diff options
Diffstat (limited to 'arch/ppc64/kernel/scanlog.c')
| -rw-r--r-- | arch/ppc64/kernel/scanlog.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/arch/ppc64/kernel/scanlog.c b/arch/ppc64/kernel/scanlog.c new file mode 100644 index 000000000000..189b81a41987 --- /dev/null +++ b/arch/ppc64/kernel/scanlog.c @@ -0,0 +1,245 @@ +/* + * 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 <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 *buf, + size_t count, loff_t *ppos) +{ + struct inode * inode = file->f_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 = HZ/2; /* 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: + if (status > 9900 && status <= 9905) { + /* No data. RTAS is hinting at a delay required + * between 1-100000 milliseconds + */ + int ms = 1; + for (; status > 9900; status--) + ms = ms * 10; + /* Use microseconds for reasonable accuracy */ + ms *= 1000; + wait_time = ms / (1000000/HZ); /* round down is fine */ + /* Fall through to sleep */ + } else { + printk(KERN_ERR "scanlog: unknown error from rtas: %d\n", status); + return -EIO; + } + } + /* Apparently no data yet. Wait and try again. */ + set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout(wait_time); + } + /*NOTREACHED*/ +} + +static ssize_t scanlog_write(struct file * file, const char * 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; +} + +struct file_operations scanlog_fops = { + .owner = THIS_MODULE, + .read = scanlog_read, + .write = scanlog_write, + .open = scanlog_open, + .release = scanlog_release, +}; + +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; +} + +void __exit scanlog_cleanup(void) +{ + if (proc_ppc64_scan_log_dump) { + if (proc_ppc64_scan_log_dump->data) + 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"); |