/*
 *  drivers/s390/cio/chsc.c
 *   S/390 common I/O routines -- channel subsystem call
 *
 *    Copyright IBM Corp. 1999,2008
 *    Author(s): Ingo Adlung (adlung@de.ibm.com)
 *               Cornelia Huck (cornelia.huck@de.ibm.com)
 *               Arnd Bergmann (arndb@de.ibm.com)
 */

#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;

/**
 * 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:
                return -EINVAL;
        case 0x0004:
                return -EOPNOTSUPP;
        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)
{
        unsigned long page;
        struct chsc_ssd_area *ssd_area;
        int ccode;
        int ret;
        int i;
        int mask;

        page = get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!page)
                return -ENOMEM;
        ssd_area = (struct chsc_ssd_area *) 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_free;
        }
        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_free;
        }
        if (!ssd_area->sch_valid) {
                ret = -ENODEV;
                goto out_free;
        }
        /* 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_free;
        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_free:
        free_page(page);
        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);
}

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(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 accessibiliy */
                chsc_process_sei_res_acc(sei_area);
                break;
        case 8: /* channel-path-configuration notification */
                chsc_process_sei_chp_config(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;
}

/**
 * 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 chp_link link;

        memset(&link, 0, sizeof(struct chp_link));
        link.chpid = chpid;
        /* Wait until previous actions have settled. */
        css_wait_for_slow_path();
        /*
         * Redo PathVerification on the devices the chpid connects to
         */

        if (on)
                for_each_subchannel_staged(s390_subchannel_vary_chpid_on,
                                           __s390_vary_chpid_on, &link);
        else
                for_each_subchannel_staged(s390_subchannel_vary_chpid_off,
                                           NULL, &link);

        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, void *page)
{
        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;

        secm_area = page;
        secm_area->request.length = 0x0050;
        secm_area->request.code = 0x0016;

        secm_area->key = PAGE_DEFAULT_KEY;
        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)
                return (ccode == 3) ? -ENODEV : -EBUSY;

        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);
        return ret;
}

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

        secm_area = (void *)get_zeroed_page(GFP_KERNEL |  GFP_DMA);
        if (!secm_area)
                return -ENOMEM;

        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);
                        free_page((unsigned long)secm_area);
                        return -ENOMEM;
                }
        }
        ret = __chsc_do_secm(css, enable, secm_area);
        if (!ret) {
                css->cm_enabled = enable;
                if (css->cm_enabled) {
                        ret = chsc_add_cmg_attr(css);
                        if (ret) {
                                memset(secm_area, 0, PAGE_SIZE);
                                __chsc_do_secm(css, 0, secm_area);
                                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);
        }
        free_page((unsigned long)secm_area);
        return ret;
}

int chsc_determine_channel_path_desc(struct chp_id chpid, int fmt, int rfmt,
                                     int c, int m,
                                     struct chsc_response_struct *resp)
{
        int ccode, ret;

        struct {
                struct chsc_header request;
                u32 : 2;
                u32 m : 1;
                u32 c : 1;
                u32 fmt : 4;
                u32 cssid : 8;
                u32 : 4;
                u32 rfmt : 4;
                u32 first_chpid : 8;
                u32 : 24;
                u32 last_chpid : 8;
                u32 zeroes1;
                struct chsc_header response;
                u8 data[PAGE_SIZE - 20];
        } __attribute__ ((packed)) *scpd_area;

        if ((rfmt == 1) && !css_general_characteristics.fcs)
                return -EINVAL;
        if ((rfmt == 2) && !css_general_characteristics.cib)
                return -EINVAL;
        scpd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!scpd_area)
                return -ENOMEM;

        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) {
                ret = (ccode == 3) ? -ENODEV : -EBUSY;
                goto out;
        }

        ret = chsc_error_from_response(scpd_area->response.code);
        if (ret == 0)
                /* Success. */
                memcpy(resp, &scpd_area->response, scpd_area->response.length);
        else
                CIO_CRW_EVENT(2, "chsc: scpd failed (rc=%04x)\n",
                              scpd_area->response.code);
out:
        free_page((unsigned long)scpd_area);
        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;
        int ret;

        chsc_resp = kzalloc(sizeof(*chsc_resp), GFP_KERNEL);
        if (!chsc_resp)
                return -ENOMEM;
        ret = chsc_determine_channel_path_desc(chpid, 0, 0, 0, 0, chsc_resp);
        if (ret)
                goto out_free;
        memcpy(desc, &chsc_resp->data, chsc_resp->length);
out_free:
        kfree(chsc_resp);
        return ret;
}

static void
chsc_initialize_cmg_chars(struct channel_path *chp, u8 cmcv,
                          struct cmg_chars *chars)
{
        switch (chp->cmg) {
        case 2:
        case 3:
                chp->cmg_chars = kmalloc(sizeof(struct cmg_chars),
                                         GFP_KERNEL);
                if (chp->cmg_chars) {
                        int i, mask;
                        struct cmg_chars *cmg_chars;

                        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;
                        }
                }
                break;
        default:
                /* No cmg-dependent data. */
                break;
        }
}

int chsc_get_channel_measurement_chars(struct channel_path *chp)
{
        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;

        scmc_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!scmc_area)
                return -ENOMEM;

        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 == 0) {
                /* Success. */
                if (!scmc_area->not_valid) {
                        chp->cmg = scmc_area->cmg;
                        chp->shared = scmc_area->shared;
                        chsc_initialize_cmg_chars(chp, scmc_area->cmcv,
                                                  (struct cmg_chars *)
                                                  &scmc_area->data);
                } else {
                        chp->cmg = -1;
                        chp->shared = -1;
                }
        } else {
                CIO_CRW_EVENT(2, "chsc: scmc failed (rc=%04x)\n",
                              scmc_area->response.code);
        }
out:
        free_page((unsigned long)scmc_area);
        return ret;
}

int __init chsc_alloc_sei_area(void)
{
        int ret;

        sei_page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!sei_page) {
                CIO_MSG_EVENT(0, "Can't allocate page for processing of "
                              "chsc machine checks!\n");
                return -ENOMEM;
        }
        ret = crw_register_handler(CRW_RSC_CSS, chsc_process_crw);
        if (ret)
                kfree(sei_page);
        return ret;
}

void __init chsc_free_sei_area(void)
{
        crw_unregister_handler(CRW_RSC_CSS);
        kfree(sei_page);
}

int __init
chsc_enable_facility(int operation_code)
{
        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;

        sda_area = (void *)get_zeroed_page(GFP_KERNEL|GFP_DMA);
        if (!sda_area)
                return -ENOMEM;
        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:
        free_page((unsigned long)sda_area);
        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[518];
        } __attribute__ ((packed)) *scsc_area;

        scsc_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!scsc_area)
                return -ENOMEM;

        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:
        free_page ((unsigned long) scsc_area);
        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;
}