "could not allocate dasd block structure");
        device->private = NULL;
        kfree(private);
        return PTR_ERR(block);
    }
    device->block = block;
    block->base = device;

    /* Read Device Characteristics */
    rdc_data = (void *) &(private->rdc_data);
    rdc_data->dev_nr = private->dev_id.devno;
    rdc_data->rdc_len = sizeof (struct dasd_diag_characteristics);

    rc = diag210((struct diag210 *) rdc_data);
    if (rc) {
        DBF_DEV_EVENT(DBF_WARNING, device, "failed to retrieve device "
                "information (rc=%d)", rc);
        rc = -EOPNOTSUPP;
        goto out;
    }

    device->default_expires = DIAG_TIMEOUT;

    /* Figure out position of label block */
    switch (private->rdc_data.vdev_class) {
    case DEV_CLASS_FBA:
        private->pt_block = 1;
        break;
    case DEV_CLASS_ECKD:
        private->pt_block = 2;
        break;
    default:
        pr_warning("%s: Device type %d is not supported "
               "in DIAG mode\n", dev_name(&device->cdev->dev),
               private->rdc_data.vdev_class);
        rc = -EOPNOTSUPP;
        goto out;
    }

    DBF_DEV_EVENT(DBF_INFO, device,
              "%04X: %04X on real %04X/%02X",
              rdc_data->dev_nr,
              rdc_data->vdev_type,
              rdc_data->rdev_type, rdc_data->rdev_model);

    /* terminate all outstanding operations */
    mdsk_term_io(device);

    /* figure out blocksize of device */
    label = (struct vtoc_cms_label *) get_zeroed_page(GFP_KERNEL);
    if (label == NULL)  {
        DBF_DEV_EVENT(DBF_WARNING, device, "%s",
                "No memory to allocate initialization request");
        rc = -ENOMEM;
        goto out;
    }
    rc = 0;
    end_block = 0;
    /* try all sizes - needed for ECKD devices */
    for (bsize = 512; bsize <= PAGE_SIZE; bsize <<= 1) {
        mdsk_init_io(device, bsize, 0, &end_block);
        memset(&bio, 0, sizeof (struct dasd_diag_bio));
        bio.type = MDSK_READ_REQ;
        bio.block_number = private->pt_block + 1;
        bio.buffer = label;
        memset(&private->iob, 0, sizeof (struct dasd_diag_rw_io));
        private->iob.dev_nr = rdc_data->dev_nr;
        private->iob.key = 0;
        private->iob.flags = 0; /* do synchronous io */
        private->iob.block_count = 1;
        private->iob.interrupt_params = 0;
        private->iob.bio_list = &bio;
        private->iob.flaga = DASD_DIAG_FLAGA_DEFAULT;
        rc = dia250(&private->iob, RW_BIO);
        if (rc == 3) {
            pr_warning("%s: A 64-bit DIAG call failed\n",
                   dev_name(&device->cdev->dev));
            rc = -EOPNOTSUPP;
            goto out_label;
        }
        mdsk_term_io(device);
        if (rc == 0)
            break;
    }
    if (bsize > PAGE_SIZE) {
        pr_warning("%s: Accessing the DASD failed because of an "
               "incorrect format (rc=%d)\n",
               dev_name(&device->cdev->dev), rc);
        rc = -EIO;
        goto out_label;
    }
    /* check for label block */
    if (memcmp(label->label_id, DASD_DIAG_CMS1,
          sizeof(DASD_DIAG_CMS1)) == 0) {
        /* get formatted blocksize from label block */
        bsize = (unsigned int) label->block_size;
        block->blocks = (unsigned long) label->block_count;
    } else
        block->blocks = end_block;
    block->bp_block = bsize;
    block->s2b_shift = 0;   /* bits to shift 512 to get a block */
    for (sb = 512; sb < bsize; sb = sb << 1)
        block->s2b_shift++;
    rc = mdsk_init_io(device, block->bp_block, 0, NULL);
    if (rc && (rc != 4)) {
        pr_warning("%s: DIAG initialization failed with rc=%d\n",
               dev_name(&device->cdev->dev), rc);
        rc = -EIO;
    } else {
        if (rc == 4)
            set_bit(DASD_FLAG_DEVICE_RO, &device->flags);
        pr_info("%s: New DASD with %ld byte/block, total size %ld "
            "KB%s\n", dev_name(&device->cdev->dev),
            (unsigned long) block->bp_block,
            (unsigned long) (block->blocks <<
                     block->s2b_shift) >> 1,
            (rc == 4) ? ", read-only device" : "");
        rc = 0;
    }
out_label:
    free_page((long) label);
out:
    if (rc) {
        device->block = NULL;
        dasd_free_block(block);
        device->private = NULL;
        kfree(private);
    }
    return rc;
}

/* Fill in virtual disk geometry for device. Return zero on success, non-zero
 * otherwise. */
static int
dasd_diag_fill_geometry(struct dasd_block *block, struct hd_geometry *geo)
{
    if (dasd_check_blocksize(block->bp_block) != 0)
        return -EINVAL;
    geo->cylinders = (block->blocks << block->s2b_shift) >> 10;
    geo->heads = 16;
    geo->sectors = 128 >> block->s2b_shift;
    return 0;
}

static dasd_erp_fn_t
dasd_diag_erp_action(struct dasd_ccw_req * cqr)
{
    return dasd_default_erp_action;
}

static dasd_erp_fn_t
dasd_diag_erp_postaction(struct dasd_ccw_req * cqr)
{
    return dasd_default_erp_postaction;
}

/* Create DASD request from block device request. Return pointer to new
 * request on success, ERR_PTR otherwise. */
static struct dasd_ccw_req *dasd_diag_build_cp(struct dasd_device *memdev,
                           struct dasd_block *block,
                           struct request *req)
{
    struct dasd_ccw_req *cqr;
    struct dasd_diag_req *dreq;
    struct dasd_diag_bio *dbio;
    struct req_iterator iter;
    struct bio_vec *bv;
    char *dst;
    unsigned int count, datasize;
    sector_t recid, first_rec, last_rec;
    unsigned int blksize, off;
    unsigned char rw_cmd;

    if (rq_data_dir(req) == READ)
        rw_cmd = MDSK_READ_REQ;
    else if (rq_data_dir(req) == WRITE)
        rw_cmd = MDSK_WRITE_REQ;
    else
        return ERR_PTR(-EINVAL);
    blksize = block->bp_block;
    /* Calculate record id of first and last block. */
    first_rec = blk_rq_pos(req) >> block->s2b_shift;
    last_rec =
        (blk_rq_pos(req) + blk_rq_sectors(req) - 1) >> block->s2b_shift;
    /* Check struct bio and count the number of blocks for the request. */
    count = 0;
    rq_for_each_segment(bv, req, iter) {
        if (bv->bv_len & (blksize - 1))
            /* Fba can only do full blocks. */
            return ERR_PTR(-EINVAL);
        count += bv->bv_len >> (block->s2b_shift + 9);
    }
    /* Paranoia. */
    if (count != last_rec - first_rec + 1)
        return ERR_PTR(-EINVAL);
    /* Build the request */
    datasize = sizeof(struct dasd_diag_req) +
        count*sizeof(struct dasd_diag_bio);
    cqr = dasd_smalloc_request(DASD_DIAG_MAGIC, 0, datasize, memdev);
    if (IS_ERR(cqr))
        return cqr;

    dreq = (struct dasd_diag_req *) cqr->data;
    dreq->block_count = count;
    dbio = dreq->bio;
    recid = first_rec;
    rq_for_each_segment(bv, req, iter) {
        dst = page_address(bv->bv_page) + bv->bv_offset;
        for (off = 0; off < bv->bv_len; off += blksize) {
            memset(dbio, 0, sizeof (struct dasd_diag_bio));
            dbio->type = rw_cmd;
            dbio->block_number = recid + 1;
            dbio->buffer = dst;
            dbio++;
            dst += blksize;
            recid++;
        }
    }
    cqr->retries = DIAG_MAX_RETRIES;
    cqr->buildclk = get_clock();
    if (blk_noretry_request(req) ||
        block->base->features & DASD_FEATURE_FAILFAST)
        set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
    cqr->startdev = memdev;
    cqr->memdev = memdev;
    cqr->block = block;
    cqr->expires = memdev->default_expires * HZ;
    cqr->status = DASD_CQR_FILLED;
    return cqr;
}

/* Release DASD request. Return non-zero if request was successful, zero
 * otherwise. */
static int
dasd_diag_free_cp(struct dasd_ccw_req *cqr, struct request *req)
{
    int status;

    status = cqr->status == DASD_CQR_DONE;
    dasd_sfree_request(cqr, cqr->memdev);
    return status;
}

static void dasd_diag_handle_terminated_request(struct dasd_ccw_req *cqr)
{
    cqr->status = DASD_CQR_FILLED;
};

/* Fill in IOCTL data for device. */
static int
dasd_diag_fill_info(struct dasd_device * device,
            struct dasd_information2_t * info)
{
    struct dasd_diag_private *private;

    private = (struct dasd_diag_private *) device->private;
    info->label_block = (unsigned int) private->pt_block;
    info->FBA_layout = 1;
    info->format = DASD_FORMAT_LDL;
    info->characteristics_size = sizeof (struct dasd_diag_characteristics);
    memcpy(info->characteristics,
           &((struct dasd_diag_private *) device->private)->rdc_data,
           sizeof (struct dasd_diag_characteristics));
    info->confdata_size = 0;
    return 0;
}

static void
dasd_diag_dump_sense(struct dasd_device *device, struct dasd_ccw_req * req,
             struct irb *stat)
{
    DBF_DEV_EVENT(DBF_WARNING, device, "%s",
            "dump sense not available for DIAG data");
}

static struct dasd_discipline dasd_diag_discipline = {
    .owner = THIS_MODULE,
    .name = "DIAG",
    .ebcname = "DIAG",
    .max_blocks = DIAG_MAX_BLOCKS,
    .check_device = dasd_diag_check_device,
    .verify_path = dasd_generic_verify_path,
    .fill_geometry = dasd_diag_fill_geometry,
    .start_IO = dasd_start_diag,
    .term_IO = dasd_diag_term_IO,
    .handle_terminated_request = dasd_diag_handle_terminated_request,
    .erp_action = dasd_diag_erp_action,
    .erp_postaction = dasd_diag_erp_postaction,
    .build_cp = dasd_diag_build_cp,
    .free_cp = dasd_diag_free_cp,
    .dump_sense = dasd_diag_dump_sense,
    .fill_info = dasd_diag_fill_info,
};

static int __init
dasd_diag_init(void)
{
    if (!MACHINE_IS_VM) {
        pr_info("Discipline %s cannot be used without z/VM\n",
            dasd_diag_discipline.name);
        return -ENODEV;
    }
    ASCEBC(dasd_diag_discipline.ebcname, 4);

    service_subclass_irq_register();
    register_external_interrupt(0x2603, dasd_ext_handler);
    dasd_diag_discipline_pointer = &dasd_diag_discipline;
    return 0;
}

static void __exit
dasd_diag_cleanup(void)
{
    unregister_external_interrupt(0x2603, dasd_ext_handler);
    service_subclass_irq_unregister();
    dasd_diag_discipline_pointer = NULL;
}

module_init(dasd_diag_init);
module_exit(dasd_diag_cleanup);