1 /*
2  * PowerNV OPAL Dump Interface
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 
12 #include <linux/kobject.h>
13 #include <linux/mm.h>
14 #include <linux/slab.h>
15 #include <linux/vmalloc.h>
16 #include <linux/pagemap.h>
17 #include <linux/delay.h>
18 
19 #include <asm/opal.h>
20 
21 #define DUMP_TYPE_FSP	0x01
22 
23 struct dump_obj {
24 	struct kobject  kobj;
25 	struct bin_attribute dump_attr;
26 	uint32_t	id;  /* becomes object name */
27 	uint32_t	type;
28 	uint32_t	size;
29 	char		*buffer;
30 };
31 #define to_dump_obj(x) container_of(x, struct dump_obj, kobj)
32 
33 struct dump_attribute {
34 	struct attribute attr;
35 	ssize_t (*show)(struct dump_obj *dump, struct dump_attribute *attr,
36 			char *buf);
37 	ssize_t (*store)(struct dump_obj *dump, struct dump_attribute *attr,
38 			 const char *buf, size_t count);
39 };
40 #define to_dump_attr(x) container_of(x, struct dump_attribute, attr)
41 
42 static ssize_t dump_id_show(struct dump_obj *dump_obj,
43 			    struct dump_attribute *attr,
44 			    char *buf)
45 {
46 	return sprintf(buf, "0x%x\n", dump_obj->id);
47 }
48 
49 static const char* dump_type_to_string(uint32_t type)
50 {
51 	switch (type) {
52 	case 0x01: return "SP Dump";
53 	case 0x02: return "System/Platform Dump";
54 	case 0x03: return "SMA Dump";
55 	default: return "unknown";
56 	}
57 }
58 
59 static ssize_t dump_type_show(struct dump_obj *dump_obj,
60 			      struct dump_attribute *attr,
61 			      char *buf)
62 {
63 
64 	return sprintf(buf, "0x%x %s\n", dump_obj->type,
65 		       dump_type_to_string(dump_obj->type));
66 }
67 
68 static ssize_t dump_ack_show(struct dump_obj *dump_obj,
69 			     struct dump_attribute *attr,
70 			     char *buf)
71 {
72 	return sprintf(buf, "ack - acknowledge dump\n");
73 }
74 
75 /*
76  * Send acknowledgement to OPAL
77  */
78 static int64_t dump_send_ack(uint32_t dump_id)
79 {
80 	int rc;
81 
82 	rc = opal_dump_ack(dump_id);
83 	if (rc)
84 		pr_warn("%s: Failed to send ack to Dump ID 0x%x (%d)\n",
85 			__func__, dump_id, rc);
86 	return rc;
87 }
88 
89 static ssize_t dump_ack_store(struct dump_obj *dump_obj,
90 			      struct dump_attribute *attr,
91 			      const char *buf,
92 			      size_t count)
93 {
94 	dump_send_ack(dump_obj->id);
95 	sysfs_remove_file_self(&dump_obj->kobj, &attr->attr);
96 	kobject_put(&dump_obj->kobj);
97 	return count;
98 }
99 
100 /* Attributes of a dump
101  * The binary attribute of the dump itself is dynamic
102  * due to the dynamic size of the dump
103  */
104 static struct dump_attribute id_attribute =
105 	__ATTR(id, S_IRUGO, dump_id_show, NULL);
106 static struct dump_attribute type_attribute =
107 	__ATTR(type, S_IRUGO, dump_type_show, NULL);
108 static struct dump_attribute ack_attribute =
109 	__ATTR(acknowledge, 0660, dump_ack_show, dump_ack_store);
110 
111 static ssize_t init_dump_show(struct dump_obj *dump_obj,
112 			      struct dump_attribute *attr,
113 			      char *buf)
114 {
115 	return sprintf(buf, "1 - initiate Service Processor(FSP) dump\n");
116 }
117 
118 static int64_t dump_fips_init(uint8_t type)
119 {
120 	int rc;
121 
122 	rc = opal_dump_init(type);
123 	if (rc)
124 		pr_warn("%s: Failed to initiate FSP dump (%d)\n",
125 			__func__, rc);
126 	return rc;
127 }
128 
129 static ssize_t init_dump_store(struct dump_obj *dump_obj,
130 			       struct dump_attribute *attr,
131 			       const char *buf,
132 			       size_t count)
133 {
134 	int rc;
135 
136 	rc = dump_fips_init(DUMP_TYPE_FSP);
137 	if (rc == OPAL_SUCCESS)
138 		pr_info("%s: Initiated FSP dump\n", __func__);
139 
140 	return count;
141 }
142 
143 static struct dump_attribute initiate_attribute =
144 	__ATTR(initiate_dump, 0600, init_dump_show, init_dump_store);
145 
146 static struct attribute *initiate_attrs[] = {
147 	&initiate_attribute.attr,
148 	NULL,
149 };
150 
151 static struct attribute_group initiate_attr_group = {
152 	.attrs = initiate_attrs,
153 };
154 
155 static struct kset *dump_kset;
156 
157 static ssize_t dump_attr_show(struct kobject *kobj,
158 			      struct attribute *attr,
159 			      char *buf)
160 {
161 	struct dump_attribute *attribute;
162 	struct dump_obj *dump;
163 
164 	attribute = to_dump_attr(attr);
165 	dump = to_dump_obj(kobj);
166 
167 	if (!attribute->show)
168 		return -EIO;
169 
170 	return attribute->show(dump, attribute, buf);
171 }
172 
173 static ssize_t dump_attr_store(struct kobject *kobj,
174 			       struct attribute *attr,
175 			       const char *buf, size_t len)
176 {
177 	struct dump_attribute *attribute;
178 	struct dump_obj *dump;
179 
180 	attribute = to_dump_attr(attr);
181 	dump = to_dump_obj(kobj);
182 
183 	if (!attribute->store)
184 		return -EIO;
185 
186 	return attribute->store(dump, attribute, buf, len);
187 }
188 
189 static const struct sysfs_ops dump_sysfs_ops = {
190 	.show = dump_attr_show,
191 	.store = dump_attr_store,
192 };
193 
194 static void dump_release(struct kobject *kobj)
195 {
196 	struct dump_obj *dump;
197 
198 	dump = to_dump_obj(kobj);
199 	vfree(dump->buffer);
200 	kfree(dump);
201 }
202 
203 static struct attribute *dump_default_attrs[] = {
204 	&id_attribute.attr,
205 	&type_attribute.attr,
206 	&ack_attribute.attr,
207 	NULL,
208 };
209 
210 static struct kobj_type dump_ktype = {
211 	.sysfs_ops = &dump_sysfs_ops,
212 	.release = &dump_release,
213 	.default_attrs = dump_default_attrs,
214 };
215 
216 static int64_t dump_read_info(uint32_t *dump_id, uint32_t *dump_size, uint32_t *dump_type)
217 {
218 	__be32 id, size, type;
219 	int rc;
220 
221 	type = cpu_to_be32(0xffffffff);
222 
223 	rc = opal_dump_info2(&id, &size, &type);
224 	if (rc == OPAL_PARAMETER)
225 		rc = opal_dump_info(&id, &size);
226 
227 	*dump_id = be32_to_cpu(id);
228 	*dump_size = be32_to_cpu(size);
229 	*dump_type = be32_to_cpu(type);
230 
231 	if (rc)
232 		pr_warn("%s: Failed to get dump info (%d)\n",
233 			__func__, rc);
234 	return rc;
235 }
236 
237 static int64_t dump_read_data(struct dump_obj *dump)
238 {
239 	struct opal_sg_list *list;
240 	uint64_t addr;
241 	int64_t rc;
242 
243 	/* Allocate memory */
244 	dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
245 	if (!dump->buffer) {
246 		pr_err("%s : Failed to allocate memory\n", __func__);
247 		rc = -ENOMEM;
248 		goto out;
249 	}
250 
251 	/* Generate SG list */
252 	list = opal_vmalloc_to_sg_list(dump->buffer, dump->size);
253 	if (!list) {
254 		rc = -ENOMEM;
255 		goto out;
256 	}
257 
258 	/* First entry address */
259 	addr = __pa(list);
260 
261 	/* Fetch data */
262 	rc = OPAL_BUSY_EVENT;
263 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
264 		rc = opal_dump_read(dump->id, addr);
265 		if (rc == OPAL_BUSY_EVENT) {
266 			opal_poll_events(NULL);
267 			msleep(20);
268 		}
269 	}
270 
271 	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
272 		pr_warn("%s: Extract dump failed for ID 0x%x\n",
273 			__func__, dump->id);
274 
275 	/* Free SG list */
276 	opal_free_sg_list(list);
277 
278 out:
279 	return rc;
280 }
281 
282 static ssize_t dump_attr_read(struct file *filep, struct kobject *kobj,
283 			      struct bin_attribute *bin_attr,
284 			      char *buffer, loff_t pos, size_t count)
285 {
286 	ssize_t rc;
287 
288 	struct dump_obj *dump = to_dump_obj(kobj);
289 
290 	if (!dump->buffer) {
291 		rc = dump_read_data(dump);
292 
293 		if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
294 			vfree(dump->buffer);
295 			dump->buffer = NULL;
296 
297 			return -EIO;
298 		}
299 		if (rc == OPAL_PARTIAL) {
300 			/* On a partial read, we just return EIO
301 			 * and rely on userspace to ask us to try
302 			 * again.
303 			 */
304 			pr_info("%s: Platform dump partially read. ID = 0x%x\n",
305 				__func__, dump->id);
306 			return -EIO;
307 		}
308 	}
309 
310 	memcpy(buffer, dump->buffer + pos, count);
311 
312 	/* You may think we could free the dump buffer now and retrieve
313 	 * it again later if needed, but due to current firmware limitation,
314 	 * that's not the case. So, once read into userspace once,
315 	 * we keep the dump around until it's acknowledged by userspace.
316 	 */
317 
318 	return count;
319 }
320 
321 static struct dump_obj *create_dump_obj(uint32_t id, size_t size,
322 					uint32_t type)
323 {
324 	struct dump_obj *dump;
325 	int rc;
326 
327 	dump = kzalloc(sizeof(*dump), GFP_KERNEL);
328 	if (!dump)
329 		return NULL;
330 
331 	dump->kobj.kset = dump_kset;
332 
333 	kobject_init(&dump->kobj, &dump_ktype);
334 
335 	sysfs_bin_attr_init(&dump->dump_attr);
336 
337 	dump->dump_attr.attr.name = "dump";
338 	dump->dump_attr.attr.mode = 0400;
339 	dump->dump_attr.size = size;
340 	dump->dump_attr.read = dump_attr_read;
341 
342 	dump->id = id;
343 	dump->size = size;
344 	dump->type = type;
345 
346 	rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
347 	if (rc) {
348 		kobject_put(&dump->kobj);
349 		return NULL;
350 	}
351 
352 	rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
353 	if (rc) {
354 		kobject_put(&dump->kobj);
355 		return NULL;
356 	}
357 
358 	pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
359 		__func__, dump->id, dump->size);
360 
361 	kobject_uevent(&dump->kobj, KOBJ_ADD);
362 
363 	return dump;
364 }
365 
366 static int process_dump(void)
367 {
368 	int rc;
369 	uint32_t dump_id, dump_size, dump_type;
370 	struct dump_obj *dump;
371 	char name[22];
372 
373 	rc = dump_read_info(&dump_id, &dump_size, &dump_type);
374 	if (rc != OPAL_SUCCESS)
375 		return rc;
376 
377 	sprintf(name, "0x%x-0x%x", dump_type, dump_id);
378 
379 	/* we may get notified twice, let's handle
380 	 * that gracefully and not create two conflicting
381 	 * entries.
382 	 */
383 	if (kset_find_obj(dump_kset, name))
384 		return 0;
385 
386 	dump = create_dump_obj(dump_id, dump_size, dump_type);
387 	if (!dump)
388 		return -1;
389 
390 	return 0;
391 }
392 
393 static void dump_work_fn(struct work_struct *work)
394 {
395 	process_dump();
396 }
397 
398 static DECLARE_WORK(dump_work, dump_work_fn);
399 
400 static void schedule_process_dump(void)
401 {
402 	schedule_work(&dump_work);
403 }
404 
405 /*
406  * New dump available notification
407  *
408  * Once we get notification, we add sysfs entries for it.
409  * We only fetch the dump on demand, and create sysfs asynchronously.
410  */
411 static int dump_event(struct notifier_block *nb,
412 		      unsigned long events, void *change)
413 {
414 	if (events & OPAL_EVENT_DUMP_AVAIL)
415 		schedule_process_dump();
416 
417 	return 0;
418 }
419 
420 static struct notifier_block dump_nb = {
421 	.notifier_call  = dump_event,
422 	.next           = NULL,
423 	.priority       = 0
424 };
425 
426 void __init opal_platform_dump_init(void)
427 {
428 	int rc;
429 
430 	/* ELOG not supported by firmware */
431 	if (!opal_check_token(OPAL_DUMP_READ))
432 		return;
433 
434 	dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
435 	if (!dump_kset) {
436 		pr_warn("%s: Failed to create dump kset\n", __func__);
437 		return;
438 	}
439 
440 	rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
441 	if (rc) {
442 		pr_warn("%s: Failed to create initiate dump attr group\n",
443 			__func__);
444 		kobject_put(&dump_kset->kobj);
445 		return;
446 	}
447 
448 	rc = opal_notifier_register(&dump_nb);
449 	if (rc) {
450 		pr_warn("%s: Can't register OPAL event notifier (%d)\n",
451 			__func__, rc);
452 		return;
453 	}
454 
455 	if (opal_check_token(OPAL_DUMP_RESEND))
456 		opal_dump_resend_notification();
457 }
458