linux/arch/powerpc/platforms/powernv/opal-elog.c
<<
>>
Prefs
   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
  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        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
 285int __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}
 320