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 <acpi/acpi_drivers.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 MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>");
46 MODULE_DESCRIPTION("Hotplug Mem Driver");
47 MODULE_LICENSE("GPL");
48
49 /* Memory Device States */
50 #define MEMORY_INVALID_STATE 0
51 #define MEMORY_POWER_ON_STATE 1
52 #define MEMORY_POWER_OFF_STATE 2
53
54 static int acpi_memory_device_add(struct acpi_device *device);
55 static int acpi_memory_device_remove(struct acpi_device *device, int type);
56 static int acpi_memory_device_start(struct acpi_device *device);
57
58 static const struct acpi_device_id memory_device_ids[] = {
59 {ACPI_MEMORY_DEVICE_HID, 0},
60 {"", 0},
61 };
62 MODULE_DEVICE_TABLE(acpi, memory_device_ids);
63
64 static 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 .start = acpi_memory_device_start,
72 },
73 };
74
75 struct 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 };
83
84 struct acpi_memory_device {
85 struct acpi_device * device;
86 unsigned int state; /* State of the memory device */
87 struct list_head res_list;
88 };
89
90 static int acpi_hotmem_initialized;
91
92 static acpi_status
93 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
94 {
95 struct acpi_memory_device *mem_device = context;
96 struct acpi_resource_address64 address64;
97 struct acpi_memory_info *info, *new;
98 acpi_status status;
99
100 status = acpi_resource_to_address64(resource, &address64);
101 if (ACPI_FAILURE(status) ||
102 (address64.resource_type != ACPI_MEMORY_RANGE))
103 return AE_OK;
104
105 list_for_each_entry(info, &mem_device->res_list, list) {
106 /* Can we combine the resource range information? */
107 if ((info->caching == address64.info.mem.caching) &&
108 (info->write_protect == address64.info.mem.write_protect) &&
109 (info->start_addr + info->length == address64.minimum)) {
110 info->length += address64.address_length;
111 return AE_OK;
112 }
113 }
114
115 new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
116 if (!new)
117 return AE_ERROR;
118
119 INIT_LIST_HEAD(&new->list);
120 new->caching = address64.info.mem.caching;
121 new->write_protect = address64.info.mem.write_protect;
122 new->start_addr = address64.minimum;
123 new->length = address64.address_length;
124 list_add_tail(&new->list, &mem_device->res_list);
125
126 return AE_OK;
127 }
128
129 static int
130 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
131 {
132 acpi_status status;
133 struct acpi_memory_info *info, *n;
134
135
136 if (!list_empty(&mem_device->res_list))
137 return 0;
138
139 status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
140 acpi_memory_get_resource, mem_device);
141 if (ACPI_FAILURE(status)) {
142 list_for_each_entry_safe(info, n, &mem_device->res_list, list)
143 kfree(info);
144 INIT_LIST_HEAD(&mem_device->res_list);
145 return -EINVAL;
146 }
147
148 return 0;
149 }
150
151 static int
152 acpi_memory_get_device(acpi_handle handle,
153 struct acpi_memory_device **mem_device)
154 {
155 acpi_status status;
156 acpi_handle phandle;
157 struct acpi_device *device = NULL;
158 struct acpi_device *pdevice = NULL;
159 int result;
160
161
162 if (!acpi_bus_get_device(handle, &device) && device)
163 goto end;
164
165 status = acpi_get_parent(handle, &phandle);
166 if (ACPI_FAILURE(status)) {
167 ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
168 return -EINVAL;
169 }
170
171 /* Get the parent device */
172 result = acpi_bus_get_device(phandle, &pdevice);
173 if (result) {
174 printk(KERN_WARNING PREFIX "Cannot get acpi bus device");
175 return -EINVAL;
176 }
177
178 /*
179 * Now add the notified device. This creates the acpi_device
180 * and invokes .add function
181 */
182 result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
183 if (result) {
184 printk(KERN_WARNING PREFIX "Cannot add acpi bus");
185 return -EINVAL;
186 }
187
188 end:
189 *mem_device = acpi_driver_data(device);
190 if (!(*mem_device)) {
191 printk(KERN_ERR "\n driver data not found");
192 return -ENODEV;
193 }
194
195 return 0;
196 }
197
198 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
199 {
200 unsigned long long current_status;
201
202 /* Get device present/absent information from the _STA */
203 if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
204 NULL, ¤t_status)))
205 return -ENODEV;
206 /*
207 * Check for device status. Device should be
208 * present/enabled/functioning.
209 */
210 if (!((current_status & ACPI_STA_DEVICE_PRESENT)
211 && (current_status & ACPI_STA_DEVICE_ENABLED)
212 && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
213 return -ENODEV;
214
215 return 0;
216 }
217
218 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
219 {
220 int result, num_enabled = 0;
221 struct acpi_memory_info *info;
222 int node;
223
224
225 /* Get the range from the _CRS */
226 result = acpi_memory_get_device_resources(mem_device);
227 if (result) {
228 printk(KERN_ERR PREFIX "get_device_resources failed\n");
229 mem_device->state = MEMORY_INVALID_STATE;
230 return result;
231 }
232
233 node = acpi_get_node(mem_device->device->handle);
234 /*
235 * Tell the VM there is more memory here...
236 * Note: Assume that this function returns zero on success
237 * We don't have memory-hot-add rollback function,now.
238 * (i.e. memory-hot-remove function)
239 */
240 list_for_each_entry(info, &mem_device->res_list, list) {
241 if (info->enabled) { /* just sanity check...*/
242 num_enabled++;
243 continue;
244 }
245 /*
246 * If the memory block size is zero, please ignore it.
247 * Don't try to do the following memory hotplug flowchart.
248 */
249 if (!info->length)
250 continue;
251 if (node < 0)
252 node = memory_add_physaddr_to_nid(info->start_addr);
253
254 result = add_memory(node, info->start_addr, info->length);
255 if (result)
256 continue;
257 info->enabled = 1;
258 num_enabled++;
259 }
260 if (!num_enabled) {
261 printk(KERN_ERR PREFIX "add_memory failed\n");
262 mem_device->state = MEMORY_INVALID_STATE;
263 return -EINVAL;
264 }
265 /*
266 * Sometimes the memory device will contain several memory blocks.
267 * When one memory block is hot-added to the system memory, it will
268 * be regarded as a success.
269 * Otherwise if the last memory block can't be hot-added to the system
270 * memory, it will be failure and the memory device can't be bound with
271 * driver.
272 */
273 return 0;
274 }
275
276 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
277 {
278 acpi_status status;
279 struct acpi_object_list arg_list;
280 union acpi_object arg;
281 unsigned long long current_status;
282
283
284 /* Issue the _EJ0 command */
285 arg_list.count = 1;
286 arg_list.pointer = &arg;
287 arg.type = ACPI_TYPE_INTEGER;
288 arg.integer.value = 1;
289 status = acpi_evaluate_object(mem_device->device->handle,
290 "_EJ0", &arg_list, NULL);
291 /* Return on _EJ0 failure */
292 if (ACPI_FAILURE(status)) {
293 ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
294 return -ENODEV;
295 }
296
297 /* Evalute _STA to check if the device is disabled */
298 status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
299 NULL, ¤t_status);
300 if (ACPI_FAILURE(status))
301 return -ENODEV;
302
303 /* Check for device status. Device should be disabled */
304 if (current_status & ACPI_STA_DEVICE_ENABLED)
305 return -EINVAL;
306
307 return 0;
308 }
309
310 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
311 {
312 int result;
313 struct acpi_memory_info *info, *n;
314
315
316 /*
317 * Ask the VM to offline this memory range.
318 * Note: Assume that this function returns zero on success
319 */
320 list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
321 if (info->enabled) {
322 result = remove_memory(info->start_addr, info->length);
323 if (result)
324 return result;
325 }
326 kfree(info);
327 }
328
329 /* Power-off and eject the device */
330 result = acpi_memory_powerdown_device(mem_device);
331 if (result) {
332 /* Set the status of the device to invalid */
333 mem_device->state = MEMORY_INVALID_STATE;
334 return result;
335 }
336
337 mem_device->state = MEMORY_POWER_OFF_STATE;
338 return result;
339 }
340
341 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
342 {
343 struct acpi_memory_device *mem_device;
344 struct acpi_device *device;
345
346
347 switch (event) {
348 case ACPI_NOTIFY_BUS_CHECK:
349 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
350 "\nReceived BUS CHECK notification for device\n"));
351 /* Fall Through */
352 case ACPI_NOTIFY_DEVICE_CHECK:
353 if (event == ACPI_NOTIFY_DEVICE_CHECK)
354 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
355 "\nReceived DEVICE CHECK notification for device\n"));
356 if (acpi_memory_get_device(handle, &mem_device)) {
357 printk(KERN_ERR PREFIX "Cannot find driver data\n");
358 return;
359 }
360
361 if (!acpi_memory_check_device(mem_device)) {
362 if (acpi_memory_enable_device(mem_device))
363 printk(KERN_ERR PREFIX
364 "Cannot enable memory device\n");
365 }
366 break;
367 case ACPI_NOTIFY_EJECT_REQUEST:
368 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
369 "\nReceived EJECT REQUEST notification for device\n"));
370
371 if (acpi_bus_get_device(handle, &device)) {
372 printk(KERN_ERR PREFIX "Device doesn't exist\n");
373 break;
374 }
375 mem_device = acpi_driver_data(device);
376 if (!mem_device) {
377 printk(KERN_ERR PREFIX "Driver Data is NULL\n");
378 break;
379 }
380
381 /*
382 * Currently disabling memory device from kernel mode
383 * TBD: Can also be disabled from user mode scripts
384 * TBD: Can also be disabled by Callback registration
385 * with generic sysfs driver
386 */
387 if (acpi_memory_disable_device(mem_device))
388 printk(KERN_ERR PREFIX
389 "Disable memory device\n");
390 /*
391 * TBD: Invoke acpi_bus_remove to cleanup data structures
392 */
393 break;
394 default:
395 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
396 "Unsupported event [0x%x]\n", event));
397 break;
398 }
399
400 return;
401 }
402
403 static int acpi_memory_device_add(struct acpi_device *device)
404 {
405 int result;
406 struct acpi_memory_device *mem_device = NULL;
407
408
409 if (!device)
410 return -EINVAL;
411
412 mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
413 if (!mem_device)
414 return -ENOMEM;
415
416 INIT_LIST_HEAD(&mem_device->res_list);
417 mem_device->device = device;
418 sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
419 sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
420 device->driver_data = mem_device;
421
422 /* Get the range from the _CRS */
423 result = acpi_memory_get_device_resources(mem_device);
424 if (result) {
425 kfree(mem_device);
426 return result;
427 }
428
429 /* Set the device state */
430 mem_device->state = MEMORY_POWER_ON_STATE;
431
432 printk(KERN_DEBUG "%s \n", acpi_device_name(device));
433
434 return result;
435 }
436
437 static int acpi_memory_device_remove(struct acpi_device *device, int type)
438 {
439 struct acpi_memory_device *mem_device = NULL;
440
441
442 if (!device || !acpi_driver_data(device))
443 return -EINVAL;
444
445 mem_device = acpi_driver_data(device);
446 kfree(mem_device);
447
448 return 0;
449 }
450
451 static int acpi_memory_device_start (struct acpi_device *device)
452 {
453 struct acpi_memory_device *mem_device;
454 int result = 0;
455
456 /*
457 * Early boot code has recognized memory area by EFI/E820.
458 * If DSDT shows these memory devices on boot, hotplug is not necessary
459 * for them. So, it just returns until completion of this driver's
460 * start up.
461 */
462 if (!acpi_hotmem_initialized)
463 return 0;
464
465 mem_device = acpi_driver_data(device);
466
467 if (!acpi_memory_check_device(mem_device)) {
468 /* call add_memory func */
469 result = acpi_memory_enable_device(mem_device);
470 if (result)
471 printk(KERN_ERR PREFIX
472 "Error in acpi_memory_enable_device\n");
473 }
474 return result;
475 }
476
477 /*
478 * Helper function to check for memory device
479 */
480 static acpi_status is_memory_device(acpi_handle handle)
481 {
482 char *hardware_id;
483 acpi_status status;
484 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
485 struct acpi_device_info *info;
486
487
488 status = acpi_get_object_info(handle, &buffer);
489 if (ACPI_FAILURE(status))
490 return status;
491
492 info = buffer.pointer;
493 if (!(info->valid & ACPI_VALID_HID)) {
494 kfree(buffer.pointer);
495 return AE_ERROR;
496 }
497
498 hardware_id = info->hardware_id.value;
499 if ((hardware_id == NULL) ||
500 (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
501 status = AE_ERROR;
502
503 kfree(buffer.pointer);
504 return status;
505 }
506
507 static acpi_status
508 acpi_memory_register_notify_handler(acpi_handle handle,
509 u32 level, void *ctxt, void **retv)
510 {
511 acpi_status status;
512
513
514 status = is_memory_device(handle);
515 if (ACPI_FAILURE(status))
516 return AE_OK; /* continue */
517
518 status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
519 acpi_memory_device_notify, NULL);
520 /* continue */
521 return AE_OK;
522 }
523
524 static acpi_status
525 acpi_memory_deregister_notify_handler(acpi_handle handle,
526 u32 level, void *ctxt, void **retv)
527 {
528 acpi_status status;
529
530
531 status = is_memory_device(handle);
532 if (ACPI_FAILURE(status))
533 return AE_OK; /* continue */
534
535 status = acpi_remove_notify_handler(handle,
536 ACPI_SYSTEM_NOTIFY,
537 acpi_memory_device_notify);
538
539 return AE_OK; /* continue */
540 }
541
542 static int __init acpi_memory_device_init(void)
543 {
544 int result;
545 acpi_status status;
546
547
548 result = acpi_bus_register_driver(&acpi_memory_device_driver);
549
550 if (result < 0)
551 return -ENODEV;
552
553 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
554 ACPI_UINT32_MAX,
555 acpi_memory_register_notify_handler,
556 NULL, NULL);
557
558 if (ACPI_FAILURE(status)) {
559 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
560 acpi_bus_unregister_driver(&acpi_memory_device_driver);
561 return -ENODEV;
562 }
563
564 acpi_hotmem_initialized = 1;
565 return 0;
566 }
567
568 static void __exit acpi_memory_device_exit(void)
569 {
570 acpi_status status;
571
572
573 /*
574 * Adding this to un-install notification handlers for all the device
575 * handles.
576 */
577 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
578 ACPI_UINT32_MAX,
579 acpi_memory_deregister_notify_handler,
580 NULL, NULL);
581
582 if (ACPI_FAILURE(status))
583 ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
584
585 acpi_bus_unregister_driver(&acpi_memory_device_driver);
586
587 return;
588 }
589
590 module_init(acpi_memory_device_init);
591 module_exit(acpi_memory_device_exit);
592
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