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
24struct 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
34struct 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
43static 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
50static 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
58static 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
67static 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
74static 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
85static struct elog_attribute id_attribute =
86	__ATTR(id, S_IRUGO, elog_id_show, NULL);
87static struct elog_attribute type_attribute =
88	__ATTR(type, S_IRUGO, elog_type_show, NULL);
89static struct elog_attribute ack_attribute =
90	__ATTR(acknowledge, 0660, elog_ack_show, elog_ack_store);
91
92static struct kset *elog_kset;
93
94static 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
110static 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
126static const struct sysfs_ops elog_sysfs_ops = {
127	.show = elog_attr_show,
128	.store = elog_attr_store,
129};
130
131static 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
140static struct attribute *elog_default_attrs[] = {
141	&id_attribute.attr,
142	&type_attribute.attr,
143	&ack_attribute.attr,
144	NULL,
145};
146
147static 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
156static 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
186static 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
240static 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
251	rc = opal_get_elog_size(&id, &size, &type);
252	if (rc != OPAL_SUCCESS) {
253		pr_err("ELOG: OPAL log info read failed\n");
254		return IRQ_HANDLED;
255	}
256
257	elog_size = be64_to_cpu(size);
258	log_id = be64_to_cpu(id);
259	elog_type = be64_to_cpu(type);
260
261	WARN_ON(elog_size > OPAL_MAX_ERRLOG_SIZE);
262
263	if (elog_size >= OPAL_MAX_ERRLOG_SIZE)
264		elog_size  =  OPAL_MAX_ERRLOG_SIZE;
265
266	sprintf(name, "0x%llx", log_id);
267
268	/* we may get notified twice, let's handle
269	 * that gracefully and not create two conflicting
270	 * entries.
271	 */
272	if (kset_find_obj(elog_kset, name))
273		return IRQ_HANDLED;
274
275	create_elog_obj(log_id, elog_size, elog_type);
276
277	return IRQ_HANDLED;
278}
279
280int __init opal_elog_init(void)
281{
282	int rc = 0, irq;
283
284	/* ELOG not supported by firmware */
285	if (!opal_check_token(OPAL_ELOG_READ))
286		return -1;
287
288	elog_kset = kset_create_and_add("elog", NULL, opal_kobj);
289	if (!elog_kset) {
290		pr_warn("%s: failed to create elog kset\n", __func__);
291		return -1;
292	}
293
294	irq = opal_event_request(ilog2(OPAL_EVENT_ERROR_LOG_AVAIL));
295	if (!irq) {
296		pr_err("%s: Can't register OPAL event irq (%d)\n",
297		       __func__, irq);
298		return irq;
299	}
300
301	rc = request_threaded_irq(irq, NULL, elog_event,
302			IRQF_TRIGGER_HIGH | IRQF_ONESHOT, "opal-elog", NULL);
303	if (rc) {
304		pr_err("%s: Can't request OPAL event irq (%d)\n",
305		       __func__, rc);
306		return rc;
307	}
308
309	/* We are now ready to pull error logs from opal. */
310	if (opal_check_token(OPAL_ELOG_RESEND))
311		opal_resend_pending_logs();
312
313	return 0;
314}
315