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 #include <linux/interrupt.h>
19 
20 #include <asm/opal.h>
21 
22 #define DUMP_TYPE_FSP	0x01
23 
24 struct dump_obj {
25 	struct kobject  kobj;
26 	struct bin_attribute dump_attr;
27 	uint32_t	id;  /* becomes object name */
28 	uint32_t	type;
29 	uint32_t	size;
30 	char		*buffer;
31 };
32 #define to_dump_obj(x) container_of(x, struct dump_obj, kobj)
33 
34 struct dump_attribute {
35 	struct attribute attr;
36 	ssize_t (*show)(struct dump_obj *dump, struct dump_attribute *attr,
37 			char *buf);
38 	ssize_t (*store)(struct dump_obj *dump, struct dump_attribute *attr,
39 			 const char *buf, size_t count);
40 };
41 #define to_dump_attr(x) container_of(x, struct dump_attribute, attr)
42 
43 static ssize_t dump_id_show(struct dump_obj *dump_obj,
44 			    struct dump_attribute *attr,
45 			    char *buf)
46 {
47 	return sprintf(buf, "0x%x\n", dump_obj->id);
48 }
49 
50 static const char* dump_type_to_string(uint32_t type)
51 {
52 	switch (type) {
53 	case 0x01: return "SP Dump";
54 	case 0x02: return "System/Platform Dump";
55 	case 0x03: return "SMA Dump";
56 	default: return "unknown";
57 	}
58 }
59 
60 static ssize_t dump_type_show(struct dump_obj *dump_obj,
61 			      struct dump_attribute *attr,
62 			      char *buf)
63 {
64 
65 	return sprintf(buf, "0x%x %s\n", dump_obj->type,
66 		       dump_type_to_string(dump_obj->type));
67 }
68 
69 static ssize_t dump_ack_show(struct dump_obj *dump_obj,
70 			     struct dump_attribute *attr,
71 			     char *buf)
72 {
73 	return sprintf(buf, "ack - acknowledge dump\n");
74 }
75 
76 /*
77  * Send acknowledgement to OPAL
78  */
79 static int64_t dump_send_ack(uint32_t dump_id)
80 {
81 	int rc;
82 
83 	rc = opal_dump_ack(dump_id);
84 	if (rc)
85 		pr_warn("%s: Failed to send ack to Dump ID 0x%x (%d)\n",
86 			__func__, dump_id, rc);
87 	return rc;
88 }
89 
90 static ssize_t dump_ack_store(struct dump_obj *dump_obj,
91 			      struct dump_attribute *attr,
92 			      const char *buf,
93 			      size_t count)
94 {
95 	dump_send_ack(dump_obj->id);
96 	sysfs_remove_file_self(&dump_obj->kobj, &attr->attr);
97 	kobject_put(&dump_obj->kobj);
98 	return count;
99 }
100 
101 /* Attributes of a dump
102  * The binary attribute of the dump itself is dynamic
103  * due to the dynamic size of the dump
104  */
105 static struct dump_attribute id_attribute =
106 	__ATTR(id, 0444, dump_id_show, NULL);
107 static struct dump_attribute type_attribute =
108 	__ATTR(type, 0444, dump_type_show, NULL);
109 static struct dump_attribute ack_attribute =
110 	__ATTR(acknowledge, 0660, dump_ack_show, dump_ack_store);
111 
112 static ssize_t init_dump_show(struct dump_obj *dump_obj,
113 			      struct dump_attribute *attr,
114 			      char *buf)
115 {
116 	return sprintf(buf, "1 - initiate Service Processor(FSP) dump\n");
117 }
118 
119 static int64_t dump_fips_init(uint8_t type)
120 {
121 	int rc;
122 
123 	rc = opal_dump_init(type);
124 	if (rc)
125 		pr_warn("%s: Failed to initiate FSP dump (%d)\n",
126 			__func__, rc);
127 	return rc;
128 }
129 
130 static ssize_t init_dump_store(struct dump_obj *dump_obj,
131 			       struct dump_attribute *attr,
132 			       const char *buf,
133 			       size_t count)
134 {
135 	int rc;
136 
137 	rc = dump_fips_init(DUMP_TYPE_FSP);
138 	if (rc == OPAL_SUCCESS)
139 		pr_info("%s: Initiated FSP dump\n", __func__);
140 
141 	return count;
142 }
143 
144 static struct dump_attribute initiate_attribute =
145 	__ATTR(initiate_dump, 0600, init_dump_show, init_dump_store);
146 
147 static struct attribute *initiate_attrs[] = {
148 	&initiate_attribute.attr,
149 	NULL,
150 };
151 
152 static struct attribute_group initiate_attr_group = {
153 	.attrs = initiate_attrs,
154 };
155 
156 static struct kset *dump_kset;
157 
158 static ssize_t dump_attr_show(struct kobject *kobj,
159 			      struct attribute *attr,
160 			      char *buf)
161 {
162 	struct dump_attribute *attribute;
163 	struct dump_obj *dump;
164 
165 	attribute = to_dump_attr(attr);
166 	dump = to_dump_obj(kobj);
167 
168 	if (!attribute->show)
169 		return -EIO;
170 
171 	return attribute->show(dump, attribute, buf);
172 }
173 
174 static ssize_t dump_attr_store(struct kobject *kobj,
175 			       struct attribute *attr,
176 			       const char *buf, size_t len)
177 {
178 	struct dump_attribute *attribute;
179 	struct dump_obj *dump;
180 
181 	attribute = to_dump_attr(attr);
182 	dump = to_dump_obj(kobj);
183 
184 	if (!attribute->store)
185 		return -EIO;
186 
187 	return attribute->store(dump, attribute, buf, len);
188 }
189 
190 static const struct sysfs_ops dump_sysfs_ops = {
191 	.show = dump_attr_show,
192 	.store = dump_attr_store,
193 };
194 
195 static void dump_release(struct kobject *kobj)
196 {
197 	struct dump_obj *dump;
198 
199 	dump = to_dump_obj(kobj);
200 	vfree(dump->buffer);
201 	kfree(dump);
202 }
203 
204 static struct attribute *dump_default_attrs[] = {
205 	&id_attribute.attr,
206 	&type_attribute.attr,
207 	&ack_attribute.attr,
208 	NULL,
209 };
210 
211 static struct kobj_type dump_ktype = {
212 	.sysfs_ops = &dump_sysfs_ops,
213 	.release = &dump_release,
214 	.default_attrs = dump_default_attrs,
215 };
216 
217 static int64_t dump_read_info(uint32_t *dump_id, uint32_t *dump_size, uint32_t *dump_type)
218 {
219 	__be32 id, size, type;
220 	int rc;
221 
222 	type = cpu_to_be32(0xffffffff);
223 
224 	rc = opal_dump_info2(&id, &size, &type);
225 	if (rc == OPAL_PARAMETER)
226 		rc = opal_dump_info(&id, &size);
227 
228 	if (rc) {
229 		pr_warn("%s: Failed to get dump info (%d)\n",
230 			__func__, rc);
231 		return rc;
232 	}
233 
234 	*dump_id = be32_to_cpu(id);
235 	*dump_size = be32_to_cpu(size);
236 	*dump_type = be32_to_cpu(type);
237 
238 	return rc;
239 }
240 
241 static int64_t dump_read_data(struct dump_obj *dump)
242 {
243 	struct opal_sg_list *list;
244 	uint64_t addr;
245 	int64_t rc;
246 
247 	/* Allocate memory */
248 	dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
249 	if (!dump->buffer) {
250 		pr_err("%s : Failed to allocate memory\n", __func__);
251 		rc = -ENOMEM;
252 		goto out;
253 	}
254 
255 	/* Generate SG list */
256 	list = opal_vmalloc_to_sg_list(dump->buffer, dump->size);
257 	if (!list) {
258 		rc = -ENOMEM;
259 		goto out;
260 	}
261 
262 	/* First entry address */
263 	addr = __pa(list);
264 
265 	/* Fetch data */
266 	rc = OPAL_BUSY_EVENT;
267 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
268 		rc = opal_dump_read(dump->id, addr);
269 		if (rc == OPAL_BUSY_EVENT) {
270 			opal_poll_events(NULL);
271 			msleep(20);
272 		}
273 	}
274 
275 	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
276 		pr_warn("%s: Extract dump failed for ID 0x%x\n",
277 			__func__, dump->id);
278 
279 	/* Free SG list */
280 	opal_free_sg_list(list);
281 
282 out:
283 	return rc;
284 }
285 
286 static ssize_t dump_attr_read(struct file *filep, struct kobject *kobj,
287 			      struct bin_attribute *bin_attr,
288 			      char *buffer, loff_t pos, size_t count)
289 {
290 	ssize_t rc;
291 
292 	struct dump_obj *dump = to_dump_obj(kobj);
293 
294 	if (!dump->buffer) {
295 		rc = dump_read_data(dump);
296 
297 		if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
298 			vfree(dump->buffer);
299 			dump->buffer = NULL;
300 
301 			return -EIO;
302 		}
303 		if (rc == OPAL_PARTIAL) {
304 			/* On a partial read, we just return EIO
305 			 * and rely on userspace to ask us to try
306 			 * again.
307 			 */
308 			pr_info("%s: Platform dump partially read. ID = 0x%x\n",
309 				__func__, dump->id);
310 			return -EIO;
311 		}
312 	}
313 
314 	memcpy(buffer, dump->buffer + pos, count);
315 
316 	/* You may think we could free the dump buffer now and retrieve
317 	 * it again later if needed, but due to current firmware limitation,
318 	 * that's not the case. So, once read into userspace once,
319 	 * we keep the dump around until it's acknowledged by userspace.
320 	 */
321 
322 	return count;
323 }
324 
325 static struct dump_obj *create_dump_obj(uint32_t id, size_t size,
326 					uint32_t type)
327 {
328 	struct dump_obj *dump;
329 	int rc;
330 
331 	dump = kzalloc(sizeof(*dump), GFP_KERNEL);
332 	if (!dump)
333 		return NULL;
334 
335 	dump->kobj.kset = dump_kset;
336 
337 	kobject_init(&dump->kobj, &dump_ktype);
338 
339 	sysfs_bin_attr_init(&dump->dump_attr);
340 
341 	dump->dump_attr.attr.name = "dump";
342 	dump->dump_attr.attr.mode = 0400;
343 	dump->dump_attr.size = size;
344 	dump->dump_attr.read = dump_attr_read;
345 
346 	dump->id = id;
347 	dump->size = size;
348 	dump->type = type;
349 
350 	rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
351 	if (rc) {
352 		kobject_put(&dump->kobj);
353 		return NULL;
354 	}
355 
356 	rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
357 	if (rc) {
358 		kobject_put(&dump->kobj);
359 		return NULL;
360 	}
361 
362 	pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
363 		__func__, dump->id, dump->size);
364 
365 	kobject_uevent(&dump->kobj, KOBJ_ADD);
366 
367 	return dump;
368 }
369 
370 static irqreturn_t process_dump(int irq, void *data)
371 {
372 	int rc;
373 	uint32_t dump_id, dump_size, dump_type;
374 	struct dump_obj *dump;
375 	char name[22];
376 	struct kobject *kobj;
377 
378 	rc = dump_read_info(&dump_id, &dump_size, &dump_type);
379 	if (rc != OPAL_SUCCESS)
380 		return rc;
381 
382 	sprintf(name, "0x%x-0x%x", dump_type, dump_id);
383 
384 	/* we may get notified twice, let's handle
385 	 * that gracefully and not create two conflicting
386 	 * entries.
387 	 */
388 	kobj = kset_find_obj(dump_kset, name);
389 	if (kobj) {
390 		/* Drop reference added by kset_find_obj() */
391 		kobject_put(kobj);
392 		return 0;
393 	}
394 
395 	dump = create_dump_obj(dump_id, dump_size, dump_type);
396 	if (!dump)
397 		return -1;
398 
399 	return IRQ_HANDLED;
400 }
401 
402 void __init opal_platform_dump_init(void)
403 {
404 	int rc;
405 	int dump_irq;
406 
407 	/* ELOG not supported by firmware */
408 	if (!opal_check_token(OPAL_DUMP_READ))
409 		return;
410 
411 	dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
412 	if (!dump_kset) {
413 		pr_warn("%s: Failed to create dump kset\n", __func__);
414 		return;
415 	}
416 
417 	rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
418 	if (rc) {
419 		pr_warn("%s: Failed to create initiate dump attr group\n",
420 			__func__);
421 		kobject_put(&dump_kset->kobj);
422 		return;
423 	}
424 
425 	dump_irq = opal_event_request(ilog2(OPAL_EVENT_DUMP_AVAIL));
426 	if (!dump_irq) {
427 		pr_err("%s: Can't register OPAL event irq (%d)\n",
428 		       __func__, dump_irq);
429 		return;
430 	}
431 
432 	rc = request_threaded_irq(dump_irq, NULL, process_dump,
433 				IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
434 				"opal-dump", NULL);
435 	if (rc) {
436 		pr_err("%s: Can't request OPAL event irq (%d)\n",
437 		       __func__, rc);
438 		return;
439 	}
440 
441 	if (opal_check_token(OPAL_DUMP_RESEND))
442 		opal_dump_resend_notification();
443 }
444