236 lines
6.2 KiB
C
236 lines
6.2 KiB
C
/*
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* c 2001 PPC 64 Team, IBM Corp
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* scan-log-data driver for PPC64 Todd Inglett <tinglett@vnet.ibm.com>
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*
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* When ppc64 hardware fails the service processor dumps internal state
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* of the system. After a reboot the operating system can access a dump
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* of this data using this driver. A dump exists if the device-tree
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* /chosen/ibm,scan-log-data property exists.
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*
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* This driver exports /proc/ppc64/scan-log-dump which can be read.
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* The driver supports only sequential reads.
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*
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* The driver looks at a write to the driver for the single word "reset".
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* If given, the driver will reset the scanlog so the platform can free it.
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/proc_fs.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <asm/uaccess.h>
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#include <asm/rtas.h>
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#include <asm/prom.h>
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#define MODULE_VERS "1.0"
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#define MODULE_NAME "scanlog"
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/* Status returns from ibm,scan-log-dump */
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#define SCANLOG_COMPLETE 0
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#define SCANLOG_HWERROR -1
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#define SCANLOG_CONTINUE 1
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#define DEBUG(A...) do { if (scanlog_debug) printk(KERN_ERR "scanlog: " A); } while (0)
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static int scanlog_debug;
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static unsigned int ibm_scan_log_dump; /* RTAS token */
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static struct proc_dir_entry *proc_ppc64_scan_log_dump; /* The proc file */
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static ssize_t scanlog_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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struct inode * inode = file->f_dentry->d_inode;
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struct proc_dir_entry *dp;
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unsigned int *data;
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int status;
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unsigned long len, off;
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unsigned int wait_time;
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dp = PDE(inode);
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data = (unsigned int *)dp->data;
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if (!data) {
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printk(KERN_ERR "scanlog: read failed no data\n");
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return -EIO;
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}
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if (count > RTAS_DATA_BUF_SIZE)
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count = RTAS_DATA_BUF_SIZE;
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if (count < 1024) {
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/* This is the min supported by this RTAS call. Rather
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* than do all the buffering we insist the user code handle
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* larger reads. As long as cp works... :)
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*/
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printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count);
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return -EINVAL;
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}
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if (!access_ok(VERIFY_WRITE, buf, count))
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return -EFAULT;
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for (;;) {
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wait_time = 500; /* default wait if no data */
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spin_lock(&rtas_data_buf_lock);
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memcpy(rtas_data_buf, data, RTAS_DATA_BUF_SIZE);
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status = rtas_call(ibm_scan_log_dump, 2, 1, NULL,
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(u32) __pa(rtas_data_buf), (u32) count);
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memcpy(data, rtas_data_buf, RTAS_DATA_BUF_SIZE);
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spin_unlock(&rtas_data_buf_lock);
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DEBUG("status=%d, data[0]=%x, data[1]=%x, data[2]=%x\n",
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status, data[0], data[1], data[2]);
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switch (status) {
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case SCANLOG_COMPLETE:
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DEBUG("hit eof\n");
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return 0;
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case SCANLOG_HWERROR:
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DEBUG("hardware error reading scan log data\n");
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return -EIO;
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case SCANLOG_CONTINUE:
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/* We may or may not have data yet */
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len = data[1];
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off = data[2];
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if (len > 0) {
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if (copy_to_user(buf, ((char *)data)+off, len))
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return -EFAULT;
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return len;
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}
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/* Break to sleep default time */
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break;
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default:
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if (status > 9900 && status <= 9905) {
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wait_time = rtas_extended_busy_delay_time(status);
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} else {
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printk(KERN_ERR "scanlog: unknown error from rtas: %d\n", status);
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return -EIO;
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}
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}
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/* Apparently no data yet. Wait and try again. */
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msleep_interruptible(wait_time);
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}
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/*NOTREACHED*/
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}
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static ssize_t scanlog_write(struct file * file, const char __user * buf,
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size_t count, loff_t *ppos)
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{
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char stkbuf[20];
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int status;
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if (count > 19) count = 19;
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if (copy_from_user (stkbuf, buf, count)) {
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return -EFAULT;
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}
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stkbuf[count] = 0;
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if (buf) {
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if (strncmp(stkbuf, "reset", 5) == 0) {
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DEBUG("reset scanlog\n");
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status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0);
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DEBUG("rtas returns %d\n", status);
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} else if (strncmp(stkbuf, "debugon", 7) == 0) {
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printk(KERN_ERR "scanlog: debug on\n");
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scanlog_debug = 1;
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} else if (strncmp(stkbuf, "debugoff", 8) == 0) {
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printk(KERN_ERR "scanlog: debug off\n");
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scanlog_debug = 0;
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}
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}
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return count;
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}
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static int scanlog_open(struct inode * inode, struct file * file)
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{
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struct proc_dir_entry *dp = PDE(inode);
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unsigned int *data = (unsigned int *)dp->data;
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if (!data) {
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printk(KERN_ERR "scanlog: open failed no data\n");
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return -EIO;
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}
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if (data[0] != 0) {
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/* This imperfect test stops a second copy of the
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* data (or a reset while data is being copied)
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*/
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return -EBUSY;
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}
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data[0] = 0; /* re-init so we restart the scan */
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return 0;
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}
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static int scanlog_release(struct inode * inode, struct file * file)
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{
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struct proc_dir_entry *dp = PDE(inode);
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unsigned int *data = (unsigned int *)dp->data;
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if (!data) {
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printk(KERN_ERR "scanlog: release failed no data\n");
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return -EIO;
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}
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data[0] = 0;
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return 0;
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}
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struct file_operations scanlog_fops = {
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.owner = THIS_MODULE,
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.read = scanlog_read,
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.write = scanlog_write,
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.open = scanlog_open,
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.release = scanlog_release,
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};
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int __init scanlog_init(void)
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{
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struct proc_dir_entry *ent;
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ibm_scan_log_dump = rtas_token("ibm,scan-log-dump");
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if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE) {
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printk(KERN_ERR "scan-log-dump not implemented on this system\n");
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return -EIO;
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}
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ent = create_proc_entry("ppc64/rtas/scan-log-dump", S_IRUSR, NULL);
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if (ent) {
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ent->proc_fops = &scanlog_fops;
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/* Ideally we could allocate a buffer < 4G */
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ent->data = kmalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
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if (!ent->data) {
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printk(KERN_ERR "Failed to allocate a buffer\n");
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remove_proc_entry("scan-log-dump", ent->parent);
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return -ENOMEM;
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}
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((unsigned int *)ent->data)[0] = 0;
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} else {
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printk(KERN_ERR "Failed to create ppc64/scan-log-dump proc entry\n");
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return -EIO;
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}
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proc_ppc64_scan_log_dump = ent;
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return 0;
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}
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void __exit scanlog_cleanup(void)
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{
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if (proc_ppc64_scan_log_dump) {
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kfree(proc_ppc64_scan_log_dump->data);
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remove_proc_entry("scan-log-dump", proc_ppc64_scan_log_dump->parent);
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}
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}
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module_init(scanlog_init);
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module_exit(scanlog_cleanup);
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MODULE_LICENSE("GPL");
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