x86, efi: Set runtime_version to the EFI spec revision
[linux/fpc-iii.git] / arch / powerpc / platforms / pseries / scanlog.c
blob554457294a2b5c8f4429b6ba4a2f99d26602c022
1 /*
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>
31 #include <asm/rtas.h>
32 #include <asm/prom.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 inode * inode = file->f_path.dentry->d_inode;
50 struct proc_dir_entry *dp;
51 unsigned int *data;
52 int status;
53 unsigned long len, off;
54 unsigned int wait_time;
56 dp = PDE(inode);
57 data = (unsigned int *)dp->data;
59 if (count > RTAS_DATA_BUF_SIZE)
60 count = RTAS_DATA_BUF_SIZE;
62 if (count < 1024) {
63 /* This is the min supported by this RTAS call. Rather
64 * than do all the buffering we insist the user code handle
65 * larger reads. As long as cp works... :)
67 printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count);
68 return -EINVAL;
71 if (!access_ok(VERIFY_WRITE, buf, count))
72 return -EFAULT;
74 for (;;) {
75 wait_time = 500; /* default wait if no data */
76 spin_lock(&rtas_data_buf_lock);
77 memcpy(rtas_data_buf, data, RTAS_DATA_BUF_SIZE);
78 status = rtas_call(ibm_scan_log_dump, 2, 1, NULL,
79 (u32) __pa(rtas_data_buf), (u32) count);
80 memcpy(data, rtas_data_buf, RTAS_DATA_BUF_SIZE);
81 spin_unlock(&rtas_data_buf_lock);
83 pr_debug("scanlog: status=%d, data[0]=%x, data[1]=%x, " \
84 "data[2]=%x\n", status, data[0], data[1], data[2]);
85 switch (status) {
86 case SCANLOG_COMPLETE:
87 pr_debug("scanlog: hit eof\n");
88 return 0;
89 case SCANLOG_HWERROR:
90 pr_debug("scanlog: hardware error reading data\n");
91 return -EIO;
92 case SCANLOG_CONTINUE:
93 /* We may or may not have data yet */
94 len = data[1];
95 off = data[2];
96 if (len > 0) {
97 if (copy_to_user(buf, ((char *)data)+off, len))
98 return -EFAULT;
99 return len;
101 /* Break to sleep default time */
102 break;
103 default:
104 /* Assume extended busy */
105 wait_time = rtas_busy_delay_time(status);
106 if (!wait_time) {
107 printk(KERN_ERR "scanlog: unknown error " \
108 "from rtas: %d\n", status);
109 return -EIO;
112 /* Apparently no data yet. Wait and try again. */
113 msleep_interruptible(wait_time);
115 /*NOTREACHED*/
118 static ssize_t scanlog_write(struct file * file, const char __user * buf,
119 size_t count, loff_t *ppos)
121 char stkbuf[20];
122 int status;
124 if (count > 19) count = 19;
125 if (copy_from_user (stkbuf, buf, count)) {
126 return -EFAULT;
128 stkbuf[count] = 0;
130 if (buf) {
131 if (strncmp(stkbuf, "reset", 5) == 0) {
132 pr_debug("scanlog: reset scanlog\n");
133 status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0);
134 pr_debug("scanlog: rtas returns %d\n", status);
137 return count;
140 static int scanlog_open(struct inode * inode, struct file * file)
142 struct proc_dir_entry *dp = PDE(inode);
143 unsigned int *data = (unsigned int *)dp->data;
145 if (data[0] != 0) {
146 /* This imperfect test stops a second copy of the
147 * data (or a reset while data is being copied)
149 return -EBUSY;
152 data[0] = 0; /* re-init so we restart the scan */
154 return 0;
157 static int scanlog_release(struct inode * inode, struct file * file)
159 struct proc_dir_entry *dp = PDE(inode);
160 unsigned int *data = (unsigned int *)dp->data;
162 data[0] = 0;
164 return 0;
167 const struct file_operations scanlog_fops = {
168 .owner = THIS_MODULE,
169 .read = scanlog_read,
170 .write = scanlog_write,
171 .open = scanlog_open,
172 .release = scanlog_release,
173 .llseek = noop_llseek,
176 static int __init scanlog_init(void)
178 struct proc_dir_entry *ent;
179 void *data;
180 int err = -ENOMEM;
182 ibm_scan_log_dump = rtas_token("ibm,scan-log-dump");
183 if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE)
184 return -ENODEV;
186 /* Ideally we could allocate a buffer < 4G */
187 data = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL);
188 if (!data)
189 goto err;
191 ent = proc_create_data("powerpc/rtas/scan-log-dump", S_IRUSR, NULL,
192 &scanlog_fops, data);
193 if (!ent)
194 goto err;
196 proc_ppc64_scan_log_dump = ent;
198 return 0;
199 err:
200 kfree(data);
201 return err;
204 static void __exit scanlog_cleanup(void)
206 if (proc_ppc64_scan_log_dump) {
207 kfree(proc_ppc64_scan_log_dump->data);
208 remove_proc_entry("scan-log-dump", proc_ppc64_scan_log_dump->parent);
212 module_init(scanlog_init);
213 module_exit(scanlog_cleanup);
214 MODULE_LICENSE("GPL");