drivers/platform/x86/intel/pmt/crashlog.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Intel Platform Monitoring Technology Crashlog driver
   4  *
   5  * Copyright (c) 2020, Intel Corporation.
   6  * All Rights Reserved.
   7  *
   8  * Author: "Alexander Duyck" <alexander.h.duyck@linux.intel.com>
   9  */
  10
  11 #include <linux/auxiliary_bus.h>
  12 #include <linux/intel_vsec.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/pci.h>
  16 #include <linux/slab.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/overflow.h>
  19
  20 #include "class.h"
  21
  22 /* Crashlog discovery header types */
  23 #define CRASH_TYPE_OOBMSM       1
  24
  25 /* Control Flags */
  26 #define CRASHLOG_FLAG_DISABLE           BIT(28)
  27
  28 /*
  29  * Bits 29 and 30 control the state of bit 31.
  30  *
  31  * Bit 29 will clear bit 31, if set, allowing a new crashlog to be captured.
  32  * Bit 30 will immediately trigger a crashlog to be generated, setting bit 31.
  33  * Bit 31 is the read-only status with a 1 indicating log is complete.
  34  */
  35 #define CRASHLOG_FLAG_TRIGGER_CLEAR     BIT(29)
  36 #define CRASHLOG_FLAG_TRIGGER_EXECUTE   BIT(30)
  37 #define CRASHLOG_FLAG_TRIGGER_COMPLETE  BIT(31)
  38 #define CRASHLOG_FLAG_TRIGGER_MASK      GENMASK(31, 28)
  39
  40 /* Crashlog Discovery Header */
  41 #define CONTROL_OFFSET          0x0
  42 #define GUID_OFFSET             0x4
  43 #define BASE_OFFSET             0x8
  44 #define SIZE_OFFSET             0xC
  45 #define GET_ACCESS(v)           ((v) & GENMASK(3, 0))
  46 #define GET_TYPE(v)             (((v) & GENMASK(7, 4)) >> 4)
  47 #define GET_VERSION(v)          (((v) & GENMASK(19, 16)) >> 16)
  48 /* size is in bytes */
  49 #define GET_SIZE(v)             ((v) * sizeof(u32))
  50
  51 struct crashlog_entry {
  52         /* entry must be first member of struct */
  53         struct intel_pmt_entry          entry;
  54         struct mutex                    control_mutex;
  55 };
  56
  57 struct pmt_crashlog_priv {
  58         int                     num_entries;
  59         struct crashlog_entry   entry[];
  60 };
  61
  62 /*
  63  * I/O
  64  */
  65 static bool pmt_crashlog_complete(struct intel_pmt_entry *entry)
  66 {
  67         u32 control = readl(entry->disc_table + CONTROL_OFFSET);
  68
  69         /* return current value of the crashlog complete flag */
  70         return !!(control & CRASHLOG_FLAG_TRIGGER_COMPLETE);
  71 }
  72
  73 static bool pmt_crashlog_disabled(struct intel_pmt_entry *entry)
  74 {
  75         u32 control = readl(entry->disc_table + CONTROL_OFFSET);
  76
  77         /* return current value of the crashlog disabled flag */
  78         return !!(control & CRASHLOG_FLAG_DISABLE);
  79 }
  80
  81 static bool pmt_crashlog_supported(struct intel_pmt_entry *entry)
  82 {
  83         u32 discovery_header = readl(entry->disc_table + CONTROL_OFFSET);
  84         u32 crash_type, version;
  85
  86         crash_type = GET_TYPE(discovery_header);
  87         version = GET_VERSION(discovery_header);
  88
  89         /*
  90          * Currently we only recognize OOBMSM version 0 devices.
  91          * We can ignore all other crashlog devices in the system.
  92          */
  93         return crash_type == CRASH_TYPE_OOBMSM && version == 0;
  94 }
  95
  96 static void pmt_crashlog_set_disable(struct intel_pmt_entry *entry,
  97                                      bool disable)
  98 {
  99         u32 control = readl(entry->disc_table + CONTROL_OFFSET);
 100
 101         /* clear trigger bits so we are only modifying disable flag */
 102         control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
 103
 104         if (disable)
 105                 control |= CRASHLOG_FLAG_DISABLE;
 106         else
 107                 control &= ~CRASHLOG_FLAG_DISABLE;
 108
 109         writel(control, entry->disc_table + CONTROL_OFFSET);
 110 }
 111
 112 static void pmt_crashlog_set_clear(struct intel_pmt_entry *entry)
 113 {
 114         u32 control = readl(entry->disc_table + CONTROL_OFFSET);
 115
 116         control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
 117         control |= CRASHLOG_FLAG_TRIGGER_CLEAR;
 118
 119         writel(control, entry->disc_table + CONTROL_OFFSET);
 120 }
 121
 122 static void pmt_crashlog_set_execute(struct intel_pmt_entry *entry)
 123 {
 124         u32 control = readl(entry->disc_table + CONTROL_OFFSET);
 125
 126         control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
 127         control |= CRASHLOG_FLAG_TRIGGER_EXECUTE;
 128
 129         writel(control, entry->disc_table + CONTROL_OFFSET);
 130 }
 131
 132 /*
 133  * sysfs
 134  */
 135 static ssize_t
 136 enable_show(struct device *dev, struct device_attribute *attr, char *buf)
 137 {
 138         struct intel_pmt_entry *entry = dev_get_drvdata(dev);
 139         int enabled = !pmt_crashlog_disabled(entry);
 140
 141         return sprintf(buf, "%d\n", enabled);
 142 }
 143
 144 static ssize_t
 145 enable_store(struct device *dev, struct device_attribute *attr,
 146             const char *buf, size_t count)
 147 {
 148         struct crashlog_entry *entry;
 149         bool enabled;
 150         int result;
 151
 152         entry = dev_get_drvdata(dev);
 153
 154         result = kstrtobool(buf, &enabled);
 155         if (result)
 156                 return result;
 157
 158         mutex_lock(&entry->control_mutex);
 159         pmt_crashlog_set_disable(&entry->entry, !enabled);
 160         mutex_unlock(&entry->control_mutex);
 161
 162         return count;
 163 }
 164 static DEVICE_ATTR_RW(enable);
 165
 166 static ssize_t
 167 trigger_show(struct device *dev, struct device_attribute *attr, char *buf)
 168 {
 169         struct intel_pmt_entry *entry;
 170         int trigger;
 171
 172         entry = dev_get_drvdata(dev);
 173         trigger = pmt_crashlog_complete(entry);
 174
 175         return sprintf(buf, "%d\n", trigger);
 176 }
 177
 178 static ssize_t
 179 trigger_store(struct device *dev, struct device_attribute *attr,
 180             const char *buf, size_t count)
 181 {
 182         struct crashlog_entry *entry;
 183         bool trigger;
 184         int result;
 185
 186         entry = dev_get_drvdata(dev);
 187
 188         result = kstrtobool(buf, &trigger);
 189         if (result)
 190                 return result;
 191
 192         mutex_lock(&entry->control_mutex);
 193
 194         if (!trigger) {
 195                 pmt_crashlog_set_clear(&entry->entry);
 196         } else if (pmt_crashlog_complete(&entry->entry)) {
 197                 /* we cannot trigger a new crash if one is still pending */
 198                 result = -EEXIST;
 199                 goto err;
 200         } else if (pmt_crashlog_disabled(&entry->entry)) {
 201                 /* if device is currently disabled, return busy */
 202                 result = -EBUSY;
 203                 goto err;
 204         } else {
 205                 pmt_crashlog_set_execute(&entry->entry);
 206         }
 207
 208         result = count;
 209 err:
 210         mutex_unlock(&entry->control_mutex);
 211         return result;
 212 }
 213 static DEVICE_ATTR_RW(trigger);
 214
 215 static struct attribute *pmt_crashlog_attrs[] = {
 216         &dev_attr_enable.attr,
 217         &dev_attr_trigger.attr,
 218         NULL
 219 };
 220
 221 static const struct attribute_group pmt_crashlog_group = {
 222         .attrs  = pmt_crashlog_attrs,
 223 };
 224
 225 static int pmt_crashlog_header_decode(struct intel_pmt_entry *entry,
 226                                       struct device *dev)
 227 {
 228         void __iomem *disc_table = entry->disc_table;
 229         struct intel_pmt_header *header = &entry->header;
 230         struct crashlog_entry *crashlog;
 231
 232         if (!pmt_crashlog_supported(entry))
 233                 return 1;
 234
 235         /* initialize control mutex */
 236         crashlog = container_of(entry, struct crashlog_entry, entry);
 237         mutex_init(&crashlog->control_mutex);
 238
 239         header->access_type = GET_ACCESS(readl(disc_table));
 240         header->guid = readl(disc_table + GUID_OFFSET);
 241         header->base_offset = readl(disc_table + BASE_OFFSET);
 242
 243         /* Size is measured in DWORDS, but accessor returns bytes */
 244         header->size = GET_SIZE(readl(disc_table + SIZE_OFFSET));
 245
 246         return 0;
 247 }
 248
 249 static DEFINE_XARRAY_ALLOC(crashlog_array);
 250 static struct intel_pmt_namespace pmt_crashlog_ns = {
 251         .name = "crashlog",
 252         .xa = &crashlog_array,
 253         .attr_grp = &pmt_crashlog_group,
 254         .pmt_header_decode = pmt_crashlog_header_decode,
 255 };
 256
 257 /*
 258  * initialization
 259  */
 260 static void pmt_crashlog_remove(struct auxiliary_device *auxdev)
 261 {
 262         struct pmt_crashlog_priv *priv = auxiliary_get_drvdata(auxdev);
 263         int i;
 264
 265         for (i = 0; i < priv->num_entries; i++)
 266                 intel_pmt_dev_destroy(&priv->entry[i].entry, &pmt_crashlog_ns);
 267 }
 268
 269 static int pmt_crashlog_probe(struct auxiliary_device *auxdev,
 270                               const struct auxiliary_device_id *id)
 271 {
 272         struct intel_vsec_device *intel_vsec_dev = auxdev_to_ivdev(auxdev);
 273         struct pmt_crashlog_priv *priv;
 274         size_t size;
 275         int i, ret;
 276
 277         size = struct_size(priv, entry, intel_vsec_dev->num_resources);
 278         priv = devm_kzalloc(&auxdev->dev, size, GFP_KERNEL);
 279         if (!priv)
 280                 return -ENOMEM;
 281
 282         auxiliary_set_drvdata(auxdev, priv);
 283
 284         for (i = 0; i < intel_vsec_dev->num_resources; i++) {
 285                 struct intel_pmt_entry *entry = &priv->entry[priv->num_entries].entry;
 286
 287                 ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, intel_vsec_dev, i);
 288                 if (ret < 0)
 289                         goto abort_probe;
 290                 if (ret)
 291                         continue;
 292
 293                 priv->num_entries++;
 294         }
 295
 296         return 0;
 297 abort_probe:
 298         pmt_crashlog_remove(auxdev);
 299         return ret;
 300 }
 301
 302 static const struct auxiliary_device_id pmt_crashlog_id_table[] = {
 303         { .name = "intel_vsec.crashlog" },
 304         {}
 305 };
 306 MODULE_DEVICE_TABLE(auxiliary, pmt_crashlog_id_table);
 307
 308 static struct auxiliary_driver pmt_crashlog_aux_driver = {
 309         .id_table       = pmt_crashlog_id_table,
 310         .remove         = pmt_crashlog_remove,
 311         .probe          = pmt_crashlog_probe,
 312 };
 313
 314 static int __init pmt_crashlog_init(void)
 315 {
 316         return auxiliary_driver_register(&pmt_crashlog_aux_driver);
 317 }
 318
 319 static void __exit pmt_crashlog_exit(void)
 320 {
 321         auxiliary_driver_unregister(&pmt_crashlog_aux_driver);
 322         xa_destroy(&crashlog_array);
 323 }
 324
 325 module_init(pmt_crashlog_init);
 326 module_exit(pmt_crashlog_exit);
 327
 328 MODULE_AUTHOR("Alexander Duyck <alexander.h.duyck@linux.intel.com>");
 329 MODULE_DESCRIPTION("Intel PMT Crashlog driver");
 330 MODULE_LICENSE("GPL v2");
 331 MODULE_IMPORT_NS("INTEL_PMT");