Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1114 insertions, 0 deletions

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
new file mode 100644
index 00000000000..b35fe12e6bf
--- /dev/null
+++ b/drivers/s390/cio/chsc.c
@@ -0,0 +1,1114 @@
+/*
+ *  drivers/s390/cio/chsc.c
+ *   S/390 common I/O routines -- channel subsystem call
+ *   $Revision: 1.119 $
+ *
+ *    Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
+ *			      IBM Corporation
+ *    Author(s): Ingo Adlung (adlung@de.ibm.com)
+ *		 Cornelia Huck (cohuck@de.ibm.com)
+ *		 Arnd Bergmann (arndb@de.ibm.com)
+ */
+
+#include <linux/module.h>
+#include <linux/config.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 "chsc.h"
+
+static struct channel_path *chps[NR_CHPIDS];
+
+static void *sei_page;
+
+static int new_channel_path(int chpid);
+
+static inline void
+set_chp_logically_online(int chp, int onoff)
+{
+	chps[chp]->state = onoff;
+}
+
+static int
+get_chp_status(int chp)
+{
+	return (chps[chp] ? chps[chp]->state : -ENODEV);
+}
+
+void
+chsc_validate_chpids(struct subchannel *sch)
+{
+	int mask, chp;
+
+	for (chp = 0; chp <= 7; chp++) {
+		mask = 0x80 >> chp;
+		if (!get_chp_status(sch->schib.pmcw.chpid[chp]))
+			/* disable using this path */
+			sch->opm &= ~mask;
+	}
+}
+
+void
+chpid_is_actually_online(int chp)
+{
+	int state;
+
+	state = get_chp_status(chp);
+	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 reserved1;
+		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 */
+	} *ssd_area;
+
+	ssd_area = page;
+
+	ssd_area->request = (struct chsc_header) {
+		.length = 0x0010,
+		.code   = 0x0004,
+	};
+
+	ssd_area->f_sch = sch->irq;
+	ssd_area->l_sch = sch->irq;
+
+	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 %04x\n", ssd_area->st, sch->irq);
+		/*
+		 * 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 %04x is %s subchannel\n",
+			      sch->irq, 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, chpid;
+		/* Allocate channel path structures, if needed. */
+		for (j = 0; j < 8; j++) {
+			chpid = sch->ssd_info.chpid[j];
+			if (chpid && (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;
+	__u8 *chpid;
+	struct schib schib;
+
+	sch = to_subchannel(dev);
+	chpid = data;
+	for (j = 0; j < 8; j++)
+		if (sch->schib.pmcw.chpid[j] == *chpid)
+			break;
+	if (j >= 8)
+		return 0;
+
+	mask = 0x80 >> j;
+	spin_lock(&sch->lock);
+
+	stsch(sch->irq, &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->vpm == mask)
+		goto out_unreg;
+
+	if ((sch->schib.scsw.actl & (SCSW_ACTL_CLEAR_PEND |
+				     SCSW_ACTL_HALT_PEND |
+				     SCSW_ACTL_START_PEND |
+				     SCSW_ACTL_RESUME_PEND)) &&
+	    (sch->schib.pmcw.lpum == mask)) {
+		int cc = cio_cancel(sch);
+		
+		if (cc == -ENODEV)
+			goto out_unreg;
+
+		if (cc == -EINVAL) {
+			cc = cio_clear(sch);
+			if (cc == -ENODEV)
+				goto out_unreg;
+			/* Call handler. */
+			if (sch->driver && sch->driver->termination)
+				sch->driver->termination(&sch->dev);
+			goto out_unlock;
+		}
+	} else 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;
+		/* 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);
+out_unlock:
+	spin_unlock(&sch->lock);
+	return 0;
+out_unreg:
+	spin_unlock(&sch->lock);
+	sch->lpm = 0;
+	if (css_enqueue_subchannel_slow(sch->irq)) {
+		css_clear_subchannel_slow_list();
+		need_rescan = 1;
+	}
+	return 0;
+}
+
+static inline void
+s390_set_chpid_offline( __u8 chpid)
+{
+	char dbf_txt[15];
+
+	sprintf(dbf_txt, "chpr%x", chpid);
+	CIO_TRACE_EVENT(2, dbf_txt);
+
+	if (get_chp_status(chpid) <= 0)
+		return;
+
+	bus_for_each_dev(&css_bus_type, NULL, &chpid,
+			 s390_subchannel_remove_chpid);
+
+	if (need_rescan || css_slow_subchannels_exist())
+		queue_work(slow_path_wq, &slow_path_work);
+}
+
+static int
+s390_process_res_acc_sch(u8 chpid, __u16 fla, u32 fla_mask,
+			 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] == chpid &&
+		    (sch->ssd_info.fla[chp] & fla_mask) == 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->irq, &sch->schib);
+	if (ccode > 0)
+		return 0;
+
+	return 0x80 >> chp;
+}
+
+static int
+s390_process_res_acc (u8 chpid, __u16 fla, u32 fla_mask)
+{
+	struct subchannel *sch;
+	int irq, rc;
+	char dbf_txt[15];
+
+	sprintf(dbf_txt, "accpr%x", chpid);
+	CIO_TRACE_EVENT( 2, dbf_txt);
+	if (fla != 0) {
+		sprintf(dbf_txt, "fla%x", 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.
+	 */
+
+	if (!get_chp_status(chpid))
+		return 0; /* no need to do the rest */
+
+	rc = 0;
+	for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
+		int chp_mask, old_lpm;
+
+		sch = get_subchannel_by_schid(irq);
+		if (!sch) {
+			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(irq, &schib)) {
+				/* We're through */
+				if (need_rescan)
+					rc = -EAGAIN;
+				break;
+			}
+			if (need_rescan) {
+				rc = -EAGAIN;
+				continue;
+			}
+			/* Put it on the slow path. */
+			ret = css_enqueue_subchannel_slow(irq);
+			if (ret) {
+				css_clear_subchannel_slow_list();
+				need_rescan = 1;
+			}
+			rc = -EAGAIN;
+			continue;
+		}
+	
+		spin_lock_irq(&sch->lock);
+
+		chp_mask = s390_process_res_acc_sch(chpid, fla, fla_mask, sch);
+
+		if (chp_mask == 0) {
+
+			spin_unlock_irq(&sch->lock);
+
+			if (fla_mask != 0)
+				break;
+			else
+				continue;
+		}
+		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);
+		if (fla_mask != 0)
+			break;
+	}
+	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];
+	} *lir;
+
+	lir = (struct 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);
+}
+
+int
+chsc_process_crw(void)
+{
+	int chpid, ret;
+	struct {
+		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;
+		u32 ccdf[96];	/* content-code dependent field */
+		/* ccdf has to be big enough for a link-incident record */
+	} *sei_area;
+
+	if (!sei_page)
+		return 0;
+	/*
+	 * build the chsc request block for store event information
+	 * and do the call
+	 * This function is only called by the machine check handler thread,
+	 * so we don't need locking for the sei_page.
+	 */
+	sei_area = sei_page;
+
+	CIO_TRACE_EVENT( 2, "prcss");
+	ret = 0;
+	do {
+		int ccode, status;
+		memset(sei_area, 0, sizeof(*sei_area));
+
+		sei_area->request = (struct chsc_header) {
+			.length = 0x0010,
+			.code   = 0x000e,
+		};
+
+		ccode = chsc(sei_area);
+		if (ccode > 0)
+			return 0;
+
+		switch (sei_area->response.code) {
+			/* for debug purposes, check for problems */
+		case 0x0001:
+			CIO_CRW_EVENT(4, "chsc_process_crw: event information "
+					"successfully stored\n");
+			break; /* everything ok */
+		case 0x0002:
+			CIO_CRW_EVENT(2,
+				      "chsc_process_crw: invalid command!\n");
+			return 0;
+		case 0x0003:
+			CIO_CRW_EVENT(2, "chsc_process_crw: error in chsc "
+				      "request block!\n");
+			return 0;
+		case 0x0005:
+			CIO_CRW_EVENT(2, "chsc_process_crw: no event "
+				      "information stored\n");
+			return 0;
+		default:
+			CIO_CRW_EVENT(2, "chsc_process_crw: chsc response %d\n",
+				      sei_area->response.code);
+			return 0;
+		}
+
+		/* Check if we might have lost some information. */
+		if (sei_area->flags & 0x40)
+			CIO_CRW_EVENT(2, "chsc_process_crw: Event information "
+				       "has been lost due to overflow!\n");
+
+		if (sei_area->rs != 4) {
+			CIO_CRW_EVENT(2, "chsc_process_crw: reporting source "
+				      "(%04X) isn't a chpid!\n",
+				      sei_area->rsid);
+			continue;
+		}
+
+		/* which kind of information was stored? */
+		switch (sei_area->cc) {
+		case 1: /* link incident*/
+			CIO_CRW_EVENT(4, "chsc_process_crw: "
+				      "channel subsystem reports link incident,"
+				      " reporting source is chpid %x\n",
+				      sei_area->rsid);
+			chpid = __get_chpid_from_lir(sei_area->ccdf);
+			if (chpid < 0)
+				CIO_CRW_EVENT(4, "%s: Invalid LIR, skipping\n",
+					      __FUNCTION__);
+			else
+				s390_set_chpid_offline(chpid);
+			break;
+			
+		case 2: /* i/o resource accessibiliy */
+			CIO_CRW_EVENT(4, "chsc_process_crw: "
+				      "channel subsystem reports some I/O "
+				      "devices may have become accessible\n");
+			pr_debug("Data received after sei: \n");
+			pr_debug("Validity flags: %x\n", sei_area->vf);
+			
+			/* allocate a new channel path structure, if needed */
+			status = get_chp_status(sei_area->rsid);
+			if (status < 0)
+				new_channel_path(sei_area->rsid);
+			else if (!status)
+				return 0;
+			if ((sei_area->vf & 0x80) == 0) {
+				pr_debug("chpid: %x\n", sei_area->rsid);
+				ret = s390_process_res_acc(sei_area->rsid,
+							   0, 0);
+			} else if ((sei_area->vf & 0xc0) == 0x80) {
+				pr_debug("chpid: %x link addr: %x\n",
+					 sei_area->rsid, sei_area->fla);
+				ret = s390_process_res_acc(sei_area->rsid,
+							   sei_area->fla,
+							   0xff00);
+			} else if ((sei_area->vf & 0xc0) == 0xc0) {
+				pr_debug("chpid: %x full link addr: %x\n",
+					 sei_area->rsid, sei_area->fla);
+				ret = s390_process_res_acc(sei_area->rsid,
+							   sei_area->fla,
+							   0xffff);
+			}
+			pr_debug("\n");
+			
+			break;
+			
+		default: /* other stuff */
+			CIO_CRW_EVENT(4, "chsc_process_crw: event %d\n",
+				      sei_area->cc);
+			break;
+		}
+	} while (sei_area->flags & 0x80);
+	return ret;
+}
+
+static int
+chp_add(int chpid)
+{
+	struct subchannel *sch;
+	int irq, ret, rc;
+	char dbf_txt[15];
+
+	if (!get_chp_status(chpid))
+		return 0; /* no need to do the rest */
+	
+	sprintf(dbf_txt, "cadd%x", chpid);
+	CIO_TRACE_EVENT(2, dbf_txt);
+
+	rc = 0;
+	for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
+		int i;
+
+		sch = get_subchannel_by_schid(irq);
+		if (!sch) {
+			struct schib schib;
+
+			if (stsch(irq, &schib)) {
+				/* We're through */
+				if (need_rescan)
+					rc = -EAGAIN;
+				break;
+			}
+			if (need_rescan) {
+				rc = -EAGAIN;
+				continue;
+			}
+			/* Put it on the slow path. */
+			ret = css_enqueue_subchannel_slow(irq);
+			if (ret) {
+				css_clear_subchannel_slow_list();
+				need_rescan = 1;
+			}
+			rc = -EAGAIN;
+			continue;
+		}
+	
+		spin_lock(&sch->lock);
+		for (i=0; i<8; i++)
+			if (sch->schib.pmcw.chpid[i] == chpid) {
+				if (stsch(sch->irq, &sch->schib) != 0) {
+					/* Endgame. */
+					spin_unlock(&sch->lock);
+					return rc;
+				}
+				break;
+			}
+		if (i==8) {
+			spin_unlock(&sch->lock);
+			return rc;
+		}
+		sch->lpm = ((sch->schib.pmcw.pim &
+			     sch->schib.pmcw.pam &
+			     sch->schib.pmcw.pom)
+			    | 0x80 >> i) & sch->opm;
+
+		if (sch->driver && sch->driver->verify)
+			sch->driver->verify(&sch->dev);
+
+		spin_unlock(&sch->lock);
+		put_device(&sch->dev);
+	}
+	return rc;
+}
+
+/* 
+ * Handling of crw machine checks with channel path source.
+ */
+int
+chp_process_crw(int chpid, int on)
+{
+	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 inline int
+__check_for_io_and_kill(struct subchannel *sch, int index)
+{
+	int cc;
+
+	if (!device_is_online(sch))
+		/* cio could be doing I/O. */
+		return 0;
+	cc = stsch(sch->irq, &sch->schib);
+	if (cc)
+		return 0;
+	if (sch->schib.scsw.actl && sch->schib.pmcw.lpum == (0x80 >> index)) {
+		device_set_waiting(sch);
+		return 1;
+	}
+	return 0;
+}
+
+static inline void
+__s390_subchannel_vary_chpid(struct subchannel *sch, __u8 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)
+			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);
+		} else {
+			sch->opm &= ~(0x80 >> chp);
+			sch->lpm &= ~(0x80 >> chp);
+			/*
+			 * Give running I/O a grace period in which it
+			 * can successfully terminate, even using the
+			 * just varied off path. Then kill it.
+			 */
+			if (!__check_for_io_and_kill(sch, chp) && !sch->lpm) {
+				if (css_enqueue_subchannel_slow(sch->irq)) {
+					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;
+	__u8 *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;
+	__u8 *chpid;
+
+	sch = to_subchannel(dev);
+	chpid = data;
+
+	__s390_subchannel_vary_chpid(sch, *chpid, 1);
+	return 0;
+}
+
+/*
+ * Function: s390_vary_chpid
+ * Varies the specified chpid online or offline
+ */
+static int
+s390_vary_chpid( __u8 chpid, int on)
+{
+	char dbf_text[15];
+	int status, irq, ret;
+	struct subchannel *sch;
+
+	sprintf(dbf_text, on?"varyon%x":"varyoff%x", chpid);
+	CIO_TRACE_EVENT( 2, dbf_text);
+
+	status = get_chp_status(chpid);
+	if (status < 0) {
+		printk(KERN_ERR "Can't vary unknown chpid %02X\n", chpid);
+		return -EINVAL;
+	}
+
+	if (!on && !status) {
+		printk(KERN_ERR "chpid %x is already offline\n", chpid);
+		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)
+		goto out;
+	/* Scan for new devices on varied on path. */
+	for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
+		struct schib schib;
+
+		if (need_rescan)
+			break;
+		sch = get_subchannel_by_schid(irq);
+		if (sch) {
+			put_device(&sch->dev);
+			continue;
+		}
+		if (stsch(irq, &schib))
+			/* We're through */
+			break;
+		/* Put it on the slow path. */
+		ret = css_enqueue_subchannel_slow(irq);
+		if (ret) {
+			css_clear_subchannel_slow_list();
+			need_rescan = 1;
+		}
+	}
+out:
+	if (need_rescan || css_slow_subchannels_exist())
+		queue_work(slow_path_wq, &slow_path_work);
+	return 0;
+}
+
+/*
+ * Files for the channel path entries.
+ */
+static ssize_t
+chp_status_show(struct device *dev, char *buf)
+{
+	struct channel_path *chp = container_of(dev, struct channel_path, dev);
+
+	if (!chp)
+		return 0;
+	return (get_chp_status(chp->id) ? sprintf(buf, "online\n") :
+		sprintf(buf, "offline\n"));
+}
+
+static ssize_t
+chp_status_write(struct device *dev, 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->id, 1);
+	else if (!strnicmp(cmd, "off", 3))
+		error = s390_vary_chpid(cp->id, 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, 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 struct attribute * chp_attrs[] = {
+	&dev_attr_status.attr,
+	&dev_attr_type.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(int 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;
+	} *scpd_area;
+
+	scpd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
+	if (!scpd_area)
+		return -ENOMEM;
+
+	scpd_area->request = (struct chsc_header) {
+		.length = 0x0010,
+		.code   = 0x0002,
+	};
+
+	scpd_area->first_chpid = chpid;
+	scpd_area->last_chpid = chpid;
+
+	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;
+}
+
+/*
+ * Entries for chpids on the system bus.
+ * This replaces /proc/chpids.
+ */
+static int
+new_channel_path(int chpid)
+{
+	struct channel_path *chp;
+	int ret;
+
+	chp = kmalloc(sizeof(struct channel_path), GFP_KERNEL);
+	if (!chp)
+		return -ENOMEM;
+	memset(chp, 0, sizeof(struct channel_path));
+
+	/* fill in status, etc. */
+	chp->id = chpid;
+	chp->state = 1;
+	chp->dev = (struct device) {
+		.parent  = &css_bus_device,
+		.release = chp_release,
+	};
+	snprintf(chp->dev.bus_id, BUS_ID_SIZE, "chp0.%x", chpid);
+
+	/* Obtain channel path description and fill it in. */
+	ret = chsc_determine_channel_path_description(chpid, &chp->desc);
+	if (ret)
+		goto out_free;
+
+	/* make it known to the system */
+	ret = device_register(&chp->dev);
+	if (ret) {
+		printk(KERN_WARNING "%s: could not register %02x\n",
+		       __func__, chpid);
+		goto out_free;
+	}
+	ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
+	if (ret) {
+		device_unregister(&chp->dev);
+		goto out_free;
+	} else
+		chps[chpid] = chp;
+	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;
+
+	chp = chps[sch->schib.pmcw.chpid[chp_no]];
+	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);
+}
+
+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];
+	} *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 = (struct chsc_header) {
+		.length = 0x0010,
+		.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);