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 
45 ACPI_MODULE_NAME("acpi_memhotplug");
46 MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>");
47 MODULE_DESCRIPTION("Hotplug Mem Driver");
48 MODULE_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 
55 static int acpi_memory_device_add(struct acpi_device *device);
56 static int acpi_memory_device_remove(struct acpi_device *device, int type);
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 		},
72 };
73 
74 struct 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 
83 struct 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 
89 static int acpi_hotmem_initialized;
90 
91 static acpi_status
92 acpi_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 
128 static int
129 acpi_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 
150 static int
151 acpi_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 
197 static 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 
217 static 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 
275 static 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 
309 static 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 
340 static 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 
423 static 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 
473 static 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  */
490 static 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 
514 static acpi_status
515 acpi_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 
531 static acpi_status
532 acpi_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 
549 static 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 
575 static 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 
597 module_init(acpi_memory_device_init);
598 module_exit(acpi_memory_device_exit);
599