/*
 * 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/signal.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, "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;
        }
}