[S390] cio: Introduce struct chp_id.

[linux-2.6/mini2440.git] / drivers / s390 / cio / chsc.c

/*
 *  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 "css.h"
#include "cio.h"
#include "cio_debug.h"
#include "ioasm.h"
#include "chpid.h"
#include "chsc.h"

static void *sei_page;

static int new_channel_path(struct chp_id chpid);

static inline struct channel_path *chpid_to_chp(struct chp_id chpid)
{
        return css[chpid.cssid]->chps[chpid.id];
}

static void set_chp_logically_online(struct chp_id chpid, int onoff)
{
        chpid_to_chp(chpid)->state = onoff;
}

static int get_chp_status(struct chp_id chpid)
{
        return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
}

void chsc_validate_chpids(struct subchannel *sch)
{
        int mask, chp;
        struct chp_id chpid;

        chp_id_init(&chpid);
        for (chp = 0; chp <= 7; chp++) {
                mask = 0x80 >> chp;
                chpid.id = sch->schib.pmcw.chpid[chp];
                if (!get_chp_status(chpid))
                        /* disable using this path */
                        sch->opm &= ~mask;
        }
}

void chpid_is_actually_online(struct chp_id chpid)
{
        int state;

        state = get_chp_status(chpid);
        if (state < 0) {
                need_rescan = 1;
                queue_work(slow_path_wq, &slow_path_work);
        } else
                WARN_ON(!state);
}

/* FIXME: this is _always_ called for every subchannel. shouldn't we
 *        process more than one at a time? */
static int
chsc_get_sch_desc_irq(struct subchannel *sch, void *page)
{
        int ccode, j;

        struct {
                struct chsc_header request;
                u16 reserved1a:10;
                u16 ssid:2;
                u16 reserved1b:4;
                u16 f_sch;        /* first subchannel */
                u16 reserved2;
                u16 l_sch;        /* last subchannel */
                u32 reserved3;
                struct chsc_header response;
                u32 reserved4;
                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)) *ssd_area;

        ssd_area = page;

        ssd_area->request.length = 0x0010;
        ssd_area->request.code = 0x0004;

        ssd_area->ssid = sch->schid.ssid;
        ssd_area->f_sch = sch->schid.sch_no;
        ssd_area->l_sch = sch->schid.sch_no;

        ccode = chsc(ssd_area);
        if (ccode > 0) {
                pr_debug("chsc returned with ccode = %d\n", ccode);
                return (ccode == 3) ? -ENODEV : -EBUSY;
        }

        switch (ssd_area->response.code) {
        case 0x0001: /* everything ok */
                break;
        case 0x0002:
                CIO_CRW_EVENT(2, "Invalid command!\n");
                return -EINVAL;
        case 0x0003:
                CIO_CRW_EVENT(2, "Error in chsc request block!\n");
                return -EINVAL;
        case 0x0004:
                CIO_CRW_EVENT(2, "Model does not provide ssd\n");
                return -EOPNOTSUPP;
        default:
                CIO_CRW_EVENT(2, "Unknown CHSC response %d\n",
                              ssd_area->response.code);
                return -EIO;
        }

        /*
         * ssd_area->st stores the type of the detected
         * subchannel, with the following definitions:
         *
         * 0: I/O subchannel:     All fields have meaning
         * 1: CHSC subchannel:    Only sch_val, st and sch
         *                        have meaning
         * 2: Message subchannel: All fields except unit_addr
         *                        have meaning
         * 3: ADM subchannel:     Only sch_val, st and sch
         *                        have meaning
         *
         * Other types are currently undefined.
         */
        if (ssd_area->st > 3) { /* uhm, that looks strange... */
                CIO_CRW_EVENT(0, "Strange subchannel type %d"
                              " for sch 0.%x.%04x\n", ssd_area->st,
                              sch->schid.ssid, sch->schid.sch_no);
                /*
                 * There may have been a new subchannel type defined in the
                 * time since this code was written; since we don't know which
                 * fields have meaning and what to do with it we just jump out
                 */
                return 0;
        } else {
                const char *type[4] = {"I/O", "chsc", "message", "ADM"};
                CIO_CRW_EVENT(6, "ssd: sch 0.%x.%04x is %s subchannel\n",
                              sch->schid.ssid, sch->schid.sch_no,
                              type[ssd_area->st]);

                sch->ssd_info.valid = 1;
                sch->ssd_info.type = ssd_area->st;
        }

        if (ssd_area->st == 0 || ssd_area->st == 2) {
                for (j = 0; j < 8; j++) {
                        if (!((0x80 >> j) & ssd_area->path_mask &
                              ssd_area->fla_valid_mask))
                                continue;
                        sch->ssd_info.chpid[j] = ssd_area->chpid[j];
                        sch->ssd_info.fla[j]   = ssd_area->fla[j];
                }
        }
        return 0;
}

int
css_get_ssd_info(struct subchannel *sch)
{
        int ret;
        void *page;

        page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!page)
                return -ENOMEM;
        spin_lock_irq(sch->lock);
        ret = chsc_get_sch_desc_irq(sch, page);
        if (ret) {
                static int cio_chsc_err_msg;
                
                if (!cio_chsc_err_msg) {
                        printk(KERN_ERR
                               "chsc_get_sch_descriptions:"
                               " Error %d while doing chsc; "
                               "processing some machine checks may "
                               "not work\n", ret);
                        cio_chsc_err_msg = 1;
                }
        }
        spin_unlock_irq(sch->lock);
        free_page((unsigned long)page);
        if (!ret) {
                int j, mask;
                struct chp_id chpid;

                chp_id_init(&chpid);
                /* Allocate channel path structures, if needed. */
                for (j = 0; j < 8; j++) {
                        mask = 0x80 >> j;
                        chpid.id = sch->ssd_info.chpid[j];
                        if ((sch->schib.pmcw.pim & mask) &&
                            (get_chp_status(chpid) < 0))
                            new_channel_path(chpid);
                }
        }
        return ret;
}

static int
s390_subchannel_remove_chpid(struct device *dev, void *data)
{
        int j;
        int mask;
        struct subchannel *sch;
        struct channel_path *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->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 ((sch->schib.scsw.actl & SCSW_ACTL_DEVACT) &&
            (sch->schib.scsw.actl & SCSW_ACTL_SCHACT) &&
            (sch->schib.pmcw.lpum == mask)) {
                int cc;

                cc = cio_clear(sch);
                if (cc == -ENODEV)
                        goto out_unreg;
                /* Request retry of internal operation. */
                device_set_intretry(sch);
                /* Call handler. */
                if (sch->driver && sch->driver->termination)
                        sch->driver->termination(&sch->dev);
                goto out_unlock;
        }

        /* trigger path verification. */
        if (sch->driver && sch->driver->verify)
                sch->driver->verify(&sch->dev);
        else if (sch->lpm == mask)
                goto out_unreg;
out_unlock:
        spin_unlock_irq(sch->lock);
        return 0;
out_unreg:
        spin_unlock_irq(sch->lock);
        sch->lpm = 0;
        if (css_enqueue_subchannel_slow(sch->schid)) {
                css_clear_subchannel_slow_list();
                need_rescan = 1;
        }
        return 0;
}

static void s390_set_chpid_offline(struct chp_id chpid)
{
        char dbf_txt[15];
        struct device *dev;

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

        if (get_chp_status(chpid) <= 0)
                return;
        dev = get_device(&(chpid_to_chp(chpid)->dev));
        bus_for_each_dev(&css_bus_type, NULL, to_channelpath(dev),
                         s390_subchannel_remove_chpid);

        if (need_rescan || css_slow_subchannels_exist())
                queue_work(slow_path_wq, &slow_path_work);
        put_device(dev);
}

struct res_acc_data {
        struct channel_path *chp;
        u32 fla_mask;
        u16 fla;
};

static int
s390_process_res_acc_sch(struct res_acc_data *res_data, struct subchannel *sch)
{
        int found;
        int chp;
        int ccode;
        
        found = 0;
        for (chp = 0; chp <= 7; chp++)
                /*
                 * check if chpid is in information updated by ssd
                 */
                if (sch->ssd_info.valid &&
                    sch->ssd_info.chpid[chp] == res_data->chp->chpid.id &&
                    (sch->ssd_info.fla[chp] & res_data->fla_mask)
                    == res_data->fla) {
                        found = 1;
                        break;
                }
        
        if (found == 0)
                return 0;

        /*
         * Do a stsch to update our subchannel structure with the
         * new path information and eventually check for logically
         * offline chpids.
         */
        ccode = stsch(sch->schid, &sch->schib);
        if (ccode > 0)
                return 0;

        return 0x80 >> chp;
}

static int
s390_process_res_acc_new_sch(struct subchannel_id schid)
{
        struct schib schib;
        int ret;
        /*
         * 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 need_rescan ? -EAGAIN : -ENXIO;

        /* Put it on the slow path. */
        ret = css_enqueue_subchannel_slow(schid);
        if (ret) {
                css_clear_subchannel_slow_list();
                need_rescan = 1;
                return -EAGAIN;
        }
        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 = s390_process_res_acc_sch(res_data, sch);

        if (chp_mask == 0) {
                spin_unlock_irq(sch->lock);
                put_device(&sch->dev);
                return 0;
        }
        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);

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


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

        sprintf(dbf_txt, "accpr%x.%02x", res_data->chp->chpid.cssid,
                res_data->chp->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.
         */
        rc = for_each_subchannel(__s390_process_res_acc, res_data);
        if (css_slow_subchannels_exist())
                rc = -EAGAIN;
        else if (rc != -EAGAIN)
                rc = 0;
        return rc;
}

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 int 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 0;
        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;
                s390_set_chpid_offline(chpid);
        }

        return 0;
}

static int chsc_process_sei_res_acc(struct chsc_sei_area *sei_area)
{
        struct res_acc_data res_data;
        struct device *dev;
        struct chp_id chpid;
        int status;
        int rc;

        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 0;
        chp_id_init(&chpid);
        chpid.id = sei_area->rsid;
        /* allocate a new channel path structure, if needed */
        status = get_chp_status(chpid);
        if (status < 0)
                new_channel_path(chpid);
        else if (!status)
                return 0;
        dev = get_device(&(chpid_to_chp(chpid)->dev));
        memset(&res_data, 0, sizeof(struct res_acc_data));
        res_data.chp = to_channelpath(dev);
        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;
        }
        rc = s390_process_res_acc(&res_data);
        put_device(dev);

        return rc;
}

static int chsc_process_sei(struct chsc_sei_area *sei_area)
{
        int rc;

        /* Check if we might have lost some information. */
        if (sei_area->flags & 0x40)
                CIO_CRW_EVENT(2, "chsc: event overflow\n");
        /* which kind of information was stored? */
        rc = 0;
        switch (sei_area->cc) {
        case 1: /* link incident*/
                rc = chsc_process_sei_link_incident(sei_area);
                break;
        case 2: /* i/o resource accessibiliy */
                rc = chsc_process_sei_res_acc(sei_area);
                break;
        default: /* other stuff */
                CIO_CRW_EVENT(4, "chsc: unhandled sei content code %d\n",
                              sei_area->cc);
                break;
        }

        return rc;
}

int chsc_process_crw(void)
{
        struct chsc_sei_area *sei_area;
        int ret;
        int rc;

        if (!sei_page)
                return 0;
        /* 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");
        ret = 0;
        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");
                        rc = chsc_process_sei(sei_area);
                        if (rc)
                                ret = rc;
                } else {
                        CIO_CRW_EVENT(2, "chsc: sei failed (rc=%04x)\n",
                                      sei_area->response.code);
                        ret = 0;
                        break;
                }
        } while (sei_area->flags & 0x80);

        return ret;
}

static int
__chp_add_new_sch(struct subchannel_id schid)
{
        struct schib schib;
        int ret;

        if (stsch_err(schid, &schib))
                /* We're through */
                return need_rescan ? -EAGAIN : -ENXIO;

        /* Put it on the slow path. */
        ret = css_enqueue_subchannel_slow(schid);
        if (ret) {
                css_clear_subchannel_slow_list();
                need_rescan = 1;
                return -EAGAIN;
        }
        return 0;
}


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

        chp = 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] == chp->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;
}

static int chp_add(struct chp_id chpid)
{
        int rc;
        char dbf_txt[15];
        struct device *dev;

        if (!get_chp_status(chpid))
                return 0; /* no need to do the rest */
        
        sprintf(dbf_txt, "cadd%x.%02x", chpid.cssid, chpid.id);
        CIO_TRACE_EVENT(2, dbf_txt);

        dev = get_device(&(chpid_to_chp(chpid)->dev));
        rc = for_each_subchannel(__chp_add, to_channelpath(dev));
        if (css_slow_subchannels_exist())
                rc = -EAGAIN;
        if (rc != -EAGAIN)
                rc = 0;
        put_device(dev);
        return rc;
}

/* 
 * Handling of crw machine checks with channel path source.
 */
int chp_process_crw(int id, int on)
{
        struct chp_id chpid;

        chp_id_init(&chpid);
        chpid.id = id;
        if (on == 0) {
                /* Path has gone. We use the link incident routine.*/
                s390_set_chpid_offline(chpid);
                return 0; /* De-register is async anyway. */
        }
        /*
         * Path has come. Allocate a new channel path structure,
         * if needed.
         */
        if (get_chp_status(chpid) < 0)
                new_channel_path(chpid);
        /* Avoid the extra overhead in process_rec_acc. */
        return chp_add(chpid);
}

static int check_for_io_on_path(struct subchannel *sch, int index)
{
        int cc;

        cc = stsch(sch->schid, &sch->schib);
        if (cc)
                return 0;
        if (sch->schib.scsw.actl && sch->schib.pmcw.lpum == (0x80 >> index))
                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) {
                        if(css_enqueue_subchannel_slow(sch->schid)) {
                                css_clear_subchannel_slow_list();
                                need_rescan = 1;
                        }
                }
                return;
        }
        /* Request retry of internal operation. */
        device_set_intretry(sch);
        /* Call handler. */
        if (sch->driver && sch->driver->termination)
                sch->driver->termination(&sch->dev);
}

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

        if (!sch->ssd_info.valid)
                return;
        
        spin_lock_irqsave(sch->lock, flags);
        old_lpm = sch->lpm;
        for (chp = 0; chp < 8; chp++) {
                if (sch->ssd_info.chpid[chp] != chpid.id)
                        continue;

                if (on) {
                        sch->opm |= (0x80 >> chp);
                        sch->lpm |= (0x80 >> chp);
                        if (!old_lpm)
                                device_trigger_reprobe(sch);
                        else if (sch->driver && sch->driver->verify)
                                sch->driver->verify(&sch->dev);
                        break;
                }
                sch->opm &= ~(0x80 >> chp);
                sch->lpm &= ~(0x80 >> chp);
                if (check_for_io_on_path(sch, chp)) {
                        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);
                } else if (!sch->lpm) {
                        if (device_trigger_verify(sch) != 0) {
                                if (css_enqueue_subchannel_slow(sch->schid)) {
                                        css_clear_subchannel_slow_list();
                                        need_rescan = 1;
                                }
                        }
                } 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. */
        if (css_enqueue_subchannel_slow(schid)) {
                css_clear_subchannel_slow_list();
                need_rescan = 1;
                return -EAGAIN;
        }
        return 0;
}

/*
 * Function: s390_vary_chpid
 * Varies the specified chpid online or offline
 */
static int s390_vary_chpid(struct chp_id chpid, int on)
{
        char dbf_text[15];
        int status;

        sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
                chpid.id);
        CIO_TRACE_EVENT( 2, dbf_text);

        status = get_chp_status(chpid);
        if (status < 0) {
                printk(KERN_ERR "Can't vary unknown chpid %x.%02x\n",
                       chpid.cssid, chpid.id);
                return -EINVAL;
        }

        if (!on && !status) {
                printk(KERN_ERR "chpid %x.%02x is already offline\n",
                       chpid.cssid, chpid.id);
                return -EINVAL;
        }

        set_chp_logically_online(chpid, 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);
        if (need_rescan || css_slow_subchannels_exist())
                queue_work(slow_path_wq, &slow_path_work);
        return 0;
}

/*
 * Channel measurement related functions
 */
static ssize_t
chp_measurement_chars_read(struct kobject *kobj, char *buf, loff_t off,
                           size_t count)
{
        struct channel_path *chp;
        unsigned int size;

        chp = to_channelpath(container_of(kobj, struct device, kobj));
        if (!chp->cmg_chars)
                return 0;

        size = sizeof(struct cmg_chars);

        if (off > size)
                return 0;
        if (off + count > size)
                count = size - off;
        memcpy(buf, chp->cmg_chars + off, count);
        return count;
}

static struct bin_attribute chp_measurement_chars_attr = {
        .attr = {
                .name = "measurement_chars",
                .mode = S_IRUSR,
                .owner = THIS_MODULE,
        },
        .size = sizeof(struct cmg_chars),
        .read = chp_measurement_chars_read,
};

static void chp_measurement_copy_block(struct cmg_entry *buf,
                        struct channel_subsystem *css, struct chp_id chpid)
{
        void *area;
        struct cmg_entry *entry, reference_buf;
        int idx;

        if (chpid.id < 128) {
                area = css->cub_addr1;
                idx = chpid.id;
        } else {
                area = css->cub_addr2;
                idx = chpid.id - 128;
        }
        entry = area + (idx * sizeof(struct cmg_entry));
        do {
                memcpy(buf, entry, sizeof(*entry));
                memcpy(&reference_buf, entry, sizeof(*entry));
        } while (reference_buf.values[0] != buf->values[0]);
}

static ssize_t
chp_measurement_read(struct kobject *kobj, char *buf, loff_t off, size_t count)
{
        struct channel_path *chp;
        struct channel_subsystem *css;
        unsigned int size;

        chp = to_channelpath(container_of(kobj, struct device, kobj));
        css = to_css(chp->dev.parent);

        size = sizeof(struct cmg_entry);

        /* Only allow single reads. */
        if (off || count < size)
                return 0;
        chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
        count = size;
        return count;
}

static struct bin_attribute chp_measurement_attr = {
        .attr = {
                .name = "measurement",
                .mode = S_IRUSR,
                .owner = THIS_MODULE,
        },
        .size = sizeof(struct cmg_entry),
        .read = chp_measurement_read,
};

static void
chsc_remove_chp_cmg_attr(struct channel_path *chp)
{
        device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
        device_remove_bin_file(&chp->dev, &chp_measurement_attr);
}

static int
chsc_add_chp_cmg_attr(struct channel_path *chp)
{
        int ret;

        ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
        if (ret)
                return ret;
        ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
        if (ret)
                device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
        return ret;
}

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

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

/*
 * Files for the channel path entries.
 */
static ssize_t
chp_status_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct channel_path *chp = container_of(dev, struct channel_path, dev);

        if (!chp)
                return 0;
        return (get_chp_status(chp->chpid) ? sprintf(buf, "online\n") :
                sprintf(buf, "offline\n"));
}

static ssize_t
chp_status_write(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
        struct channel_path *cp = container_of(dev, struct channel_path, dev);
        char cmd[10];
        int num_args;
        int error;

        num_args = sscanf(buf, "%5s", cmd);
        if (!num_args)
                return count;

        if (!strnicmp(cmd, "on", 2))
                error = s390_vary_chpid(cp->chpid, 1);
        else if (!strnicmp(cmd, "off", 3))
                error = s390_vary_chpid(cp->chpid, 0);
        else
                error = -EINVAL;

        return error < 0 ? error : count;

}

static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);

static ssize_t
chp_type_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct channel_path *chp = container_of(dev, struct channel_path, dev);

        if (!chp)
                return 0;
        return sprintf(buf, "%x\n", chp->desc.desc);
}

static DEVICE_ATTR(type, 0444, chp_type_show, NULL);

static ssize_t
chp_cmg_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct channel_path *chp = to_channelpath(dev);

        if (!chp)
                return 0;
        if (chp->cmg == -1) /* channel measurements not available */
                return sprintf(buf, "unknown\n");
        return sprintf(buf, "%x\n", chp->cmg);
}

static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);

static ssize_t
chp_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct channel_path *chp = to_channelpath(dev);

        if (!chp)
                return 0;
        if (chp->shared == -1) /* channel measurements not available */
                return sprintf(buf, "unknown\n");
        return sprintf(buf, "%x\n", chp->shared);
}

static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);

static struct attribute * chp_attrs[] = {
        &dev_attr_status.attr,
        &dev_attr_type.attr,
        &dev_attr_cmg.attr,
        &dev_attr_shared.attr,
        NULL,
};

static struct attribute_group chp_attr_group = {
        .attrs = chp_attrs,
};

static void
chp_release(struct device *dev)
{
        struct channel_path *cp;
        
        cp = container_of(dev, struct channel_path, dev);
        kfree(cp);
}

static 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;
        }
}

static 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;
}

/*
 * Entries for chpids on the system bus.
 * This replaces /proc/chpids.
 */
static int new_channel_path(struct chp_id chpid)
{
        struct channel_path *chp;
        int ret;

        chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
        if (!chp)
                return -ENOMEM;

        /* fill in status, etc. */
        chp->chpid = chpid;
        chp->state = 1;
        chp->dev.parent = &css[chpid.cssid]->device;
        chp->dev.release = chp_release;
        snprintf(chp->dev.bus_id, BUS_ID_SIZE, "chp%x.%02x", chpid.cssid,
                 chpid.id);

        /* Obtain channel path description and fill it in. */
        ret = chsc_determine_channel_path_description(chpid, &chp->desc);
        if (ret)
                goto out_free;
        /* Get channel-measurement characteristics. */
        if (css_characteristics_avail && css_chsc_characteristics.scmc
            && css_chsc_characteristics.secm) {
                ret = chsc_get_channel_measurement_chars(chp);
                if (ret)
                        goto out_free;
        } else {
                static int msg_done;

                if (!msg_done) {
                        printk(KERN_WARNING "cio: Channel measurements not "
                               "available, continuing.\n");
                        msg_done = 1;
                }
                chp->cmg = -1;
        }

        /* make it known to the system */
        ret = device_register(&chp->dev);
        if (ret) {
                printk(KERN_WARNING "%s: could not register %x.%02x\n",
                       __func__, chpid.cssid, chpid.id);
                goto out_free;
        }
        ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
        if (ret) {
                device_unregister(&chp->dev);
                goto out_free;
        }
        mutex_lock(&css[chpid.cssid]->mutex);
        if (css[chpid.cssid]->cm_enabled) {
                ret = chsc_add_chp_cmg_attr(chp);
                if (ret) {
                        sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
                        device_unregister(&chp->dev);
                        mutex_unlock(&css[chpid.cssid]->mutex);
                        goto out_free;
                }
        }
        css[chpid.cssid]->chps[chpid.id] = chp;
        mutex_unlock(&css[chpid.cssid]->mutex);
        return ret;
out_free:
        kfree(chp);
        return ret;
}

void *
chsc_get_chp_desc(struct subchannel *sch, int chp_no)
{
        struct channel_path *chp;
        struct channel_path_desc *desc;
        struct chp_id chpid;

        chp_id_init(&chpid);
        chpid.id = sch->schib.pmcw.chpid[chp_no];
        chp = chpid_to_chp(chpid);
        if (!chp)
                return NULL;
        desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
        if (!desc)
                return NULL;
        memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
        return desc;
}

static int __init
chsc_alloc_sei_area(void)
{
        sei_page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!sei_page)
                printk(KERN_WARNING"Can't allocate page for processing of " \
                       "chsc machine checks!\n");
        return (sei_page ? 0 : -ENOMEM);
}

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;
}

subsys_initcall(chsc_alloc_sei_area);

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) {
                printk(KERN_WARNING"cio: 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) {
                printk(KERN_WARNING"cio: Was not able to determine " \
                       "available CHSCs, cc=%i.\n", result);
                result = -EIO;
                goto exit;
        }

        if (scsc_area->response.code != 1) {
                printk(KERN_WARNING"cio: 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);