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1da177e4 LT |
1 | /* |
2 | * c 2001 PPC 64 Team, IBM Corp | |
3 | * | |
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. | |
8 | * | |
9 | * scan-log-data driver for PPC64 Todd Inglett <tinglett@vnet.ibm.com> | |
10 | * | |
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. | |
15 | * | |
188917e1 | 16 | * This driver exports /proc/powerpc/scan-log-dump which can be read. |
1da177e4 LT |
17 | * The driver supports only sequential reads. |
18 | * | |
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. | |
21 | */ | |
22 | ||
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> | |
0287ebed | 28 | #include <linux/delay.h> |
5a0e3ad6 | 29 | #include <linux/slab.h> |
1da177e4 LT |
30 | #include <asm/uaccess.h> |
31 | #include <asm/rtas.h> | |
32 | #include <asm/prom.h> | |
33 | ||
34 | #define MODULE_VERS "1.0" | |
35 | #define MODULE_NAME "scanlog" | |
36 | ||
37 | /* Status returns from ibm,scan-log-dump */ | |
38 | #define SCANLOG_COMPLETE 0 | |
39 | #define SCANLOG_HWERROR -1 | |
40 | #define SCANLOG_CONTINUE 1 | |
41 | ||
1da177e4 | 42 | |
1da177e4 LT |
43 | static unsigned int ibm_scan_log_dump; /* RTAS token */ |
44 | static struct proc_dir_entry *proc_ppc64_scan_log_dump; /* The proc file */ | |
45 | ||
efa54579 | 46 | static ssize_t scanlog_read(struct file *file, char __user *buf, |
1da177e4 LT |
47 | size_t count, loff_t *ppos) |
48 | { | |
b4d1ab58 | 49 | struct inode * inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
50 | struct proc_dir_entry *dp; |
51 | unsigned int *data; | |
52 | int status; | |
53 | unsigned long len, off; | |
54 | unsigned int wait_time; | |
55 | ||
56 | dp = PDE(inode); | |
57 | data = (unsigned int *)dp->data; | |
58 | ||
1da177e4 LT |
59 | if (count > RTAS_DATA_BUF_SIZE) |
60 | count = RTAS_DATA_BUF_SIZE; | |
61 | ||
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... :) | |
66 | */ | |
67 | printk(KERN_ERR "scanlog: cannot perform a small read (%ld)\n", count); | |
68 | return -EINVAL; | |
69 | } | |
70 | ||
71 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
72 | return -EFAULT; | |
73 | ||
74 | for (;;) { | |
0287ebed | 75 | wait_time = 500; /* default wait if no data */ |
1da177e4 LT |
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); | |
82 | ||
f7ebf352 ME |
83 | pr_debug("scanlog: status=%d, data[0]=%x, data[1]=%x, " \ |
84 | "data[2]=%x\n", status, data[0], data[1], data[2]); | |
1da177e4 LT |
85 | switch (status) { |
86 | case SCANLOG_COMPLETE: | |
f7ebf352 | 87 | pr_debug("scanlog: hit eof\n"); |
1da177e4 LT |
88 | return 0; |
89 | case SCANLOG_HWERROR: | |
f7ebf352 | 90 | pr_debug("scanlog: hardware error reading data\n"); |
1da177e4 LT |
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; | |
100 | } | |
101 | /* Break to sleep default time */ | |
102 | break; | |
103 | default: | |
7932f0b8 JR |
104 | /* Assume extended busy */ |
105 | wait_time = rtas_busy_delay_time(status); | |
106 | if (!wait_time) { | |
f7ebf352 ME |
107 | printk(KERN_ERR "scanlog: unknown error " \ |
108 | "from rtas: %d\n", status); | |
1da177e4 LT |
109 | return -EIO; |
110 | } | |
111 | } | |
112 | /* Apparently no data yet. Wait and try again. */ | |
0287ebed | 113 | msleep_interruptible(wait_time); |
1da177e4 LT |
114 | } |
115 | /*NOTREACHED*/ | |
116 | } | |
117 | ||
efa54579 | 118 | static ssize_t scanlog_write(struct file * file, const char __user * buf, |
1da177e4 LT |
119 | size_t count, loff_t *ppos) |
120 | { | |
121 | char stkbuf[20]; | |
122 | int status; | |
123 | ||
124 | if (count > 19) count = 19; | |
125 | if (copy_from_user (stkbuf, buf, count)) { | |
126 | return -EFAULT; | |
127 | } | |
128 | stkbuf[count] = 0; | |
129 | ||
130 | if (buf) { | |
131 | if (strncmp(stkbuf, "reset", 5) == 0) { | |
f7ebf352 | 132 | pr_debug("scanlog: reset scanlog\n"); |
1da177e4 | 133 | status = rtas_call(ibm_scan_log_dump, 2, 1, NULL, 0, 0); |
f7ebf352 | 134 | pr_debug("scanlog: rtas returns %d\n", status); |
1da177e4 LT |
135 | } |
136 | } | |
137 | return count; | |
138 | } | |
139 | ||
140 | static int scanlog_open(struct inode * inode, struct file * file) | |
141 | { | |
142 | struct proc_dir_entry *dp = PDE(inode); | |
143 | unsigned int *data = (unsigned int *)dp->data; | |
144 | ||
1da177e4 LT |
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) | |
148 | */ | |
149 | return -EBUSY; | |
150 | } | |
151 | ||
152 | data[0] = 0; /* re-init so we restart the scan */ | |
153 | ||
154 | return 0; | |
155 | } | |
156 | ||
157 | static int scanlog_release(struct inode * inode, struct file * file) | |
158 | { | |
159 | struct proc_dir_entry *dp = PDE(inode); | |
160 | unsigned int *data = (unsigned int *)dp->data; | |
161 | ||
1da177e4 LT |
162 | data[0] = 0; |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
5dfe4c96 | 167 | const struct file_operations scanlog_fops = { |
1da177e4 LT |
168 | .owner = THIS_MODULE, |
169 | .read = scanlog_read, | |
170 | .write = scanlog_write, | |
171 | .open = scanlog_open, | |
172 | .release = scanlog_release, | |
173 | }; | |
174 | ||
8446196a | 175 | static int __init scanlog_init(void) |
1da177e4 LT |
176 | { |
177 | struct proc_dir_entry *ent; | |
f61fb8a5 NL |
178 | void *data; |
179 | int err = -ENOMEM; | |
1da177e4 LT |
180 | |
181 | ibm_scan_log_dump = rtas_token("ibm,scan-log-dump"); | |
f61fb8a5 NL |
182 | if (ibm_scan_log_dump == RTAS_UNKNOWN_SERVICE) |
183 | return -ENODEV; | |
1da177e4 | 184 | |
f61fb8a5 NL |
185 | /* Ideally we could allocate a buffer < 4G */ |
186 | data = kzalloc(RTAS_DATA_BUF_SIZE, GFP_KERNEL); | |
187 | if (!data) | |
188 | goto err; | |
189 | ||
188917e1 | 190 | ent = proc_create_data("powerpc/rtas/scan-log-dump", S_IRUSR, NULL, |
9185ef67 | 191 | &scanlog_fops, data); |
f61fb8a5 NL |
192 | if (!ent) |
193 | goto err; | |
194 | ||
1da177e4 LT |
195 | proc_ppc64_scan_log_dump = ent; |
196 | ||
197 | return 0; | |
f61fb8a5 NL |
198 | err: |
199 | kfree(data); | |
200 | return err; | |
1da177e4 LT |
201 | } |
202 | ||
8446196a | 203 | static void __exit scanlog_cleanup(void) |
1da177e4 LT |
204 | { |
205 | if (proc_ppc64_scan_log_dump) { | |
b2325fe1 | 206 | kfree(proc_ppc64_scan_log_dump->data); |
1da177e4 LT |
207 | remove_proc_entry("scan-log-dump", proc_ppc64_scan_log_dump->parent); |
208 | } | |
209 | } | |
210 | ||
211 | module_init(scanlog_init); | |
212 | module_exit(scanlog_cleanup); | |
213 | MODULE_LICENSE("GPL"); |