chsc.c

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/*
 *   S/390 common I/O routines -- channel subsystem call
 *
 *    Copyright IBM Corp. 1999, 2010
 *    Author(s): Ingo Adlung ([email protected])
 *       Cornelia Huck ([email protected])
 *       Arnd Bergmann ([email protected])
 */

#define KMSG_COMPONENT "cio"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/device.h>

#include <asm/cio.h>
#include <asm/chpid.h>
#include <asm/chsc.h>
#include <asm/crw.h>

#include "css.h"
#include "cio.h"
#include "cio_debug.h"
#include "ioasm.h"
#include "chp.h"
#include "chsc.h"

static void *sei_page;
static void *chsc_page;
static DEFINE_SPINLOCK(chsc_page_lock);

int chsc_error_from_response(int response)
{
    switch (response) {
    case 0x0001:
        return 0;
    case 0x0002:
    case 0x0003:
    case 0x0006:
    case 0x0007:
    case 0x0008:
    case 0x000a:
    case 0x0104:
        return -EINVAL;
    case 0x0004:
        return -EOPNOTSUPP;
    case 0x000b:
        return -EBUSY;
    case 0x0100:
    case 0x0102:
        return -ENOMEM;
    default:
        return -EIO;
    }
}
EXPORT_SYMBOL_GPL(chsc_error_from_response);

struct chsc_ssd_area {
    struct chsc_header request;
    u16 :10;
    u16 ssid:2;
    u16 :4;
    u16 f_sch;    /* first subchannel */
    u16 :16;
    u16 l_sch;    /* last subchannel */
    u32 :32;
    struct chsc_header response;
    u32 :32;
    u8 sch_valid : 1;
    u8 dev_valid : 1;
    u8 st        : 3; /* subchannel type */
    u8 zeroes    : 3;
    u8  unit_addr;    /* unit address */
    u16 devno;    /* device number */
    u8 path_mask;
    u8 fla_valid_mask;
    u16 sch;      /* subchannel */
    u8 chpid[8];      /* chpids 0-7 */
    u16 fla[8];   /* full link addresses 0-7 */
} __attribute__ ((packed));

int chsc_get_ssd_info(struct subchannel_id schid, struct chsc_ssd_info *ssd)
{
    struct chsc_ssd_area *ssd_area;
    int ccode;
    int ret;
    int i;
    int mask;

    spin_lock_irq(&chsc_page_lock);
    memset(chsc_page, 0, PAGE_SIZE);
    ssd_area = chsc_page;
    ssd_area->request.length = 0x0010;
    ssd_area->request.code = 0x0004;
    ssd_area->ssid = schid.ssid;
    ssd_area->f_sch = schid.sch_no;
    ssd_area->l_sch = schid.sch_no;

    ccode = chsc(ssd_area);
    /* Check response. */
    if (ccode > 0) {
        ret = (ccode == 3) ? -ENODEV : -EBUSY;
        goto out;
    }
    ret = chsc_error_from_response(ssd_area->response.code);
    if (ret != 0) {
        CIO_MSG_EVENT(2, "chsc: ssd failed for 0.%x.%04x (rc=%04x)\n",
                  schid.ssid, schid.sch_no,
                  ssd_area->response.code);
        goto out;
    }
    if (!ssd_area->sch_valid) {
        ret = -ENODEV;
        goto out;
    }
    /* Copy data */
    ret = 0;
    memset(ssd, 0, sizeof(struct chsc_ssd_info));
    if ((ssd_area->st != SUBCHANNEL_TYPE_IO) &&
        (ssd_area->st != SUBCHANNEL_TYPE_MSG))
        goto out;
    ssd->path_mask = ssd_area->path_mask;
    ssd->fla_valid_mask = ssd_area->fla_valid_mask;
    for (i = 0; i < 8; i++) {
        mask = 0x80 >> i;
        if (ssd_area->path_mask & mask) {
            chp_id_init(&ssd->chpid[i]);
            ssd->chpid[i].id = ssd_area->chpid[i];
        }
        if (ssd_area->fla_valid_mask & mask)
            ssd->fla[i] = ssd_area->fla[i];
    }
out:
    spin_unlock_irq(&chsc_page_lock);
    return ret;
}

static int s390_subchannel_remove_chpid(struct subchannel *sch, void *data)
{
    spin_lock_irq(sch->lock);
    if (sch->driver && sch->driver->chp_event)
        if (sch->driver->chp_event(sch, data, CHP_OFFLINE) != 0)
            goto out_unreg;
    spin_unlock_irq(sch->lock);
    return 0;

out_unreg:
    sch->lpm = 0;
    spin_unlock_irq(sch->lock);
    css_schedule_eval(sch->schid);
    return 0;
}

void chsc_chp_offline(struct chp_id chpid)
{
    char dbf_txt[15];
    struct chp_link link;

    sprintf(dbf_txt, "chpr%x.%02x", chpid.cssid, chpid.id);
    CIO_TRACE_EVENT(2, dbf_txt);

    if (chp_get_status(chpid) <= 0)
        return;
    memset(&link, 0, sizeof(struct chp_link));
    link.chpid = chpid;
    /* Wait until previous actions have settled. */
    css_wait_for_slow_path();
    for_each_subchannel_staged(s390_subchannel_remove_chpid, NULL, &link);
}

static int s390_process_res_acc_new_sch(struct subchannel_id schid, void *data)
{
    struct schib schib;
    /*
     * We don't know the device yet, but since a path
     * may be available now to the device we'll have
     * to do recognition again.
     * Since we don't have any idea about which chpid
     * that beast may be on we'll have to do a stsch
     * on all devices, grr...
     */
    if (stsch_err(schid, &schib))
        /* We're through */
        return -ENXIO;

    /* Put it on the slow path. */
    css_schedule_eval(schid);
    return 0;
}

static int __s390_process_res_acc(struct subchannel *sch, void *data)
{
    spin_lock_irq(sch->lock);
    if (sch->driver && sch->driver->chp_event)
        sch->driver->chp_event(sch, data, CHP_ONLINE);
    spin_unlock_irq(sch->lock);

    return 0;
}

static void s390_process_res_acc(struct chp_link *link)
{
    char dbf_txt[15];

    sprintf(dbf_txt, "accpr%x.%02x", link->chpid.cssid,
        link->chpid.id);
    CIO_TRACE_EVENT( 2, dbf_txt);
    if (link->fla != 0) {
        sprintf(dbf_txt, "fla%x", link->fla);
        CIO_TRACE_EVENT( 2, dbf_txt);
    }
    /* Wait until previous actions have settled. */
    css_wait_for_slow_path();
    /*
     * I/O resources may have become accessible.
     * Scan through all subchannels that may be concerned and
     * do a validation on those.
     * The more information we have (info), the less scanning
     * will we have to do.
     */
    for_each_subchannel_staged(__s390_process_res_acc,
                   s390_process_res_acc_new_sch, link);
}

static int
__get_chpid_from_lir(void *data)
{
    struct lir {
        u8  iq;
        u8  ic;
        u16 sci;
        /* incident-node descriptor */
        u32 indesc[28];
        /* attached-node descriptor */
        u32 andesc[28];
        /* incident-specific information */
        u32 isinfo[28];
    } __attribute__ ((packed)) *lir;

    lir = data;
    if (!(lir->iq&0x80))
        /* NULL link incident record */
        return -EINVAL;
    if (!(lir->indesc[0]&0xc0000000))
        /* node descriptor not valid */
        return -EINVAL;
    if (!(lir->indesc[0]&0x10000000))
        /* don't handle device-type nodes - FIXME */
        return -EINVAL;
    /* Byte 3 contains the chpid. Could also be CTCA, but we don't care */

    return (u16) (lir->indesc[0]&0x000000ff);
}

struct chsc_sei_area {
    struct chsc_header request;
    u32 reserved1;
    u32 reserved2;
    u32 reserved3;
    struct chsc_header response;
    u32 reserved4;
    u8  flags;
    u8  vf;     /* validity flags */
    u8  rs;     /* reporting source */
    u8  cc;     /* content code */
    u16 fla;    /* full link address */
    u16 rsid;   /* reporting source id */
    u32 reserved5;
    u32 reserved6;
    u8 ccdf[4096 - 16 - 24];    /* content-code dependent field */
    /* ccdf has to be big enough for a link-incident record */
} __attribute__ ((packed));

static void chsc_process_sei_link_incident(struct chsc_sei_area *sei_area)
{
    struct chp_id chpid;
    int id;

    CIO_CRW_EVENT(4, "chsc: link incident (rs=%02x, rs_id=%04x)\n",
              sei_area->rs, sei_area->rsid);
    if (sei_area->rs != 4)
        return;
    id = __get_chpid_from_lir(sei_area->ccdf);
    if (id < 0)
        CIO_CRW_EVENT(4, "chsc: link incident - invalid LIR\n");
    else {
        chp_id_init(&chpid);
        chpid.id = id;
        chsc_chp_offline(chpid);
    }
}

static void chsc_process_sei_res_acc(struct chsc_sei_area *sei_area)
{
    struct chp_link link;
    struct chp_id chpid;
    int status;

    CIO_CRW_EVENT(4, "chsc: resource accessibility event (rs=%02x, "
              "rs_id=%04x)\n", sei_area->rs, sei_area->rsid);
    if (sei_area->rs != 4)
        return;
    chp_id_init(&chpid);
    chpid.id = sei_area->rsid;
    /* allocate a new channel path structure, if needed */
    status = chp_get_status(chpid);
    if (status < 0)
        chp_new(chpid);
    else if (!status)
        return;
    memset(&link, 0, sizeof(struct chp_link));
    link.chpid = chpid;
    if ((sei_area->vf & 0xc0) != 0) {
        link.fla = sei_area->fla;
        if ((sei_area->vf & 0xc0) == 0xc0)
            /* full link address */
            link.fla_mask = 0xffff;
        else
            /* link address */
            link.fla_mask = 0xff00;
    }
    s390_process_res_acc(&link);
}

static void chsc_process_sei_chp_avail(struct chsc_sei_area *sei_area)
{
    struct channel_path *chp;
    struct chp_id chpid;
    u8 *data;
    int num;

    CIO_CRW_EVENT(4, "chsc: channel path availability information\n");
    if (sei_area->rs != 0)
        return;
    data = sei_area->ccdf;
    chp_id_init(&chpid);
    for (num = 0; num <= __MAX_CHPID; num++) {
        if (!chp_test_bit(data, num))
            continue;
        chpid.id = num;

        CIO_CRW_EVENT(4, "Update information for channel path "
                  "%x.%02x\n", chpid.cssid, chpid.id);
        chp = chpid_to_chp(chpid);
        if (!chp) {
            chp_new(chpid);
            continue;
        }
        mutex_lock(&chp->lock);
        chsc_determine_base_channel_path_desc(chpid, &chp->desc);
        mutex_unlock(&chp->lock);
    }
}

struct chp_config_data {
    u8 map[32];
    u8 op;
    u8 pc;
};

static void chsc_process_sei_chp_config(struct chsc_sei_area *sei_area)
{
    struct chp_config_data *data;
    struct chp_id chpid;
    int num;
    char *events[3] = {"configure", "deconfigure", "cancel deconfigure"};

    CIO_CRW_EVENT(4, "chsc: channel-path-configuration notification\n");
    if (sei_area->rs != 0)
        return;
    data = (struct chp_config_data *) &(sei_area->ccdf);
    chp_id_init(&chpid);
    for (num = 0; num <= __MAX_CHPID; num++) {
        if (!chp_test_bit(data->map, num))
            continue;
        chpid.id = num;
        pr_notice("Processing %s for channel path %x.%02x\n",
              events[data->op], chpid.cssid, chpid.id);
        switch (data->op) {
        case 0:
            chp_cfg_schedule(chpid, 1);
            break;
        case 1:
            chp_cfg_schedule(chpid, 0);
            break;
        case 2:
            chp_cfg_cancel_deconfigure(chpid);
            break;
        }
    }
}

static void chsc_process_sei_scm_change(struct chsc_sei_area *sei_area)
{
    int ret;

    CIO_CRW_EVENT(4, "chsc: scm change notification\n");
    if (sei_area->rs != 7)
        return;

    ret = scm_update_information();
    if (ret)
        CIO_CRW_EVENT(0, "chsc: updating change notification"
                  " failed (rc=%d).\n", ret);
}

static void chsc_process_sei(struct chsc_sei_area *sei_area)
{
    /* Check if we might have lost some information. */
    if (sei_area->flags & 0x40) {
        CIO_CRW_EVENT(2, "chsc: event overflow\n");
        css_schedule_eval_all();
    }
    /* which kind of information was stored? */
    switch (sei_area->cc) {
    case 1: /* link incident*/
        chsc_process_sei_link_incident(sei_area);
        break;
    case 2: /* i/o resource accessibility */
        chsc_process_sei_res_acc(sei_area);
        break;
    case 7: /* channel-path-availability information */
        chsc_process_sei_chp_avail(sei_area);
        break;
    case 8: /* channel-path-configuration notification */
        chsc_process_sei_chp_config(sei_area);
        break;
    case 12: /* scm change notification */
        chsc_process_sei_scm_change(sei_area);
        break;
    default: /* other stuff */
        CIO_CRW_EVENT(4, "chsc: unhandled sei content code %d\n",
                  sei_area->cc);
        break;
    }
}

static void chsc_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
{
    struct chsc_sei_area *sei_area;

    if (overflow) {
        css_schedule_eval_all();
        return;
    }
    CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
              "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
              crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
              crw0->erc, crw0->rsid);
    if (!sei_page)
        return;
    /* Access to sei_page is serialized through machine check handler
     * thread, so no need for locking. */
    sei_area = sei_page;

    CIO_TRACE_EVENT(2, "prcss");
    do {
        memset(sei_area, 0, sizeof(*sei_area));
        sei_area->request.length = 0x0010;
        sei_area->request.code = 0x000e;
        if (chsc(sei_area))
            break;

        if (sei_area->response.code == 0x0001) {
            CIO_CRW_EVENT(4, "chsc: sei successful\n");
            chsc_process_sei(sei_area);
        } else {
            CIO_CRW_EVENT(2, "chsc: sei failed (rc=%04x)\n",
                      sei_area->response.code);
            break;
        }
    } while (sei_area->flags & 0x80);
}

void chsc_chp_online(struct chp_id chpid)
{
    char dbf_txt[15];
    struct chp_link link;

    sprintf(dbf_txt, "cadd%x.%02x", chpid.cssid, chpid.id);
    CIO_TRACE_EVENT(2, dbf_txt);

    if (chp_get_status(chpid) != 0) {
        memset(&link, 0, sizeof(struct chp_link));
        link.chpid = chpid;
        /* Wait until previous actions have settled. */
        css_wait_for_slow_path();
        for_each_subchannel_staged(__s390_process_res_acc, NULL,
                       &link);
    }
}

static void __s390_subchannel_vary_chpid(struct subchannel *sch,
                     struct chp_id chpid, int on)
{
    unsigned long flags;
    struct chp_link link;

    memset(&link, 0, sizeof(struct chp_link));
    link.chpid = chpid;
    spin_lock_irqsave(sch->lock, flags);
    if (sch->driver && sch->driver->chp_event)
        sch->driver->chp_event(sch, &link,
                       on ? CHP_VARY_ON : CHP_VARY_OFF);
    spin_unlock_irqrestore(sch->lock, flags);
}

static int s390_subchannel_vary_chpid_off(struct subchannel *sch, void *data)
{
    struct chp_id *chpid = data;

    __s390_subchannel_vary_chpid(sch, *chpid, 0);
    return 0;
}

static int s390_subchannel_vary_chpid_on(struct subchannel *sch, void *data)
{
    struct chp_id *chpid = data;

    __s390_subchannel_vary_chpid(sch, *chpid, 1);
    return 0;
}

static int
__s390_vary_chpid_on(struct subchannel_id schid, void *data)
{
    struct schib schib;

    if (stsch_err(schid, &schib))
        /* We're through */
        return -ENXIO;
    /* Put it on the slow path. */
    css_schedule_eval(schid);
    return 0;
}

int chsc_chp_vary(struct chp_id chpid, int on)
{
    struct channel_path *chp = chpid_to_chp(chpid);

    /* Wait until previous actions have settled. */
    css_wait_for_slow_path();
    /*
     * Redo PathVerification on the devices the chpid connects to
     */
    if (on) {
        /* Try to update the channel path descritor. */
        chsc_determine_base_channel_path_desc(chpid, &chp->desc);
        for_each_subchannel_staged(s390_subchannel_vary_chpid_on,
                       __s390_vary_chpid_on, &chpid);
    } else
        for_each_subchannel_staged(s390_subchannel_vary_chpid_off,
                       NULL, &chpid);

    return 0;
}

static void
chsc_remove_cmg_attr(struct channel_subsystem *css)
{
    int i;

    for (i = 0; i <= __MAX_CHPID; i++) {
        if (!css->chps[i])
            continue;
        chp_remove_cmg_attr(css->chps[i]);
    }
}

static int
chsc_add_cmg_attr(struct channel_subsystem *css)
{
    int i, ret;

    ret = 0;
    for (i = 0; i <= __MAX_CHPID; i++) {
        if (!css->chps[i])
            continue;
        ret = chp_add_cmg_attr(css->chps[i]);
        if (ret)
            goto cleanup;
    }
    return ret;
cleanup:
    for (--i; i >= 0; i--) {
        if (!css->chps[i])
            continue;
        chp_remove_cmg_attr(css->chps[i]);
    }
    return ret;
}

int __chsc_do_secm(struct channel_subsystem *css, int enable)
{
    struct {
        struct chsc_header request;
        u32 operation_code : 2;
        u32 : 30;
        u32 key : 4;
        u32 : 28;
        u32 zeroes1;
        u32 cub_addr1;
        u32 zeroes2;
        u32 cub_addr2;
        u32 reserved[13];
        struct chsc_header response;
        u32 status : 8;
        u32 : 4;
        u32 fmt : 4;
        u32 : 16;
    } __attribute__ ((packed)) *secm_area;
    int ret, ccode;

    spin_lock_irq(&chsc_page_lock);
    memset(chsc_page, 0, PAGE_SIZE);
    secm_area = chsc_page;
    secm_area->request.length = 0x0050;
    secm_area->request.code = 0x0016;

    secm_area->key = PAGE_DEFAULT_KEY >> 4;
    secm_area->cub_addr1 = (u64)(unsigned long)css->cub_addr1;
    secm_area->cub_addr2 = (u64)(unsigned long)css->cub_addr2;

    secm_area->operation_code = enable ? 0 : 1;

    ccode = chsc(secm_area);
    if (ccode > 0) {
        ret = (ccode == 3) ? -ENODEV : -EBUSY;
        goto out;
    }

    switch (secm_area->response.code) {
    case 0x0102:
    case 0x0103:
        ret = -EINVAL;
        break;
    default:
        ret = chsc_error_from_response(secm_area->response.code);
    }
    if (ret != 0)
        CIO_CRW_EVENT(2, "chsc: secm failed (rc=%04x)\n",
                  secm_area->response.code);
out:
    spin_unlock_irq(&chsc_page_lock);
    return ret;
}

int
chsc_secm(struct channel_subsystem *css, int enable)
{
    int ret;

    if (enable && !css->cm_enabled) {
        css->cub_addr1 = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
        css->cub_addr2 = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!css->cub_addr1 || !css->cub_addr2) {
            free_page((unsigned long)css->cub_addr1);
            free_page((unsigned long)css->cub_addr2);
            return -ENOMEM;
        }
    }
    ret = __chsc_do_secm(css, enable);
    if (!ret) {
        css->cm_enabled = enable;
        if (css->cm_enabled) {
            ret = chsc_add_cmg_attr(css);
            if (ret) {
                __chsc_do_secm(css, 0);
                css->cm_enabled = 0;
            }
        } else
            chsc_remove_cmg_attr(css);
    }
    if (!css->cm_enabled) {
        free_page((unsigned long)css->cub_addr1);
        free_page((unsigned long)css->cub_addr2);
    }
    return ret;
}

int chsc_determine_channel_path_desc(struct chp_id chpid, int fmt, int rfmt,
                     int c, int m, void *page)
{
    struct chsc_scpd *scpd_area;
    int ccode, ret;

    if ((rfmt == 1) && !css_general_characteristics.fcs)
        return -EINVAL;
    if ((rfmt == 2) && !css_general_characteristics.cib)
        return -EINVAL;

    memset(page, 0, PAGE_SIZE);
    scpd_area = page;
    scpd_area->request.length = 0x0010;
    scpd_area->request.code = 0x0002;
    scpd_area->cssid = chpid.cssid;
    scpd_area->first_chpid = chpid.id;
    scpd_area->last_chpid = chpid.id;
    scpd_area->m = m;
    scpd_area->c = c;
    scpd_area->fmt = fmt;
    scpd_area->rfmt = rfmt;

    ccode = chsc(scpd_area);
    if (ccode > 0)
        return (ccode == 3) ? -ENODEV : -EBUSY;

    ret = chsc_error_from_response(scpd_area->response.code);
    if (ret)
        CIO_CRW_EVENT(2, "chsc: scpd failed (rc=%04x)\n",
                  scpd_area->response.code);
    return ret;
}
EXPORT_SYMBOL_GPL(chsc_determine_channel_path_desc);

int chsc_determine_base_channel_path_desc(struct chp_id chpid,
                      struct channel_path_desc *desc)
{
    struct chsc_response_struct *chsc_resp;
    struct chsc_scpd *scpd_area;
    unsigned long flags;
    int ret;

    spin_lock_irqsave(&chsc_page_lock, flags);
    scpd_area = chsc_page;
    ret = chsc_determine_channel_path_desc(chpid, 0, 0, 0, 0, scpd_area);
    if (ret)
        goto out;
    chsc_resp = (void *)&scpd_area->response;
    memcpy(desc, &chsc_resp->data, sizeof(*desc));
out:
    spin_unlock_irqrestore(&chsc_page_lock, flags);
    return ret;
}

int chsc_determine_fmt1_channel_path_desc(struct chp_id chpid,
                      struct channel_path_desc_fmt1 *desc)
{
    struct chsc_response_struct *chsc_resp;
    struct chsc_scpd *scpd_area;
    int ret;

    spin_lock_irq(&chsc_page_lock);
    scpd_area = chsc_page;
    ret = chsc_determine_channel_path_desc(chpid, 0, 0, 1, 0, scpd_area);
    if (ret)
        goto out;
    chsc_resp = (void *)&scpd_area->response;
    memcpy(desc, &chsc_resp->data, sizeof(*desc));
out:
    spin_unlock_irq(&chsc_page_lock);
    return ret;
}

static void
chsc_initialize_cmg_chars(struct channel_path *chp, u8 cmcv,
              struct cmg_chars *chars)
{
    struct cmg_chars *cmg_chars;
    int i, mask;

    cmg_chars = chp->cmg_chars;
    for (i = 0; i < NR_MEASUREMENT_CHARS; i++) {
        mask = 0x80 >> (i + 3);
        if (cmcv & mask)
            cmg_chars->values[i] = chars->values[i];
        else
            cmg_chars->values[i] = 0;
    }
}

int chsc_get_channel_measurement_chars(struct channel_path *chp)
{
    struct cmg_chars *cmg_chars;
    int ccode, ret;

    struct {
        struct chsc_header request;
        u32 : 24;
        u32 first_chpid : 8;
        u32 : 24;
        u32 last_chpid : 8;
        u32 zeroes1;
        struct chsc_header response;
        u32 zeroes2;
        u32 not_valid : 1;
        u32 shared : 1;
        u32 : 22;
        u32 chpid : 8;
        u32 cmcv : 5;
        u32 : 11;
        u32 cmgq : 8;
        u32 cmg : 8;
        u32 zeroes3;
        u32 data[NR_MEASUREMENT_CHARS];
    } __attribute__ ((packed)) *scmc_area;

    chp->cmg_chars = NULL;
    cmg_chars = kmalloc(sizeof(*cmg_chars), GFP_KERNEL);
    if (!cmg_chars)
        return -ENOMEM;

    spin_lock_irq(&chsc_page_lock);
    memset(chsc_page, 0, PAGE_SIZE);
    scmc_area = chsc_page;
    scmc_area->request.length = 0x0010;
    scmc_area->request.code = 0x0022;
    scmc_area->first_chpid = chp->chpid.id;
    scmc_area->last_chpid = chp->chpid.id;

    ccode = chsc(scmc_area);
    if (ccode > 0) {
        ret = (ccode == 3) ? -ENODEV : -EBUSY;
        goto out;
    }

    ret = chsc_error_from_response(scmc_area->response.code);
    if (ret) {
        CIO_CRW_EVENT(2, "chsc: scmc failed (rc=%04x)\n",
                  scmc_area->response.code);
        goto out;
    }
    if (scmc_area->not_valid) {
        chp->cmg = -1;
        chp->shared = -1;
        goto out;
    }
    chp->cmg = scmc_area->cmg;
    chp->shared = scmc_area->shared;
    if (chp->cmg != 2 && chp->cmg != 3) {
        /* No cmg-dependent data. */
        goto out;
    }
    chp->cmg_chars = cmg_chars;
    chsc_initialize_cmg_chars(chp, scmc_area->cmcv,
                  (struct cmg_chars *) &scmc_area->data);
out:
    spin_unlock_irq(&chsc_page_lock);
    if (!chp->cmg_chars)
        kfree(cmg_chars);

    return ret;
}

int __init chsc_init(void)
{
    int ret;

    sei_page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
    chsc_page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
    if (!sei_page || !chsc_page) {
        ret = -ENOMEM;
        goto out_err;
    }
    ret = crw_register_handler(CRW_RSC_CSS, chsc_process_crw);
    if (ret)
        goto out_err;
    return ret;
out_err:
    free_page((unsigned long)chsc_page);
    free_page((unsigned long)sei_page);
    return ret;
}

void __init chsc_init_cleanup(void)
{
    crw_unregister_handler(CRW_RSC_CSS);
    free_page((unsigned long)chsc_page);
    free_page((unsigned long)sei_page);
}

int chsc_enable_facility(int operation_code)
{
    unsigned long flags;
    int ret;
    struct {
        struct chsc_header request;
        u8 reserved1:4;
        u8 format:4;
        u8 reserved2;
        u16 operation_code;
        u32 reserved3;
        u32 reserved4;
        u32 operation_data_area[252];
        struct chsc_header response;
        u32 reserved5:4;
        u32 format2:4;
        u32 reserved6:24;
    } __attribute__ ((packed)) *sda_area;

    spin_lock_irqsave(&chsc_page_lock, flags);
    memset(chsc_page, 0, PAGE_SIZE);
    sda_area = chsc_page;
    sda_area->request.length = 0x0400;
    sda_area->request.code = 0x0031;
    sda_area->operation_code = operation_code;

    ret = chsc(sda_area);
    if (ret > 0) {
        ret = (ret == 3) ? -ENODEV : -EBUSY;
        goto out;
    }

    switch (sda_area->response.code) {
    case 0x0101:
        ret = -EOPNOTSUPP;
        break;
    default:
        ret = chsc_error_from_response(sda_area->response.code);
    }
    if (ret != 0)
        CIO_CRW_EVENT(2, "chsc: sda (oc=%x) failed (rc=%04x)\n",
                  operation_code, sda_area->response.code);
out:
    spin_unlock_irqrestore(&chsc_page_lock, flags);
    return ret;
}

struct css_general_char css_general_characteristics;
struct css_chsc_char css_chsc_characteristics;

int __init
chsc_determine_css_characteristics(void)
{
    int result;
    struct {
        struct chsc_header request;
        u32 reserved1;
        u32 reserved2;
        u32 reserved3;
        struct chsc_header response;
        u32 reserved4;
        u32 general_char[510];
        u32 chsc_char[508];
    } __attribute__ ((packed)) *scsc_area;

    spin_lock_irq(&chsc_page_lock);
    memset(chsc_page, 0, PAGE_SIZE);
    scsc_area = chsc_page;
    scsc_area->request.length = 0x0010;
    scsc_area->request.code = 0x0010;

    result = chsc(scsc_area);
    if (result) {
        result = (result == 3) ? -ENODEV : -EBUSY;
        goto exit;
    }

    result = chsc_error_from_response(scsc_area->response.code);
    if (result == 0) {
        memcpy(&css_general_characteristics, scsc_area->general_char,
               sizeof(css_general_characteristics));
        memcpy(&css_chsc_characteristics, scsc_area->chsc_char,
               sizeof(css_chsc_characteristics));
    } else
        CIO_CRW_EVENT(2, "chsc: scsc failed (rc=%04x)\n",
                  scsc_area->response.code);
exit:
    spin_unlock_irq(&chsc_page_lock);
    return result;
}

EXPORT_SYMBOL_GPL(css_general_characteristics);
EXPORT_SYMBOL_GPL(css_chsc_characteristics);

int chsc_sstpc(void *page, unsigned int op, u16 ctrl)
{
    struct {
        struct chsc_header request;
        unsigned int rsvd0;
        unsigned int op : 8;
        unsigned int rsvd1 : 8;
        unsigned int ctrl : 16;
        unsigned int rsvd2[5];
        struct chsc_header response;
        unsigned int rsvd3[7];
    } __attribute__ ((packed)) *rr;
    int rc;

    memset(page, 0, PAGE_SIZE);
    rr = page;
    rr->request.length = 0x0020;
    rr->request.code = 0x0033;
    rr->op = op;
    rr->ctrl = ctrl;
    rc = chsc(rr);
    if (rc)
        return -EIO;
    rc = (rr->response.code == 0x0001) ? 0 : -EIO;
    return rc;
}

int chsc_sstpi(void *page, void *result, size_t size)
{
    struct {
        struct chsc_header request;
        unsigned int rsvd0[3];
        struct chsc_header response;
        char data[size];
    } __attribute__ ((packed)) *rr;
    int rc;

    memset(page, 0, PAGE_SIZE);
    rr = page;
    rr->request.length = 0x0010;
    rr->request.code = 0x0038;
    rc = chsc(rr);
    if (rc)
        return -EIO;
    memcpy(result, &rr->data, size);
    return (rr->response.code == 0x0001) ? 0 : -EIO;
}

int chsc_siosl(struct subchannel_id schid)
{
    struct {
        struct chsc_header request;
        u32 word1;
        struct subchannel_id sid;
        u32 word3;
        struct chsc_header response;
        u32 word[11];
    } __attribute__ ((packed)) *siosl_area;
    unsigned long flags;
    int ccode;
    int rc;

    spin_lock_irqsave(&chsc_page_lock, flags);
    memset(chsc_page, 0, PAGE_SIZE);
    siosl_area = chsc_page;
    siosl_area->request.length = 0x0010;
    siosl_area->request.code = 0x0046;
    siosl_area->word1 = 0x80000000;
    siosl_area->sid = schid;

    ccode = chsc(siosl_area);
    if (ccode > 0) {
        if (ccode == 3)
            rc = -ENODEV;
        else
            rc = -EBUSY;
        CIO_MSG_EVENT(2, "chsc: chsc failed for 0.%x.%04x (ccode=%d)\n",
                  schid.ssid, schid.sch_no, ccode);
        goto out;
    }
    rc = chsc_error_from_response(siosl_area->response.code);
    if (rc)
        CIO_MSG_EVENT(2, "chsc: siosl failed for 0.%x.%04x (rc=%04x)\n",
                  schid.ssid, schid.sch_no,
                  siosl_area->response.code);
    else
        CIO_MSG_EVENT(4, "chsc: siosl succeeded for 0.%x.%04x\n",
                  schid.ssid, schid.sch_no);
out:
    spin_unlock_irqrestore(&chsc_page_lock, flags);
    return rc;
}
EXPORT_SYMBOL_GPL(chsc_siosl);

int chsc_scm_info(struct chsc_scm_info *scm_area, u64 token)
{
    int ccode, ret;

    memset(scm_area, 0, sizeof(*scm_area));
    scm_area->request.length = 0x0020;
    scm_area->request.code = 0x004C;
    scm_area->reqtok = token;

    ccode = chsc(scm_area);
    if (ccode > 0) {
        ret = (ccode == 3) ? -ENODEV : -EBUSY;
        goto out;
    }
    ret = chsc_error_from_response(scm_area->response.code);
    if (ret != 0)
        CIO_MSG_EVENT(2, "chsc: scm info failed (rc=%04x)\n",
                  scm_area->response.code);
out:
    return ret;
}
EXPORT_SYMBOL_GPL(chsc_scm_info);