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, S_IRUGO, dump_id_show, NULL);
107 static struct dump_attribute type_attribute =
108 	__ATTR(type, S_IRUGO, 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 	*dump_id = be32_to_cpu(id);
229 	*dump_size = be32_to_cpu(size);
230 	*dump_type = be32_to_cpu(type);
231 
232 	if (rc)
233 		pr_warn("%s: Failed to get dump info (%d)\n",
234 			__func__, rc);
235 	return rc;
236 }
237 
238 static int64_t dump_read_data(struct dump_obj *dump)
239 {
240 	struct opal_sg_list *list;
241 	uint64_t addr;
242 	int64_t rc;
243 
244 	/* Allocate memory */
245 	dump->buffer = vzalloc(PAGE_ALIGN(dump->size));
246 	if (!dump->buffer) {
247 		pr_err("%s : Failed to allocate memory\n", __func__);
248 		rc = -ENOMEM;
249 		goto out;
250 	}
251 
252 	/* Generate SG list */
253 	list = opal_vmalloc_to_sg_list(dump->buffer, dump->size);
254 	if (!list) {
255 		rc = -ENOMEM;
256 		goto out;
257 	}
258 
259 	/* First entry address */
260 	addr = __pa(list);
261 
262 	/* Fetch data */
263 	rc = OPAL_BUSY_EVENT;
264 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
265 		rc = opal_dump_read(dump->id, addr);
266 		if (rc == OPAL_BUSY_EVENT) {
267 			opal_poll_events(NULL);
268 			msleep(20);
269 		}
270 	}
271 
272 	if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL)
273 		pr_warn("%s: Extract dump failed for ID 0x%x\n",
274 			__func__, dump->id);
275 
276 	/* Free SG list */
277 	opal_free_sg_list(list);
278 
279 out:
280 	return rc;
281 }
282 
283 static ssize_t dump_attr_read(struct file *filep, struct kobject *kobj,
284 			      struct bin_attribute *bin_attr,
285 			      char *buffer, loff_t pos, size_t count)
286 {
287 	ssize_t rc;
288 
289 	struct dump_obj *dump = to_dump_obj(kobj);
290 
291 	if (!dump->buffer) {
292 		rc = dump_read_data(dump);
293 
294 		if (rc != OPAL_SUCCESS && rc != OPAL_PARTIAL) {
295 			vfree(dump->buffer);
296 			dump->buffer = NULL;
297 
298 			return -EIO;
299 		}
300 		if (rc == OPAL_PARTIAL) {
301 			/* On a partial read, we just return EIO
302 			 * and rely on userspace to ask us to try
303 			 * again.
304 			 */
305 			pr_info("%s: Platform dump partially read. ID = 0x%x\n",
306 				__func__, dump->id);
307 			return -EIO;
308 		}
309 	}
310 
311 	memcpy(buffer, dump->buffer + pos, count);
312 
313 	/* You may think we could free the dump buffer now and retrieve
314 	 * it again later if needed, but due to current firmware limitation,
315 	 * that's not the case. So, once read into userspace once,
316 	 * we keep the dump around until it's acknowledged by userspace.
317 	 */
318 
319 	return count;
320 }
321 
322 static struct dump_obj *create_dump_obj(uint32_t id, size_t size,
323 					uint32_t type)
324 {
325 	struct dump_obj *dump;
326 	int rc;
327 
328 	dump = kzalloc(sizeof(*dump), GFP_KERNEL);
329 	if (!dump)
330 		return NULL;
331 
332 	dump->kobj.kset = dump_kset;
333 
334 	kobject_init(&dump->kobj, &dump_ktype);
335 
336 	sysfs_bin_attr_init(&dump->dump_attr);
337 
338 	dump->dump_attr.attr.name = "dump";
339 	dump->dump_attr.attr.mode = 0400;
340 	dump->dump_attr.size = size;
341 	dump->dump_attr.read = dump_attr_read;
342 
343 	dump->id = id;
344 	dump->size = size;
345 	dump->type = type;
346 
347 	rc = kobject_add(&dump->kobj, NULL, "0x%x-0x%x", type, id);
348 	if (rc) {
349 		kobject_put(&dump->kobj);
350 		return NULL;
351 	}
352 
353 	rc = sysfs_create_bin_file(&dump->kobj, &dump->dump_attr);
354 	if (rc) {
355 		kobject_put(&dump->kobj);
356 		return NULL;
357 	}
358 
359 	pr_info("%s: New platform dump. ID = 0x%x Size %u\n",
360 		__func__, dump->id, dump->size);
361 
362 	kobject_uevent(&dump->kobj, KOBJ_ADD);
363 
364 	return dump;
365 }
366 
367 static irqreturn_t process_dump(int irq, void *data)
368 {
369 	int rc;
370 	uint32_t dump_id, dump_size, dump_type;
371 	struct dump_obj *dump;
372 	char name[22];
373 	struct kobject *kobj;
374 
375 	rc = dump_read_info(&dump_id, &dump_size, &dump_type);
376 	if (rc != OPAL_SUCCESS)
377 		return rc;
378 
379 	sprintf(name, "0x%x-0x%x", dump_type, dump_id);
380 
381 	/* we may get notified twice, let's handle
382 	 * that gracefully and not create two conflicting
383 	 * entries.
384 	 */
385 	kobj = kset_find_obj(dump_kset, name);
386 	if (kobj) {
387 		/* Drop reference added by kset_find_obj() */
388 		kobject_put(kobj);
389 		return 0;
390 	}
391 
392 	dump = create_dump_obj(dump_id, dump_size, dump_type);
393 	if (!dump)
394 		return -1;
395 
396 	return IRQ_HANDLED;
397 }
398 
399 void __init opal_platform_dump_init(void)
400 {
401 	int rc;
402 	int dump_irq;
403 
404 	/* ELOG not supported by firmware */
405 	if (!opal_check_token(OPAL_DUMP_READ))
406 		return;
407 
408 	dump_kset = kset_create_and_add("dump", NULL, opal_kobj);
409 	if (!dump_kset) {
410 		pr_warn("%s: Failed to create dump kset\n", __func__);
411 		return;
412 	}
413 
414 	rc = sysfs_create_group(&dump_kset->kobj, &initiate_attr_group);
415 	if (rc) {
416 		pr_warn("%s: Failed to create initiate dump attr group\n",
417 			__func__);
418 		kobject_put(&dump_kset->kobj);
419 		return;
420 	}
421 
422 	dump_irq = opal_event_request(ilog2(OPAL_EVENT_DUMP_AVAIL));
423 	if (!dump_irq) {
424 		pr_err("%s: Can't register OPAL event irq (%d)\n",
425 		       __func__, dump_irq);
426 		return;
427 	}
428 
429 	rc = request_threaded_irq(dump_irq, NULL, process_dump,
430 				IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
431 				"opal-dump", NULL);
432 	if (rc) {
433 		pr_err("%s: Can't request OPAL event irq (%d)\n",
434 		       __func__, rc);
435 		return;
436 	}
437 
438 	if (opal_check_token(OPAL_DUMP_RESEND))
439 		opal_dump_resend_notification();
440 }
441