arch/powerpc/platforms/powernv/opal-elog.c

   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 <linux/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, 0444, elog_id_show, NULL);
  87 static struct elog_attribute type_attribute =
  88         __ATTR(type, 0444, 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 }