[POWERPC] iseries: A new iSeries console

This driver uses the hvc_console.c infrastructure that is used by the
pSeries virtual and RTAS consoles.  This will allow us to make viocons.c
obsolete and is another step along the way to a combined kernel (as
viocons could not coexist with CONFIG_VT).

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

arch/powerpc/platforms/iseries/Kconfig

@@ -3,7 +3,11 @@ menu "iSeries device drivers"
 	depends on PPC_ISERIES
 
 config VIOCONS
-	tristate "iSeries Virtual Console Support"
+	tristate "iSeries Virtual Console Support (Obsolete)"
+	help
+	  This is the old virtual console driver for legacy iSeries.
+	  You should use the iSeries Hypervisor Virtual Console
+	  support instead.
 
 config VIODASD
 	tristate "iSeries Virtual I/O disk support"

arch/powerpc/platforms/iseries/dt.c

@@ -298,7 +298,8 @@ static void __init dt_vdevices(struct iseries_flat_dt *dt)
 	dt_prop_u32(dt, "#address-cells", 1);
 	dt_prop_u32(dt, "#size-cells", 0);
 
-	dt_do_vdevice(dt, "vty", reg, -1, device_type_serial, NULL, 1);
+	dt_do_vdevice(dt, "vty", reg, -1, device_type_serial,
+			"IBM,iSeries-vty", 1);
 	reg++;
 
 	dt_do_vdevice(dt, "v-scsi", reg, -1, device_type_vscsi,

drivers/char/Kconfig

@@ -610,6 +610,13 @@ config HVC_CONSOLE
 	  console. This driver allows each pSeries partition to have a console
 	  which is accessed via the HMC.
 
+config HVC_ISERIES
+	bool "iSeries Hypervisor Virtual Console support"
+	depends on PPC_ISERIES && !VIOCONS
+	select HVC_DRIVER
+	help
+	  iSeries machines support a hypervisor virtual console.
+
 config HVC_RTAS
 	bool "IBM RTAS Console support"
 	depends on PPC_RTAS

drivers/char/Makefile

@@ -42,6 +42,7 @@ obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o
 obj-$(CONFIG_SX)		+= sx.o generic_serial.o
 obj-$(CONFIG_RIO)		+= rio/ generic_serial.o
 obj-$(CONFIG_HVC_CONSOLE)	+= hvc_vio.o hvsi.o
+obj-$(CONFIG_HVC_ISERIES)	+= hvc_iseries.o
 obj-$(CONFIG_HVC_RTAS)		+= hvc_rtas.o
 obj-$(CONFIG_HVC_DRIVER)	+= hvc_console.o
 obj-$(CONFIG_RAW_DRIVER)	+= raw.o

drivers/char/hvc_iseries.c

@@ -0,0 +1,593 @@
+/*
+ * iSeries vio driver interface to hvc_console.c
+ *
+ * This code is based heavily on hvc_vio.c and viocons.c
+ *
+ * Copyright (C) 2006 Stephen Rothwell, IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+#include <stdarg.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/console.h>
+
+#include <asm/hvconsole.h>
+#include <asm/vio.h>
+#include <asm/prom.h>
+#include <asm/iseries/vio.h>
+#include <asm/iseries/hv_call.h>
+#include <asm/iseries/hv_lp_config.h>
+#include <asm/iseries/hv_lp_event.h>
+
+#include "hvc_console.h"
+
+#define VTTY_PORTS 10
+
+static DEFINE_SPINLOCK(consolelock);
+static DEFINE_SPINLOCK(consoleloglock);
+
+static const char hvc_driver_name[] = "hvc_console";
+
+#define IN_BUF_SIZE	200
+
+/*
+ * Our port information.
+ */
+static struct port_info {
+	HvLpIndex lp;
+	u64 seq;	/* sequence number of last HV send */
+	u64 ack;	/* last ack from HV */
+	struct hvc_struct *hp;
+	int in_start;
+	int in_end;
+	unsigned char in_buf[IN_BUF_SIZE];
+} port_info[VTTY_PORTS] = {
+	[ 0 ... VTTY_PORTS - 1 ] = {
+		.lp = HvLpIndexInvalid
+	}
+};
+
+#define viochar_is_console(pi)	((pi) == &port_info[0])
+
+static struct vio_device_id hvc_driver_table[] __devinitdata = {
+	{"serial", "IBM,iSeries-vty"},
+	{ "", "" }
+};
+MODULE_DEVICE_TABLE(vio, hvc_driver_table);
+
+static void hvlog(char *fmt, ...)
+{
+	int i;
+	unsigned long flags;
+	va_list args;
+	static char buf[256];
+
+	spin_lock_irqsave(&consoleloglock, flags);
+	va_start(args, fmt);
+	i = vscnprintf(buf, sizeof(buf) - 1, fmt, args);
+	va_end(args);
+	buf[i++] = '\r';
+	HvCall_writeLogBuffer(buf, i);
+	spin_unlock_irqrestore(&consoleloglock, flags);
+}
+
+/*
+ * Initialize the common fields in a charLpEvent
+ */
+static void init_data_event(struct viocharlpevent *viochar, HvLpIndex lp)
+{
+	struct HvLpEvent *hev = &viochar->event;
+
+	memset(viochar, 0, sizeof(struct viocharlpevent));
+
+	hev->flags = HV_LP_EVENT_VALID | HV_LP_EVENT_DEFERRED_ACK |
+		HV_LP_EVENT_INT;
+	hev->xType = HvLpEvent_Type_VirtualIo;
+	hev->xSubtype = viomajorsubtype_chario | viochardata;
+	hev->xSourceLp = HvLpConfig_getLpIndex();
+	hev->xTargetLp = lp;
+	hev->xSizeMinus1 = sizeof(struct viocharlpevent);
+	hev->xSourceInstanceId = viopath_sourceinst(lp);
+	hev->xTargetInstanceId = viopath_targetinst(lp);
+}
+
+static int get_chars(uint32_t vtermno, char *buf, int count)
+{
+	struct port_info *pi;
+	int n = 0;
+	unsigned long flags;
+
+	if (vtermno >= VTTY_PORTS)
+		return -EINVAL;
+	if (count == 0)
+		return 0;
+
+	pi = &port_info[vtermno];
+	spin_lock_irqsave(&consolelock, flags);
+
+	if (pi->in_end == 0)
+		goto done;
+
+	n = pi->in_end - pi->in_start;
+	if (n > count)
+		n = count;
+	memcpy(buf, &pi->in_buf[pi->in_start], n);
+	pi->in_start += n;
+	if (pi->in_start == pi->in_end) {
+		pi->in_start = 0;
+		pi->in_end = 0;
+	}
+done:
+	spin_unlock_irqrestore(&consolelock, flags);
+	return n;
+}
+
+static int put_chars(uint32_t vtermno, const char *buf, int count)
+{
+	struct viocharlpevent *viochar;
+	struct port_info *pi;
+	HvLpEvent_Rc hvrc;
+	unsigned long flags;
+	int sent = 0;
+
+	if (vtermno >= VTTY_PORTS)
+		return -EINVAL;
+
+	pi = &port_info[vtermno];
+
+	spin_lock_irqsave(&consolelock, flags);
+
+	if (viochar_is_console(pi) && !viopath_isactive(pi->lp)) {
+		spin_lock_irqsave(&consoleloglock, flags);
+		HvCall_writeLogBuffer(buf, count);
+		spin_unlock_irqrestore(&consoleloglock, flags);
+		sent = count;
+		goto done;
+	}
+
+	viochar = vio_get_event_buffer(viomajorsubtype_chario);
+	if (viochar == NULL) {
+		hvlog("\n\rviocons: Can't get viochar buffer.");
+		goto done;
+	}
+
+	while ((count > 0) && ((pi->seq - pi->ack) < VIOCHAR_WINDOW)) {
+		int len;
+
+		len = (count > VIOCHAR_MAX_DATA) ? VIOCHAR_MAX_DATA : count;
+
+		if (viochar_is_console(pi)) {
+			spin_lock_irqsave(&consoleloglock, flags);
+			HvCall_writeLogBuffer(buf, len);
+			spin_unlock_irqrestore(&consoleloglock, flags);
+		}
+
+		init_data_event(viochar, pi->lp);
+
+		viochar->len = len;
+		viochar->event.xCorrelationToken = pi->seq++;
+		viochar->event.xSizeMinus1 =
+			offsetof(struct viocharlpevent, data) + len;
+
+		memcpy(viochar->data, buf, len);
+
+		hvrc = HvCallEvent_signalLpEvent(&viochar->event);
+		if (hvrc)
+			hvlog("\n\rerror sending event! return code %d\n\r",
+				(int)hvrc);
+		sent += len;
+		count -= len;
+		buf += len;
+	}
+
+	vio_free_event_buffer(viomajorsubtype_chario, viochar);
+done:
+	spin_unlock_irqrestore(&consolelock, flags);
+	return sent;
+}
+
+static struct hv_ops hvc_get_put_ops = {
+	.get_chars = get_chars,
+	.put_chars = put_chars,
+};
+
+static int __devinit hvc_vio_probe(struct vio_dev *vdev,
+			const struct vio_device_id *id)
+{
+	struct hvc_struct *hp;
+	struct port_info *pi;
+
+	/* probed with invalid parameters. */
+	if (!vdev || !id)
+		return -EPERM;
+
+	if (vdev->unit_address >= VTTY_PORTS)
+		return -ENODEV;
+
+	pi = &port_info[vdev->unit_address];
+
+	hp = hvc_alloc(vdev->unit_address, vdev->irq, &hvc_get_put_ops);
+	if (IS_ERR(hp))
+		return PTR_ERR(hp);
+	pi->hp = hp;
+	dev_set_drvdata(&vdev->dev, pi);
+
+	return 0;
+}
+
+static int __devexit hvc_vio_remove(struct vio_dev *vdev)
+{
+	struct port_info *pi = dev_get_drvdata(&vdev->dev);
+	struct hvc_struct *hp = pi->hp;
+
+	return hvc_remove(hp);
+}
+
+static struct vio_driver hvc_vio_driver = {
+	.id_table	= hvc_driver_table,
+	.probe		= hvc_vio_probe,
+	.remove		= hvc_vio_remove,
+	.driver		= {
+		.name	= hvc_driver_name,
+		.owner	= THIS_MODULE,
+	}
+};
+
+static void hvc_open_event(struct HvLpEvent *event)
+{
+	unsigned long flags;
+	struct viocharlpevent *cevent = (struct viocharlpevent *)event;
+	u8 port = cevent->virtual_device;
+	struct port_info *pi;
+	int reject = 0;
+
+	if (hvlpevent_is_ack(event)) {
+		if (port >= VTTY_PORTS)
+			return;
+
+		spin_lock_irqsave(&consolelock, flags);
+
+		pi = &port_info[port];
+		if (event->xRc == HvLpEvent_Rc_Good) {
+			pi->seq = pi->ack = 0;
+			/*
+			 * This line allows connections from the primary
+			 * partition but once one is connected from the
+			 * primary partition nothing short of a reboot
+			 * of linux will allow access from the hosting
+			 * partition again without a required iSeries fix.
+			 */
+			pi->lp = event->xTargetLp;
+		}
+
+		spin_unlock_irqrestore(&consolelock, flags);
+		if (event->xRc != HvLpEvent_Rc_Good)
+			printk(KERN_WARNING
+			       "hvc: handle_open_event: event->xRc == (%d).\n",
+			       event->xRc);
+
+		if (event->xCorrelationToken != 0) {
+			atomic_t *aptr= (atomic_t *)event->xCorrelationToken;
+			atomic_set(aptr, 1);
+		} else
+			printk(KERN_WARNING
+			       "hvc: weird...got open ack without atomic\n");
+		return;
+	}
+
+	/* This had better require an ack, otherwise complain */
+	if (!hvlpevent_need_ack(event)) {
+		printk(KERN_WARNING "hvc: viocharopen without ack bit!\n");
+		return;
+	}
+
+	spin_lock_irqsave(&consolelock, flags);
+
+	/* Make sure this is a good virtual tty */
+	if (port >= VTTY_PORTS) {
+		event->xRc = HvLpEvent_Rc_SubtypeError;
+		cevent->subtype_result_code = viorc_openRejected;
+		/*
+		 * Flag state here since we can't printk while holding
+		 * the consolelock spinlock.
+		 */
+		reject = 1;
+	} else {
+		pi = &port_info[port];
+		if ((pi->lp != HvLpIndexInvalid) &&
+				(pi->lp != event->xSourceLp)) {
+			/*
+			 * If this is tty is already connected to a different
+			 * partition, fail.
+			 */
+			event->xRc = HvLpEvent_Rc_SubtypeError;
+			cevent->subtype_result_code = viorc_openRejected;
+			reject = 2;
+		} else {
+			pi->lp = event->xSourceLp;
+			event->xRc = HvLpEvent_Rc_Good;
+			cevent->subtype_result_code = viorc_good;
+			pi->seq = pi->ack = 0;
+		}
+	}
+
+	spin_unlock_irqrestore(&consolelock, flags);
+
+	if (reject == 1)
+		printk(KERN_WARNING "hvc: open rejected: bad virtual tty.\n");
+	else if (reject == 2)
+		printk(KERN_WARNING "hvc: open rejected: console in exclusive "
+				"use by another partition.\n");
+
+	/* Return the acknowledgement */
+	HvCallEvent_ackLpEvent(event);
+}
+
+/*
+ * Handle a close charLpEvent.  This should ONLY be an Interrupt because the
+ * virtual console should never actually issue a close event to the hypervisor
+ * because the virtual console never goes away.  A close event coming from the
+ * hypervisor simply means that there are no client consoles connected to the
+ * virtual console.
+ */
+static void hvc_close_event(struct HvLpEvent *event)
+{
+	unsigned long flags;
+	struct viocharlpevent *cevent = (struct viocharlpevent *)event;
+	u8 port = cevent->virtual_device;
+
+	if (!hvlpevent_is_int(event)) {
+		printk(KERN_WARNING
+			"hvc: got unexpected close acknowlegement\n");
+		return;
+	}
+
+	if (port >= VTTY_PORTS) {
+		printk(KERN_WARNING
+			"hvc: close message from invalid virtual device.\n");
+		return;
+	}
+
+	/* For closes, just mark the console partition invalid */
+	spin_lock_irqsave(&consolelock, flags);
+
+	if (port_info[port].lp == event->xSourceLp)
+		port_info[port].lp = HvLpIndexInvalid;
+
+	spin_unlock_irqrestore(&consolelock, flags);
+}
+
+static void hvc_data_event(struct HvLpEvent *event)
+{
+	unsigned long flags;
+	struct viocharlpevent *cevent = (struct viocharlpevent *)event;
+	struct port_info *pi;
+	int n;
+	u8 port = cevent->virtual_device;
+
+	if (port >= VTTY_PORTS) {
+		printk(KERN_WARNING "hvc: data on invalid virtual device %d\n",
+				port);
+		return;
+	}
+	if (cevent->len == 0)
+		return;
+
+	/*
+	 * Change 05/01/2003 - Ryan Arnold: If a partition other than
+	 * the current exclusive partition tries to send us data
+	 * events then just drop them on the floor because we don't
+	 * want his stinking data.  He isn't authorized to receive
+	 * data because he wasn't the first one to get the console,
+	 * therefore he shouldn't be allowed to send data either.
+	 * This will work without an iSeries fix.
+	 */
+	pi = &port_info[port];
+	if (pi->lp != event->xSourceLp)
+		return;
+
+	spin_lock_irqsave(&consolelock, flags);
+
+	n = IN_BUF_SIZE - pi->in_end;
+	if (n > cevent->len)
+		n = cevent->len;
+	if (n > 0) {
+		memcpy(&pi->in_buf[pi->in_end], cevent->data, n);
+		pi->in_end += n;
+	}
+	spin_unlock_irqrestore(&consolelock, flags);
+	if (n == 0)
+		printk(KERN_WARNING "hvc: input buffer overflow\n");
+}
+
+static void hvc_ack_event(struct HvLpEvent *event)
+{
+	struct viocharlpevent *cevent = (struct viocharlpevent *)event;
+	unsigned long flags;
+	u8 port = cevent->virtual_device;
+
+	if (port >= VTTY_PORTS) {
+		printk(KERN_WARNING "hvc: data on invalid virtual device\n");
+		return;
+	}
+
+	spin_lock_irqsave(&consolelock, flags);
+	port_info[port].ack = event->xCorrelationToken;
+	spin_unlock_irqrestore(&consolelock, flags);
+}
+
+static void hvc_config_event(struct HvLpEvent *event)
+{
+	struct viocharlpevent *cevent = (struct viocharlpevent *)event;
+
+	if (cevent->data[0] == 0x01)
+		printk(KERN_INFO "hvc: window resized to %d: %d: %d: %d\n",
+		       cevent->data[1], cevent->data[2],
+		       cevent->data[3], cevent->data[4]);
+	else
+		printk(KERN_WARNING "hvc: unknown config event\n");
+}
+
+static void hvc_handle_event(struct HvLpEvent *event)
+{
+	int charminor;
+
+	if (event == NULL)
+		return;
+
+	charminor = event->xSubtype & VIOMINOR_SUBTYPE_MASK;
+	switch (charminor) {
+	case viocharopen:
+		hvc_open_event(event);
+		break;
+	case viocharclose:
+		hvc_close_event(event);
+		break;
+	case viochardata:
+		hvc_data_event(event);
+		break;
+	case viocharack:
+		hvc_ack_event(event);
+		break;
+	case viocharconfig:
+		hvc_config_event(event);
+		break;
+	default:
+		if (hvlpevent_is_int(event) && hvlpevent_need_ack(event)) {
+			event->xRc = HvLpEvent_Rc_InvalidSubtype;
+			HvCallEvent_ackLpEvent(event);
+		}
+	}
+}
+
+static int send_open(HvLpIndex remoteLp, void *sem)
+{
+	return HvCallEvent_signalLpEventFast(remoteLp,
+			HvLpEvent_Type_VirtualIo,
+			viomajorsubtype_chario | viocharopen,
+			HvLpEvent_AckInd_DoAck, HvLpEvent_AckType_ImmediateAck,
+			viopath_sourceinst(remoteLp),
+			viopath_targetinst(remoteLp),
+			(u64)(unsigned long)sem, VIOVERSION << 16,
+			0, 0, 0, 0);
+}
+
+static int hvc_vio_init(void)
+{
+	atomic_t wait_flag;
+	int rc;
+
+	/* +2 for fudge */
+	rc = viopath_open(HvLpConfig_getPrimaryLpIndex(),
+			viomajorsubtype_chario, VIOCHAR_WINDOW + 2);
+	if (rc)
+		printk(KERN_WARNING "hvc: error opening to primary %d\n", rc);
+
+	if (viopath_hostLp == HvLpIndexInvalid)
+		vio_set_hostlp();
+
+	/*
+	 * And if the primary is not the same as the hosting LP, open to the
+	 * hosting lp
+	 */
+	if ((viopath_hostLp != HvLpIndexInvalid) &&
+	    (viopath_hostLp != HvLpConfig_getPrimaryLpIndex())) {
+		printk(KERN_INFO "hvc: open path to hosting (%d)\n",
+				viopath_hostLp);
+		rc = viopath_open(viopath_hostLp, viomajorsubtype_chario,
+				VIOCHAR_WINDOW + 2);	/* +2 for fudge */
+		if (rc)
+			printk(KERN_WARNING
+				"error opening to partition %d: %d\n",
+				viopath_hostLp, rc);
+	}
+
+	if (vio_setHandler(viomajorsubtype_chario, hvc_handle_event) < 0)
+		printk(KERN_WARNING
+			"hvc: error seting handler for console events!\n");
+
+	/*
+	 * First, try to open the console to the hosting lp.
+	 * Wait on a semaphore for the response.
+	 */
+	atomic_set(&wait_flag, 0);
+	if ((viopath_isactive(viopath_hostLp)) &&
+	    (send_open(viopath_hostLp, &wait_flag) == 0)) {
+		printk(KERN_INFO "hvc: hosting partition %d\n", viopath_hostLp);
+		while (atomic_read(&wait_flag) == 0)
+			mb();
+		atomic_set(&wait_flag, 0);
+	}
+
+	/*
+	 * If we don't have an active console, try the primary
+	 */
+	if ((!viopath_isactive(port_info[0].lp)) &&
+	    (viopath_isactive(HvLpConfig_getPrimaryLpIndex())) &&
+	    (send_open(HvLpConfig_getPrimaryLpIndex(), &wait_flag) == 0)) {
+		printk(KERN_INFO "hvc: opening console to primary partition\n");
+		while (atomic_read(&wait_flag) == 0)
+			mb();
+	}
+
+	/* Register as a vio device to receive callbacks */
+	rc = vio_register_driver(&hvc_vio_driver);
+
+	return rc;
+}
+module_init(hvc_vio_init); /* after drivers/char/hvc_console.c */
+
+static void hvc_vio_exit(void)
+{
+	vio_unregister_driver(&hvc_vio_driver);
+}
+module_exit(hvc_vio_exit);
+
+/* the device tree order defines our numbering */
+static int hvc_find_vtys(void)
+{
+	struct device_node *vty;
+	int num_found = 0;
+
+	for (vty = of_find_node_by_name(NULL, "vty"); vty != NULL;
+			vty = of_find_node_by_name(vty, "vty")) {
+		uint32_t *vtermno;
+
+		/* We have statically defined space for only a certain number
+		 * of console adapters.
+		 */
+		if ((num_found >= MAX_NR_HVC_CONSOLES) ||
+				(num_found >= VTTY_PORTS))
+			break;
+
+		vtermno = (uint32_t *)get_property(vty, "reg", NULL);
+		if (!vtermno)
+			continue;
+
+		if (!device_is_compatible(vty, "IBM,iSeries-vty"))
+			continue;
+
+		if (num_found == 0)
+			add_preferred_console("hvc", 0, NULL);
+		hvc_instantiate(*vtermno, num_found, &hvc_get_put_ops);
+		++num_found;
+	}
+
+	return num_found;
+}
+console_initcall(hvc_find_vtys);

drivers/char/viocons.c

@@ -43,7 +43,6 @@
 #include <linux/sysrq.h>
 
 #include <asm/iseries/vio.h>
-
 #include <asm/iseries/hv_lp_event.h>
 #include <asm/iseries/hv_call_event.h>
 #include <asm/iseries/hv_lp_config.h>
@@ -67,35 +66,6 @@ static int vio_sysrq_pressed;
 extern int sysrq_enabled;
 #endif
 
-/*
- * The structure of the events that flow between us and OS/400.  You can't
- * mess with this unless the OS/400 side changes too
- */
-struct viocharlpevent {
-	struct HvLpEvent event;
-	u32 reserved;
-	u16 version;
-	u16 subtype_result_code;
-	u8 virtual_device;
-	u8 len;
-	u8 data[VIOCHAR_MAX_DATA];
-};
-
-#define VIOCHAR_WINDOW		10
-#define VIOCHAR_HIGHWATERMARK	3
-
-enum viocharsubtype {
-	viocharopen = 0x0001,
-	viocharclose = 0x0002,
-	viochardata = 0x0003,
-	viocharack = 0x0004,
-	viocharconfig = 0x0005
-};
-
-enum viochar_rc {
-	viochar_rc_ebusy = 1
-};
-
 #define VIOCHAR_NUM_BUF		16
 
 /*
@@ -1183,6 +1153,7 @@ static int __init viocons_init(void)
 		port_info[i].magic = VIOTTY_MAGIC;
 	}
 	HvCall_setLogBufferFormatAndCodepage(HvCall_LogBuffer_ASCII, 437);
+	add_preferred_console("viocons", 0, NULL);
 	register_console(&viocons_early);
 	return 0;
 }

include/asm-powerpc/iseries/vio.h

@@ -122,6 +122,34 @@ enum viorc {
 	viorc_openRejected = 0x0301
 };
 
+/*
+ * The structure of the events that flow between us and OS/400 for chario
+ * events.  You can't mess with this unless the OS/400 side changes too.
+ */
+struct viocharlpevent {
+	struct HvLpEvent event;
+	u32 reserved;
+	u16 version;
+	u16 subtype_result_code;
+	u8 virtual_device;
+	u8 len;
+	u8 data[VIOCHAR_MAX_DATA];
+};
+
+#define VIOCHAR_WINDOW		10
+
+enum viocharsubtype {
+	viocharopen = 0x0001,
+	viocharclose = 0x0002,
+	viochardata = 0x0003,
+	viocharack = 0x0004,
+	viocharconfig = 0x0005
+};
+
+enum viochar_rc {
+	viochar_rc_ebusy = 1
+};
+
 struct device;
 
 extern struct device *iSeries_vio_dev;