s390/cio: add eadm subchannel driver

This driver allows usage of EADM subchannels. EADM subchannels
act as a communication vehicle for SCM increments.

Signed-off-by: Sebastian Ott <[e-mail]>
Signed-off-by: Martin Schwidefsky <[e-mail]>

arch/s390/Kconfig

···
 	help
 	  Bus driver for Storage Class Memory.
 
+config EADM_SCH
+	def_tristate m
+	prompt "Support for EADM subchannels"
+	depends on SCM_BUS
+	help
+	  This driver allows usage of EADM subchannels. EADM subchannels act
+	  as a communication vehicle for SCM increments.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called eadm_sch.
+
 endmenu
 
 menu "Dump support"

arch/s390/include/asm/isc.h

···
 /* Regular I/O interrupts. */
 #define IO_SCH_ISC 3			/* regular I/O subchannels */
 #define CONSOLE_ISC 1			/* console I/O subchannel */
+#define EADM_SCH_ISC 4			/* EADM subchannels */
 #define CHSC_SCH_ISC 7			/* CHSC subchannels */
 /* Adapter interrupts. */
 #define QDIO_AIRQ_ISC IO_SCH_ISC	/* I/O subchannel in qdio mode */

drivers/s390/cio/Makefile

···
 ccw_device-objs += device_id.o device_pgid.o device_status.o
 obj-y += ccw_device.o cmf.o
 obj-$(CONFIG_CHSC_SCH) += chsc_sch.o
+obj-$(CONFIG_EADM_SCH) += eadm_sch.o
 obj-$(CONFIG_SCM_BUS) += scm.o
 obj-$(CONFIG_CCWGROUP) += ccwgroup.o
 

drivers/s390/cio/eadm_sch.c

···
+/*
+ * Driver for s390 eadm subchannels
+ *
+ * Copyright IBM Corp. 2012
+ * Author(s): Sebastian Ott <[e-mail]>
+ */
+
+#include <linux/workqueue.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+
+#include <asm/css_chars.h>
+#include <asm/debug.h>
+#include <asm/isc.h>
+#include <asm/cio.h>
+#include <asm/scsw.h>
+#include <asm/eadm.h>
+
+#include "eadm_sch.h"
+#include "ioasm.h"
+#include "cio.h"
+#include "css.h"
+#include "orb.h"
+
+MODULE_DESCRIPTION("driver for s390 eadm subchannels");
+MODULE_LICENSE("GPL");
+
+#define EADM_TIMEOUT (5 * HZ)
+static DEFINE_SPINLOCK(list_lock);
+static LIST_HEAD(eadm_list);
+
+static debug_info_t *eadm_debug;
+
+#define EADM_LOG(imp, txt) do {					\
+		debug_text_event(eadm_debug, imp, txt);		\
+	} while (0)
+
+static void EADM_LOG_HEX(int level, void *data, int length)
+{
+	if (level > eadm_debug->level)
+		return;
+	while (length > 0) {
+		debug_event(eadm_debug, level, data, length);
+		length -= eadm_debug->buf_size;
+		data += eadm_debug->buf_size;
+	}
+}
+
+static void orb_init(union orb *orb)
+{
+	memset(orb, 0, sizeof(union orb));
+	orb->eadm.compat1 = 1;
+	orb->eadm.compat2 = 1;
+	orb->eadm.fmt = 1;
+	orb->eadm.x = 1;
+}
+
+static int eadm_subchannel_start(struct subchannel *sch, struct aob *aob)
+{
+	union orb *orb = &get_eadm_private(sch)->orb;
+	int cc;
+
+	orb_init(orb);
+	orb->eadm.aob = (u32)__pa(aob);
+	orb->eadm.intparm = (u32)(addr_t)sch;
+	orb->eadm.key = PAGE_DEFAULT_KEY >> 4;
+
+	EADM_LOG(6, "start");
+	EADM_LOG_HEX(6, &sch->schid, sizeof(sch->schid));
+
+	cc = ssch(sch->schid, orb);
+	switch (cc) {
+	case 0:
+		sch->schib.scsw.eadm.actl |= SCSW_ACTL_START_PEND;
+		break;
+	case 1:		/* status pending */
+	case 2:		/* busy */
+		return -EBUSY;
+	case 3:		/* not operational */
+		return -ENODEV;
+	}
+	return 0;
+}
+
+static int eadm_subchannel_clear(struct subchannel *sch)
+{
+	int cc;
+
+	cc = csch(sch->schid);
+	if (cc)
+		return -ENODEV;
+
+	sch->schib.scsw.eadm.actl |= SCSW_ACTL_CLEAR_PEND;
+	return 0;
+}
+
+static void eadm_subchannel_timeout(unsigned long data)
+{
+	struct subchannel *sch = (struct subchannel *) data;
+
+	spin_lock_irq(sch->lock);
+	EADM_LOG(1, "timeout");
+	EADM_LOG_HEX(1, &sch->schid, sizeof(sch->schid));
+	if (eadm_subchannel_clear(sch))
+		EADM_LOG(0, "clear failed");
+	spin_unlock_irq(sch->lock);
+}
+
+static void eadm_subchannel_set_timeout(struct subchannel *sch, int expires)
+{
+	struct eadm_private *private = get_eadm_private(sch);
+
+	if (expires == 0) {
+		del_timer(&private->timer);
+		return;
+	}
+	if (timer_pending(&private->timer)) {
+		if (mod_timer(&private->timer, jiffies + expires))
+			return;
+	}
+	private->timer.function = eadm_subchannel_timeout;
+	private->timer.data = (unsigned long) sch;
+	private->timer.expires = jiffies + expires;
+	add_timer(&private->timer);
+}
+
+static void eadm_subchannel_irq(struct subchannel *sch)
+{
+	struct eadm_private *private = get_eadm_private(sch);
+	struct eadm_scsw *scsw = &sch->schib.scsw.eadm;
+	struct irb *irb = (struct irb *)&S390_lowcore.irb;
+	int error = 0;
+
+	EADM_LOG(6, "irq");
+	EADM_LOG_HEX(6, irb, sizeof(*irb));
+
+	if ((scsw->stctl & (SCSW_STCTL_ALERT_STATUS | SCSW_STCTL_STATUS_PEND))
+	    && scsw->eswf == 1 && irb->esw.eadm.erw.r)
+		error = -EIO;
+
+	if (scsw->fctl & SCSW_FCTL_CLEAR_FUNC)
+		error = -ETIMEDOUT;
+
+	eadm_subchannel_set_timeout(sch, 0);
+
+	if (private->state != EADM_BUSY) {
+		EADM_LOG(1, "irq unsol");
+		EADM_LOG_HEX(1, irb, sizeof(*irb));
+		private->state = EADM_NOT_OPER;
+		css_sched_sch_todo(sch, SCH_TODO_EVAL);
+		return;
+	}
+	scm_irq_handler((struct aob *)(unsigned long)scsw->aob, error);
+	private->state = EADM_IDLE;
+}
+
+static struct subchannel *eadm_get_idle_sch(void)
+{
+	struct eadm_private *private;
+	struct subchannel *sch;
+	unsigned long flags;
+
+	spin_lock_irqsave(&list_lock, flags);
+	list_for_each_entry(private, &eadm_list, head) {
+		sch = private->sch;
+		spin_lock(sch->lock);
+		if (private->state == EADM_IDLE) {
+			private->state = EADM_BUSY;
+			list_move_tail(&private->head, &eadm_list);
+			spin_unlock(sch->lock);
+			spin_unlock_irqrestore(&list_lock, flags);
+
+			return sch;
+		}
+		spin_unlock(sch->lock);
+	}
+	spin_unlock_irqrestore(&list_lock, flags);
+
+	return NULL;
+}
+
+static int eadm_start_aob(struct aob *aob)
+{
+	struct eadm_private *private;
+	struct subchannel *sch;
+	unsigned long flags;
+	int ret;
+
+	sch = eadm_get_idle_sch();
+	if (!sch)
+		return -EBUSY;
+
+	spin_lock_irqsave(sch->lock, flags);
+	eadm_subchannel_set_timeout(sch, EADM_TIMEOUT);
+	ret = eadm_subchannel_start(sch, aob);
+	if (!ret)
+		goto out_unlock;
+
+	/* Handle start subchannel failure. */
+	eadm_subchannel_set_timeout(sch, 0);
+	private = get_eadm_private(sch);
+	private->state = EADM_NOT_OPER;
+	css_sched_sch_todo(sch, SCH_TODO_EVAL);
+
+out_unlock:
+	spin_unlock_irqrestore(sch->lock, flags);
+
+	return ret;
+}
+
+static int eadm_subchannel_probe(struct subchannel *sch)
+{
+	struct eadm_private *private;
+	int ret;
+
+	private = kzalloc(sizeof(*private), GFP_KERNEL | GFP_DMA);
+	if (!private)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&private->head);
+	init_timer(&private->timer);
+
+	spin_lock_irq(sch->lock);
+	set_eadm_private(sch, private);
+	private->state = EADM_IDLE;
+	private->sch = sch;
+	sch->isc = EADM_SCH_ISC;
+	ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch);
+	if (ret) {
+		set_eadm_private(sch, NULL);
+		spin_unlock_irq(sch->lock);
+		kfree(private);
+		goto out;
+	}
+	spin_unlock_irq(sch->lock);
+
+	spin_lock_irq(&list_lock);
+	list_add(&private->head, &eadm_list);
+	spin_unlock_irq(&list_lock);
+
+	if (dev_get_uevent_suppress(&sch->dev)) {
+		dev_set_uevent_suppress(&sch->dev, 0);
+		kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
+	}
+out:
+	return ret;
+}
+
+static void eadm_quiesce(struct subchannel *sch)
+{
+	int ret;
+
+	do {
+		spin_lock_irq(sch->lock);
+		ret = cio_disable_subchannel(sch);
+		spin_unlock_irq(sch->lock);
+	} while (ret == -EBUSY);
+}
+
+static int eadm_subchannel_remove(struct subchannel *sch)
+{
+	struct eadm_private *private = get_eadm_private(sch);
+
+	spin_lock_irq(&list_lock);
+	list_del(&private->head);
+	spin_unlock_irq(&list_lock);
+
+	eadm_quiesce(sch);
+
+	spin_lock_irq(sch->lock);
+	set_eadm_private(sch, NULL);
+	spin_unlock_irq(sch->lock);
+
+	kfree(private);
+
+	return 0;
+}
+
+static void eadm_subchannel_shutdown(struct subchannel *sch)
+{
+	eadm_quiesce(sch);
+}
+
+static int eadm_subchannel_freeze(struct subchannel *sch)
+{
+	return cio_disable_subchannel(sch);
+}
+
+static int eadm_subchannel_restore(struct subchannel *sch)
+{
+	return cio_enable_subchannel(sch, (u32)(unsigned long)sch);
+}
+
+/**
+ * eadm_subchannel_sch_event - process subchannel event
+ * @sch: subchannel
+ * @process: non-zero if function is called in process context
+ *
+ * An unspecified event occurred for this subchannel. Adjust data according
+ * to the current operational state of the subchannel. Return zero when the
+ * event has been handled sufficiently or -EAGAIN when this function should
+ * be called again in process context.
+ */
+static int eadm_subchannel_sch_event(struct subchannel *sch, int process)
+{
+	struct eadm_private *private;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(sch->lock, flags);
+	if (!device_is_registered(&sch->dev))
+		goto out_unlock;
+
+	if (work_pending(&sch->todo_work))
+		goto out_unlock;
+
+	if (cio_update_schib(sch)) {
+		css_sched_sch_todo(sch, SCH_TODO_UNREG);
+		goto out_unlock;
+	}
+	private = get_eadm_private(sch);
+	if (private->state == EADM_NOT_OPER)
+		private->state = EADM_IDLE;
+
+out_unlock:
+	spin_unlock_irqrestore(sch->lock, flags);
+
+	return ret;
+}
+
+static struct css_device_id eadm_subchannel_ids[] = {
+	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_ADM, },
+	{ /* end of list */ },
+};
+MODULE_DEVICE_TABLE(css, eadm_subchannel_ids);
+
+static struct css_driver eadm_subchannel_driver = {
+	.drv = {
+		.name = "eadm_subchannel",
+		.owner = THIS_MODULE,
+	},
+	.subchannel_type = eadm_subchannel_ids,
+	.irq = eadm_subchannel_irq,
+	.probe = eadm_subchannel_probe,
+	.remove = eadm_subchannel_remove,
+	.shutdown = eadm_subchannel_shutdown,
+	.sch_event = eadm_subchannel_sch_event,
+	.freeze = eadm_subchannel_freeze,
+	.thaw = eadm_subchannel_restore,
+	.restore = eadm_subchannel_restore,
+};
+
+static struct eadm_ops eadm_ops = {
+	.eadm_start = eadm_start_aob,
+	.owner = THIS_MODULE,
+};
+
+static int __init eadm_sch_init(void)
+{
+	int ret;
+
+	if (!css_general_characteristics.eadm)
+		return -ENXIO;
+
+	eadm_debug = debug_register("eadm_log", 16, 1, 16);
+	if (!eadm_debug)
+		return -ENOMEM;
+
+	debug_register_view(eadm_debug, &debug_hex_ascii_view);
+	debug_set_level(eadm_debug, 2);
+
+	isc_register(EADM_SCH_ISC);
+	ret = css_driver_register(&eadm_subchannel_driver);
+	if (ret)
+		goto cleanup;
+
+	register_eadm_ops(&eadm_ops);
+	return ret;
+
+cleanup:
+	isc_unregister(EADM_SCH_ISC);
+	debug_unregister(eadm_debug);
+	return ret;
+}
+
+static void __exit eadm_sch_exit(void)
+{
+	unregister_eadm_ops(&eadm_ops);
+	css_driver_unregister(&eadm_subchannel_driver);
+	isc_unregister(EADM_SCH_ISC);
+	debug_unregister(eadm_debug);
+}
+module_init(eadm_sch_init);
+module_exit(eadm_sch_exit);

drivers/s390/cio/eadm_sch.h

···
+#ifndef EADM_SCH_H
+#define EADM_SCH_H
+
+#include <linux/device.h>
+#include <linux/timer.h>
+#include <linux/list.h>
+#include "orb.h"
+
+struct eadm_private {
+	union orb orb;
+	enum {EADM_IDLE, EADM_BUSY, EADM_NOT_OPER} state;
+	struct timer_list timer;
+	struct list_head head;
+	struct subchannel *sch;
+} __aligned(8);
+
+#define get_eadm_private(n) ((struct eadm_private *)dev_get_drvdata(&n->dev))
+#define set_eadm_private(n, p) (dev_set_drvdata(&n->dev, p))
+
+#endif