linux/drivers/acpi/acpi_memhotplug.c
<<
>>
Prefs
   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 <acpi/acpi_drivers.h>
  35
  36#define ACPI_MEMORY_DEVICE_CLASS                "memory"
  37#define ACPI_MEMORY_DEVICE_HID                  "PNP0C80"
  38#define ACPI_MEMORY_DEVICE_NAME                 "Hotplug Mem Device"
  39
  40#define _COMPONENT              ACPI_MEMORY_DEVICE_COMPONENT
  41
  42#undef PREFIX
  43#define         PREFIX          "ACPI:memory_hp:"
  44
  45ACPI_MODULE_NAME("acpi_memhotplug");
  46MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>");
  47MODULE_DESCRIPTION("Hotplug Mem Driver");
  48MODULE_LICENSE("GPL");
  49
  50/* Memory Device States */
  51#define MEMORY_INVALID_STATE    0
  52#define MEMORY_POWER_ON_STATE   1
  53#define MEMORY_POWER_OFF_STATE  2
  54
  55static int acpi_memory_device_add(struct acpi_device *device);
  56static int acpi_memory_device_remove(struct acpi_device *device, int type);
  57
  58static const struct acpi_device_id memory_device_ids[] = {
  59        {ACPI_MEMORY_DEVICE_HID, 0},
  60        {"", 0},
  61};
  62MODULE_DEVICE_TABLE(acpi, memory_device_ids);
  63
  64static struct acpi_driver acpi_memory_device_driver = {
  65        .name = "acpi_memhotplug",
  66        .class = ACPI_MEMORY_DEVICE_CLASS,
  67        .ids = memory_device_ids,
  68        .ops = {
  69                .add = acpi_memory_device_add,
  70                .remove = acpi_memory_device_remove,
  71                },
  72};
  73
  74struct acpi_memory_info {
  75        struct list_head list;
  76        u64 start_addr;         /* Memory Range start physical addr */
  77        u64 length;             /* Memory Range length */
  78        unsigned short caching; /* memory cache attribute */
  79        unsigned short write_protect;   /* memory read/write attribute */
  80        unsigned int enabled:1;
  81};
  82
  83struct acpi_memory_device {
  84        struct acpi_device * device;
  85        unsigned int state;     /* State of the memory device */
  86        struct list_head res_list;
  87};
  88
  89static int acpi_hotmem_initialized;
  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 int
 129acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 130{
 131        acpi_status status;
 132        struct acpi_memory_info *info, *n;
 133
 134
 135        if (!list_empty(&mem_device->res_list))
 136                return 0;
 137
 138        status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
 139                                     acpi_memory_get_resource, mem_device);
 140        if (ACPI_FAILURE(status)) {
 141                list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 142                        kfree(info);
 143                INIT_LIST_HEAD(&mem_device->res_list);
 144                return -EINVAL;
 145        }
 146
 147        return 0;
 148}
 149
 150static int
 151acpi_memory_get_device(acpi_handle handle,
 152                       struct acpi_memory_device **mem_device)
 153{
 154        acpi_status status;
 155        acpi_handle phandle;
 156        struct acpi_device *device = NULL;
 157        struct acpi_device *pdevice = NULL;
 158        int result;
 159
 160
 161        if (!acpi_bus_get_device(handle, &device) && device)
 162                goto end;
 163
 164        status = acpi_get_parent(handle, &phandle);
 165        if (ACPI_FAILURE(status)) {
 166                ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
 167                return -EINVAL;
 168        }
 169
 170        /* Get the parent device */
 171        result = acpi_bus_get_device(phandle, &pdevice);
 172        if (result) {
 173                printk(KERN_WARNING PREFIX "Cannot get acpi bus device");
 174                return -EINVAL;
 175        }
 176
 177        /*
 178         * Now add the notified device.  This creates the acpi_device
 179         * and invokes .add function
 180         */
 181        result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
 182        if (result) {
 183                printk(KERN_WARNING PREFIX "Cannot add acpi bus");
 184                return -EINVAL;
 185        }
 186
 187      end:
 188        *mem_device = acpi_driver_data(device);
 189        if (!(*mem_device)) {
 190                printk(KERN_ERR "\n driver data not found");
 191                return -ENODEV;
 192        }
 193
 194        return 0;
 195}
 196
 197static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 198{
 199        unsigned long long current_status;
 200
 201        /* Get device present/absent information from the _STA */
 202        if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
 203                                               NULL, &current_status)))
 204                return -ENODEV;
 205        /*
 206         * Check for device status. Device should be
 207         * present/enabled/functioning.
 208         */
 209        if (!((current_status & ACPI_STA_DEVICE_PRESENT)
 210              && (current_status & ACPI_STA_DEVICE_ENABLED)
 211              && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
 212                return -ENODEV;
 213
 214        return 0;
 215}
 216
 217static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 218{
 219        int result, num_enabled = 0;
 220        struct acpi_memory_info *info;
 221        int node;
 222
 223
 224        /* Get the range from the _CRS */
 225        result = acpi_memory_get_device_resources(mem_device);
 226        if (result) {
 227                printk(KERN_ERR PREFIX "get_device_resources failed\n");
 228                mem_device->state = MEMORY_INVALID_STATE;
 229                return result;
 230        }
 231
 232        node = acpi_get_node(mem_device->device->handle);
 233        /*
 234         * Tell the VM there is more memory here...
 235         * Note: Assume that this function returns zero on success
 236         * We don't have memory-hot-add rollback function,now.
 237         * (i.e. memory-hot-remove function)
 238         */
 239        list_for_each_entry(info, &mem_device->res_list, list) {
 240                if (info->enabled) { /* just sanity check...*/
 241                        num_enabled++;
 242                        continue;
 243                }
 244                /*
 245                 * If the memory block size is zero, please ignore it.
 246                 * Don't try to do the following memory hotplug flowchart.
 247                 */
 248                if (!info->length)
 249                        continue;
 250                if (node < 0)
 251                        node = memory_add_physaddr_to_nid(info->start_addr);
 252
 253                result = add_memory(node, info->start_addr, info->length);
 254                if (result)
 255                        continue;
 256                info->enabled = 1;
 257                num_enabled++;
 258        }
 259        if (!num_enabled) {
 260                printk(KERN_ERR PREFIX "add_memory failed\n");
 261                mem_device->state = MEMORY_INVALID_STATE;
 262                return -EINVAL;
 263        }
 264        /*
 265         * Sometimes the memory device will contain several memory blocks.
 266         * When one memory block is hot-added to the system memory, it will
 267         * be regarded as a success.
 268         * Otherwise if the last memory block can't be hot-added to the system
 269         * memory, it will be failure and the memory device can't be bound with
 270         * driver.
 271         */
 272        return 0;
 273}
 274
 275static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
 276{
 277        acpi_status status;
 278        struct acpi_object_list arg_list;
 279        union acpi_object arg;
 280        unsigned long long current_status;
 281
 282
 283        /* Issue the _EJ0 command */
 284        arg_list.count = 1;
 285        arg_list.pointer = &arg;
 286        arg.type = ACPI_TYPE_INTEGER;
 287        arg.integer.value = 1;
 288        status = acpi_evaluate_object(mem_device->device->handle,
 289                                      "_EJ0", &arg_list, NULL);
 290        /* Return on _EJ0 failure */
 291        if (ACPI_FAILURE(status)) {
 292                ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
 293                return -ENODEV;
 294        }
 295
 296        /* Evalute _STA to check if the device is disabled */
 297        status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
 298                                       NULL, &current_status);
 299        if (ACPI_FAILURE(status))
 300                return -ENODEV;
 301
 302        /* Check for device status.  Device should be disabled */
 303        if (current_status & ACPI_STA_DEVICE_ENABLED)
 304                return -EINVAL;
 305
 306        return 0;
 307}
 308
 309static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
 310{
 311        int result;
 312        struct acpi_memory_info *info, *n;
 313
 314
 315        /*
 316         * Ask the VM to offline this memory range.
 317         * Note: Assume that this function returns zero on success
 318         */
 319        list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 320                if (info->enabled) {
 321                        result = remove_memory(info->start_addr, info->length);
 322                        if (result)
 323                                return result;
 324                }
 325                kfree(info);
 326        }
 327
 328        /* Power-off and eject the device */
 329        result = acpi_memory_powerdown_device(mem_device);
 330        if (result) {
 331                /* Set the status of the device to invalid */
 332                mem_device->state = MEMORY_INVALID_STATE;
 333                return result;
 334        }
 335
 336        mem_device->state = MEMORY_POWER_OFF_STATE;
 337        return result;
 338}
 339
 340static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 341{
 342        struct acpi_memory_device *mem_device;
 343        struct acpi_device *device;
 344        u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
 345
 346        switch (event) {
 347        case ACPI_NOTIFY_BUS_CHECK:
 348                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 349                                  "\nReceived BUS CHECK notification for device\n"));
 350                /* Fall Through */
 351        case ACPI_NOTIFY_DEVICE_CHECK:
 352                if (event == ACPI_NOTIFY_DEVICE_CHECK)
 353                        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 354                                          "\nReceived DEVICE CHECK notification for device\n"));
 355                if (acpi_memory_get_device(handle, &mem_device)) {
 356                        printk(KERN_ERR PREFIX "Cannot find driver data\n");
 357                        break;
 358                }
 359
 360                if (acpi_memory_check_device(mem_device))
 361                        break;
 362
 363                if (acpi_memory_enable_device(mem_device)) {
 364                        printk(KERN_ERR PREFIX "Cannot enable memory device\n");
 365                        break;
 366                }
 367
 368                ost_code = ACPI_OST_SC_SUCCESS;
 369                break;
 370
 371        case ACPI_NOTIFY_EJECT_REQUEST:
 372                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 373                                  "\nReceived EJECT REQUEST notification for device\n"));
 374
 375                if (acpi_bus_get_device(handle, &device)) {
 376                        printk(KERN_ERR PREFIX "Device doesn't exist\n");
 377                        break;
 378                }
 379                mem_device = acpi_driver_data(device);
 380                if (!mem_device) {
 381                        printk(KERN_ERR PREFIX "Driver Data is NULL\n");
 382                        break;
 383                }
 384
 385                /*
 386                 * Currently disabling memory device from kernel mode
 387                 * TBD: Can also be disabled from user mode scripts
 388                 * TBD: Can also be disabled by Callback registration
 389                 *      with generic sysfs driver
 390                 */
 391                if (acpi_memory_disable_device(mem_device)) {
 392                        printk(KERN_ERR PREFIX "Disable memory device\n");
 393                        /*
 394                         * If _EJ0 was called but failed, _OST is not
 395                         * necessary.
 396                         */
 397                        if (mem_device->state == MEMORY_INVALID_STATE)
 398                                return;
 399
 400                        break;
 401                }
 402
 403                /*
 404                 * TBD: Invoke acpi_bus_remove to cleanup data structures
 405                 */
 406
 407                /* _EJ0 succeeded; _OST is not necessary */
 408                return;
 409
 410        default:
 411                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 412                                  "Unsupported event [0x%x]\n", event));
 413
 414                /* non-hotplug event; possibly handled by other handler */
 415                return;
 416        }
 417
 418        /* Inform firmware that the hotplug operation has completed */
 419        (void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
 420        return;
 421}
 422
 423static int acpi_memory_device_add(struct acpi_device *device)
 424{
 425        int result;
 426        struct acpi_memory_device *mem_device = NULL;
 427
 428
 429        if (!device)
 430                return -EINVAL;
 431
 432        mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 433        if (!mem_device)
 434                return -ENOMEM;
 435
 436        INIT_LIST_HEAD(&mem_device->res_list);
 437        mem_device->device = device;
 438        sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 439        sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 440        device->driver_data = mem_device;
 441
 442        /* Get the range from the _CRS */
 443        result = acpi_memory_get_device_resources(mem_device);
 444        if (result) {
 445                kfree(mem_device);
 446                return result;
 447        }
 448
 449        /* Set the device state */
 450        mem_device->state = MEMORY_POWER_ON_STATE;
 451
 452        printk(KERN_DEBUG "%s \n", acpi_device_name(device));
 453
 454        /*
 455         * Early boot code has recognized memory area by EFI/E820.
 456         * If DSDT shows these memory devices on boot, hotplug is not necessary
 457         * for them. So, it just returns until completion of this driver's
 458         * start up.
 459         */
 460        if (!acpi_hotmem_initialized)
 461                return 0;
 462
 463        if (!acpi_memory_check_device(mem_device)) {
 464                /* call add_memory func */
 465                result = acpi_memory_enable_device(mem_device);
 466                if (result)
 467                        printk(KERN_ERR PREFIX
 468                                "Error in acpi_memory_enable_device\n");
 469        }
 470        return result;
 471}
 472
 473static int acpi_memory_device_remove(struct acpi_device *device, int type)
 474{
 475        struct acpi_memory_device *mem_device = NULL;
 476
 477
 478        if (!device || !acpi_driver_data(device))
 479                return -EINVAL;
 480
 481        mem_device = acpi_driver_data(device);
 482        kfree(mem_device);
 483
 484        return 0;
 485}
 486
 487/*
 488 * Helper function to check for memory device
 489 */
 490static acpi_status is_memory_device(acpi_handle handle)
 491{
 492        char *hardware_id;
 493        acpi_status status;
 494        struct acpi_device_info *info;
 495
 496        status = acpi_get_object_info(handle, &info);
 497        if (ACPI_FAILURE(status))
 498                return status;
 499
 500        if (!(info->valid & ACPI_VALID_HID)) {
 501                kfree(info);
 502                return AE_ERROR;
 503        }
 504
 505        hardware_id = info->hardware_id.string;
 506        if ((hardware_id == NULL) ||
 507            (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
 508                status = AE_ERROR;
 509
 510        kfree(info);
 511        return status;
 512}
 513
 514static acpi_status
 515acpi_memory_register_notify_handler(acpi_handle handle,
 516                                    u32 level, void *ctxt, void **retv)
 517{
 518        acpi_status status;
 519
 520
 521        status = is_memory_device(handle);
 522        if (ACPI_FAILURE(status))
 523                return AE_OK;   /* continue */
 524
 525        status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 526                                             acpi_memory_device_notify, NULL);
 527        /* continue */
 528        return AE_OK;
 529}
 530
 531static acpi_status
 532acpi_memory_deregister_notify_handler(acpi_handle handle,
 533                                      u32 level, void *ctxt, void **retv)
 534{
 535        acpi_status status;
 536
 537
 538        status = is_memory_device(handle);
 539        if (ACPI_FAILURE(status))
 540                return AE_OK;   /* continue */
 541
 542        status = acpi_remove_notify_handler(handle,
 543                                            ACPI_SYSTEM_NOTIFY,
 544                                            acpi_memory_device_notify);
 545
 546        return AE_OK;   /* continue */
 547}
 548
 549static int __init acpi_memory_device_init(void)
 550{
 551        int result;
 552        acpi_status status;
 553
 554
 555        result = acpi_bus_register_driver(&acpi_memory_device_driver);
 556
 557        if (result < 0)
 558                return -ENODEV;
 559
 560        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 561                                     ACPI_UINT32_MAX,
 562                                     acpi_memory_register_notify_handler, NULL,
 563                                     NULL, NULL);
 564
 565        if (ACPI_FAILURE(status)) {
 566                ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 567                acpi_bus_unregister_driver(&acpi_memory_device_driver);
 568                return -ENODEV;
 569        }
 570
 571        acpi_hotmem_initialized = 1;
 572        return 0;
 573}
 574
 575static void __exit acpi_memory_device_exit(void)
 576{
 577        acpi_status status;
 578
 579
 580        /*
 581         * Adding this to un-install notification handlers for all the device
 582         * handles.
 583         */
 584        status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 585                                     ACPI_UINT32_MAX,
 586                                     acpi_memory_deregister_notify_handler, NULL,
 587                                     NULL, NULL);
 588
 589        if (ACPI_FAILURE(status))
 590                ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
 591
 592        acpi_bus_unregister_driver(&acpi_memory_device_driver);
 593
 594        return;
 595}
 596
 597module_init(acpi_memory_device_init);
 598module_exit(acpi_memory_device_exit);
 599
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.