2 * c 2001 PPC 64 Team, IBM Corp
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * scan-log-data driver for PPC64 Todd Inglett <tinglett@vnet.ibm.com>
11 * When ppc64 hardware fails the service processor dumps internal state
12 * of the system. After a reboot the operating system can access a dump
13 * of this data using this driver. A dump exists if the device-tree
14 * /chosen/ibm,scan-log-data property exists.
16 * This driver exports /proc/powerpc/scan-log-dump which can be read.
17 * The driver supports only sequential reads.
19 * The driver looks at a write to the driver for the single word "reset".
20 * If given, the driver will reset the scanlog so the platform can free it.
23 #include <linux/module.h>
24 #include <linux/types.h>
25 #include <linux/errno.h>
26 #include <linux/proc_fs.h>
27 #include <linux/init.h>
28 #include <linux/delay.h>
29 #include <linux/slab.h>
30 #include <asm/uaccess.h>
34 #define MODULE_VERS "1.0"
35 #define MODULE_NAME "scanlog"
37 /* Status returns from ibm,scan-log-dump */
38 #define SCANLOG_COMPLETE 0
39 #define SCANLOG_HWERROR -1
40 #define SCANLOG_CONTINUE 1
43 static unsigned int ibm_scan_log_dump
; /* RTAS token */
44 static struct proc_dir_entry
*proc_ppc64_scan_log_dump
; /* The proc file */
46 static ssize_t
scanlog_read(struct file
*file
, char __user
*buf
,
47 size_t count
, loff_t
*ppos
)
49 struct proc_dir_entry
*dp
= PDE(file_inode(file
));
50 unsigned int *data
= (unsigned int *)dp
->data
;
52 unsigned long len
, off
;
53 unsigned int wait_time
;
55 if (count
> RTAS_DATA_BUF_SIZE
)
56 count
= RTAS_DATA_BUF_SIZE
;
59 /* This is the min supported by this RTAS call. Rather
60 * than do all the buffering we insist the user code handle
61 * larger reads. As long as cp works... :)
63 printk(KERN_ERR
"scanlog: cannot perform a small read (%ld)\n", count
);
67 if (!access_ok(VERIFY_WRITE
, buf
, count
))
71 wait_time
= 500; /* default wait if no data */
72 spin_lock(&rtas_data_buf_lock
);
73 memcpy(rtas_data_buf
, data
, RTAS_DATA_BUF_SIZE
);
74 status
= rtas_call(ibm_scan_log_dump
, 2, 1, NULL
,
75 (u32
) __pa(rtas_data_buf
), (u32
) count
);
76 memcpy(data
, rtas_data_buf
, RTAS_DATA_BUF_SIZE
);
77 spin_unlock(&rtas_data_buf_lock
);
79 pr_debug("scanlog: status=%d, data[0]=%x, data[1]=%x, " \
80 "data[2]=%x\n", status
, data
[0], data
[1], data
[2]);
82 case SCANLOG_COMPLETE
:
83 pr_debug("scanlog: hit eof\n");
86 pr_debug("scanlog: hardware error reading data\n");
88 case SCANLOG_CONTINUE
:
89 /* We may or may not have data yet */
93 if (copy_to_user(buf
, ((char *)data
)+off
, len
))
97 /* Break to sleep default time */
100 /* Assume extended busy */
101 wait_time
= rtas_busy_delay_time(status
);
103 printk(KERN_ERR
"scanlog: unknown error " \
104 "from rtas: %d\n", status
);
108 /* Apparently no data yet. Wait and try again. */
109 msleep_interruptible(wait_time
);
114 static ssize_t
scanlog_write(struct file
* file
, const char __user
* buf
,
115 size_t count
, loff_t
*ppos
)
120 if (count
> 19) count
= 19;
121 if (copy_from_user (stkbuf
, buf
, count
)) {
127 if (strncmp(stkbuf
, "reset", 5) == 0) {
128 pr_debug("scanlog: reset scanlog\n");
129 status
= rtas_call(ibm_scan_log_dump
, 2, 1, NULL
, 0, 0);
130 pr_debug("scanlog: rtas returns %d\n", status
);
136 static int scanlog_open(struct inode
* inode
, struct file
* file
)
138 struct proc_dir_entry
*dp
= PDE(inode
);
139 unsigned int *data
= (unsigned int *)dp
->data
;
142 /* This imperfect test stops a second copy of the
143 * data (or a reset while data is being copied)
148 data
[0] = 0; /* re-init so we restart the scan */
153 static int scanlog_release(struct inode
* inode
, struct file
* file
)
155 struct proc_dir_entry
*dp
= PDE(inode
);
156 unsigned int *data
= (unsigned int *)dp
->data
;
163 const struct file_operations scanlog_fops
= {
164 .owner
= THIS_MODULE
,
165 .read
= scanlog_read
,
166 .write
= scanlog_write
,
167 .open
= scanlog_open
,
168 .release
= scanlog_release
,
169 .llseek
= noop_llseek
,
172 static int __init
scanlog_init(void)
174 struct proc_dir_entry
*ent
;
178 ibm_scan_log_dump
= rtas_token("ibm,scan-log-dump");
179 if (ibm_scan_log_dump
== RTAS_UNKNOWN_SERVICE
)
182 /* Ideally we could allocate a buffer < 4G */
183 data
= kzalloc(RTAS_DATA_BUF_SIZE
, GFP_KERNEL
);
187 ent
= proc_create_data("powerpc/rtas/scan-log-dump", S_IRUSR
, NULL
,
188 &scanlog_fops
, data
);
192 proc_ppc64_scan_log_dump
= ent
;
200 static void __exit
scanlog_cleanup(void)
202 if (proc_ppc64_scan_log_dump
) {
203 kfree(proc_ppc64_scan_log_dump
->data
);
204 remove_proc_entry("scan-log-dump", proc_ppc64_scan_log_dump
->parent
);
208 module_init(scanlog_init
);
209 module_exit(scanlog_cleanup
);
210 MODULE_LICENSE("GPL");