/*
 * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
 *
 * 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.
 *
 * Communication to userspace based on kernel/printk.c
 */

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/vmalloc.h>
#include <linux/spinlock.h>
#include <linux/cpu.h>

#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/rtas.h>
#include <asm/prom.h>
#include <asm/nvram.h>
#include <asm/atomic.h>

#if 0
#define DEBUG(A...)     printk(KERN_ERR A)
#else
#define DEBUG(A...)
#endif

static spinlock_t rtasd_log_lock = SPIN_LOCK_UNLOCKED;

DECLARE_WAIT_QUEUE_HEAD(rtas_log_wait);

static char *rtas_log_buf;
static unsigned long rtas_log_start;
static unsigned long rtas_log_size;

static int surveillance_timeout = -1;
static unsigned int rtas_event_scan_rate;
static unsigned int rtas_error_log_max;
static unsigned int rtas_error_log_buffer_max;

extern volatile int no_more_logging;

volatile int error_log_cnt = 0;

/*
 * Since we use 32 bit RTAS, the physical address of this must be below
 * 4G or else bad things happen. Allocate this in the kernel data and
 * make it big enough.
 */
static unsigned char logdata[RTAS_ERROR_LOG_MAX];

/* To see this info, grep RTAS /var/log/messages and each entry
 * will be collected together with obvious begin/end.
 * There will be a unique identifier on the begin and end lines.
 * This will persist across reboots.
 *
 * format of error logs returned from RTAS:
 * bytes        (size)  : contents
 * --------------------------------------------------------
 * 0-7          (8)     : rtas_error_log
 * 8-47         (40)    : extended info
 * 48-51        (4)     : vendor id
 * 52-1023 (vendor specific) : location code and debug data
 */
static void printk_log_rtas(char *buf, int len)
{

        int i,j,n;
        int perline = 16;
        char buffer[64];
        char * str = "RTAS event";

        printk(RTAS_DEBUG "%d -------- %s begin --------\n", error_log_cnt, str);

        /*
         * Print perline bytes on each line, each line will start
         * with RTAS and a changing number, so syslogd will
         * print lines that are otherwise the same.  Separate every
         * 4 bytes with a space.
         */
        for (i=0; i < len; i++) {
                j = i % perline;
                if (j == 0) {
                        memset(buffer, 0, sizeof(buffer));
                        n = sprintf(buffer, "RTAS %d:", i/perline);
                }

                if ((i % 4) == 0)
                        n += sprintf(buffer+n, " ");

                n += sprintf(buffer+n, "%02x", (unsigned char)buf[i]);

                if (j == (perline-1))
                        printk(KERN_DEBUG "%s\n", buffer);
        }
        if ((i % perline) != 0)
                printk(KERN_DEBUG "%s\n", buffer);

        printk(RTAS_DEBUG "%d -------- %s end ----------\n", error_log_cnt, str);
}

static int log_rtas_len(char * buf)
{
        int len;
        struct rtas_error_log *err;

        /* rtas fixed header */
        len = 8;
        err = (struct rtas_error_log *)buf;
        if (err->extended_log_length) {

                /* extended header */
                len += err->extended_log_length;
        }

        if (len > rtas_error_log_max)
                len = rtas_error_log_max;

        return len;
}

/*
 * First write to nvram, if fatal error, that is the only
 * place we log the info.  The error will be picked up
 * on the next reboot by rtasd.  If not fatal, run the
 * method for the type of error.  Currently, only RTAS
 * errors have methods implemented, but in the future
 * there might be a need to store data in nvram before a
 * call to panic().
 *
 * XXX We write to nvram periodically, to indicate error has
 * been written and sync'd, but there is a possibility
 * that if we don't shutdown correctly, a duplicate error
 * record will be created on next reboot.
 */
void pSeries_log_error(char *buf, unsigned int err_type, int fatal)
{
        unsigned long offset;
        unsigned long s;
        int len = 0;

        DEBUG("logging event\n");

        if (buf == NULL)
                return;

        spin_lock_irqsave(&rtasd_log_lock, s);

        /* get length and increase count */
        switch (err_type & ERR_TYPE_MASK) {
        case ERR_TYPE_RTAS_LOG:
                len = log_rtas_len(buf);
                if (!(err_type & ERR_FLAG_BOOT))
                        error_log_cnt++;
                break;
        case ERR_TYPE_KERNEL_PANIC:
        default:
                spin_unlock_irqrestore(&rtasd_log_lock, s);
                return;
        }

        /* Write error to NVRAM */
        if (!no_more_logging && !(err_type & ERR_FLAG_BOOT))
                nvram_write_error_log(buf, len, err_type);

        /* Check to see if we need to or have stopped logging */
        if (fatal || no_more_logging) {
                no_more_logging = 1;
                spin_unlock_irqrestore(&rtasd_log_lock, s);
                return;
        }

        /* call type specific method for error */
        switch (err_type & ERR_TYPE_MASK) {
        case ERR_TYPE_RTAS_LOG:
                /* put into syslog and error_log file */
                printk_log_rtas(buf, len);

                offset = rtas_error_log_buffer_max *
                        ((rtas_log_start+rtas_log_size) & LOG_NUMBER_MASK);

                /* First copy over sequence number */
                memcpy(&rtas_log_buf[offset], (void *) &error_log_cnt, sizeof(int));

                /* Second copy over error log data */
                offset += sizeof(int);
                memcpy(&rtas_log_buf[offset], buf, len);

                if (rtas_log_size < LOG_NUMBER)
                        rtas_log_size += 1;
                else
                        rtas_log_start += 1;

                spin_unlock_irqrestore(&rtasd_log_lock, s);
                wake_up_interruptible(&rtas_log_wait);
                break;
        case ERR_TYPE_KERNEL_PANIC:
        default:
                spin_unlock_irqrestore(&rtasd_log_lock, s);
                return;
        }

}


static int rtas_log_open(struct inode * inode, struct file * file)
{
        return 0;
}

static int rtas_log_release(struct inode * inode, struct file * file)
{
        return 0;
}

/* This will check if all events are logged, if they are then, we
 * know that we can safely clear the events in NVRAM.
 * Next we'll sit and wait for something else to log.
 */
static ssize_t rtas_log_read(struct file * file, char * buf,
                         size_t count, loff_t *ppos)
{
        int error;
        char *tmp;
        unsigned long s;
        unsigned long offset;

        if (!buf || count < rtas_error_log_buffer_max)
                return -EINVAL;

        count = rtas_error_log_buffer_max;

        error = verify_area(VERIFY_WRITE, buf, count);
        if (error)
                return -EFAULT;

        tmp = kmalloc(count, GFP_KERNEL);
        if (!tmp)
                return -ENOMEM;


        spin_lock_irqsave(&rtasd_log_lock, s);
        /* if it's 0, then we know we got the last one (the one in NVRAM) */
        if (rtas_log_size == 0 && !no_more_logging)
                nvram_clear_error_log();
        spin_unlock_irqrestore(&rtasd_log_lock, s);


        error = wait_event_interruptible(rtas_log_wait, rtas_log_size);
        if (error)
                goto out;

        spin_lock_irqsave(&rtasd_log_lock, s);
        offset = rtas_error_log_buffer_max * (rtas_log_start & LOG_NUMBER_MASK);
        memcpy(tmp, &rtas_log_buf[offset], count);

        rtas_log_start += 1;
        rtas_log_size -= 1;
        spin_unlock_irqrestore(&rtasd_log_lock, s);

        error = copy_to_user(buf, tmp, count) ? -EFAULT : count;
out:
        kfree(tmp);
        return error;
}

static unsigned int rtas_log_poll(struct file *file, poll_table * wait)
{
        poll_wait(file, &rtas_log_wait, wait);
        if (rtas_log_size)
                return POLLIN | POLLRDNORM;
        return 0;
}

struct file_operations proc_rtas_log_operations = {
        .read =         rtas_log_read,
        .poll =         rtas_log_poll,
        .open =         rtas_log_open,
        .release =      rtas_log_release,
};

static int enable_surveillance(int timeout)
{
        int error;

        error = rtas_call(rtas_token("set-indicator"), 3, 1, NULL,
                          SURVEILLANCE_TOKEN, 0, timeout);

        if (error) {
                printk(KERN_ERR "rtasd: could not enable surveillance\n");
                return -1;
        }

        return 0;
}

static int get_eventscan_parms(void)
{
        struct device_node *node;
        int *ip;

        node = of_find_node_by_path("/rtas");

        ip = (int *)get_property(node, "rtas-event-scan-rate", NULL);
        if (ip == NULL) {
                printk(KERN_ERR "rtasd: no rtas-event-scan-rate\n");
                of_node_put(node);
                return -1;
        }
        rtas_event_scan_rate = *ip;
        DEBUG("rtas-event-scan-rate %d\n", rtas_event_scan_rate);

        ip = (int *)get_property(node, "rtas-error-log-max", NULL);
        if (ip == NULL) {
                printk(KERN_ERR "rtasd: no rtas-error-log-max\n");
                of_node_put(node);
                return -1;
        }
        rtas_error_log_max = *ip;
        DEBUG("rtas-error-log-max %d\n", rtas_error_log_max);

        if (rtas_error_log_max > RTAS_ERROR_LOG_MAX) {
                printk(KERN_ERR "rtasd: truncated error log from %d to %d bytes\n", rtas_error_log_max, RTAS_ERROR_LOG_MAX);
                rtas_error_log_max = RTAS_ERROR_LOG_MAX;
        }

        /* Make room for the sequence number */
        rtas_error_log_buffer_max = rtas_error_log_max + sizeof(int);

        of_node_put(node);

        return 0;
}

static void do_event_scan(int event_scan)
{
        int error;
        do {
                memset(logdata, 0, rtas_error_log_max);
                error = rtas_call(event_scan, 4, 1, NULL,
                                  RTAS_EVENT_SCAN_ALL_EVENTS, 0,
                                  __pa(logdata), rtas_error_log_max);
                if (error == -1) {
                        printk(KERN_ERR "event-scan failed\n");
                        break;
                }

                if (error == 0)
                        pSeries_log_error(logdata, ERR_TYPE_RTAS_LOG, 0);

        } while(error == 0);
}

static int rtasd(void *unused)
{
        unsigned int err_type;
        int cpu = 0;
        int event_scan = rtas_token("event-scan");
        int rc;

        daemonize("rtasd");

        if (event_scan == RTAS_UNKNOWN_SERVICE || get_eventscan_parms() == -1)
                goto error;

        rtas_log_buf = vmalloc(rtas_error_log_buffer_max*LOG_NUMBER);
        if (!rtas_log_buf) {
                printk(KERN_ERR "rtasd: no memory\n");
                goto error;
        }

        /* We can use rtas_log_buf now */
        no_more_logging = 0;

        printk(KERN_ERR "RTAS daemon started\n");

        DEBUG("will sleep for %d jiffies\n", (HZ*60/rtas_event_scan_rate) / 2);

        /* See if we have any error stored in NVRAM */
        memset(logdata, 0, rtas_error_log_max);

        rc = nvram_read_error_log(logdata, rtas_error_log_max, &err_type);
        if (!rc) {
                if (err_type != ERR_FLAG_ALREADY_LOGGED) {
                        pSeries_log_error(logdata, err_type | ERR_FLAG_BOOT, 0);
                }
        }

        /* First pass. */
        lock_cpu_hotplug();
        for_each_online_cpu(cpu) {
                DEBUG("scheduling on %d\n", cpu);
                set_cpus_allowed(current, cpumask_of_cpu(cpu));
                DEBUG("watchdog scheduled on cpu %d\n", smp_processor_id());

                do_event_scan(event_scan);
                set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout(HZ);
        }
        unlock_cpu_hotplug();

        if (surveillance_timeout != -1) {
                DEBUG("enabling surveillance\n");
                enable_surveillance(surveillance_timeout);
                DEBUG("surveillance enabled\n");
        }

        lock_cpu_hotplug();
        cpu = first_cpu(cpu_online_map);
        for (;;) {
                set_cpus_allowed(current, cpumask_of_cpu(cpu));
                do_event_scan(event_scan);
                set_cpus_allowed(current, CPU_MASK_ALL);

                /* Drop hotplug lock, and sleep for a bit (at least
                 * one second since some machines have problems if we
                 * call event-scan too quickly). */
                unlock_cpu_hotplug();
                set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout((HZ*60/rtas_event_scan_rate) / 2);
                lock_cpu_hotplug();

                cpu = next_cpu(cpu, cpu_online_map);
                if (cpu == NR_CPUS)
                        cpu = first_cpu(cpu_online_map);
        }

error:
        /* Should delete proc entries */
        return -EINVAL;
}

static int __init rtas_init(void)
{
        struct proc_dir_entry *entry;

        /* No RTAS, only warn if we are on a pSeries box  */
        if (rtas_token("event-scan") == RTAS_UNKNOWN_SERVICE) {
                if (systemcfg->platform & PLATFORM_PSERIES);
                        printk(KERN_ERR "rtasd: no RTAS on system\n");
                return 1;
        }

        entry = create_proc_entry("ppc64/rtas/error_log", S_IRUSR, NULL);
        if (entry)
                entry->proc_fops = &proc_rtas_log_operations;
        else
                printk(KERN_ERR "Failed to create error_log proc entry\n");

        if (kernel_thread(rtasd, NULL, CLONE_FS) < 0)
                printk(KERN_ERR "Failed to start RTAS daemon\n");

        return 0;
}

static int __init surveillance_setup(char *str)
{
        int i;

        if (get_option(&str,&i)) {
                if (i >= 0 && i <= 255)
                        surveillance_timeout = i;
        }

        return 1;
}

__initcall(rtas_init);
__setup("surveillance=", surveillance_setup);