drivers/char/snsc.c - linux - Git at Google

 /*
  * SN Platform system controller communication support
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
  * Copyright (C) 2004, 2006 Silicon Graphics, Inc. All rights reserved.
  */

 /*
  * System controller communication driver
  *
  * This driver allows a user process to communicate with the system
  * controller (a.k.a. "IRouter") network in an SGI SN system.
  */

 #include <linux/interrupt.h>
 #include <linux/sched.h>
 #include <linux/device.h>
 #include <linux/poll.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <asm/sn/io.h>
 #include <asm/sn/sn_sal.h>
 #include <asm/sn/module.h>
 #include <asm/sn/geo.h>
 #include <asm/sn/nodepda.h>
 #include "snsc.h"

 #define SYSCTL_BASENAME	"snsc"

 #define SCDRV_BUFSZ	2048
 #define SCDRV_TIMEOUT	1000

 static DEFINE_MUTEX(scdrv_mutex);
 static irqreturn_t
 scdrv_interrupt(int irq, void *subch_data)
 {
 	struct subch_data_s *sd = subch_data;
 	unsigned long flags;
 	int status;

 	spin_lock_irqsave(&sd->sd_rlock, flags);
 	spin_lock(&sd->sd_wlock);
 	status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);

 	if (status > 0) {
 		if (status & SAL_IROUTER_INTR_RECV) {
 			wake_up(&sd->sd_rq);
 		}
 		if (status & SAL_IROUTER_INTR_XMIT) {
 			ia64_sn_irtr_intr_disable
 			    (sd->sd_nasid, sd->sd_subch,
 			     SAL_IROUTER_INTR_XMIT);
 			wake_up(&sd->sd_wq);
 		}
 	}
 	spin_unlock(&sd->sd_wlock);
 	spin_unlock_irqrestore(&sd->sd_rlock, flags);
 	return IRQ_HANDLED;
 }

 /*
  * scdrv_open
  *
  * Reserve a subchannel for system controller communication.
  */

 static int
 scdrv_open(struct inode *inode, struct file *file)
 {
 	struct sysctl_data_s *scd;
 	struct subch_data_s *sd;
 	int rv;

 	/* look up device info for this device file */
 	scd = container_of(inode->i_cdev, struct sysctl_data_s, scd_cdev);

 	/* allocate memory for subchannel data */
 	sd = kzalloc(sizeof (struct subch_data_s), GFP_KERNEL);
 	if (sd == NULL) {
 		printk("%s: couldn't allocate subchannel data\n",
 		       __func__);
 		return -ENOMEM;
 	}

 	/* initialize subch_data_s fields */
 	sd->sd_nasid = scd->scd_nasid;
 	sd->sd_subch = ia64_sn_irtr_open(scd->scd_nasid);

 	if (sd->sd_subch < 0) {
 		kfree(sd);
 		printk("%s: couldn't allocate subchannel\n", __func__);
 		return -EBUSY;
 	}

 	spin_lock_init(&sd->sd_rlock);
 	spin_lock_init(&sd->sd_wlock);
 	init_waitqueue_head(&sd->sd_rq);
 	init_waitqueue_head(&sd->sd_wq);
 	sema_init(&sd->sd_rbs, 1);
 	sema_init(&sd->sd_wbs, 1);

 	file->private_data = sd;

 	/* hook this subchannel up to the system controller interrupt */
 	mutex_lock(&scdrv_mutex);
 	rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
 			 IRQF_SHARED | IRQF_DISABLED,
 			 SYSCTL_BASENAME, sd);
 	if (rv) {
 		ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
 		kfree(sd);
 		printk("%s: irq request failed (%d)\n", __func__, rv);
 		mutex_unlock(&scdrv_mutex);
 		return -EBUSY;
 	}
 	mutex_unlock(&scdrv_mutex);
 	return 0;
 }

 /*
  * scdrv_release
  *
  * Release a previously-reserved subchannel.
  */

 static int
 scdrv_release(struct inode *inode, struct file *file)
 {
 	struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 	int rv;

 	/* free the interrupt */
 	free_irq(SGI_UART_VECTOR, sd);

 	/* ask SAL to close the subchannel */
 	rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);

 	kfree(sd);
 	return rv;
 }

 /*
  * scdrv_read
  *
  * Called to read bytes from the open IRouter pipe.
  *
  */

 static inline int
 read_status_check(struct subch_data_s *sd, int *len)
 {
 	return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
 }

 static ssize_t
 scdrv_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos)
 {
 	int status;
 	int len;
 	unsigned long flags;
 	struct subch_data_s *sd = (struct subch_data_s *) file->private_data;

 	/* try to get control of the read buffer */
 	if (down_trylock(&sd->sd_rbs)) {
 		/* somebody else has it now;
 		 * if we're non-blocking, then exit...
 		 */
 		if (file->f_flags & O_NONBLOCK) {
 			return -EAGAIN;
 		}
 		/* ...or if we want to block, then do so here */
 		if (down_interruptible(&sd->sd_rbs)) {
 			/* something went wrong with wait */
 			return -ERESTARTSYS;
 		}
 	}

 	/* anything to read? */
 	len = CHUNKSIZE;
 	spin_lock_irqsave(&sd->sd_rlock, flags);
 	status = read_status_check(sd, &len);

 	/* if not, and we're blocking I/O, loop */
 	while (status < 0) {
 		DECLARE_WAITQUEUE(wait, current);

 		if (file->f_flags & O_NONBLOCK) {
 			spin_unlock_irqrestore(&sd->sd_rlock, flags);
 			up(&sd->sd_rbs);
 			return -EAGAIN;
 		}

 		len = CHUNKSIZE;
 		set_current_state(TASK_INTERRUPTIBLE);
 		add_wait_queue(&sd->sd_rq, &wait);
 		spin_unlock_irqrestore(&sd->sd_rlock, flags);

 		schedule_timeout(SCDRV_TIMEOUT);

 		remove_wait_queue(&sd->sd_rq, &wait);
 		if (signal_pending(current)) {
 			/* wait was interrupted */
 			up(&sd->sd_rbs);
 			return -ERESTARTSYS;
 		}

 		spin_lock_irqsave(&sd->sd_rlock, flags);
 		status = read_status_check(sd, &len);
 	}
 	spin_unlock_irqrestore(&sd->sd_rlock, flags);

 	if (len > 0) {
 		/* we read something in the last read_status_check(); copy
 		 * it out to user space
 		 */
 		if (count < len) {
 			pr_debug("%s: only accepting %d of %d bytes\n",
 				 __func__, (int) count, len);
 		}
 		len = min((int) count, len);
 		if (copy_to_user(buf, sd->sd_rb, len))
 			len = -EFAULT;
 	}

 	/* release the read buffer and wake anyone who might be
 	 * waiting for it
 	 */
 	up(&sd->sd_rbs);

 	/* return the number of characters read in */
 	return len;
 }

 /*
  * scdrv_write
  *
  * Writes a chunk of an IRouter packet (or other system controller data)
  * to the system controller.
  *
  */
 static inline int
 write_status_check(struct subch_data_s *sd, int count)
 {
 	return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
 }

 static ssize_t
 scdrv_write(struct file *file, const char __user *buf,
 	    size_t count, loff_t *f_pos)
 {
 	unsigned long flags;
 	int status;
 	struct subch_data_s *sd = (struct subch_data_s *) file->private_data;

 	/* try to get control of the write buffer */
 	if (down_trylock(&sd->sd_wbs)) {
 		/* somebody else has it now;
 		 * if we're non-blocking, then exit...
 		 */
 		if (file->f_flags & O_NONBLOCK) {
 			return -EAGAIN;
 		}
 		/* ...or if we want to block, then do so here */
 		if (down_interruptible(&sd->sd_wbs)) {
 			/* something went wrong with wait */
 			return -ERESTARTSYS;
 		}
 	}

 	count = min((int) count, CHUNKSIZE);
 	if (copy_from_user(sd->sd_wb, buf, count)) {
 		up(&sd->sd_wbs);
 		return -EFAULT;
 	}

 	/* try to send the buffer */
 	spin_lock_irqsave(&sd->sd_wlock, flags);
 	status = write_status_check(sd, count);

 	/* if we failed, and we want to block, then loop */
 	while (status <= 0) {
 		DECLARE_WAITQUEUE(wait, current);

 		if (file->f_flags & O_NONBLOCK) {
 			spin_unlock(&sd->sd_wlock);
 			up(&sd->sd_wbs);
 			return -EAGAIN;
 		}

 		set_current_state(TASK_INTERRUPTIBLE);
 		add_wait_queue(&sd->sd_wq, &wait);
 		spin_unlock_irqrestore(&sd->sd_wlock, flags);

 		schedule_timeout(SCDRV_TIMEOUT);

 		remove_wait_queue(&sd->sd_wq, &wait);
 		if (signal_pending(current)) {
 			/* wait was interrupted */
 			up(&sd->sd_wbs);
 			return -ERESTARTSYS;
 		}

 		spin_lock_irqsave(&sd->sd_wlock, flags);
 		status = write_status_check(sd, count);
 	}
 	spin_unlock_irqrestore(&sd->sd_wlock, flags);

 	/* release the write buffer and wake anyone who's waiting for it */
 	up(&sd->sd_wbs);

 	/* return the number of characters accepted (should be the complete
 	 * "chunk" as requested)
 	 */
 	if ((status >= 0) && (status < count)) {
 		pr_debug("Didn't accept the full chunk; %d of %d\n",
 			 status, (int) count);
 	}
 	return status;
 }

 static unsigned int
 scdrv_poll(struct file *file, struct poll_table_struct *wait)
 {
 	unsigned int mask = 0;
 	int status = 0;
 	struct subch_data_s *sd = (struct subch_data_s *) file->private_data;
 	unsigned long flags;

 	poll_wait(file, &sd->sd_rq, wait);
 	poll_wait(file, &sd->sd_wq, wait);

 	spin_lock_irqsave(&sd->sd_rlock, flags);
 	spin_lock(&sd->sd_wlock);
 	status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
 	spin_unlock(&sd->sd_wlock);
 	spin_unlock_irqrestore(&sd->sd_rlock, flags);

 	if (status > 0) {
 		if (status & SAL_IROUTER_INTR_RECV) {
 			mask |= POLLIN | POLLRDNORM;
 		}
 		if (status & SAL_IROUTER_INTR_XMIT) {
 			mask |= POLLOUT | POLLWRNORM;
 		}
 	}

 	return mask;
 }

 static const struct file_operations scdrv_fops = {
 	.owner =	THIS_MODULE,
 	.read =		scdrv_read,
 	.write =	scdrv_write,
 	.poll =		scdrv_poll,
 	.open =		scdrv_open,
 	.release =	scdrv_release,
 };

 static struct class *snsc_class;

 /*
  * scdrv_init
  *
  * Called at boot time to initialize the system controller communication
  * facility.
  */
 int __init
 scdrv_init(void)
 {
 	geoid_t geoid;
 	cnodeid_t cnode;
 	char devname[32];
 	char *devnamep;
 	struct sysctl_data_s *scd;
 	void *salbuf;
 	dev_t first_dev, dev;
 	nasid_t event_nasid;

 	if (!ia64_platform_is("sn2"))
 		return -ENODEV;

 	event_nasid = ia64_sn_get_console_nasid();

 	if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
 				SYSCTL_BASENAME) < 0) {
 		printk("%s: failed to register SN system controller device\n",
 		       __func__);
 		return -ENODEV;
 	}
 	snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);

 	for (cnode = 0; cnode < num_cnodes; cnode++) {
 			geoid = cnodeid_get_geoid(cnode);
 			devnamep = devname;
 			format_module_id(devnamep, geo_module(geoid),
 					 MODULE_FORMAT_BRIEF);
 			devnamep = devname + strlen(devname);
 			sprintf(devnamep, "^%d#%d", geo_slot(geoid),
 				geo_slab(geoid));

 			/* allocate sysctl device data */
 			scd = kzalloc(sizeof (struct sysctl_data_s),
 				      GFP_KERNEL);
 			if (!scd) {
 				printk("%s: failed to allocate device info"
 				       "for %s/%s\n", __func__,
 				       SYSCTL_BASENAME, devname);
 				continue;
 			}

 			/* initialize sysctl device data fields */
 			scd->scd_nasid = cnodeid_to_nasid(cnode);
 			if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
 				printk("%s: failed to allocate driver buffer"
 				       "(%s%s)\n", __func__,
 				       SYSCTL_BASENAME, devname);
 				kfree(scd);
 				continue;
 			}

 			if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
 					      SCDRV_BUFSZ) < 0) {
 				printk
 				    ("%s: failed to initialize SAL for"
 				     " system controller communication"
 				     " (%s/%s): outdated PROM?\n",
 				     __func__, SYSCTL_BASENAME, devname);
 				kfree(scd);
 				kfree(salbuf);
 				continue;
 			}

 			dev = first_dev + cnode;
 			cdev_init(&scd->scd_cdev, &scdrv_fops);
 			if (cdev_add(&scd->scd_cdev, dev, 1)) {
 				printk("%s: failed to register system"
 				       " controller device (%s%s)\n",
 				       __func__, SYSCTL_BASENAME, devname);
 				kfree(scd);
 				kfree(salbuf);
 				continue;
 			}

 			device_create(snsc_class, NULL, dev, NULL,
 				      "%s", devname);

 			ia64_sn_irtr_intr_enable(scd->scd_nasid,
 						 0 /*ignored */ ,
 						 SAL_IROUTER_INTR_RECV);

                         /* on the console nasid, prepare to receive
                          * system controller environmental events
                          */
                         if(scd->scd_nasid == event_nasid) {
                                 scdrv_event_init(scd);
                         }
 	}
 	return 0;
 }

 module_init(scdrv_init);
	/*
	* SN Platform system controller communication support
	*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*
	* Copyright (C) 2004, 2006 Silicon Graphics, Inc. All rights reserved.
	*/

	/*
	* System controller communication driver
	*
	* This driver allows a user process to communicate with the system
	* controller (a.k.a. "IRouter") network in an SGI SN system.
	*/

	#include <linux/interrupt.h>
	#include <linux/sched.h>
	#include <linux/device.h>
	#include <linux/poll.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/mutex.h>
	#include <asm/sn/io.h>
	#include <asm/sn/sn_sal.h>
	#include <asm/sn/module.h>
	#include <asm/sn/geo.h>
	#include <asm/sn/nodepda.h>
	#include "snsc.h"

	#define SYSCTL_BASENAME "snsc"

	#define SCDRV_BUFSZ 2048
	#define SCDRV_TIMEOUT 1000

	static DEFINE_MUTEX(scdrv_mutex);
	static irqreturn_t
	scdrv_interrupt(int irq, void *subch_data)
	{
	struct subch_data_s *sd = subch_data;
	unsigned long flags;
	int status;

	spin_lock_irqsave(&sd->sd_rlock, flags);
	spin_lock(&sd->sd_wlock);
	status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);

	if (status > 0) {
	if (status & SAL_IROUTER_INTR_RECV) {
	wake_up(&sd->sd_rq);
	}
	if (status & SAL_IROUTER_INTR_XMIT) {
	ia64_sn_irtr_intr_disable
	(sd->sd_nasid, sd->sd_subch,
	SAL_IROUTER_INTR_XMIT);
	wake_up(&sd->sd_wq);
	}
	}
	spin_unlock(&sd->sd_wlock);
	spin_unlock_irqrestore(&sd->sd_rlock, flags);
	return IRQ_HANDLED;
	}

	/*
	* scdrv_open
	*
	* Reserve a subchannel for system controller communication.
	*/

	static int
	scdrv_open(struct inode inode, struct file file)
	{
	struct sysctl_data_s *scd;
	struct subch_data_s *sd;
	int rv;

	/* look up device info for this device file */
	scd = container_of(inode->i_cdev, struct sysctl_data_s, scd_cdev);

	/* allocate memory for subchannel data */
	sd = kzalloc(sizeof (struct subch_data_s), GFP_KERNEL);
	if (sd == NULL) {
	printk("%s: couldn't allocate subchannel data\n",
	__func__);
	return -ENOMEM;
	}

	/* initialize subch_data_s fields */
	sd->sd_nasid = scd->scd_nasid;
	sd->sd_subch = ia64_sn_irtr_open(scd->scd_nasid);

	if (sd->sd_subch < 0) {
	kfree(sd);
	printk("%s: couldn't allocate subchannel\n", __func__);
	return -EBUSY;
	}

	spin_lock_init(&sd->sd_rlock);
	spin_lock_init(&sd->sd_wlock);
	init_waitqueue_head(&sd->sd_rq);
	init_waitqueue_head(&sd->sd_wq);
	sema_init(&sd->sd_rbs, 1);
	sema_init(&sd->sd_wbs, 1);

	file->private_data = sd;

	/* hook this subchannel up to the system controller interrupt */
	mutex_lock(&scdrv_mutex);
	rv = request_irq(SGI_UART_VECTOR, scdrv_interrupt,
	IRQF_SHARED \| IRQF_DISABLED,
	SYSCTL_BASENAME, sd);
	if (rv) {
	ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);
	kfree(sd);
	printk("%s: irq request failed (%d)\n", __func__, rv);
	mutex_unlock(&scdrv_mutex);
	return -EBUSY;
	}
	mutex_unlock(&scdrv_mutex);
	return 0;
	}

	/*
	* scdrv_release
	*
	* Release a previously-reserved subchannel.
	*/

	static int
	scdrv_release(struct inode inode, struct file file)
	{
	struct subch_data_s sd = (struct subch_data_s ) file->private_data;
	int rv;

	/* free the interrupt */
	free_irq(SGI_UART_VECTOR, sd);

	/* ask SAL to close the subchannel */
	rv = ia64_sn_irtr_close(sd->sd_nasid, sd->sd_subch);

	kfree(sd);
	return rv;
	}

	/*
	* scdrv_read
	*
	* Called to read bytes from the open IRouter pipe.
	*
	*/

	static inline int
	read_status_check(struct subch_data_s sd, int len)
	{
	return ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch, sd->sd_rb, len);
	}

	static ssize_t
	scdrv_read(struct file file, char __user buf, size_t count, loff_t *f_pos)
	{
	int status;
	int len;
	unsigned long flags;
	struct subch_data_s sd = (struct subch_data_s ) file->private_data;

	/* try to get control of the read buffer */
	if (down_trylock(&sd->sd_rbs)) {
	/* somebody else has it now;
	* if we're non-blocking, then exit...
	*/
	if (file->f_flags & O_NONBLOCK) {
	return -EAGAIN;
	}
	/* ...or if we want to block, then do so here */
	if (down_interruptible(&sd->sd_rbs)) {
	/* something went wrong with wait */
	return -ERESTARTSYS;
	}
	}

	/* anything to read? */
	len = CHUNKSIZE;
	spin_lock_irqsave(&sd->sd_rlock, flags);
	status = read_status_check(sd, &len);

	/* if not, and we're blocking I/O, loop */
	while (status < 0) {
	DECLARE_WAITQUEUE(wait, current);

	if (file->f_flags & O_NONBLOCK) {
	spin_unlock_irqrestore(&sd->sd_rlock, flags);
	up(&sd->sd_rbs);
	return -EAGAIN;
	}

	len = CHUNKSIZE;
	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&sd->sd_rq, &wait);
	spin_unlock_irqrestore(&sd->sd_rlock, flags);

	schedule_timeout(SCDRV_TIMEOUT);

	remove_wait_queue(&sd->sd_rq, &wait);
	if (signal_pending(current)) {
	/* wait was interrupted */
	up(&sd->sd_rbs);
	return -ERESTARTSYS;
	}

	spin_lock_irqsave(&sd->sd_rlock, flags);
	status = read_status_check(sd, &len);
	}
	spin_unlock_irqrestore(&sd->sd_rlock, flags);

	if (len > 0) {
	/* we read something in the last read_status_check(); copy
	* it out to user space
	*/
	if (count < len) {
	pr_debug("%s: only accepting %d of %d bytes\n",
	__func__, (int) count, len);
	}
	len = min((int) count, len);
	if (copy_to_user(buf, sd->sd_rb, len))
	len = -EFAULT;
	}

	/* release the read buffer and wake anyone who might be
	* waiting for it
	*/
	up(&sd->sd_rbs);

	/* return the number of characters read in */
	return len;
	}

	/*
	* scdrv_write
	*
	* Writes a chunk of an IRouter packet (or other system controller data)
	* to the system controller.
	*
	*/
	static inline int
	write_status_check(struct subch_data_s *sd, int count)
	{
	return ia64_sn_irtr_send(sd->sd_nasid, sd->sd_subch, sd->sd_wb, count);
	}

	static ssize_t
	scdrv_write(struct file file, const char __user buf,
	size_t count, loff_t *f_pos)
	{
	unsigned long flags;
	int status;
	struct subch_data_s sd = (struct subch_data_s ) file->private_data;

	/* try to get control of the write buffer */
	if (down_trylock(&sd->sd_wbs)) {
	/* somebody else has it now;
	* if we're non-blocking, then exit...
	*/
	if (file->f_flags & O_NONBLOCK) {
	return -EAGAIN;
	}
	/* ...or if we want to block, then do so here */
	if (down_interruptible(&sd->sd_wbs)) {
	/* something went wrong with wait */
	return -ERESTARTSYS;
	}
	}

	count = min((int) count, CHUNKSIZE);
	if (copy_from_user(sd->sd_wb, buf, count)) {
	up(&sd->sd_wbs);
	return -EFAULT;
	}

	/* try to send the buffer */
	spin_lock_irqsave(&sd->sd_wlock, flags);
	status = write_status_check(sd, count);

	/* if we failed, and we want to block, then loop */
	while (status <= 0) {
	DECLARE_WAITQUEUE(wait, current);

	if (file->f_flags & O_NONBLOCK) {
	spin_unlock(&sd->sd_wlock);
	up(&sd->sd_wbs);
	return -EAGAIN;
	}

	set_current_state(TASK_INTERRUPTIBLE);
	add_wait_queue(&sd->sd_wq, &wait);
	spin_unlock_irqrestore(&sd->sd_wlock, flags);

	schedule_timeout(SCDRV_TIMEOUT);

	remove_wait_queue(&sd->sd_wq, &wait);
	if (signal_pending(current)) {
	/* wait was interrupted */
	up(&sd->sd_wbs);
	return -ERESTARTSYS;
	}

	spin_lock_irqsave(&sd->sd_wlock, flags);
	status = write_status_check(sd, count);
	}
	spin_unlock_irqrestore(&sd->sd_wlock, flags);

	/* release the write buffer and wake anyone who's waiting for it */
	up(&sd->sd_wbs);

	/* return the number of characters accepted (should be the complete
	* "chunk" as requested)
	*/
	if ((status >= 0) && (status < count)) {
	pr_debug("Didn't accept the full chunk; %d of %d\n",
	status, (int) count);
	}
	return status;
	}

	static unsigned int
	scdrv_poll(struct file file, struct poll_table_struct wait)
	{
	unsigned int mask = 0;
	int status = 0;
	struct subch_data_s sd = (struct subch_data_s ) file->private_data;
	unsigned long flags;

	poll_wait(file, &sd->sd_rq, wait);
	poll_wait(file, &sd->sd_wq, wait);

	spin_lock_irqsave(&sd->sd_rlock, flags);
	spin_lock(&sd->sd_wlock);
	status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);
	spin_unlock(&sd->sd_wlock);
	spin_unlock_irqrestore(&sd->sd_rlock, flags);

	if (status > 0) {
	if (status & SAL_IROUTER_INTR_RECV) {
	mask \|= POLLIN \| POLLRDNORM;
	}
	if (status & SAL_IROUTER_INTR_XMIT) {
	mask \|= POLLOUT \| POLLWRNORM;
	}
	}

	return mask;
	}

	static const struct file_operations scdrv_fops = {
	.owner = THIS_MODULE,
	.read = scdrv_read,
	.write = scdrv_write,
	.poll = scdrv_poll,
	.open = scdrv_open,
	.release = scdrv_release,
	};

	static struct class *snsc_class;

	/*
	* scdrv_init
	*
	* Called at boot time to initialize the system controller communication
	* facility.
	*/
	int __init
	scdrv_init(void)
	{
	geoid_t geoid;
	cnodeid_t cnode;
	char devname[32];
	char *devnamep;
	struct sysctl_data_s *scd;
	void *salbuf;
	dev_t first_dev, dev;
	nasid_t event_nasid;

	if (!ia64_platform_is("sn2"))
	return -ENODEV;

	event_nasid = ia64_sn_get_console_nasid();

	if (alloc_chrdev_region(&first_dev, 0, num_cnodes,
	SYSCTL_BASENAME) < 0) {
	printk("%s: failed to register SN system controller device\n",
	__func__);
	return -ENODEV;
	}
	snsc_class = class_create(THIS_MODULE, SYSCTL_BASENAME);

	for (cnode = 0; cnode < num_cnodes; cnode++) {
	geoid = cnodeid_get_geoid(cnode);
	devnamep = devname;
	format_module_id(devnamep, geo_module(geoid),
	MODULE_FORMAT_BRIEF);
	devnamep = devname + strlen(devname);
	sprintf(devnamep, "^%d#%d", geo_slot(geoid),
	geo_slab(geoid));

	/* allocate sysctl device data */
	scd = kzalloc(sizeof (struct sysctl_data_s),
	GFP_KERNEL);
	if (!scd) {
	printk("%s: failed to allocate device info"
	"for %s/%s\n", __func__,
	SYSCTL_BASENAME, devname);
	continue;
	}

	/* initialize sysctl device data fields */
	scd->scd_nasid = cnodeid_to_nasid(cnode);
	if (!(salbuf = kmalloc(SCDRV_BUFSZ, GFP_KERNEL))) {
	printk("%s: failed to allocate driver buffer"
	"(%s%s)\n", __func__,
	SYSCTL_BASENAME, devname);
	kfree(scd);
	continue;
	}

	if (ia64_sn_irtr_init(scd->scd_nasid, salbuf,
	SCDRV_BUFSZ) < 0) {
	printk
	("%s: failed to initialize SAL for"
	" system controller communication"
	" (%s/%s): outdated PROM?\n",
	__func__, SYSCTL_BASENAME, devname);
	kfree(scd);
	kfree(salbuf);
	continue;
	}

	dev = first_dev + cnode;
	cdev_init(&scd->scd_cdev, &scdrv_fops);
	if (cdev_add(&scd->scd_cdev, dev, 1)) {
	printk("%s: failed to register system"
	" controller device (%s%s)\n",
	__func__, SYSCTL_BASENAME, devname);
	kfree(scd);
	kfree(salbuf);
	continue;
	}

	device_create(snsc_class, NULL, dev, NULL,
	"%s", devname);

	ia64_sn_irtr_intr_enable(scd->scd_nasid,
	0 /ignored / ,
	SAL_IROUTER_INTR_RECV);

	/* on the console nasid, prepare to receive
	* system controller environmental events
	*/
	if(scd->scd_nasid == event_nasid) {
	scdrv_event_init(scd);
	}
	}
	return 0;
	}

	module_init(scdrv_init);