/*
 *  drivers/s390/cio/chsc.c
 *   S/390 common I/O routines -- channel subsystem call
 *
 *    Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
 *                            IBM Corporation
 *    Author(s): Ingo Adlung (adlung@de.ibm.com)
 *               Cornelia Huck (cornelia.huck@de.ibm.com)
 *               Arnd Bergmann (arndb@de.ibm.com)
 */

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

static void *sei_page;

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;
        }
        if (ssd_area->response.code != 0x0001) {
                CIO_MSG_EVENT(2, "chsc: ssd failed for 0.%x.%04x (rc=%04x)\n",
                              schid.ssid, schid.sch_no,
                              ssd_area->response.code);
                ret = -EIO;
                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 != 0) && (ssd_area->st != 2))
                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 check_for_io_on_path(struct subchannel *sch, int mask)
{
        int cc;

        cc = stsch(sch->schid, &sch->schib);
        if (cc)
                return 0;
        if (sch->schib.scsw.actl && sch->schib.pmcw.lpum == mask)
                return 1;
        return 0;
}

static void terminate_internal_io(struct subchannel *sch)
{
        if (cio_clear(sch)) {
                /* Recheck device in case clear failed. */
                sch->lpm = 0;
                if (device_trigger_verify(sch) != 0)
                        css_schedule_eval(sch->schid);
                return;
        }
        /* Request retry of internal operation. */
        device_set_intretry(sch);
        /* Call handler. */
        if (sch->driver && sch->driver->termination)
                sch->driver->termination(&sch->dev);
}

static int
s390_subchannel_remove_chpid(struct device *dev, void *data)
{
        int j;
        int mask;
        struct subchannel *sch;
        struct chp_id *chpid;
        struct schib schib;

        sch = to_subchannel(dev);
        chpid = data;
        for (j = 0; j < 8; j++) {
                mask = 0x80 >> j;
                if ((sch->schib.pmcw.pim & mask) &&
                    (sch->schib.pmcw.chpid[j] == chpid->id))
                        break;
        }
        if (j >= 8)
                return 0;

        spin_lock_irq(sch->lock);

        stsch(sch->schid, &schib);
        if (!schib.pmcw.dnv)
                goto out_unreg;
        memcpy(&sch->schib, &schib, sizeof(struct schib));
        /* Check for single path devices. */
        if (sch->schib.pmcw.pim == 0x80)
                goto out_unreg;

        if (check_for_io_on_path(sch, mask)) {
                if (device_is_online(sch))
                        device_kill_io(sch);
                else {
                        terminate_internal_io(sch);
                        /* Re-start path verification. */
                        if (sch->driver && sch->driver->verify)
                                sch->driver->verify(&sch->dev);
                }
        } else {
                /* trigger path verification. */
                if (sch->driver && sch->driver->verify)
                        sch->driver->verify(&sch->dev);
                else if (sch->lpm == mask)
                        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];

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

        if (chp_get_status(chpid) <= 0)
                return;
        bus_for_each_dev(&css_bus_type, NULL, &chpid,
                         s390_subchannel_remove_chpid);
}

static int
s390_process_res_acc_new_sch(struct subchannel_id schid)
{
        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;
}

struct res_acc_data {
        struct chp_id chpid;
        u32 fla_mask;
        u16 fla;
};

static int get_res_chpid_mask(struct chsc_ssd_info *ssd,
                              struct res_acc_data *data)
{
        int i;
        int mask;

        for (i = 0; i < 8; i++) {
                mask = 0x80 >> i;
                if (!(ssd->path_mask & mask))
                        continue;
                if (!chp_id_is_equal(&ssd->chpid[i], &data->chpid))
                        continue;
                if ((ssd->fla_valid_mask & mask) &&
                    ((ssd->fla[i] & data->fla_mask) != data->fla))
                        continue;
                return mask;
        }
        return 0;
}

static int
__s390_process_res_acc(struct subchannel_id schid, void *data)
{
        int chp_mask, old_lpm;
        struct res_acc_data *res_data;
        struct subchannel *sch;

        res_data = data;
        sch = get_subchannel_by_schid(schid);
        if (!sch)
                /* Check if a subchannel is newly available. */
                return s390_process_res_acc_new_sch(schid);

        spin_lock_irq(sch->lock);
        chp_mask = get_res_chpid_mask(&sch->ssd_info, res_data);
        if (chp_mask == 0)
                goto out;
        if (stsch(sch->schid, &sch->schib))
                goto out;
        old_lpm = sch->lpm;
        sch->lpm = ((sch->schib.pmcw.pim &
                     sch->schib.pmcw.pam &
                     sch->schib.pmcw.pom)
                    | chp_mask) & sch->opm;
        if (!old_lpm && sch->lpm)
                device_trigger_reprobe(sch);
        else if (sch->driver && sch->driver->verify)
                sch->driver->verify(&sch->dev);
out:
        spin_unlock_irq(sch->lock);
        put_device(&sch->dev);
        return 0;
}

static void s390_process_res_acc (struct res_acc_data *res_data)
{
        char dbf_txt[15];

        sprintf(dbf_txt, "accpr%x.%02x", res_data->chpid.cssid,
                res_data->chpid.id);
        CIO_TRACE_EVENT( 2, dbf_txt);
        if (res_data->fla != 0) {
                sprintf(dbf_txt, "fla%x", res_data->fla);
                CIO_TRACE_EVENT( 2, dbf_txt);
        }

        /*
         * 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(__s390_process_res_acc, res_data);
}

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 res_acc_data res_data;
        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(&res_data, 0, sizeof(struct res_acc_data));
        res_data.chpid = chpid;
        if ((sei_area->vf & 0xc0) != 0) {
                res_data.fla = sei_area->fla;
                if ((sei_area->vf & 0xc0) == 0xc0)
                        /* full link address */
                        res_data.fla_mask = 0xffff;
                else
                        /* link address */
                        res_data.fla_mask = 0xff00;
        }
        s390_process_res_acc(&res_data);
}

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;

        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;
                printk(KERN_WARNING "cio: processing configure event %d for "
                       "chpid %x.%02x\n", 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;
        }
}

void chsc_process_crw(void)
{
        struct chsc_sei_area *sei_area;

        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);
}

static int
__chp_add_new_sch(struct subchannel_id schid)
{
        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;
}


static int
__chp_add(struct subchannel_id schid, void *data)
{
        int i, mask;
        struct chp_id *chpid;
        struct subchannel *sch;

        chpid = data;
        sch = get_subchannel_by_schid(schid);
        if (!sch)
                /* Check if the subchannel is now available. */
                return __chp_add_new_sch(schid);
        spin_lock_irq(sch->lock);
        for (i=0; i<8; i++) {
                mask = 0x80 >> i;
                if ((sch->schib.pmcw.pim & mask) &&
                    (sch->schib.pmcw.chpid[i] == chpid->id)) {
                        if (stsch(sch->schid, &sch->schib) != 0) {
                                /* Endgame. */
                                spin_unlock_irq(sch->lock);
                                return -ENXIO;
                        }
                        break;
                }
        }
        if (i==8) {
                spin_unlock_irq(sch->lock);
                return 0;
        }
        sch->lpm = ((sch->schib.pmcw.pim &
                     sch->schib.pmcw.pam &
                     sch->schib.pmcw.pom)
                    | mask) & sch->opm;

        if (sch->driver && sch->driver->verify)
                sch->driver->verify(&sch->dev);

        spin_unlock_irq(sch->lock);
        put_device(&sch->dev);
        return 0;
}

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

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

        if (chp_get_status(chpid) != 0)
                for_each_subchannel(__chp_add, &chpid);
}

static void __s390_subchannel_vary_chpid(struct subchannel *sch,
                                         struct chp_id chpid, int on)
{
        int chp, old_lpm;
        int mask;
        unsigned long flags;

        spin_lock_irqsave(sch->lock, flags);
        old_lpm = sch->lpm;
        for (chp = 0; chp < 8; chp++) {
                mask = 0x80 >> chp;
                if (!(sch->ssd_info.path_mask & mask))
                        continue;
                if (!chp_id_is_equal(&sch->ssd_info.chpid[chp], &chpid))
                        continue;

                if (on) {
                        sch->opm |= mask;
                        sch->lpm |= mask;
                        if (!old_lpm)
                                device_trigger_reprobe(sch);
                        else if (sch->driver && sch->driver->verify)
                                sch->driver->verify(&sch->dev);
                        break;
                }
                sch->opm &= ~mask;
                sch->lpm &= ~mask;
                if (check_for_io_on_path(sch, mask)) {
                        if (device_is_online(sch))
                                /* Path verification is done after killing. */
                                device_kill_io(sch);
                        else {
                                /* Kill and retry internal I/O. */
                                terminate_internal_io(sch);
                                /* Re-start path verification. */
                                if (sch->driver && sch->driver->verify)
                                        sch->driver->verify(&sch->dev);
                        }
                } else if (!sch->lpm) {
                        if (device_trigger_verify(sch) != 0)
                                css_schedule_eval(sch->schid);
                } else if (sch->driver && sch->driver->verify)
                        sch->driver->verify(&sch->dev);
                break;
        }
        spin_unlock_irqrestore(sch->lock, flags);
}

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

        sch = to_subchannel(dev);
        chpid = data;

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

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

        sch = to_subchannel(dev);
        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;
        struct subchannel *sch;

        sch = get_subchannel_by_schid(schid);
        if (sch) {
                put_device(&sch->dev);
                return 0;
        }
        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)
{
        /*
         * Redo PathVerification on the devices the chpid connects to
         */

        bus_for_each_dev(&css_bus_type, NULL, &chpid, on ?
                         s390_subchannel_vary_chpid_on :
                         s390_subchannel_vary_chpid_off);
        if (on)
                /* Scan for new devices on varied on path. */
                for_each_subchannel(__s390_vary_chpid_on, NULL);
        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;
}

static 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 0x0001: /* Success. */
                ret = 0;
                break;
        case 0x0003: /* Invalid block. */
        case 0x0007: /* Invalid format. */
        case 0x0008: /* Other invalid block. */
                CIO_CRW_EVENT(2, "Error in chsc request block!\n");
                ret = -EINVAL;
                break;
        case 0x0004: /* Command not provided in model. */
                CIO_CRW_EVENT(2, "Model does not provide secm\n");
                ret = -EOPNOTSUPP;
                break;
        case 0x0102: /* cub adresses incorrect */
                CIO_CRW_EVENT(2, "Invalid addresses in chsc request block\n");
                ret = -EINVAL;
                break;
        case 0x0103: /* key error */
                CIO_CRW_EVENT(2, "Access key error in secm\n");
                ret = -EINVAL;
                break;
        case 0x0105: /* error while starting */
                CIO_CRW_EVENT(2, "Error while starting channel measurement\n");
                ret = -EIO;
                break;
        default:
                CIO_CRW_EVENT(2, "Unknown CHSC response %d\n",
                              secm_area->response.code);
                ret = -EIO;
        }
        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;

        mutex_lock(&css->mutex);
        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);
                        mutex_unlock(&css->mutex);
                        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);
        }
        mutex_unlock(&css->mutex);
        free_page((unsigned long)secm_area);
        return ret;
}

int chsc_determine_channel_path_description(struct chp_id chpid,
                                            struct channel_path_desc *desc)
{
        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 channel_path_desc desc;
        } __attribute__ ((packed)) *scpd_area;

        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->first_chpid = chpid.id;
        scpd_area->last_chpid = chpid.id;

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

        switch (scpd_area->response.code) {
        case 0x0001: /* Success. */
                memcpy(desc, &scpd_area->desc,
                       sizeof(struct channel_path_desc));
                ret = 0;
                break;
        case 0x0003: /* Invalid block. */
        case 0x0007: /* Invalid format. */
        case 0x0008: /* Other invalid block. */
                CIO_CRW_EVENT(2, "Error in chsc request block!\n");
                ret = -EINVAL;
                break;
        case 0x0004: /* Command not provided in model. */
                CIO_CRW_EVENT(2, "Model does not provide scpd\n");
                ret = -EOPNOTSUPP;
                break;
        default:
                CIO_CRW_EVENT(2, "Unknown CHSC response %d\n",
                              scpd_area->response.code);
                ret = -EIO;
        }
out:
        free_page((unsigned long)scpd_area);
        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;
        }

        switch (scmc_area->response.code) {
        case 0x0001: /* 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;
                }
                ret = 0;
                break;
        case 0x0003: /* Invalid block. */
        case 0x0007: /* Invalid format. */
        case 0x0008: /* Invalid bit combination. */
                CIO_CRW_EVENT(2, "Error in chsc request block!\n");
                ret = -EINVAL;
                break;
        case 0x0004: /* Command not provided. */
                CIO_CRW_EVENT(2, "Model does not provide scmc\n");
                ret = -EOPNOTSUPP;
                break;
        default:
                CIO_CRW_EVENT(2, "Unknown CHSC response %d\n",
                              scmc_area->response.code);
                ret = -EIO;
        }
out:
        free_page((unsigned long)scmc_area);
        return ret;
}

int __init chsc_alloc_sei_area(void)
{
        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 (sei_page ? 0 : -ENOMEM);
}

void __init chsc_free_sei_area(void)
{
        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 0x0001: /* everything ok */
                ret = 0;
                break;
        case 0x0003: /* invalid request block */
        case 0x0007:
                ret = -EINVAL;
                break;
        case 0x0004: /* command not provided */
        case 0x0101: /* facility not provided */
                ret = -EOPNOTSUPP;
                break;
        default: /* something went wrong */
                ret = -EIO;
        }
 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) {
                CIO_MSG_EVENT(0, "Was not able to determine available"
                              "CHSCs due to no memory.\n");
                return -ENOMEM;
        }

        scsc_area->request.length = 0x0010;
        scsc_area->request.code = 0x0010;

        result = chsc(scsc_area);
        if (result) {
                CIO_MSG_EVENT(0, "Was not able to determine available CHSCs, "
                              "cc=%i.\n", result);
                result = -EIO;
                goto exit;
        }

        if (scsc_area->response.code != 1) {
                CIO_MSG_EVENT(0, "Was not able to determine "
                              "available CHSCs.\n");
                result = -EIO;
                goto exit;
        }
        memcpy(&css_general_characteristics, scsc_area->general_char,
               sizeof(css_general_characteristics));
        memcpy(&css_chsc_characteristics, scsc_area->chsc_char,
               sizeof(css_chsc_characteristics));
exit:
        free_page ((unsigned long) scsc_area);
        return result;
}

EXPORT_SYMBOL_GPL(css_general_characteristics);
EXPORT_SYMBOL_GPL(css_chsc_characteristics);