Root/drivers/acpi/acpi_memhotplug.c

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

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