// SPDX-License-Identifier: GPL-2.0
/*
 *   S/390 common I/O routines -- channel subsystem call
 *
 *    Copyright IBM Corp. 1999,2012
 *    Author(s): Ingo Adlung (adlung@de.ibm.com)
 *               Cornelia Huck (cornelia.huck@de.ibm.com)
 *               Arnd Bergmann (arndb@de.ibm.com)
 */

#define pr_fmt(fmt) "cio: " fmt

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

#include <asm/cio.h>
#include <asm/chpid.h>
#include <asm/chsc.h>
#include <asm/crw.h>
#include <asm/isc.h>
#include <asm/ebcdic.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);

#define SEI_VF_FLA      0xc0 /* VF flag for Full Link Address */
#define SEI_RS_CHPID    0x4  /* 4 in RS field indicates CHPID */

static BLOCKING_NOTIFIER_HEAD(chsc_notifiers);

int chsc_notifier_register(struct notifier_block *nb)
{
        return blocking_notifier_chain_register(&chsc_notifiers, nb);
}
EXPORT_SYMBOL(chsc_notifier_register);

int chsc_notifier_unregister(struct notifier_block *nb)
{
        return blocking_notifier_chain_unregister(&chsc_notifiers, nb);
}
EXPORT_SYMBOL(chsc_notifier_unregister);

/**
 * chsc_error_from_response() - convert a chsc response to an error
 * @response: chsc response code
 *
 * Returns an appropriate Linux error code for @response.
 */
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:
        case 0x0106:            /* "Wrong Channel Parm" for the op 0x003d */
                return -EOPNOTSUPP;
        case 0x000b:
        case 0x0107:            /* "Channel busy" for the op 0x003d */
                return -EBUSY;
        case 0x0100:
        case 0x0102:
                return -ENOMEM;
        case 0x0108:            /* "HW limit exceeded" for the op 0x003d */
                return -EUSERS;
        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 */
} __packed __aligned(PAGE_SIZE);

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

        spin_lock_irqsave(&chsc_page_lock, flags);
        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_irqrestore(&chsc_page_lock, flags);
        return ret;
}

/**
 * chsc_ssqd() - store subchannel QDIO data (SSQD)
 * @schid: id of the subchannel on which SSQD is performed
 * @ssqd: request and response block for SSQD
 *
 * Returns 0 on success.
 */
int chsc_ssqd(struct subchannel_id schid, struct chsc_ssqd_area *ssqd)
{
        memset(ssqd, 0, sizeof(*ssqd));
        ssqd->request.length = 0x0010;
        ssqd->request.code = 0x0024;
        ssqd->first_sch = schid.sch_no;
        ssqd->last_sch = schid.sch_no;
        ssqd->ssid = schid.ssid;

        if (chsc(ssqd))
                return -EIO;

        return chsc_error_from_response(ssqd->response.code);
}
EXPORT_SYMBOL_GPL(chsc_ssqd);

/**
 * chsc_sadc() - set adapter device controls (SADC)
 * @schid: id of the subchannel on which SADC is performed
 * @scssc: request and response block for SADC
 * @summary_indicator_addr: summary indicator address
 * @subchannel_indicator_addr: subchannel indicator address
 * @isc: Interruption Subclass for this subchannel
 *
 * Returns 0 on success.
 */
int chsc_sadc(struct subchannel_id schid, struct chsc_scssc_area *scssc,
              dma64_t summary_indicator_addr, dma64_t subchannel_indicator_addr, u8 isc)
{
        memset(scssc, 0, sizeof(*scssc));
        scssc->request.length = 0x0fe0;
        scssc->request.code = 0x0021;
        scssc->operation_code = 0;

        scssc->summary_indicator_addr = summary_indicator_addr;
        scssc->subchannel_indicator_addr = subchannel_indicator_addr;

        scssc->ks = PAGE_DEFAULT_KEY >> 4;
        scssc->kc = PAGE_DEFAULT_KEY >> 4;
        scssc->isc = isc;
        scssc->schid = schid;

        /* enable the time delay disablement facility */
        if (css_general_characteristics.aif_tdd)
                scssc->word_with_d_bit = 0x10000000;

        if (chsc(scssc))
                return -EIO;

        return chsc_error_from_response(scssc->response.code);
}
EXPORT_SYMBOL_GPL(chsc_sadc);

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)
{
        struct channel_path *chp = chpid_to_chp(chpid);
        struct chp_link link;
        char dbf_txt[15];

        scnprintf(dbf_txt, sizeof(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();

        mutex_lock(&chp->lock);
        chp_update_desc(chp);
        mutex_unlock(&chp->lock);

        for_each_subchannel_staged(s390_subchannel_remove_chpid, NULL, &link);
}

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];

        scnprintf(dbf_txt, sizeof(dbf_txt), "accpr%x.%02x", link->chpid.cssid,
                  link->chpid.id);
        CIO_TRACE_EVENT( 2, dbf_txt);
        if (link->fla != 0) {
                scnprintf(dbf_txt, sizeof(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, NULL, link);
        css_schedule_reprobe();
}

static int process_fces_event(struct subchannel *sch, void *data)
{
        spin_lock_irq(&sch->lock);
        if (sch->driver && sch->driver->chp_event)
                sch->driver->chp_event(sch, data, CHP_FCES_EVENT);
        spin_unlock_irq(&sch->lock);
        return 0;
}

struct chsc_sei_nt0_area {
        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 reserved1;
        u32 reserved2;
        /* ccdf has to be big enough for a link-incident record */
        u8  ccdf[PAGE_SIZE - 24 - 16];  /* content-code dependent field */
} __packed;

struct chsc_sei_nt2_area {
        u8  flags;                      /* p and v bit */
        u8  reserved1;
        u8  reserved2;
        u8  cc;                         /* content code */
        u32 reserved3[13];
        u8  ccdf[PAGE_SIZE - 24 - 56];  /* content-code dependent field */
} __packed;

#define CHSC_SEI_NT0    (1ULL << 63)
#define CHSC_SEI_NT2    (1ULL << 61)

struct chsc_sei {
        struct chsc_header request;
        u32 reserved1;
        u64 ntsm;                       /* notification type mask */
        struct chsc_header response;
        u32 :24;
        u8 nt;
        union {
                struct chsc_sei_nt0_area nt0_area;
                struct chsc_sei_nt2_area nt2_area;
                u8 nt_area[PAGE_SIZE - 24];
        } u;
} __packed __aligned(PAGE_SIZE);

/*
 * Link Incident Record as defined in SA22-7202, "ESCON I/O Interface"
 */

#define LIR_IQ_CLASS_INFO               0
#define LIR_IQ_CLASS_DEGRADED           1
#define LIR_IQ_CLASS_NOT_OPERATIONAL    2

struct lir {
        struct {
                u32 null:1;
                u32 reserved:3;
                u32 class:2;
                u32 reserved2:2;
        } __packed iq;
        u32 ic:8;
        u32 reserved:16;
        struct node_descriptor incident_node;
        struct node_descriptor attached_node;
        u8 reserved2[32];
} __packed;

#define PARAMS_LEN      10      /* PARAMS=xx,xxxxxx */
#define NODEID_LEN      35      /* NODEID=tttttt/mdl,mmm.ppssssssssssss,xxxx */

/* Copy EBCDIC text, convert to ASCII and optionally add delimiter. */
static char *store_ebcdic(char *dest, const char *src, unsigned long len,
                          char delim)
{
        memcpy(dest, src, len);
        EBCASC(dest, len);

        if (delim)
                dest[len++] = delim;

        return dest + len;
}

static void chsc_link_from_sei(struct chp_link *link,
                                struct chsc_sei_nt0_area *sei_area)
{
        if ((sei_area->vf & SEI_VF_FLA) != 0) {
                link->fla       = sei_area->fla;
                link->fla_mask  = ((sei_area->vf & SEI_VF_FLA) == SEI_VF_FLA) ?
                                                        0xffff : 0xff00;
        }
}

/* Format node ID and parameters for output in LIR log message. */
static void format_node_data(char *params, char *id, struct node_descriptor *nd)
{
        memset(params, 0, PARAMS_LEN);
        memset(id, 0, NODEID_LEN);

        if (nd->validity != ND_VALIDITY_VALID) {
                strscpy(params, "n/a", PARAMS_LEN);
                strscpy(id, "n/a", NODEID_LEN);
                return;
        }

        /* PARAMS=xx,xxxxxx */
        snprintf(params, PARAMS_LEN, "%02x,%06x", nd->byte0, nd->params);
        /* NODEID=tttttt/mdl,mmm.ppssssssssssss,xxxx */
        id = store_ebcdic(id, nd->type, sizeof(nd->type), '/');
        id = store_ebcdic(id, nd->model, sizeof(nd->model), ',');
        id = store_ebcdic(id, nd->manufacturer, sizeof(nd->manufacturer), '.');
        id = store_ebcdic(id, nd->plant, sizeof(nd->plant), 0);
        id = store_ebcdic(id, nd->seq, sizeof(nd->seq), ',');
        sprintf(id, "%04X", nd->tag);
}

static void chsc_process_sei_link_incident(struct chsc_sei_nt0_area *sei_area)
{
        struct lir *lir = (struct lir *) &sei_area->ccdf;
        char iuparams[PARAMS_LEN], iunodeid[NODEID_LEN], auparams[PARAMS_LEN],
             aunodeid[NODEID_LEN];

        CIO_CRW_EVENT(4, "chsc: link incident (rs=%02x, rs_id=%04x, iq=%02x)\n",
                      sei_area->rs, sei_area->rsid, sei_area->ccdf[0]);

        /* Ignore NULL Link Incident Records. */
        if (lir->iq.null)
                return;

        /* Inform user that a link requires maintenance actions because it has
         * become degraded or not operational. Note that this log message is
         * the primary intention behind a Link Incident Record. */

        format_node_data(iuparams, iunodeid, &lir->incident_node);
        format_node_data(auparams, aunodeid, &lir->attached_node);

        switch (lir->iq.class) {
        case LIR_IQ_CLASS_DEGRADED:
                pr_warn("Link degraded: RS=%02x RSID=%04x IC=%02x "
                        "IUPARAMS=%s IUNODEID=%s AUPARAMS=%s AUNODEID=%s\n",
                        sei_area->rs, sei_area->rsid, lir->ic, iuparams,
                        iunodeid, auparams, aunodeid);
                break;
        case LIR_IQ_CLASS_NOT_OPERATIONAL:
                pr_err("Link stopped: RS=%02x RSID=%04x IC=%02x "
                       "IUPARAMS=%s IUNODEID=%s AUPARAMS=%s AUNODEID=%s\n",
                       sei_area->rs, sei_area->rsid, lir->ic, iuparams,
                       iunodeid, auparams, aunodeid);
                break;
        default:
                break;
        }
}

static void chsc_process_sei_res_acc(struct chsc_sei_nt0_area *sei_area)
{
        struct channel_path *chp;
        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)
                return;

        if (status < 0) {
                chp_new(chpid);
        } else {
                chp = chpid_to_chp(chpid);
                mutex_lock(&chp->lock);
                chp_update_desc(chp);
                mutex_unlock(&chp->lock);
        }
        memset(&link, 0, sizeof(struct chp_link));
        link.chpid = chpid;
        chsc_link_from_sei(&link, sei_area);
        s390_process_res_acc(&link);
}

static void chsc_process_sei_chp_avail(struct chsc_sei_nt0_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);
                chp_update_desc(chp);
                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_nt0_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_nt0_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_scm_avail(struct chsc_sei_nt0_area *sei_area)
{
        int ret;

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

        ret = scm_process_availability_information();
        if (ret)
                CIO_CRW_EVENT(0, "chsc: process availability information"
                              " failed (rc=%d).\n", ret);
}

static void chsc_process_sei_ap_cfg_chg(struct chsc_sei_nt0_area *sei_area)
{
        CIO_CRW_EVENT(3, "chsc: ap config changed\n");
        if (sei_area->rs != 5)
                return;

        blocking_notifier_call_chain(&chsc_notifiers,
                                     CHSC_NOTIFY_AP_CFG, NULL);
}

static void chsc_process_sei_fces_event(struct chsc_sei_nt0_area *sei_area)
{
        struct chp_link link;
        struct chp_id chpid;
        struct channel_path *chp;

        CIO_CRW_EVENT(4,
        "chsc: FCES status notification (rs=%02x, rs_id=%04x, FCES-status=%x)\n",
                sei_area->rs, sei_area->rsid, sei_area->ccdf[0]);

        if (sei_area->rs != SEI_RS_CHPID)
                return;
        chp_id_init(&chpid);
        chpid.id = sei_area->rsid;

        /* Ignore the event on unknown/invalid chp */
        chp = chpid_to_chp(chpid);
        if (!chp)
                return;

        memset(&link, 0, sizeof(struct chp_link));
        link.chpid = chpid;
        chsc_link_from_sei(&link, sei_area);

        for_each_subchannel_staged(process_fces_event, NULL, &link);
}

static void chsc_process_sei_nt2(struct chsc_sei_nt2_area *sei_area)
{
        switch (sei_area->cc) {
        case 1:
                zpci_event_error(sei_area->ccdf);
                break;
        case 2:
                zpci_event_availability(sei_area->ccdf);
                break;
        default:
                CIO_CRW_EVENT(2, "chsc: sei nt2 unhandled cc=%d\n",
                              sei_area->cc);
                break;
        }
}

static void chsc_process_sei_nt0(struct chsc_sei_nt0_area *sei_area)
{
        /* 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 3: /* ap config changed */
                chsc_process_sei_ap_cfg_chg(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;
        case 14: /* scm available notification */
                chsc_process_sei_scm_avail(sei_area);
                break;
        case 15: /* FCES event notification */
                chsc_process_sei_fces_event(sei_area);
                break;
        default: /* other stuff */
                CIO_CRW_EVENT(2, "chsc: sei nt0 unhandled cc=%d\n",
                              sei_area->cc);
                break;
        }

        /* 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();
        }
}

static void chsc_process_event_information(struct chsc_sei *sei, u64 ntsm)
{
        static int ntsm_unsupported;

        while (true) {
                memset(sei, 0, sizeof(*sei));
                sei->request.length = 0x0010;
                sei->request.code = 0x000e;
                if (!ntsm_unsupported)
                        sei->ntsm = ntsm;

                if (chsc(sei))
                        break;

                if (sei->response.code != 0x0001) {
                        CIO_CRW_EVENT(2, "chsc: sei failed (rc=%04x, ntsm=%llx)\n",
                                      sei->response.code, sei->ntsm);

                        if (sei->response.code == 3 && sei->ntsm) {
                                /* Fallback for old firmware. */
                                ntsm_unsupported = 1;
                                continue;
                        }
                        break;
                }

                CIO_CRW_EVENT(2, "chsc: sei successful (nt=%d)\n", sei->nt);
                switch (sei->nt) {
                case 0:
                        chsc_process_sei_nt0(&sei->u.nt0_area);
                        break;
                case 2:
                        chsc_process_sei_nt2(&sei->u.nt2_area);
                        break;
                default:
                        CIO_CRW_EVENT(2, "chsc: unhandled nt: %d\n", sei->nt);
                        break;
                }

                if (!(sei->u.nt0_area.flags & 0x80))
                        break;
        }
}

/*
 * Handle channel subsystem related CRWs.
 * Use store event information to find out what's going on.
 *
 * Note: Access to sei_page is serialized through machine check handler
 * thread, so no need for locking.
 */
static void chsc_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
{
        struct chsc_sei *sei = sei_page;

        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);

        CIO_TRACE_EVENT(2, "prcss");
        chsc_process_event_information(sei, CHSC_SEI_NT0 | CHSC_SEI_NT2);
}

void chsc_chp_online(struct chp_id chpid)
{
        struct channel_path *chp = chpid_to_chp(chpid);
        struct chp_link link;
        char dbf_txt[15];

        scnprintf(dbf_txt, sizeof(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();

                mutex_lock(&chp->lock);
                chp_update_desc(chp);
                mutex_unlock(&chp->lock);

                for_each_subchannel_staged(__s390_process_res_acc, NULL,
                                           &link);
                css_schedule_reprobe();
        }
}

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;
}

/**
 * chsc_chp_vary - propagate channel-path vary operation to subchannels
 * @chpid: channl-path ID
 * @on: non-zero for vary online, zero for vary offline
 */
int chsc_chp_vary(struct chp_id chpid, int on)
{
        struct channel_path *chp = chpid_to_chp(chpid);

        /*
         * Redo PathVerification on the devices the chpid connects to
         */
        if (on) {
                /* Try to update the channel path description. */
                chp_update_desc(chp);
                for_each_subchannel_staged(s390_subchannel_vary_chpid_on,
                                           NULL, &chpid);
                css_schedule_reprobe();
        } 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:
        while (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 : 1;
                u32 e : 1;
                u32 : 28;
                u32 key : 4;
                u32 : 28;
                dma64_t cub[CSS_NUM_CUB_PAGES];
                dma64_t ecub[CSS_NUM_ECUB_PAGES];
                u32 reserved[5];
                struct chsc_header response;
                u32 status : 8;
                u32 : 4;
                u32 fmt : 4;
                u32 : 16;
        } __packed *secm_area;
        unsigned long flags;
        int ret, ccode, i;

        spin_lock_irqsave(&chsc_page_lock, flags);
        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->e = 1;

        for (i = 0; i < CSS_NUM_CUB_PAGES; i++)
                secm_area->cub[i] = (__force dma64_t)virt_to_dma32(css->cub[i]);
        for (i = 0; i < CSS_NUM_ECUB_PAGES; i++)
                secm_area->ecub[i] = virt_to_dma64(css->ecub[i]);

        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_irqrestore(&chsc_page_lock, flags);
        return ret;
}

static int cub_alloc(struct channel_subsystem *css)
{
        int i;

        for (i = 0; i < CSS_NUM_CUB_PAGES; i++) {
                css->cub[i] = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
                if (!css->cub[i])
                        return -ENOMEM;
        }
        for (i = 0; i < CSS_NUM_ECUB_PAGES; i++) {
                css->ecub[i] = (void *)get_zeroed_page(GFP_KERNEL);
                if (!css->ecub[i])
                        return -ENOMEM;
        }

        return 0;
}

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

        for (i = 0; i < CSS_NUM_CUB_PAGES; i++) {
                free_page((unsigned long)css->cub[i]);
                css->cub[i] = NULL;
        }
        for (i = 0; i < CSS_NUM_ECUB_PAGES; i++) {
                free_page((unsigned long)css->ecub[i]);
                css->ecub[i] = NULL;
        }
}

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

        if (enable && !css->cm_enabled) {
                ret = cub_alloc(css);
                if (ret)
                        goto out;
        }
        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);
        }

out:
        if (!css->cm_enabled)
                cub_free(css);

        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 || rfmt == 0) && c == 1 &&
            !css_general_characteristics.fcs)
                return -EINVAL;
        if ((rfmt == 2) && !css_general_characteristics.cib)
                return -EINVAL;
        if ((rfmt == 3) && !css_general_characteristics.util_str)
                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);

#define chsc_det_chp_desc(FMT, c)                                       \
int chsc_determine_fmt##FMT##_channel_path_desc(                        \
        struct chp_id chpid, struct channel_path_desc_fmt##FMT *desc)   \
{                                                                       \
        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, FMT, c, 0,     \
                                               scpd_area);              \
        if (ret)                                                        \
                goto out;                                               \
                                                                        \
        memcpy(desc, scpd_area->data, sizeof(*desc));                   \
out:                                                                    \
        spin_unlock_irqrestore(&chsc_page_lock, flags);                 \
        return ret;                                                     \
}

chsc_det_chp_desc(0, 0)
chsc_det_chp_desc(1, 1)
chsc_det_chp_desc(3, 0)

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

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

static unsigned long scmc_get_speed(u32 s, u32 p)
{
        unsigned long speed = s;

        if (!p)
                p = 8;
        while (p--)
                speed *= 10;

        return speed;
}

int chsc_get_channel_measurement_chars(struct channel_path *chp)
{
        unsigned long flags;
        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;
                struct cmg_cmcb cmcb;
        } *scmc_area;

        chp->shared = -1;
        chp->cmg = -1;
        chp->extended = 0;
        chp->speed = 0;

        if (!css_chsc_characteristics.scmc || !css_chsc_characteristics.secm)
                return -EINVAL;

        spin_lock_irqsave(&chsc_page_lock, flags);
        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;
        }
        chp->cmcb = scmc_area->cmcb;
        if (scmc_area->cmcb.not_valid)
                goto out;

        chp->cmg = scmc_area->cmcb.cmg;
        chp->shared = scmc_area->cmcb.shared;
        chp->extended = scmc_area->cmcb.extended;
        chp->speed = scmc_get_speed(scmc_area->cmcb.cmgs, scmc_area->cmcb.cmgp);
        chsc_initialize_cmg_chars(chp, scmc_area->cmcb.cmcv,
                                  (struct cmg_chars *)&scmc_area->cmcb.data);
out:
        spin_unlock_irqrestore(&chsc_page_lock, flags);
        return ret;
}

int __init chsc_init(void)
{
        int ret;

        sei_page = (void *)get_zeroed_page(GFP_KERNEL);
        chsc_page = (void *)get_zeroed_page(GFP_KERNEL);
        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(struct chsc_sda_area *sda_area, int operation_code)
{
        int ret;

        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);
        }
out:
        return ret;
}

int chsc_enable_facility(int operation_code)
{
        struct chsc_sda_area *sda_area;
        unsigned long flags;
        int ret;

        spin_lock_irqsave(&chsc_page_lock, flags);
        memset(chsc_page, 0, PAGE_SIZE);
        sda_area = chsc_page;

        ret = __chsc_enable_facility(sda_area, operation_code);
        if (ret != 0)
                CIO_CRW_EVENT(2, "chsc: sda (oc=%x) failed (rc=%04x)\n",
                              operation_code, sda_area->response.code);

        spin_unlock_irqrestore(&chsc_page_lock, flags);
        return ret;
}

int __init chsc_get_cssid_iid(int idx, u8 *cssid, u8 *iid)
{
        struct {
                struct chsc_header request;
                u8 atype;
                u32 : 24;
                u32 reserved1[6];
                struct chsc_header response;
                u32 reserved2[3];
                struct {
                        u8 cssid;
                        u8 iid;
                        u32 : 16;
                } list[];
        } *sdcal_area;
        int ret;

        spin_lock_irq(&chsc_page_lock);
        memset(chsc_page, 0, PAGE_SIZE);
        sdcal_area = chsc_page;
        sdcal_area->request.length = 0x0020;
        sdcal_area->request.code = 0x0034;
        sdcal_area->atype = 4;

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

        ret = chsc_error_from_response(sdcal_area->response.code);
        if (ret) {
                CIO_CRW_EVENT(2, "chsc: sdcal failed (rc=%04x)\n",
                              sdcal_area->response.code);
                goto exit;
        }

        if ((addr_t) &sdcal_area->list[idx] <
            (addr_t) &sdcal_area->response + sdcal_area->response.length) {
                *cssid = sdcal_area->list[idx].cssid;
                *iid = sdcal_area->list[idx].iid;
        }
        else
                ret = -ENODEV;
exit:
        spin_unlock_irq(&chsc_page_lock);
        return ret;
}

struct css_general_char css_general_characteristics;
struct css_chsc_char css_chsc_characteristics;

int __init
chsc_determine_css_characteristics(void)
{
        unsigned long flags;
        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];
        } *scsc_area;

        spin_lock_irqsave(&chsc_page_lock, flags);
        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_irqrestore(&chsc_page_lock, flags);
        return result;
}

EXPORT_SYMBOL_GPL(css_general_characteristics);
EXPORT_SYMBOL_GPL(css_chsc_characteristics);

int chsc_sstpc(void *page, unsigned int op, u16 ctrl, long *clock_delta)
{
        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[3];
                s64 clock_delta;
                unsigned int rsvd4[2];
        } *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;
        if (clock_delta)
                *clock_delta = rr->clock_delta;
        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[];
        } *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_stzi(void *page, void *result, size_t size)
{
        struct {
                struct chsc_header request;
                unsigned int rsvd0[3];
                struct chsc_header response;
                char data[];
        } *rr;
        int rc;

        memset(page, 0, PAGE_SIZE);
        rr = page;
        rr->request.length = 0x0010;
        rr->request.code = 0x003e;
        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];
        } *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);

/**
 * chsc_scm_info() - store SCM information (SSI)
 * @scm_area: request and response block for SSI
 * @token: continuation token
 *
 * Returns 0 on success.
 */
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);

/**
 * chsc_pnso() - Perform Network-Subchannel Operation
 * @schid:              id of the subchannel on which PNSO is performed
 * @pnso_area:          request and response block for the operation
 * @oc:                 Operation Code
 * @resume_token:       resume token for multiblock response
 * @cnc:                Boolean change-notification control
 *
 * pnso_area must be allocated by the caller with get_zeroed_page(GFP_KERNEL)
 *
 * Returns 0 on success.
 */
int chsc_pnso(struct subchannel_id schid, struct chsc_pnso_area *pnso_area,
              u8 oc, struct chsc_pnso_resume_token resume_token, int cnc)
{
        memset(pnso_area, 0, sizeof(*pnso_area));
        pnso_area->request.length = 0x0030;
        pnso_area->request.code = 0x003d; /* network-subchannel operation */
        pnso_area->m       = schid.m;
        pnso_area->ssid  = schid.ssid;
        pnso_area->sch   = schid.sch_no;
        pnso_area->cssid = schid.cssid;
        pnso_area->oc    = oc;
        pnso_area->resume_token = resume_token;
        pnso_area->n       = (cnc != 0);
        if (chsc(pnso_area))
                return -EIO;
        return chsc_error_from_response(pnso_area->response.code);
}

int chsc_sgib(u32 origin)
{
        struct {
                struct chsc_header request;
                u16 op;
                u8  reserved01[2];
                u8  reserved02:4;
                u8  fmt:4;
                u8  reserved03[7];
                /* operation data area begin */
                u8  reserved04[4];
                u32 gib_origin;
                u8  reserved05[10];
                u8  aix;
                u8  reserved06[4029];
                struct chsc_header response;
                u8  reserved07[4];
        } *sgib_area;
        int ret;

        spin_lock_irq(&chsc_page_lock);
        memset(chsc_page, 0, PAGE_SIZE);
        sgib_area = chsc_page;
        sgib_area->request.length = 0x0fe0;
        sgib_area->request.code = 0x0021;
        sgib_area->op = 0x1;
        sgib_area->gib_origin = origin;

        ret = chsc(sgib_area);
        if (ret == 0)
                ret = chsc_error_from_response(sgib_area->response.code);
        spin_unlock_irq(&chsc_page_lock);

        return ret;
}
EXPORT_SYMBOL_GPL(chsc_sgib);

#define SCUD_REQ_LEN    0x10 /* SCUD request block length */
#define SCUD_REQ_CMD    0x4b /* SCUD Command Code */

struct chse_cudb {
        u16 flags:8;
        u16 chp_valid:8;
        u16 cu;
        u32 esm_valid:8;
        u32:24;
        u8 chpid[8];
        u32:32;
        u32:32;
        u8 esm[8];
        u32 efla[8];
} __packed;

struct chsc_scud {
        struct chsc_header request;
        u16:4;
        u16 fmt:4;
        u16 cssid:8;
        u16 first_cu;
        u16:16;
        u16 last_cu;
        u32:32;
        struct chsc_header response;
        u16:4;
        u16 fmt_resp:4;
        u32:24;
        struct chse_cudb cudb[];
} __packed;

/**
 * chsc_scud() - Store control-unit description.
 * @cu:         number of the control-unit
 * @esm:        8 1-byte endpoint security mode values
 * @esm_valid:  validity mask for @esm
 *
 * Interface to retrieve information about the endpoint security
 * modes for up to 8 paths of a control unit.
 *
 * Returns 0 on success.
 */
int chsc_scud(u16 cu, u64 *esm, u8 *esm_valid)
{
        struct chsc_scud *scud = chsc_page;
        int ret;

        spin_lock_irq(&chsc_page_lock);
        memset(chsc_page, 0, PAGE_SIZE);
        scud->request.length = SCUD_REQ_LEN;
        scud->request.code = SCUD_REQ_CMD;
        scud->fmt = 0;
        scud->cssid = 0;
        scud->first_cu = cu;
        scud->last_cu = cu;

        ret = chsc(scud);
        if (!ret)
                ret = chsc_error_from_response(scud->response.code);

        if (!ret && (scud->response.length <= 8 || scud->fmt_resp != 0
                        || !(scud->cudb[0].flags & 0x80)
                        || scud->cudb[0].cu != cu)) {

                CIO_MSG_EVENT(2, "chsc: scud failed rc=%04x, L2=%04x "
                        "FMT=%04x, cudb.flags=%02x, cudb.cu=%04x",
                        scud->response.code, scud->response.length,
                        scud->fmt_resp, scud->cudb[0].flags, scud->cudb[0].cu);
                ret = -EINVAL;
        }

        if (ret)
                goto out;

        memcpy(esm, scud->cudb[0].esm, sizeof(*esm));
        *esm_valid = scud->cudb[0].esm_valid;
out:
        spin_unlock_irq(&chsc_page_lock);
        return ret;
}
EXPORT_SYMBOL_GPL(chsc_scud);