linux/drivers/acpi/acpi_memhotplug.c
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   1/*
   2 * Copyright (C) 2004 Intel Corporation <naveen.b.s@intel.com>
   3 *
   4 * All rights reserved.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or (at
   9 * your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful, but
  12 * WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  14 * NON INFRINGEMENT.  See the GNU General Public License for more
  15 * details.
  16 *
  17 * You should have received a copy of the GNU General Public License
  18 * along with this program; if not, write to the Free Software
  19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 *
  21 *
  22 * ACPI based HotPlug driver that supports Memory Hotplug
  23 * This driver fields notifications from firmware for memory add
  24 * and remove operations and alerts the VM of the affected memory
  25 * ranges.
  26 */
  27
  28#include <linux/kernel.h>
  29#include <linux/module.h>
  30#include <linux/init.h>
  31#include <linux/types.h>
  32#include <linux/memory_hotplug.h>
  33#include <linux/slab.h>
  34#include <linux/acpi.h>
  35#include <acpi/acpi_drivers.h>
  36
  37#define ACPI_MEMORY_DEVICE_CLASS                "memory"
  38#define ACPI_MEMORY_DEVICE_HID                  "PNP0C80"
  39#define ACPI_MEMORY_DEVICE_NAME                 "Hotplug Mem Device"
  40
  41#define _COMPONENT              ACPI_MEMORY_DEVICE_COMPONENT
  42
  43#undef PREFIX
  44#define         PREFIX          "ACPI:memory_hp:"
  45
  46ACPI_MODULE_NAME("acpi_memhotplug");
  47MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>");
  48MODULE_DESCRIPTION("Hotplug Mem Driver");
  49MODULE_LICENSE("GPL");
  50
  51/* Memory Device States */
  52#define MEMORY_INVALID_STATE    0
  53#define MEMORY_POWER_ON_STATE   1
  54#define MEMORY_POWER_OFF_STATE  2
  55
  56static int acpi_memory_device_add(struct acpi_device *device);
  57static int acpi_memory_device_remove(struct acpi_device *device, int type);
  58
  59static const struct acpi_device_id memory_device_ids[] = {
  60        {ACPI_MEMORY_DEVICE_HID, 0},
  61        {"", 0},
  62};
  63MODULE_DEVICE_TABLE(acpi, memory_device_ids);
  64
  65static struct acpi_driver acpi_memory_device_driver = {
  66        .name = "acpi_memhotplug",
  67        .class = ACPI_MEMORY_DEVICE_CLASS,
  68        .ids = memory_device_ids,
  69        .ops = {
  70                .add = acpi_memory_device_add,
  71                .remove = acpi_memory_device_remove,
  72                },
  73};
  74
  75struct acpi_memory_info {
  76        struct list_head list;
  77        u64 start_addr;         /* Memory Range start physical addr */
  78        u64 length;             /* Memory Range length */
  79        unsigned short caching; /* memory cache attribute */
  80        unsigned short write_protect;   /* memory read/write attribute */
  81        unsigned int enabled:1;
  82        unsigned int failed:1;
  83};
  84
  85struct acpi_memory_device {
  86        struct acpi_device * device;
  87        unsigned int state;     /* State of the memory device */
  88        struct list_head res_list;
  89};
  90
  91static acpi_status
  92acpi_memory_get_resource(struct acpi_resource *resource, void *context)
  93{
  94        struct acpi_memory_device *mem_device = context;
  95        struct acpi_resource_address64 address64;
  96        struct acpi_memory_info *info, *new;
  97        acpi_status status;
  98
  99        status = acpi_resource_to_address64(resource, &address64);
 100        if (ACPI_FAILURE(status) ||
 101            (address64.resource_type != ACPI_MEMORY_RANGE))
 102                return AE_OK;
 103
 104        list_for_each_entry(info, &mem_device->res_list, list) {
 105                /* Can we combine the resource range information? */
 106                if ((info->caching == address64.info.mem.caching) &&
 107                    (info->write_protect == address64.info.mem.write_protect) &&
 108                    (info->start_addr + info->length == address64.minimum)) {
 109                        info->length += address64.address_length;
 110                        return AE_OK;
 111                }
 112        }
 113
 114        new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
 115        if (!new)
 116                return AE_ERROR;
 117
 118        INIT_LIST_HEAD(&new->list);
 119        new->caching = address64.info.mem.caching;
 120        new->write_protect = address64.info.mem.write_protect;
 121        new->start_addr = address64.minimum;
 122        new->length = address64.address_length;
 123        list_add_tail(&new->list, &mem_device->res_list);
 124
 125        return AE_OK;
 126}
 127
 128static void
 129acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
 130{
 131        struct acpi_memory_info *info, *n;
 132
 133        list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 134                kfree(info);
 135        INIT_LIST_HEAD(&mem_device->res_list);
 136}
 137
 138static int
 139acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 140{
 141        acpi_status status;
 142
 143        if (!list_empty(&mem_device->res_list))
 144                return 0;
 145
 146        status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
 147                                     acpi_memory_get_resource, mem_device);
 148        if (ACPI_FAILURE(status)) {
 149                acpi_memory_free_device_resources(mem_device);
 150                return -EINVAL;
 151        }
 152
 153        return 0;
 154}
 155
 156static int
 157acpi_memory_get_device(acpi_handle handle,
 158                       struct acpi_memory_device **mem_device)
 159{
 160        acpi_status status;
 161        acpi_handle phandle;
 162        struct acpi_device *device = NULL;
 163        struct acpi_device *pdevice = NULL;
 164        int result;
 165
 166
 167        if (!acpi_bus_get_device(handle, &device) && device)
 168                goto end;
 169
 170        status = acpi_get_parent(handle, &phandle);
 171        if (ACPI_FAILURE(status)) {
 172                ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
 173                return -EINVAL;
 174        }
 175
 176        /* Get the parent device */
 177        result = acpi_bus_get_device(phandle, &pdevice);
 178        if (result) {
 179                acpi_handle_warn(phandle, "Cannot get acpi bus device\n");
 180                return -EINVAL;
 181        }
 182
 183        /*
 184         * Now add the notified device.  This creates the acpi_device
 185         * and invokes .add function
 186         */
 187        result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
 188        if (result) {
 189                acpi_handle_warn(handle, "Cannot add acpi bus\n");
 190                return -EINVAL;
 191        }
 192
 193      end:
 194        *mem_device = acpi_driver_data(device);
 195        if (!(*mem_device)) {
 196                dev_err(&device->dev, "driver data not found\n");
 197                return -ENODEV;
 198        }
 199
 200        return 0;
 201}
 202
 203static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 204{
 205        unsigned long long current_status;
 206
 207        /* Get device present/absent information from the _STA */
 208        if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
 209                                               NULL, &current_status)))
 210                return -ENODEV;
 211        /*
 212         * Check for device status. Device should be
 213         * present/enabled/functioning.
 214         */
 215        if (!((current_status & ACPI_STA_DEVICE_PRESENT)
 216              && (current_status & ACPI_STA_DEVICE_ENABLED)
 217              && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
 218                return -ENODEV;
 219
 220        return 0;
 221}
 222
 223static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 224{
 225        int result, num_enabled = 0;
 226        struct acpi_memory_info *info;
 227        int node;
 228
 229        node = acpi_get_node(mem_device->device->handle);
 230        /*
 231         * Tell the VM there is more memory here...
 232         * Note: Assume that this function returns zero on success
 233         * We don't have memory-hot-add rollback function,now.
 234         * (i.e. memory-hot-remove function)
 235         */
 236        list_for_each_entry(info, &mem_device->res_list, list) {
 237                if (info->enabled) { /* just sanity check...*/
 238                        num_enabled++;
 239                        continue;
 240                }
 241                /*
 242                 * If the memory block size is zero, please ignore it.
 243                 * Don't try to do the following memory hotplug flowchart.
 244                 */
 245                if (!info->length)
 246                        continue;
 247                if (node < 0)
 248                        node = memory_add_physaddr_to_nid(info->start_addr);
 249
 250                result = add_memory(node, info->start_addr, info->length);
 251
 252                /*
 253                 * If the memory block has been used by the kernel, add_memory()
 254                 * returns -EEXIST. If add_memory() returns the other error, it
 255                 * means that this memory block is not used by the kernel.
 256                 */
 257                if (result && result != -EEXIST) {
 258                        info->failed = 1;
 259                        continue;
 260                }
 261
 262                if (!result)
 263                        info->enabled = 1;
 264                /*
 265                 * Add num_enable even if add_memory() returns -EEXIST, so the
 266                 * device is bound to this driver.
 267                 */
 268                num_enabled++;
 269        }
 270        if (!num_enabled) {
 271                dev_err(&mem_device->device->dev, "add_memory failed\n");
 272                mem_device->state = MEMORY_INVALID_STATE;
 273                return -EINVAL;
 274        }
 275        /*
 276         * Sometimes the memory device will contain several memory blocks.
 277         * When one memory block is hot-added to the system memory, it will
 278         * be regarded as a success.
 279         * Otherwise if the last memory block can't be hot-added to the system
 280         * memory, it will be failure and the memory device can't be bound with
 281         * driver.
 282         */
 283        return 0;
 284}
 285
 286static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
 287{
 288        int result = 0;
 289        struct acpi_memory_info *info, *n;
 290
 291        list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 292                if (info->failed)
 293                        /* The kernel does not use this memory block */
 294                        continue;
 295
 296                if (!info->enabled)
 297                        /*
 298                         * The kernel uses this memory block, but it may be not
 299                         * managed by us.
 300                         */
 301                        return -EBUSY;
 302
 303                result = remove_memory(info->start_addr, info->length);
 304                if (result)
 305                        return result;
 306
 307                list_del(&info->list);
 308                kfree(info);
 309        }
 310
 311        return result;
 312}
 313
 314static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 315{
 316        struct acpi_memory_device *mem_device;
 317        struct acpi_device *device;
 318        struct acpi_eject_event *ej_event = NULL;
 319        u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 320
 321        switch (event) {
 322        case ACPI_NOTIFY_BUS_CHECK:
 323                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 324                                  "\nReceived BUS CHECK notification for device\n"));
 325                /* Fall Through */
 326        case ACPI_NOTIFY_DEVICE_CHECK:
 327                if (event == ACPI_NOTIFY_DEVICE_CHECK)
 328                        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 329                                          "\nReceived DEVICE CHECK notification for device\n"));
 330                if (acpi_memory_get_device(handle, &mem_device)) {
 331                        acpi_handle_err(handle, "Cannot find driver data\n");
 332                        break;
 333                }
 334
 335                ost_code = ACPI_OST_SC_SUCCESS;
 336                break;
 337
 338        case ACPI_NOTIFY_EJECT_REQUEST:
 339                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 340                                  "\nReceived EJECT REQUEST notification for device\n"));
 341
 342                if (acpi_bus_get_device(handle, &device)) {
 343                        acpi_handle_err(handle, "Device doesn't exist\n");
 344                        break;
 345                }
 346                mem_device = acpi_driver_data(device);
 347                if (!mem_device) {
 348                        acpi_handle_err(handle, "Driver Data is NULL\n");
 349                        break;
 350                }
 351
 352                ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
 353                if (!ej_event) {
 354                        pr_err(PREFIX "No memory, dropping EJECT\n");
 355                        break;
 356                }
 357
 358                ej_event->handle = handle;
 359                ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
 360                acpi_os_hotplug_execute(acpi_bus_hot_remove_device,
 361                                        (void *)ej_event);
 362
 363                /* eject is performed asynchronously */
 364                return;
 365        default:
 366                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 367                                  "Unsupported event [0x%x]\n", event));
 368
 369                /* non-hotplug event; possibly handled by other handler */
 370                return;
 371        }
 372
 373        /* Inform firmware that the hotplug operation has completed */
 374        (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
 375        return;
 376}
 377
 378static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
 379{
 380        if (!mem_device)
 381                return;
 382
 383        acpi_memory_free_device_resources(mem_device);
 384        kfree(mem_device);
 385}
 386
 387static int acpi_memory_device_add(struct acpi_device *device)
 388{
 389        int result;
 390        struct acpi_memory_device *mem_device = NULL;
 391
 392
 393        if (!device)
 394                return -EINVAL;
 395
 396        mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 397        if (!mem_device)
 398                return -ENOMEM;
 399
 400        INIT_LIST_HEAD(&mem_device->res_list);
 401        mem_device->device = device;
 402        sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 403        sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 404        device->driver_data = mem_device;
 405
 406        /* Get the range from the _CRS */
 407        result = acpi_memory_get_device_resources(mem_device);
 408        if (result) {
 409                kfree(mem_device);
 410                return result;
 411        }
 412
 413        /* Set the device state */
 414        mem_device->state = MEMORY_POWER_ON_STATE;
 415
 416        pr_debug("%s\n", acpi_device_name(device));
 417
 418        if (!acpi_memory_check_device(mem_device)) {
 419                /* call add_memory func */
 420                result = acpi_memory_enable_device(mem_device);
 421                if (result) {
 422                        dev_err(&device->dev,
 423                                "Error in acpi_memory_enable_device\n");
 424                        acpi_memory_device_free(mem_device);
 425                }
 426        }
 427        return result;
 428}
 429
 430static int acpi_memory_device_remove(struct acpi_device *device, int type)
 431{
 432        struct acpi_memory_device *mem_device = NULL;
 433        int result;
 434
 435        if (!device || !acpi_driver_data(device))
 436                return -EINVAL;
 437
 438        mem_device = acpi_driver_data(device);
 439
 440        result = acpi_memory_remove_memory(mem_device);
 441        if (result)
 442                return result;
 443
 444        acpi_memory_device_free(mem_device);
 445
 446        return 0;
 447}
 448
 449/*
 450 * Helper function to check for memory device
 451 */
 452static acpi_status is_memory_device(acpi_handle handle)
 453{
 454        char *hardware_id;
 455        acpi_status status;
 456        struct acpi_device_info *info;
 457
 458        status = acpi_get_object_info(handle, &info);
 459        if (ACPI_FAILURE(status))
 460                return status;
 461
 462        if (!(info->valid & ACPI_VALID_HID)) {
 463                kfree(info);
 464                return AE_ERROR;
 465        }
 466
 467        hardware_id = info->hardware_id.string;
 468        if ((hardware_id == NULL) ||
 469            (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 470                status = AE_ERROR;
 471
 472        kfree(info);
 473        return status;
 474}
 475
 476static acpi_status
 477acpi_memory_register_notify_handler(acpi_handle handle,
 478                                    u32 level, void *ctxt, void **retv)
 479{
 480        acpi_status status;
 481
 482
 483        status = is_memory_device(handle);
 484        if (ACPI_FAILURE(status))
 485                return AE_OK;   /* continue */
 486
 487        status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 488                                             acpi_memory_device_notify, NULL);
 489        /* continue */
 490        return AE_OK;
 491}
 492
 493static acpi_status
 494acpi_memory_deregister_notify_handler(acpi_handle handle,
 495                                      u32 level, void *ctxt, void **retv)
 496{
 497        acpi_status status;
 498
 499
 500        status = is_memory_device(handle);
 501        if (ACPI_FAILURE(status))
 502                return AE_OK;   /* continue */
 503
 504        status = acpi_remove_notify_handler(handle,
 505                                            ACPI_SYSTEM_NOTIFY,
 506                                            acpi_memory_device_notify);
 507
 508        return AE_OK;   /* continue */
 509}
 510
 511static int __init acpi_memory_device_init(void)
 512{
 513        int result;
 514        acpi_status status;
 515
 516
 517        result = acpi_bus_register_driver(&acpi_memory_device_driver);
 518
 519        if (result < 0)
 520                return -ENODEV;
 521
 522        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 523                                     ACPI_UINT32_MAX,
 524                                     acpi_memory_register_notify_handler, NULL,
 525                                     NULL, NULL);
 526
 527        if (ACPI_FAILURE(status)) {
 528                ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 529                acpi_bus_unregister_driver(&acpi_memory_device_driver);
 530                return -ENODEV;
 531        }
 532
 533        return 0;
 534}
 535
 536static void __exit acpi_memory_device_exit(void)
 537{
 538        acpi_status status;
 539
 540
 541        /*
 542         * Adding this to un-install notification handlers for all the device
 543         * handles.
 544         */
 545        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 546                                     ACPI_UINT32_MAX,
 547                                     acpi_memory_deregister_notify_handler, NULL,
 548                                     NULL, NULL);
 549
 550        if (ACPI_FAILURE(status))
 551                ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 552
 553        acpi_bus_unregister_driver(&acpi_memory_device_driver);
 554
 555        return;
 556}
 557
 558module_init(acpi_memory_device_init);
 559module_exit(acpi_memory_device_exit);
 560
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