drivers/s390/cio/chsc.c

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

#define 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 <linux/mutex.h>
#include <linux/pci.h>

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

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

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

/**
 * chsc_error_from_response() - convert a chsc response to an error
 * @response: chsc response code
 *
 * Returns an appropriate Linux error code for @response.
 */
int chsc_error_from_response(int response)
{
	switch (response) {
	case 0x0001:
		return 0;
	case 0x0002:
	case 0x0003:
	case 0x0006:
	case 0x0007:
	case 0x0008:
	case 0x000a:
	case 0x0104:
		return -EINVAL;
	case 0x0004:
		return -EOPNOTSUPP;
	case 0x000b:
	case 0x0107:		/* "Channel busy" for the op 0x003d */
		return -EBUSY;
	case 0x0100:
	case 0x0102:
		return -ENOMEM;
	default:
		return -EIO;
	}
}
EXPORT_SYMBOL_GPL(chsc_error_from_response);

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

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

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

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

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

	if (chsc(ssqd))
		return -EIO;

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

/**
 * chsc_sadc() - set adapter device controls (SADC)
 * @schid: id of the subchannel on which SADC is performed
 * @scssc: request and response block for SADC
 * @summary_indicator_addr: summary indicator address
 * @subchannel_indicator_addr: subchannel indicator address
 *
 * Returns 0 on success.
 */
int chsc_sadc(struct subchannel_id schid, struct chsc_scssc_area *scssc,
	      u64 summary_indicator_addr, u64 subchannel_indicator_addr)
{
	memset(scssc, 0, sizeof(*scssc));
	scssc->request.length = 0x0fe0;
	scssc->request.code = 0x0021;
	scssc->operation_code = 0;

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

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

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

	if (chsc(scssc))
		return -EIO;

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

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

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

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

	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();

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

	for_each_subchannel_staged(s390_subchannel_remove_chpid, NULL, &link);
}

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

	return 0;
}

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

	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, NULL, link);
	css_schedule_reprobe();
}

struct chsc_sei_nt0_area {
	u8  flags;
	u8  vf;				/* validity flags */
	u8  rs;				/* reporting source */
	u8  cc;				/* content code */
	u16 fla;			/* full link address */
	u16 rsid;			/* reporting source id */
	u32 reserved1;
	u32 reserved2;
	/* ccdf has to be big enough for a link-incident record */
	u8  ccdf[PAGE_SIZE - 24 - 16];	/* content-code dependent field */
} __packed;

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

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

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

/*
 * Node Descriptor as defined in SA22-7204, "Common I/O-Device Commands"
 */

#define ND_VALIDITY_VALID	0
#define ND_VALIDITY_OUTDATED	1
#define ND_VALIDITY_INVALID	2

struct node_descriptor {
	/* Flags. */
	union {
		struct {
			u32 validity:3;
			u32 reserved:5;
		} __packed;
		u8 byte0;
	} __packed;

	/* Node parameters. */
	u32 params:24;

	/* Node ID. */
	char type[6];
	char model[3];
	char manufacturer[3];
	char plant[2];
	char seq[12];
	u16 tag;
} __packed;

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

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

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

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

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

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

	return dest + len;
}

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

	if (nd->validity != ND_VALIDITY_VALID) {
		strncpy(params, "n/a", PARAMS_LEN - 1);
		strncpy(id, "n/a", NODEID_LEN - 1);
		return;
	}

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

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

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

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

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

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

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

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

	CIO_CRW_EVENT(4, "chsc: resource accessibility event (rs=%02x, "
		      "rs_id=%04x)\n", sei_area->rs, sei_area->rsid);
	if (sei_area->rs != 4)
		return;
	chp_id_init(&chpid);
	chpid.id = sei_area->rsid;
	/* allocate a new channel path structure, if needed */
	status = chp_get_status(chpid);
	if (!status)
		return;

	if (status < 0) {
		chp_new(chpid);
	} else {
		chp = chpid_to_chp(chpid);
		mutex_lock(&chp->lock);
		chp_update_desc(chp);
		mutex_unlock(&chp->lock);
	}
	memset(&link, 0, sizeof(struct chp_link));
	link.chpid = chpid;
	if ((sei_area->vf & 0xc0) != 0) {
		link.fla = sei_area->fla;
		if ((sei_area->vf & 0xc0) == 0xc0)
			/* full link address */
			link.fla_mask = 0xffff;
		else
			/* link address */
			link.fla_mask = 0xff00;
	}
	s390_process_res_acc(&link);
}

static void chsc_process_sei_chp_avail(struct chsc_sei_nt0_area *sei_area)
{
	struct channel_path *chp;
	struct chp_id chpid;
	u8 *data;
	int num;

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

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

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

static void chsc_process_sei_chp_config(struct chsc_sei_nt0_area *sei_area)
{
	struct chp_config_data *data;
	struct chp_id chpid;
	int num;
	char *events[3] = {"configure", "deconfigure", "cancel deconfigure"};

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

static void chsc_process_sei_scm_change(struct chsc_sei_nt0_area *sei_area)
{
	int ret;

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

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

static void chsc_process_sei_scm_avail(struct chsc_sei_nt0_area *sei_area)
{
	int ret;

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

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

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

static void chsc_process_sei_nt0(struct chsc_sei_nt0_area *sei_area)
{
	/* which kind of information was stored? */
	switch (sei_area->cc) {
	case 1: /* link incident*/
		chsc_process_sei_link_incident(sei_area);
		break;
	case 2: /* i/o resource accessibility */
		chsc_process_sei_res_acc(sei_area);
		break;
	case 7: /* channel-path-availability information */
		chsc_process_sei_chp_avail(sei_area);
		break;
	case 8: /* channel-path-configuration notification */
		chsc_process_sei_chp_config(sei_area);
		break;
	case 12: /* scm change notification */
		chsc_process_sei_scm_change(sei_area);
		break;
	case 14: /* scm available notification */
		chsc_process_sei_scm_avail(sei_area);
		break;
	default: /* other stuff */
		CIO_CRW_EVENT(2, "chsc: sei nt0 unhandled cc=%d\n",
			      sei_area->cc);
		break;
	}

	/* Check if we might have lost some information. */
	if (sei_area->flags & 0x40) {
		CIO_CRW_EVENT(2, "chsc: event overflow\n");
		css_schedule_eval_all();
	}
}

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

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

		if (chsc(sei))
			break;

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

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

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

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

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

	if (overflow) {
		css_schedule_eval_all();
		return;
	}
	CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
		      "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
		      crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
		      crw0->erc, crw0->rsid);

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

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

	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();

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

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

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

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

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

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

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

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

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

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

	return 0;
}

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

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

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

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

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

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

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

	secm_area->operation_code = enable ? 0 : 1;

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

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

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

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

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

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

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

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

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

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

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

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

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

int chsc_get_channel_measurement_chars(struct channel_path *chp)
{
	unsigned long flags;
	int ccode, ret;

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

	chp->shared = -1;
	chp->cmg = -1;

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

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

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

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

	chp->cmg = scmc_area->cmg;
	chp->shared = scmc_area->shared;
	if (chp->cmg != 2 && chp->cmg != 3) {
		/* No cmg-dependent data. */
		goto out;
	}
	chsc_initialize_cmg_chars(chp, scmc_area->cmcv,
				  (struct cmg_chars *) &scmc_area->data);
out:
	spin_unlock_irqrestore(&chsc_page_lock, flags);
	return ret;
}

int __init chsc_init(void)
{
	int ret;

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

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

int __chsc_enable_facility(struct chsc_sda_area *sda_area, int operation_code)
{
	int ret;

	sda_area->request.length = 0x0400;
	sda_area->request.code = 0x0031;
	sda_area->operation_code = operation_code;

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

	switch (sda_area->response.code) {
	case 0x0101:
		ret = -EOPNOTSUPP;
		break;
	default:
		ret = chsc_error_from_response(sda_area->response.code);
	}
out:
	return ret;
}

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

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

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

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

int __init chsc_get_cssid(int idx)
{
	struct {
		struct chsc_header request;
		u8 atype;
		u32 : 24;
		u32 reserved1[6];
		struct chsc_header response;
		u32 reserved2[3];
		struct {
			u8 cssid;
			u32 : 24;
		} list[0];
	} __packed *sdcal_area;
	int ret;

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

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

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

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

struct css_general_char css_general_characteristics;
struct css_chsc_char css_chsc_characteristics;

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

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

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

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

EXPORT_SYMBOL_GPL(css_general_characteristics);
EXPORT_SYMBOL_GPL(css_chsc_characteristics);

int chsc_sstpc(void *page, unsigned int op, u16 ctrl, u64 *clock_delta)
{
	struct {
		struct chsc_header request;
		unsigned int rsvd0;
		unsigned int op : 8;
		unsigned int rsvd1 : 8;
		unsigned int ctrl : 16;
		unsigned int rsvd2[5];
		struct chsc_header response;
		unsigned int rsvd3[3];
		u64 clock_delta;
		unsigned int rsvd4[2];
	} __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;
	if (clock_delta)
		*clock_delta = rr->clock_delta;
	return rc;
}

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

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

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

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

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

/**
 * chsc_scm_info() - store SCM information (SSI)
 * @scm_area: request and response block for SSI
 * @token: continuation token
 *
 * Returns 0 on success.
 */
int chsc_scm_info(struct chsc_scm_info *scm_area, u64 token)
{
	int ccode, ret;

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

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

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