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 
57 static const struct acpi_device_id memory_device_ids[] = {
58 	{ACPI_MEMORY_DEVICE_HID, 0},
59 	{"", 0},
60 };
61 MODULE_DEVICE_TABLE(acpi, memory_device_ids);
62 
63 static struct acpi_driver acpi_memory_device_driver = {
64 	.name = "acpi_memhotplug",
65 	.class = ACPI_MEMORY_DEVICE_CLASS,
66 	.ids = memory_device_ids,
67 	.ops = {
68 		.add = acpi_memory_device_add,
69 		.remove = acpi_memory_device_remove,
70 		},
71 };
72 
73 struct acpi_memory_info {
74 	struct list_head list;
75 	u64 start_addr;		/* Memory Range start physical addr */
76 	u64 length;		/* Memory Range length */
77 	unsigned short caching;	/* memory cache attribute */
78 	unsigned short write_protect;	/* memory read/write attribute */
79 	unsigned int enabled:1;
80 };
81 
82 struct acpi_memory_device {
83 	struct acpi_device * device;
84 	unsigned int state;	/* State of the memory device */
85 	struct list_head res_list;
86 };
87 
88 static int acpi_hotmem_initialized;
89 
90 static acpi_status
91 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
92 {
93 	struct acpi_memory_device *mem_device = context;
94 	struct acpi_resource_address64 address64;
95 	struct acpi_memory_info *info, *new;
96 	acpi_status status;
97 
98 	status = acpi_resource_to_address64(resource, &address64);
99 	if (ACPI_FAILURE(status) ||
100 	    (address64.resource_type != ACPI_MEMORY_RANGE))
101 		return AE_OK;
102 
103 	list_for_each_entry(info, &mem_device->res_list, list) {
104 		/* Can we combine the resource range information? */
105 		if ((info->caching == address64.info.mem.caching) &&
106 		    (info->write_protect == address64.info.mem.write_protect) &&
107 		    (info->start_addr + info->length == address64.minimum)) {
108 			info->length += address64.address_length;
109 			return AE_OK;
110 		}
111 	}
112 
113 	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
114 	if (!new)
115 		return AE_ERROR;
116 
117 	INIT_LIST_HEAD(&new->list);
118 	new->caching = address64.info.mem.caching;
119 	new->write_protect = address64.info.mem.write_protect;
120 	new->start_addr = address64.minimum;
121 	new->length = address64.address_length;
122 	list_add_tail(&new->list, &mem_device->res_list);
123 
124 	return AE_OK;
125 }
126 
127 static int
128 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
129 {
130 	acpi_status status;
131 	struct acpi_memory_info *info, *n;
132 
133 
134 	if (!list_empty(&mem_device->res_list))
135 		return 0;
136 
137 	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
138 				     acpi_memory_get_resource, mem_device);
139 	if (ACPI_FAILURE(status)) {
140 		list_for_each_entry_safe(info, n, &mem_device->res_list, list)
141 			kfree(info);
142 		INIT_LIST_HEAD(&mem_device->res_list);
143 		return -EINVAL;
144 	}
145 
146 	return 0;
147 }
148 
149 static int
150 acpi_memory_get_device(acpi_handle handle,
151 		       struct acpi_memory_device **mem_device)
152 {
153 	acpi_status status;
154 	acpi_handle phandle;
155 	struct acpi_device *device = NULL;
156 	struct acpi_device *pdevice = NULL;
157 	int result;
158 
159 
160 	if (!acpi_bus_get_device(handle, &device) && device)
161 		goto end;
162 
163 	status = acpi_get_parent(handle, &phandle);
164 	if (ACPI_FAILURE(status)) {
165 		ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
166 		return -EINVAL;
167 	}
168 
169 	/* Get the parent device */
170 	result = acpi_bus_get_device(phandle, &pdevice);
171 	if (result) {
172 		printk(KERN_WARNING PREFIX "Cannot get acpi bus device");
173 		return -EINVAL;
174 	}
175 
176 	/*
177 	 * Now add the notified device.  This creates the acpi_device
178 	 * and invokes .add function
179 	 */
180 	result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
181 	if (result) {
182 		printk(KERN_WARNING PREFIX "Cannot add acpi bus");
183 		return -EINVAL;
184 	}
185 
186       end:
187 	*mem_device = acpi_driver_data(device);
188 	if (!(*mem_device)) {
189 		printk(KERN_ERR "\n driver data not found");
190 		return -ENODEV;
191 	}
192 
193 	return 0;
194 }
195 
196 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
197 {
198 	unsigned long long current_status;
199 
200 	/* Get device present/absent information from the _STA */
201 	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
202 					       NULL, &current_status)))
203 		return -ENODEV;
204 	/*
205 	 * Check for device status. Device should be
206 	 * present/enabled/functioning.
207 	 */
208 	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
209 	      && (current_status & ACPI_STA_DEVICE_ENABLED)
210 	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
211 		return -ENODEV;
212 
213 	return 0;
214 }
215 
216 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
217 {
218 	int result, num_enabled = 0;
219 	struct acpi_memory_info *info;
220 	int node;
221 
222 
223 	/* Get the range from the _CRS */
224 	result = acpi_memory_get_device_resources(mem_device);
225 	if (result) {
226 		printk(KERN_ERR PREFIX "get_device_resources failed\n");
227 		mem_device->state = MEMORY_INVALID_STATE;
228 		return result;
229 	}
230 
231 	node = acpi_get_node(mem_device->device->handle);
232 	/*
233 	 * Tell the VM there is more memory here...
234 	 * Note: Assume that this function returns zero on success
235 	 * We don't have memory-hot-add rollback function,now.
236 	 * (i.e. memory-hot-remove function)
237 	 */
238 	list_for_each_entry(info, &mem_device->res_list, list) {
239 		if (info->enabled) { /* just sanity check...*/
240 			num_enabled++;
241 			continue;
242 		}
243 		/*
244 		 * If the memory block size is zero, please ignore it.
245 		 * Don't try to do the following memory hotplug flowchart.
246 		 */
247 		if (!info->length)
248 			continue;
249 		if (node < 0)
250 			node = memory_add_physaddr_to_nid(info->start_addr);
251 
252 		result = add_memory(node, info->start_addr, info->length);
253 		if (result)
254 			continue;
255 		info->enabled = 1;
256 		num_enabled++;
257 	}
258 	if (!num_enabled) {
259 		printk(KERN_ERR PREFIX "add_memory failed\n");
260 		mem_device->state = MEMORY_INVALID_STATE;
261 		return -EINVAL;
262 	}
263 	/*
264 	 * Sometimes the memory device will contain several memory blocks.
265 	 * When one memory block is hot-added to the system memory, it will
266 	 * be regarded as a success.
267 	 * Otherwise if the last memory block can't be hot-added to the system
268 	 * memory, it will be failure and the memory device can't be bound with
269 	 * driver.
270 	 */
271 	return 0;
272 }
273 
274 static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
275 {
276 	acpi_status status;
277 	struct acpi_object_list arg_list;
278 	union acpi_object arg;
279 	unsigned long long current_status;
280 
281 
282 	/* Issue the _EJ0 command */
283 	arg_list.count = 1;
284 	arg_list.pointer = &arg;
285 	arg.type = ACPI_TYPE_INTEGER;
286 	arg.integer.value = 1;
287 	status = acpi_evaluate_object(mem_device->device->handle,
288 				      "_EJ0", &arg_list, NULL);
289 	/* Return on _EJ0 failure */
290 	if (ACPI_FAILURE(status)) {
291 		ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
292 		return -ENODEV;
293 	}
294 
295 	/* Evalute _STA to check if the device is disabled */
296 	status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
297 				       NULL, &current_status);
298 	if (ACPI_FAILURE(status))
299 		return -ENODEV;
300 
301 	/* Check for device status.  Device should be disabled */
302 	if (current_status & ACPI_STA_DEVICE_ENABLED)
303 		return -EINVAL;
304 
305 	return 0;
306 }
307 
308 static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
309 {
310 	int result;
311 	struct acpi_memory_info *info, *n;
312 
313 
314 	/*
315 	 * Ask the VM to offline this memory range.
316 	 * Note: Assume that this function returns zero on success
317 	 */
318 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
319 		if (info->enabled) {
320 			result = remove_memory(info->start_addr, info->length);
321 			if (result)
322 				return result;
323 		}
324 		kfree(info);
325 	}
326 
327 	/* Power-off and eject the device */
328 	result = acpi_memory_powerdown_device(mem_device);
329 	if (result) {
330 		/* Set the status of the device to invalid */
331 		mem_device->state = MEMORY_INVALID_STATE;
332 		return result;
333 	}
334 
335 	mem_device->state = MEMORY_POWER_OFF_STATE;
336 	return result;
337 }
338 
339 static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
340 {
341 	struct acpi_memory_device *mem_device;
342 	struct acpi_device *device;
343 
344 
345 	switch (event) {
346 	case ACPI_NOTIFY_BUS_CHECK:
347 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
348 				  "\nReceived BUS CHECK notification for device\n"));
349 		/* Fall Through */
350 	case ACPI_NOTIFY_DEVICE_CHECK:
351 		if (event == ACPI_NOTIFY_DEVICE_CHECK)
352 			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
353 					  "\nReceived DEVICE CHECK notification for device\n"));
354 		if (acpi_memory_get_device(handle, &mem_device)) {
355 			printk(KERN_ERR PREFIX "Cannot find driver data\n");
356 			return;
357 		}
358 
359 		if (!acpi_memory_check_device(mem_device)) {
360 			if (acpi_memory_enable_device(mem_device))
361 				printk(KERN_ERR PREFIX
362 					    "Cannot enable memory device\n");
363 		}
364 		break;
365 	case ACPI_NOTIFY_EJECT_REQUEST:
366 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
367 				  "\nReceived EJECT REQUEST notification for device\n"));
368 
369 		if (acpi_bus_get_device(handle, &device)) {
370 			printk(KERN_ERR PREFIX "Device doesn't exist\n");
371 			break;
372 		}
373 		mem_device = acpi_driver_data(device);
374 		if (!mem_device) {
375 			printk(KERN_ERR PREFIX "Driver Data is NULL\n");
376 			break;
377 		}
378 
379 		/*
380 		 * Currently disabling memory device from kernel mode
381 		 * TBD: Can also be disabled from user mode scripts
382 		 * TBD: Can also be disabled by Callback registration
383 		 *      with generic sysfs driver
384 		 */
385 		if (acpi_memory_disable_device(mem_device))
386 			printk(KERN_ERR PREFIX
387 				    "Disable memory device\n");
388 		/*
389 		 * TBD: Invoke acpi_bus_remove to cleanup data structures
390 		 */
391 		break;
392 	default:
393 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
394 				  "Unsupported event [0x%x]\n", event));
395 		break;
396 	}
397 
398 	return;
399 }
400 
401 static int acpi_memory_device_add(struct acpi_device *device)
402 {
403 	int result;
404 	struct acpi_memory_device *mem_device = NULL;
405 
406 
407 	if (!device)
408 		return -EINVAL;
409 
410 	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
411 	if (!mem_device)
412 		return -ENOMEM;
413 
414 	INIT_LIST_HEAD(&mem_device->res_list);
415 	mem_device->device = device;
416 	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
417 	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
418 	device->driver_data = mem_device;
419 
420 	/* Get the range from the _CRS */
421 	result = acpi_memory_get_device_resources(mem_device);
422 	if (result) {
423 		kfree(mem_device);
424 		return result;
425 	}
426 
427 	/* Set the device state */
428 	mem_device->state = MEMORY_POWER_ON_STATE;
429 
430 	printk(KERN_DEBUG "%s \n", acpi_device_name(device));
431 
432 	/*
433 	 * Early boot code has recognized memory area by EFI/E820.
434 	 * If DSDT shows these memory devices on boot, hotplug is not necessary
435 	 * for them. So, it just returns until completion of this driver's
436 	 * start up.
437 	 */
438 	if (!acpi_hotmem_initialized)
439 		return 0;
440 
441 	if (!acpi_memory_check_device(mem_device)) {
442 		/* call add_memory func */
443 		result = acpi_memory_enable_device(mem_device);
444 		if (result)
445 			printk(KERN_ERR PREFIX
446 				"Error in acpi_memory_enable_device\n");
447 	}
448 	return result;
449 }
450 
451 static int acpi_memory_device_remove(struct acpi_device *device, int type)
452 {
453 	struct acpi_memory_device *mem_device = NULL;
454 
455 
456 	if (!device || !acpi_driver_data(device))
457 		return -EINVAL;
458 
459 	mem_device = acpi_driver_data(device);
460 	kfree(mem_device);
461 
462 	return 0;
463 }
464 
465 /*
466  * Helper function to check for memory device
467  */
468 static acpi_status is_memory_device(acpi_handle handle)
469 {
470 	char *hardware_id;
471 	acpi_status status;
472 	struct acpi_device_info *info;
473 
474 	status = acpi_get_object_info(handle, &info);
475 	if (ACPI_FAILURE(status))
476 		return status;
477 
478 	if (!(info->valid & ACPI_VALID_HID)) {
479 		kfree(info);
480 		return AE_ERROR;
481 	}
482 
483 	hardware_id = info->hardware_id.string;
484 	if ((hardware_id == NULL) ||
485 	    (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
486 		status = AE_ERROR;
487 
488 	kfree(info);
489 	return status;
490 }
491 
492 static acpi_status
493 acpi_memory_register_notify_handler(acpi_handle handle,
494 				    u32 level, void *ctxt, void **retv)
495 {
496 	acpi_status status;
497 
498 
499 	status = is_memory_device(handle);
500 	if (ACPI_FAILURE(status))
501 		return AE_OK;	/* continue */
502 
503 	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
504 					     acpi_memory_device_notify, NULL);
505 	/* continue */
506 	return AE_OK;
507 }
508 
509 static acpi_status
510 acpi_memory_deregister_notify_handler(acpi_handle handle,
511 				      u32 level, void *ctxt, void **retv)
512 {
513 	acpi_status status;
514 
515 
516 	status = is_memory_device(handle);
517 	if (ACPI_FAILURE(status))
518 		return AE_OK;	/* continue */
519 
520 	status = acpi_remove_notify_handler(handle,
521 					    ACPI_SYSTEM_NOTIFY,
522 					    acpi_memory_device_notify);
523 
524 	return AE_OK;	/* continue */
525 }
526 
527 static int __init acpi_memory_device_init(void)
528 {
529 	int result;
530 	acpi_status status;
531 
532 
533 	result = acpi_bus_register_driver(&acpi_memory_device_driver);
534 
535 	if (result < 0)
536 		return -ENODEV;
537 
538 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
539 				     ACPI_UINT32_MAX,
540 				     acpi_memory_register_notify_handler,
541 				     NULL, NULL);
542 
543 	if (ACPI_FAILURE(status)) {
544 		ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
545 		acpi_bus_unregister_driver(&acpi_memory_device_driver);
546 		return -ENODEV;
547 	}
548 
549 	acpi_hotmem_initialized = 1;
550 	return 0;
551 }
552 
553 static void __exit acpi_memory_device_exit(void)
554 {
555 	acpi_status status;
556 
557 
558 	/*
559 	 * Adding this to un-install notification handlers for all the device
560 	 * handles.
561 	 */
562 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
563 				     ACPI_UINT32_MAX,
564 				     acpi_memory_deregister_notify_handler,
565 				     NULL, NULL);
566 
567 	if (ACPI_FAILURE(status))
568 		ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
569 
570 	acpi_bus_unregister_driver(&acpi_memory_device_driver);
571 
572 	return;
573 }
574 
575 module_init(acpi_memory_device_init);
576 module_exit(acpi_memory_device_exit);
577