drivers/acpi/acpi_memhotplug.c

   1 /*
   2  * Copyright (C) 2004, 2013 Intel Corporation
   3  * Author: Naveen B S <naveen.b.s@intel.com>
   4  * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
   5  *
   6  * All rights reserved.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or (at
  11  * your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  16  * NON INFRINGEMENT.  See the GNU General Public License for more
  17  * details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22  *
  23  *
  24  * ACPI based HotPlug driver that supports Memory Hotplug
  25  * This driver fields notifications from firmware for memory add
  26  * and remove operations and alerts the VM of the affected memory
  27  * ranges.
  28  */
  29
  30 #include <linux/acpi.h>
  31 #include <linux/memory_hotplug.h>
  32
  33 #include "internal.h"
  34
  35 #define ACPI_MEMORY_DEVICE_CLASS                "memory"
  36 #define ACPI_MEMORY_DEVICE_HID                  "PNP0C80"
  37 #define ACPI_MEMORY_DEVICE_NAME                 "Hotplug Mem Device"
  38
  39 #define _COMPONENT              ACPI_MEMORY_DEVICE_COMPONENT
  40
  41 #undef PREFIX
  42 #define         PREFIX          "ACPI:memory_hp:"
  43
  44 ACPI_MODULE_NAME("acpi_memhotplug");
  45
  46 /* Memory Device States */
  47 #define MEMORY_INVALID_STATE    0
  48 #define MEMORY_POWER_ON_STATE   1
  49 #define MEMORY_POWER_OFF_STATE  2
  50
  51 static int acpi_memory_device_add(struct acpi_device *device,
  52                                   const struct acpi_device_id *not_used);
  53 static void acpi_memory_device_remove(struct acpi_device *device);
  54
  55 static const struct acpi_device_id memory_device_ids[] = {
  56         {ACPI_MEMORY_DEVICE_HID, 0},
  57         {"", 0},
  58 };
  59
  60 static struct acpi_scan_handler memory_device_handler = {
  61         .ids = memory_device_ids,
  62         .attach = acpi_memory_device_add,
  63         .detach = acpi_memory_device_remove,
  64         .hotplug = {
  65                 .enabled = true,
  66         },
  67 };
  68
  69 struct acpi_memory_info {
  70         struct list_head list;
  71         u64 start_addr;         /* Memory Range start physical addr */
  72         u64 length;             /* Memory Range length */
  73         unsigned short caching; /* memory cache attribute */
  74         unsigned short write_protect;   /* memory read/write attribute */
  75         unsigned int enabled:1;
  76         unsigned int failed:1;
  77 };
  78
  79 struct acpi_memory_device {
  80         struct acpi_device * device;
  81         unsigned int state;     /* State of the memory device */
  82         struct list_head res_list;
  83 };
  84
  85 static acpi_status
  86 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
  87 {
  88         struct acpi_memory_device *mem_device = context;
  89         struct acpi_resource_address64 address64;
  90         struct acpi_memory_info *info, *new;
  91         acpi_status status;
  92
  93         status = acpi_resource_to_address64(resource, &address64);
  94         if (ACPI_FAILURE(status) ||
  95             (address64.resource_type != ACPI_MEMORY_RANGE))
  96                 return AE_OK;
  97
  98         list_for_each_entry(info, &mem_device->res_list, list) {
  99                 /* Can we combine the resource range information? */
 100                 if ((info->caching == address64.info.mem.caching) &&
 101                     (info->write_protect == address64.info.mem.write_protect) &&
 102                     (info->start_addr + info->length == address64.minimum)) {
 103                         info->length += address64.address_length;
 104                         return AE_OK;
 105                 }
 106         }
 107
 108         new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
 109         if (!new)
 110                 return AE_ERROR;
 111
 112         INIT_LIST_HEAD(&new->list);
 113         new->caching = address64.info.mem.caching;
 114         new->write_protect = address64.info.mem.write_protect;
 115         new->start_addr = address64.minimum;
 116         new->length = address64.address_length;
 117         list_add_tail(&new->list, &mem_device->res_list);
 118
 119         return AE_OK;
 120 }
 121
 122 static void
 123 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
 124 {
 125         struct acpi_memory_info *info, *n;
 126
 127         list_for_each_entry_safe(info, n, &mem_device->res_list, list)
 128                 kfree(info);
 129         INIT_LIST_HEAD(&mem_device->res_list);
 130 }
 131
 132 static int
 133 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
 134 {
 135         acpi_status status;
 136
 137         if (!list_empty(&mem_device->res_list))
 138                 return 0;
 139
 140         status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
 141                                      acpi_memory_get_resource, mem_device);
 142         if (ACPI_FAILURE(status)) {
 143                 acpi_memory_free_device_resources(mem_device);
 144                 return -EINVAL;
 145         }
 146
 147         return 0;
 148 }
 149
 150 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
 151 {
 152         unsigned long long current_status;
 153
 154         /* Get device present/absent information from the _STA */
 155         if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
 156                                                NULL, &current_status)))
 157                 return -ENODEV;
 158         /*
 159          * Check for device status. Device should be
 160          * present/enabled/functioning.
 161          */
 162         if (!((current_status & ACPI_STA_DEVICE_PRESENT)
 163               && (current_status & ACPI_STA_DEVICE_ENABLED)
 164               && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
 165                 return -ENODEV;
 166
 167         return 0;
 168 }
 169
 170 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 171 {
 172         int result, num_enabled = 0;
 173         struct acpi_memory_info *info;
 174         int node;
 175
 176         node = acpi_get_node(mem_device->device->handle);
 177         /*
 178          * Tell the VM there is more memory here...
 179          * Note: Assume that this function returns zero on success
 180          * We don't have memory-hot-add rollback function,now.
 181          * (i.e. memory-hot-remove function)
 182          */
 183         list_for_each_entry(info, &mem_device->res_list, list) {
 184                 if (info->enabled) { /* just sanity check...*/
 185                         num_enabled++;
 186                         continue;
 187                 }
 188                 /*
 189                  * If the memory block size is zero, please ignore it.
 190                  * Don't try to do the following memory hotplug flowchart.
 191                  */
 192                 if (!info->length)
 193                         continue;
 194                 if (node < 0)
 195                         node = memory_add_physaddr_to_nid(info->start_addr);
 196
 197                 result = add_memory(node, info->start_addr, info->length);
 198
 199                 /*
 200                  * If the memory block has been used by the kernel, add_memory()
 201                  * returns -EEXIST. If add_memory() returns the other error, it
 202                  * means that this memory block is not used by the kernel.
 203                  */
 204                 if (result && result != -EEXIST) {
 205                         info->failed = 1;
 206                         continue;
 207                 }
 208
 209                 info->enabled = 1;
 210
 211                 /*
 212                  * Add num_enable even if add_memory() returns -EEXIST, so the
 213                  * device is bound to this driver.
 214                  */
 215                 num_enabled++;
 216         }
 217         if (!num_enabled) {
 218                 dev_err(&mem_device->device->dev, "add_memory failed\n");
 219                 mem_device->state = MEMORY_INVALID_STATE;
 220                 return -EINVAL;
 221         }
 222         /*
 223          * Sometimes the memory device will contain several memory blocks.
 224          * When one memory block is hot-added to the system memory, it will
 225          * be regarded as a success.
 226          * Otherwise if the last memory block can't be hot-added to the system
 227          * memory, it will be failure and the memory device can't be bound with
 228          * driver.
 229          */
 230         return 0;
 231 }
 232
 233 static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
 234 {
 235         int result = 0, nid;
 236         struct acpi_memory_info *info, *n;
 237
 238         nid = acpi_get_node(mem_device->device->handle);
 239
 240         list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
 241                 if (info->failed)
 242                         /* The kernel does not use this memory block */
 243                         continue;
 244
 245                 if (!info->enabled)
 246                         /*
 247                          * The kernel uses this memory block, but it may be not
 248                          * managed by us.
 249                          */
 250                         return -EBUSY;
 251
 252                 if (nid < 0)
 253                         nid = memory_add_physaddr_to_nid(info->start_addr);
 254                 result = remove_memory(nid, info->start_addr, info->length);
 255                 if (result)
 256                         return result;
 257
 258                 list_del(&info->list);
 259                 kfree(info);
 260         }
 261
 262         return result;
 263 }
 264
 265 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
 266 {
 267         if (!mem_device)
 268                 return;
 269
 270         acpi_memory_free_device_resources(mem_device);
 271         mem_device->device->driver_data = NULL;
 272         kfree(mem_device);
 273 }
 274
 275 static int acpi_memory_device_add(struct acpi_device *device,
 276                                   const struct acpi_device_id *not_used)
 277 {
 278         struct acpi_memory_device *mem_device;
 279         int result;
 280
 281         if (!device)
 282                 return -EINVAL;
 283
 284         mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
 285         if (!mem_device)
 286                 return -ENOMEM;
 287
 288         INIT_LIST_HEAD(&mem_device->res_list);
 289         mem_device->device = device;
 290         sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
 291         sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
 292         device->driver_data = mem_device;
 293
 294         /* Get the range from the _CRS */
 295         result = acpi_memory_get_device_resources(mem_device);
 296         if (result) {
 297                 kfree(mem_device);
 298                 return result;
 299         }
 300
 301         /* Set the device state */
 302         mem_device->state = MEMORY_POWER_ON_STATE;
 303
 304         result = acpi_memory_check_device(mem_device);
 305         if (result) {
 306                 acpi_memory_device_free(mem_device);
 307                 return 0;
 308         }
 309
 310         result = acpi_memory_enable_device(mem_device);
 311         if (result) {
 312                 dev_err(&device->dev, "acpi_memory_enable_device() error\n");
 313                 acpi_memory_device_free(mem_device);
 314                 return -ENODEV;
 315         }
 316
 317         dev_dbg(&device->dev, "Memory device configured by ACPI\n");
 318         return 1;
 319 }
 320
 321 static void acpi_memory_device_remove(struct acpi_device *device)
 322 {
 323         struct acpi_memory_device *mem_device;
 324
 325         if (!device || !acpi_driver_data(device))
 326                 return;
 327
 328         mem_device = acpi_driver_data(device);
 329         acpi_memory_remove_memory(mem_device);
 330         acpi_memory_device_free(mem_device);
 331 }
 332
 333 void __init acpi_memory_hotplug_init(void)
 334 {
 335         acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
 336 }