path: root/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 <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 != SUBCHANNEL_TYPE_IO) &&
	    (ssd_area->st != SUBCHANNEL_TYPE_MSG))
		goto out_free;
	ssd->path_mask = ssd_area->path_mask;
	ssd->fla_valid_mask = ssd_area->fla_valid_mask;
	for (i = 0; i < 8; i++) {
		mask = 0x80 >> i;
		if (ssd_area->path_mask & mask) {
			chp_id_init(&ssd->chpid[i]);
			ssd->chpid[i].id = ssd_area->chpid[i];
		}
		if (ssd_area->fla_valid_mask & mask)
			ssd->fla[i] = ssd_area->fla[i];
	}
out_free:
	free_page(page);
	return ret;
}

static int 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);
}

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 (!css_sch_is_valid(&schib))
		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);
		}
	} else {
		/* trigger path verification. */
		if (sch->driver && sch->driver->verify)
			sch->driver->verify(sch);
		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);
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);

	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);
			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);
			}
		} 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);
		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);