Logo Search packages:      
Sourcecode: linux version File versions  Download package

scanlog.c

/*
 *  c 2001 PPC 64 Team, IBM Corp
 *
 *      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.
 *
 * scan-log-data driver for PPC64  Todd Inglett <tinglett@vnet.ibm.com>
 *
 * When ppc64 hardware fails the service processor dumps internal state
 * of the system.  After a reboot the operating system can access a dump
 * of this data using this driver.  A dump exists if the device-tree
 * /chosen/ibm,scan-log-data property exists.
 *
 * This driver exports /proc/ppc64/scan-log-dump which can be read.
 * The driver supports only sequential reads.
 *
 * The driver looks at a write to the driver for the single word "reset".
 * If given, the driver will reset the scanlog so the platform can free it.
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/proc_fs.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/uaccess.h>
#include <asm/rtas.h>
#include <asm/prom.h>

#define MODULE_VERS "1.0"
#define MODULE_NAME "scanlog"

/* Status returns from ibm,scan-log-dump */
#define SCANLOG_COMPLETE 0
#define SCANLOG_HWERROR -1
#define SCANLOG_CONTINUE 1

#define DEBUG(A...) do { if (scanlog_debug) printk(KERN_ERR "scanlog: " A); } while (0)

static int scanlog_debug;
static unsigned int ibm_scan_log_dump;                /* RTAS token */
static struct proc_dir_entry *proc_ppc64_scan_log_dump;     /* The proc file */

static ssize_t scanlog_read(struct file *file, char __user *buf,
                      size_t count, loff_t *ppos)
{
        struct inode * inode = file->f_path.dentry->d_inode;
      struct proc_dir_entry *dp;
      unsigned int *data;
      int status;
      unsigned long len, off;
      unsigned int wait_time;

        dp = PDE(inode);
      data = (unsigned int *)dp->data;

      if (!data) {
            printk(KERN_ERR "scanlog: read failed no data\n");
            return -EIO;
      }

      if (count > RTAS_DATA_BUF_SIZE)
            count = RTAS_DATA_BUF_SIZE;

      if (count < 1024) {
            /* This is the min supported by this RTAS call.  Rather
             * than do all the buffering we insist the user code handle
             * larger reads.  As long as cp works... :)
             */
            printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count);
            return -EINVAL;
      }

      if (!access_ok(VERIFY_WRITE, buf, count))
            return -EFAULT;

      for (;;) {
            wait_time = 500;  /* default wait if no data */
            spin_lock(&rtas_data_buf_lock);
            memcpy(rtas_data_buf, data, RTAS_DATA_BUF_SIZE);
            status = rtas_call(ibm_scan_log_dump, 2, 1, NULL,
                           (u32) __pa(rtas_data_buf), (u32) count);
            memcpy(data, rtas_data_buf, RTAS_DATA_BUF_SIZE);
            spin_unlock(&rtas_data_buf_lock);

            DEBUG("status=%d, data[0]=%x, data[1]=%x, data[2]=%x\n",
                  status, data[0], data[1], data[2]);
            switch (status) {
                case SCANLOG_COMPLETE:
                  DEBUG("hit eof\n");
                  return 0;
                case SCANLOG_HWERROR:
                  DEBUG("hardware error reading scan log data\n");
                  return -EIO;
                case SCANLOG_CONTINUE:
                  /* We may or may not have data yet */
                  len = data[1];
                  off = data[2];
                  if (len > 0) {
                        if (copy_to_user(buf, ((char *)data)+off, len))
                              return -EFAULT;
                        return len;
                  }
                  /* Break to sleep default time */
                  break;
                default:
                  /* Assume extended busy */
                  wait_time = rtas_busy_delay_time(status);
                  if (!wait_time) {
                        printk(KERN_ERR "scanlog: unknown error from rtas: %d\n", status);
                        return -EIO;
                  }
            }
            /* Apparently no data yet.  Wait and try again. */
            msleep_interruptible(wait_time);
      }
      /*NOTREACHED*/
}

static ssize_t scanlog_write(struct file * file, const char __user * buf,
                       size_t count, loff_t *ppos)
{
      char stkbuf[20];
      int status;

      if (count > 19) count = 19;
      if (copy_from_user (stkbuf, buf, count)) {
            return -EFAULT;
      }
      stkbuf[count] = 0;

      if (buf) {
            if (strncmp(stkbuf, "reset", 5) == 0) {
                  DEBUG("reset scanlog\n");
                  status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0);
                  DEBUG("rtas returns %d\n", status);
            } else if (strncmp(stkbuf, "debugon", 7) == 0) {
                  printk(KERN_ERR "scanlog: debug on\n");
                  scanlog_debug = 1;
            } else if (strncmp(stkbuf, "debugoff", 8) == 0) {
                  printk(KERN_ERR "scanlog: debug off\n");
                  scanlog_debug = 0;
            }
      }
      return count;
}

static int scanlog_open(struct inode * inode, struct file * file)
{
      struct proc_dir_entry *dp = PDE(inode);
      unsigned int *data = (unsigned int *)dp->data;

      if (!data) {
            printk(KERN_ERR "scanlog: open failed no data\n");
            return -EIO;
      }

      if (data[0] != 0) {
            /* This imperfect test stops a second copy of the
             * data (or a reset while data is being copied)
             */
            return -EBUSY;
      }

      data[0] = 0;      /* re-init so we restart the scan */

      return 0;
}

static int scanlog_release(struct inode * inode, struct file * file)
{
      struct proc_dir_entry *dp = PDE(inode);
      unsigned int *data = (unsigned int *)dp->data;

      if (!data) {
            printk(KERN_ERR "scanlog: release failed no data\n");
            return -EIO;
      }
      data[0] = 0;

      return 0;
}

const struct file_operations scanlog_fops = {
      .owner            = THIS_MODULE,
      .read       = scanlog_read,
      .write            = scanlog_write,
      .open       = scanlog_open,
      .release    = scanlog_release,
};

static int __init scanlog_init(void)
{
      struct proc_dir_entry *ent;

      ibm_scan_log_dump = rtas_token("ibm,scan-log-dump");
      if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE) {
            printk(KERN_ERR "scan-log-dump not implemented on this system\n");
            return -EIO;
      }

        ent = create_proc_entry("ppc64/rtas/scan-log-dump",  S_IRUSR, NULL);
      if (ent) {
            ent->proc_fops = &scanlog_fops;
            /* Ideally we could allocate a buffer < 4G */
            ent->data = kmalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
            if (!ent->data) {
                  printk(KERN_ERR "Failed to allocate a buffer\n");
                  remove_proc_entry("scan-log-dump", ent->parent);
                  return -ENOMEM;
            }
            ((unsigned int *)ent->data)[0] = 0;
      } else {
            printk(KERN_ERR "Failed to create ppc64/scan-log-dump proc entry\n");
            return -EIO;
      }
      proc_ppc64_scan_log_dump = ent;

      return 0;
}

static void __exit scanlog_cleanup(void)
{
      if (proc_ppc64_scan_log_dump) {
            kfree(proc_ppc64_scan_log_dump->data);
            remove_proc_entry("scan-log-dump", proc_ppc64_scan_log_dump->parent);
      }
}

module_init(scanlog_init);
module_exit(scanlog_cleanup);
MODULE_LICENSE("GPL");

Generated by  Doxygen 1.6.0   Back to index