drivers/char/hvc_iseries.c - kernel/prism - Git at Google

 /*
  * 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/firmware.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)) {
 		HvCall_writeLogBuffer(buf, count);
 		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))
 			HvCall_writeLogBuffer(buf, len);

 		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,
 	.notifier_add = notifier_add_irq,
 	.notifier_del = notifier_del_irq,
 	.notifier_hangup = notifier_hangup_irq,
 };

 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,
 			VIOCHAR_MAX_DATA);
 	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		= __devexit_p(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 __init 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 __init hvc_vio_init(void)
 {
 	atomic_t wait_flag;
 	int rc;

 	if (!firmware_has_feature(FW_FEATURE_ISERIES))
 		return -EIO;

 	/* +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 __exit hvc_vio_exit(void)
 {
 	vio_unregister_driver(&hvc_vio_driver);
 }
 module_exit(hvc_vio_exit);

 /* the device tree order defines our numbering */
 static int __init 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")) {
 		const 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)) {
 			of_node_put(vty);
 			break;
 		}

 		vtermno = of_get_property(vty, "reg", NULL);
 		if (!vtermno)
 			continue;

 		if (!of_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);
	/*
	* 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/firmware.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)) {
	HvCall_writeLogBuffer(buf, count);
	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))
	HvCall_writeLogBuffer(buf, len);

	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,
	.notifier_add = notifier_add_irq,
	.notifier_del = notifier_del_irq,
	.notifier_hangup = notifier_hangup_irq,
	};

	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,
	VIOCHAR_MAX_DATA);
	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 = __devexit_p(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 __init 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 __init hvc_vio_init(void)
	{
	atomic_t wait_flag;
	int rc;

	if (!firmware_has_feature(FW_FEATURE_ISERIES))
	return -EIO;

	/* +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 __exit hvc_vio_exit(void)
	{
	vio_unregister_driver(&hvc_vio_driver);
	}
	module_exit(hvc_vio_exit);

	/* the device tree order defines our numbering */
	static int __init 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")) {
	const 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)) {
	of_node_put(vty);
	break;
	}

	vtermno = of_get_property(vty, "reg", NULL);
	if (!vtermno)
	continue;

	if (!of_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);