1 /*
2  * Error log support on PowerNV.
3  *
4  * Copyright 2013,2014 IBM Corp.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/of.h>
15 #include <linux/slab.h>
16 #include <linux/sysfs.h>
17 #include <linux/fs.h>
18 #include <linux/vmalloc.h>
19 #include <linux/fcntl.h>
20 #include <linux/kobject.h>
21 #include <asm/uaccess.h>
22 #include <asm/opal.h>
23 
24 struct elog_obj {
25 	struct kobject kobj;
26 	struct bin_attribute raw_attr;
27 	uint64_t id;
28 	uint64_t type;
29 	size_t size;
30 	char *buffer;
31 };
32 #define to_elog_obj(x) container_of(x, struct elog_obj, kobj)
33 
34 struct elog_attribute {
35 	struct attribute attr;
36 	ssize_t (*show)(struct elog_obj *elog, struct elog_attribute *attr,
37 			char *buf);
38 	ssize_t (*store)(struct elog_obj *elog, struct elog_attribute *attr,
39 			 const char *buf, size_t count);
40 };
41 #define to_elog_attr(x) container_of(x, struct elog_attribute, attr)
42 
43 static ssize_t elog_id_show(struct elog_obj *elog_obj,
44 			    struct elog_attribute *attr,
45 			    char *buf)
46 {
47 	return sprintf(buf, "0x%llx\n", elog_obj->id);
48 }
49 
50 static const char *elog_type_to_string(uint64_t type)
51 {
52 	switch (type) {
53 	case 0: return "PEL";
54 	default: return "unknown";
55 	}
56 }
57 
58 static ssize_t elog_type_show(struct elog_obj *elog_obj,
59 			      struct elog_attribute *attr,
60 			      char *buf)
61 {
62 	return sprintf(buf, "0x%llx %s\n",
63 		       elog_obj->type,
64 		       elog_type_to_string(elog_obj->type));
65 }
66 
67 static ssize_t elog_ack_show(struct elog_obj *elog_obj,
68 			     struct elog_attribute *attr,
69 			     char *buf)
70 {
71 	return sprintf(buf, "ack - acknowledge log message\n");
72 }
73 
74 static ssize_t elog_ack_store(struct elog_obj *elog_obj,
75 			      struct elog_attribute *attr,
76 			      const char *buf,
77 			      size_t count)
78 {
79 	opal_send_ack_elog(elog_obj->id);
80 	sysfs_remove_file_self(&elog_obj->kobj, &attr->attr);
81 	kobject_put(&elog_obj->kobj);
82 	return count;
83 }
84 
85 static struct elog_attribute id_attribute =
86 	__ATTR(id, S_IRUGO, elog_id_show, NULL);
87 static struct elog_attribute type_attribute =
88 	__ATTR(type, S_IRUGO, elog_type_show, NULL);
89 static struct elog_attribute ack_attribute =
90 	__ATTR(acknowledge, 0660, elog_ack_show, elog_ack_store);
91 
92 static struct kset *elog_kset;
93 
94 static ssize_t elog_attr_show(struct kobject *kobj,
95 			      struct attribute *attr,
96 			      char *buf)
97 {
98 	struct elog_attribute *attribute;
99 	struct elog_obj *elog;
100 
101 	attribute = to_elog_attr(attr);
102 	elog = to_elog_obj(kobj);
103 
104 	if (!attribute->show)
105 		return -EIO;
106 
107 	return attribute->show(elog, attribute, buf);
108 }
109 
110 static ssize_t elog_attr_store(struct kobject *kobj,
111 			       struct attribute *attr,
112 			       const char *buf, size_t len)
113 {
114 	struct elog_attribute *attribute;
115 	struct elog_obj *elog;
116 
117 	attribute = to_elog_attr(attr);
118 	elog = to_elog_obj(kobj);
119 
120 	if (!attribute->store)
121 		return -EIO;
122 
123 	return attribute->store(elog, attribute, buf, len);
124 }
125 
126 static const struct sysfs_ops elog_sysfs_ops = {
127 	.show = elog_attr_show,
128 	.store = elog_attr_store,
129 };
130 
131 static void elog_release(struct kobject *kobj)
132 {
133 	struct elog_obj *elog;
134 
135 	elog = to_elog_obj(kobj);
136 	kfree(elog->buffer);
137 	kfree(elog);
138 }
139 
140 static struct attribute *elog_default_attrs[] = {
141 	&id_attribute.attr,
142 	&type_attribute.attr,
143 	&ack_attribute.attr,
144 	NULL,
145 };
146 
147 static struct kobj_type elog_ktype = {
148 	.sysfs_ops = &elog_sysfs_ops,
149 	.release = &elog_release,
150 	.default_attrs = elog_default_attrs,
151 };
152 
153 /* Maximum size of a single log on FSP is 16KB */
154 #define OPAL_MAX_ERRLOG_SIZE	16384
155 
156 static ssize_t raw_attr_read(struct file *filep, struct kobject *kobj,
157 			     struct bin_attribute *bin_attr,
158 			     char *buffer, loff_t pos, size_t count)
159 {
160 	int opal_rc;
161 
162 	struct elog_obj *elog = to_elog_obj(kobj);
163 
164 	/* We may have had an error reading before, so let's retry */
165 	if (!elog->buffer) {
166 		elog->buffer = kzalloc(elog->size, GFP_KERNEL);
167 		if (!elog->buffer)
168 			return -EIO;
169 
170 		opal_rc = opal_read_elog(__pa(elog->buffer),
171 					 elog->size, elog->id);
172 		if (opal_rc != OPAL_SUCCESS) {
173 			pr_err("ELOG: log read failed for log-id=%llx\n",
174 			       elog->id);
175 			kfree(elog->buffer);
176 			elog->buffer = NULL;
177 			return -EIO;
178 		}
179 	}
180 
181 	memcpy(buffer, elog->buffer + pos, count);
182 
183 	return count;
184 }
185 
186 static struct elog_obj *create_elog_obj(uint64_t id, size_t size, uint64_t type)
187 {
188 	struct elog_obj *elog;
189 	int rc;
190 
191 	elog = kzalloc(sizeof(*elog), GFP_KERNEL);
192 	if (!elog)
193 		return NULL;
194 
195 	elog->kobj.kset = elog_kset;
196 
197 	kobject_init(&elog->kobj, &elog_ktype);
198 
199 	sysfs_bin_attr_init(&elog->raw_attr);
200 
201 	elog->raw_attr.attr.name = "raw";
202 	elog->raw_attr.attr.mode = 0400;
203 	elog->raw_attr.size = size;
204 	elog->raw_attr.read = raw_attr_read;
205 
206 	elog->id = id;
207 	elog->size = size;
208 	elog->type = type;
209 
210 	elog->buffer = kzalloc(elog->size, GFP_KERNEL);
211 
212 	if (elog->buffer) {
213 		rc = opal_read_elog(__pa(elog->buffer),
214 					 elog->size, elog->id);
215 		if (rc != OPAL_SUCCESS) {
216 			pr_err("ELOG: log read failed for log-id=%llx\n",
217 			       elog->id);
218 			kfree(elog->buffer);
219 			elog->buffer = NULL;
220 		}
221 	}
222 
223 	rc = kobject_add(&elog->kobj, NULL, "0x%llx", id);
224 	if (rc) {
225 		kobject_put(&elog->kobj);
226 		return NULL;
227 	}
228 
229 	rc = sysfs_create_bin_file(&elog->kobj, &elog->raw_attr);
230 	if (rc) {
231 		kobject_put(&elog->kobj);
232 		return NULL;
233 	}
234 
235 	kobject_uevent(&elog->kobj, KOBJ_ADD);
236 
237 	return elog;
238 }
239 
240 static irqreturn_t elog_event(int irq, void *data)
241 {
242 	__be64 size;
243 	__be64 id;
244 	__be64 type;
245 	uint64_t elog_size;
246 	uint64_t log_id;
247 	uint64_t elog_type;
248 	int rc;
249 	char name[2+16+1];
250 	struct kobject *kobj;
251 
252 	rc = opal_get_elog_size(&id, &size, &type);
253 	if (rc != OPAL_SUCCESS) {
254 		pr_err("ELOG: OPAL log info read failed\n");
255 		return IRQ_HANDLED;
256 	}
257 
258 	elog_size = be64_to_cpu(size);
259 	log_id = be64_to_cpu(id);
260 	elog_type = be64_to_cpu(type);
261 
262 	WARN_ON(elog_size > OPAL_MAX_ERRLOG_SIZE);
263 
264 	if (elog_size >= OPAL_MAX_ERRLOG_SIZE)
265 		elog_size  =  OPAL_MAX_ERRLOG_SIZE;
266 
267 	sprintf(name, "0x%llx", log_id);
268 
269 	/* we may get notified twice, let's handle
270 	 * that gracefully and not create two conflicting
271 	 * entries.
272 	 */
273 	kobj = kset_find_obj(elog_kset, name);
274 	if (kobj) {
275 		/* Drop reference added by kset_find_obj() */
276 		kobject_put(kobj);
277 		return IRQ_HANDLED;
278 	}
279 
280 	create_elog_obj(log_id, elog_size, elog_type);
281 
282 	return IRQ_HANDLED;
283 }
284 
285 int __init opal_elog_init(void)
286 {
287 	int rc = 0, irq;
288 
289 	/* ELOG not supported by firmware */
290 	if (!opal_check_token(OPAL_ELOG_READ))
291 		return -1;
292 
293 	elog_kset = kset_create_and_add("elog", NULL, opal_kobj);
294 	if (!elog_kset) {
295 		pr_warn("%s: failed to create elog kset\n", __func__);
296 		return -1;
297 	}
298 
299 	irq = opal_event_request(ilog2(OPAL_EVENT_ERROR_LOG_AVAIL));
300 	if (!irq) {
301 		pr_err("%s: Can't register OPAL event irq (%d)\n",
302 		       __func__, irq);
303 		return irq;
304 	}
305 
306 	rc = request_threaded_irq(irq, NULL, elog_event,
307 			IRQF_TRIGGER_HIGH | IRQF_ONESHOT, "opal-elog", NULL);
308 	if (rc) {
309 		pr_err("%s: Can't request OPAL event irq (%d)\n",
310 		       __func__, rc);
311 		return rc;
312 	}
313 
314 	/* We are now ready to pull error logs from opal. */
315 	if (opal_check_token(OPAL_ELOG_RESEND))
316 		opal_resend_pending_logs();
317 
318 	return 0;
319 }
320