snsc_event.c

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/*
 * 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 event handler
 *
 * These routines deal with environmental events arriving from the
 * system controllers.
 */

#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
#include <asm/sn/sn_sal.h>
#include <asm/unaligned.h>
#include "snsc.h"

static struct subch_data_s *event_sd;

void scdrv_event(unsigned long);
DECLARE_TASKLET(sn_sysctl_event, scdrv_event, 0);

/*
 * scdrv_event_interrupt
 *
 * Pull incoming environmental events off the physical link to the
 * system controller and put them in a temporary holding area in SAL.
 * Schedule scdrv_event() to move them along to their ultimate
 * destination.
 */
static irqreturn_t
scdrv_event_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);
    status = ia64_sn_irtr_intr(sd->sd_nasid, sd->sd_subch);

    if ((status > 0) && (status & SAL_IROUTER_INTR_RECV)) {
        tasklet_schedule(&sn_sysctl_event);
    }
    spin_unlock_irqrestore(&sd->sd_rlock, flags);
    return IRQ_HANDLED;
}


/*
 * scdrv_parse_event
 *
 * Break an event (as read from SAL) into useful pieces so we can decide
 * what to do with it.
 */
static int
scdrv_parse_event(char *event, int *src, int *code, int *esp_code, char *desc)
{
    char *desc_end;

    /* record event source address */
    *src = get_unaligned_be32(event);
    event += 4;             /* move on to event code */

    /* record the system controller's event code */
    *code = get_unaligned_be32(event);
    event += 4;         /* move on to event arguments */

    /* how many arguments are in the packet? */
    if (*event++ != 2) {
        /* if not 2, give up */
        return -1;
    }

    /* parse out the ESP code */
    if (*event++ != IR_ARG_INT) {
        /* not an integer argument, so give up */
        return -1;
    }
    *esp_code = get_unaligned_be32(event);
    event += 4;

    /* parse out the event description */
    if (*event++ != IR_ARG_ASCII) {
        /* not an ASCII string, so give up */
        return -1;
    }
    event[CHUNKSIZE-1] = '\0';  /* ensure this string ends! */
    event += 2;             /* skip leading CR/LF */
    desc_end = desc + sprintf(desc, "%s", event);

    /* strip trailing CR/LF (if any) */
    for (desc_end--;
         (desc_end != desc) && ((*desc_end == 0xd) || (*desc_end == 0xa));
         desc_end--) {
        *desc_end = '\0';
    }

    return 0;
}


/*
 * scdrv_event_severity
 *
 * Figure out how urgent a message we should write to the console/syslog
 * via printk.
 */
static char *
scdrv_event_severity(int code)
{
    int ev_class = (code & EV_CLASS_MASK);
    int ev_severity = (code & EV_SEVERITY_MASK);
    char *pk_severity = KERN_NOTICE;

    switch (ev_class) {
    case EV_CLASS_POWER:
        switch (ev_severity) {
        case EV_SEVERITY_POWER_LOW_WARNING:
        case EV_SEVERITY_POWER_HIGH_WARNING:
            pk_severity = KERN_WARNING;
            break;
        case EV_SEVERITY_POWER_HIGH_FAULT:
        case EV_SEVERITY_POWER_LOW_FAULT:
            pk_severity = KERN_ALERT;
            break;
        }
        break;
    case EV_CLASS_FAN:
        switch (ev_severity) {
        case EV_SEVERITY_FAN_WARNING:
            pk_severity = KERN_WARNING;
            break;
        case EV_SEVERITY_FAN_FAULT:
            pk_severity = KERN_CRIT;
            break;
        }
        break;
    case EV_CLASS_TEMP:
        switch (ev_severity) {
        case EV_SEVERITY_TEMP_ADVISORY:
            pk_severity = KERN_WARNING;
            break;
        case EV_SEVERITY_TEMP_CRITICAL:
            pk_severity = KERN_CRIT;
            break;
        case EV_SEVERITY_TEMP_FAULT:
            pk_severity = KERN_ALERT;
            break;
        }
        break;
    case EV_CLASS_ENV:
        pk_severity = KERN_ALERT;
        break;
    case EV_CLASS_TEST_FAULT:
        pk_severity = KERN_ALERT;
        break;
    case EV_CLASS_TEST_WARNING:
        pk_severity = KERN_WARNING;
        break;
    case EV_CLASS_PWRD_NOTIFY:
        pk_severity = KERN_ALERT;
        break;
    }

    return pk_severity;
}


/*
 * scdrv_dispatch_event
 *
 * Do the right thing with an incoming event.  That's often nothing
 * more than printing it to the system log.  For power-down notifications
 * we start a graceful shutdown.
 */
static void
scdrv_dispatch_event(char *event, int len)
{
    static int snsc_shutting_down = 0;
    int code, esp_code, src, class;
    char desc[CHUNKSIZE];
    char *severity;

    if (scdrv_parse_event(event, &src, &code, &esp_code, desc) < 0) {
        /* ignore uninterpretible event */
        return;
    }

    /* how urgent is the message? */
    severity = scdrv_event_severity(code);

    class = (code & EV_CLASS_MASK);

    if (class == EV_CLASS_PWRD_NOTIFY || code == ENV_PWRDN_PEND) {
        if (snsc_shutting_down)
            return;

        snsc_shutting_down = 1;

        /* give a message for each type of event */
        if (class == EV_CLASS_PWRD_NOTIFY)
            printk(KERN_NOTICE "Power off indication received."
                   " Sending SIGPWR to init...\n");
        else if (code == ENV_PWRDN_PEND)
            printk(KERN_CRIT "WARNING: Shutting down the system"
                   " due to a critical environmental condition."
                   " Sending SIGPWR to init...\n");

        /* give a SIGPWR signal to init proc */
        kill_cad_pid(SIGPWR, 0);
    } else {
        /* print to system log */
        printk("%s|$(0x%x)%s\n", severity, esp_code, desc);
    }
}


/*
 * scdrv_event
 *
 * Called as a tasklet when an event arrives from the L1.  Read the event
 * from where it's temporarily stored in SAL and call scdrv_dispatch_event()
 * to send it on its way.  Keep trying to read events until SAL indicates
 * that there are no more immediately available.
 */
void
scdrv_event(unsigned long dummy)
{
    int status;
    int len;
    unsigned long flags;
    struct subch_data_s *sd = event_sd;

    /* anything to read? */
    len = CHUNKSIZE;
    spin_lock_irqsave(&sd->sd_rlock, flags);
    status = ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch,
                   sd->sd_rb, &len);

    while (!(status < 0)) {
        spin_unlock_irqrestore(&sd->sd_rlock, flags);
        scdrv_dispatch_event(sd->sd_rb, len);
        len = CHUNKSIZE;
        spin_lock_irqsave(&sd->sd_rlock, flags);
        status = ia64_sn_irtr_recv(sd->sd_nasid, sd->sd_subch,
                       sd->sd_rb, &len);
    }
    spin_unlock_irqrestore(&sd->sd_rlock, flags);
}


/*
 * scdrv_event_init
 *
 * Sets up a system controller subchannel to begin receiving event
 * messages. This is sort of a specialized version of scdrv_open()
 * in drivers/char/sn_sysctl.c.
 */
void
scdrv_event_init(struct sysctl_data_s *scd)
{
    int rv;

    event_sd = kzalloc(sizeof (struct subch_data_s), GFP_KERNEL);
    if (event_sd == NULL) {
        printk(KERN_WARNING "%s: couldn't allocate subchannel info"
               " for event monitoring\n", __func__);
        return;
    }

    /* initialize subch_data_s fields */
    event_sd->sd_nasid = scd->scd_nasid;
    spin_lock_init(&event_sd->sd_rlock);

    /* ask the system controllers to send events to this node */
    event_sd->sd_subch = ia64_sn_sysctl_event_init(scd->scd_nasid);

    if (event_sd->sd_subch < 0) {
        kfree(event_sd);
        printk(KERN_WARNING "%s: couldn't open event subchannel\n",
               __func__);
        return;
    }

    /* hook event subchannel up to the system controller interrupt */
    rv = request_irq(SGI_UART_VECTOR, scdrv_event_interrupt,
             IRQF_SHARED | IRQF_DISABLED,
             "system controller events", event_sd);
    if (rv) {
        printk(KERN_WARNING "%s: irq request failed (%d)\n",
               __func__, rv);
        ia64_sn_irtr_close(event_sd->sd_nasid, event_sd->sd_subch);
        kfree(event_sd);
        return;
    }
}