2 * Copyright (C) 2012 Intel Corporation
3 * Author: Liu Jinsong <jinsong.liu@intel.com>
4 * Author: Jiang Yunhong <yunhong.jiang@intel.com>
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.
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
18 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/types.h>
24 #include <linux/cpu.h>
25 #include <linux/acpi.h>
26 #include <linux/uaccess.h>
27 #include <acpi/processor.h>
29 #include <xen/interface/platform.h>
30 #include <asm/xen/hypercall.h>
32 #define PREFIX "ACPI:xen_cpu_hotplug:"
34 #define INSTALL_NOTIFY_HANDLER 0
35 #define UNINSTALL_NOTIFY_HANDLER 1
37 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr);
39 /* --------------------------------------------------------------------------
41 -------------------------------------------------------------------------- */
43 static int xen_acpi_processor_enable(struct acpi_device *device)
45 acpi_status status = 0;
46 unsigned long long value;
47 union acpi_object object = { 0 };
48 struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
49 struct acpi_processor *pr;
51 pr = acpi_driver_data(device);
53 pr_err(PREFIX "Cannot find driver data\n");
57 if (!strcmp(acpi_device_hid(device), ACPI_PROCESSOR_OBJECT_HID)) {
58 /* Declared with "Processor" statement; match ProcessorID */
59 status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
60 if (ACPI_FAILURE(status)) {
61 pr_err(PREFIX "Evaluating processor object\n");
65 pr->acpi_id = object.processor.proc_id;
67 /* Declared with "Device" statement; match _UID */
68 status = acpi_evaluate_integer(pr->handle, METHOD_NAME__UID,
70 if (ACPI_FAILURE(status)) {
71 pr_err(PREFIX "Evaluating processor _UID\n");
78 pr->id = xen_pcpu_id(pr->acpi_id);
81 /* This cpu is not presented at hypervisor, try to hotadd it */
82 if (ACPI_FAILURE(xen_acpi_cpu_hotadd(pr))) {
83 pr_err(PREFIX "Hotadd CPU (acpi_id = %d) failed.\n",
91 static int xen_acpi_processor_add(struct acpi_device *device)
94 struct acpi_processor *pr;
99 pr = kzalloc(sizeof(struct acpi_processor), GFP_KERNEL);
103 pr->handle = device->handle;
104 strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
105 strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
106 device->driver_data = pr;
108 ret = xen_acpi_processor_enable(device);
110 pr_err(PREFIX "Error when enabling Xen processor\n");
115 static int xen_acpi_processor_remove(struct acpi_device *device)
117 struct acpi_processor *pr;
122 pr = acpi_driver_data(device);
130 /*--------------------------------------------------------------
131 Acpi processor hotplug support
132 --------------------------------------------------------------*/
134 static int is_processor_present(acpi_handle handle)
137 unsigned long long sta = 0;
140 status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
142 if (ACPI_SUCCESS(status) && (sta & ACPI_STA_DEVICE_PRESENT))
146 * _STA is mandatory for a processor that supports hot plug
148 if (status == AE_NOT_FOUND)
149 pr_info(PREFIX "Processor does not support hot plug\n");
151 pr_info(PREFIX "Processor Device is not present");
155 static int xen_apic_id(acpi_handle handle)
157 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
158 union acpi_object *obj;
159 struct acpi_madt_local_apic *lapic;
162 if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer)))
165 if (!buffer.length || !buffer.pointer)
168 obj = buffer.pointer;
169 if (obj->type != ACPI_TYPE_BUFFER ||
170 obj->buffer.length < sizeof(*lapic)) {
171 kfree(buffer.pointer);
175 lapic = (struct acpi_madt_local_apic *)obj->buffer.pointer;
177 if (lapic->header.type != ACPI_MADT_TYPE_LOCAL_APIC ||
178 !(lapic->lapic_flags & ACPI_MADT_ENABLED)) {
179 kfree(buffer.pointer);
183 apic_id = (uint32_t)lapic->id;
184 kfree(buffer.pointer);
185 buffer.length = ACPI_ALLOCATE_BUFFER;
186 buffer.pointer = NULL;
191 static int xen_hotadd_cpu(struct acpi_processor *pr)
193 int cpu_id, apic_id, pxm;
194 struct xen_platform_op op;
196 apic_id = xen_apic_id(pr->handle);
198 pr_err(PREFIX "Failed to get apic_id for acpi_id %d\n",
203 pxm = xen_acpi_get_pxm(pr->handle);
205 pr_err(PREFIX "Failed to get _PXM for acpi_id %d\n",
210 op.cmd = XENPF_cpu_hotadd;
211 op.u.cpu_add.apic_id = apic_id;
212 op.u.cpu_add.acpi_id = pr->acpi_id;
213 op.u.cpu_add.pxm = pxm;
215 cpu_id = HYPERVISOR_dom0_op(&op);
217 pr_err(PREFIX "Failed to hotadd CPU for acpi_id %d\n",
223 static acpi_status xen_acpi_cpu_hotadd(struct acpi_processor *pr)
225 if (!is_processor_present(pr->handle))
228 pr->id = xen_hotadd_cpu(pr);
233 * Sync with Xen hypervisor, providing new /sys/.../xen_cpuX
234 * interface after cpu hotadded.
236 xen_pcpu_hotplug_sync();
241 static int acpi_processor_device_remove(struct acpi_device *device)
243 pr_debug(PREFIX "Xen does not support CPU hotremove\n");
248 static void acpi_processor_hotplug_notify(acpi_handle handle,
249 u32 event, void *data)
251 struct acpi_processor *pr;
252 struct acpi_device *device = NULL;
253 u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
256 acpi_scan_lock_acquire();
259 case ACPI_NOTIFY_BUS_CHECK:
260 case ACPI_NOTIFY_DEVICE_CHECK:
261 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
262 "Processor driver received %s event\n",
263 (event == ACPI_NOTIFY_BUS_CHECK) ?
264 "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK"));
266 if (!is_processor_present(handle))
269 acpi_bus_get_device(handle, &device);
270 if (acpi_device_enumerated(device))
273 result = acpi_bus_scan(handle);
275 pr_err(PREFIX "Unable to add the device\n");
279 acpi_bus_get_device(handle, &device);
280 if (!acpi_device_enumerated(device)) {
281 pr_err(PREFIX "Missing device object\n");
284 ost_code = ACPI_OST_SC_SUCCESS;
287 case ACPI_NOTIFY_EJECT_REQUEST:
288 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
289 "received ACPI_NOTIFY_EJECT_REQUEST\n"));
291 if (acpi_bus_get_device(handle, &device)) {
292 pr_err(PREFIX "Device don't exist, dropping EJECT\n");
295 pr = acpi_driver_data(device);
297 pr_err(PREFIX "Driver data is NULL, dropping EJECT\n");
302 * TBD: implement acpi_processor_device_remove if Xen support
303 * CPU hotremove in the future.
305 acpi_processor_device_remove(device);
309 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
310 "Unsupported event [0x%x]\n", event));
312 /* non-hotplug event; possibly handled by other handler */
316 (void) acpi_evaluate_ost(handle, event, ost_code, NULL);
319 acpi_scan_lock_release();
322 static acpi_status is_processor_device(acpi_handle handle)
324 struct acpi_device_info *info;
328 status = acpi_get_object_info(handle, &info);
329 if (ACPI_FAILURE(status))
332 if (info->type == ACPI_TYPE_PROCESSOR) {
334 return AE_OK; /* found a processor object */
337 if (!(info->valid & ACPI_VALID_HID)) {
342 hid = info->hardware_id.string;
343 if ((hid == NULL) || strcmp(hid, ACPI_PROCESSOR_DEVICE_HID)) {
349 return AE_OK; /* found a processor device object */
353 processor_walk_namespace_cb(acpi_handle handle,
354 u32 lvl, void *context, void **rv)
357 int *action = context;
359 status = is_processor_device(handle);
360 if (ACPI_FAILURE(status))
361 return AE_OK; /* not a processor; continue to walk */
364 case INSTALL_NOTIFY_HANDLER:
365 acpi_install_notify_handler(handle,
367 acpi_processor_hotplug_notify,
370 case UNINSTALL_NOTIFY_HANDLER:
371 acpi_remove_notify_handler(handle,
373 acpi_processor_hotplug_notify);
379 /* found a processor; skip walking underneath */
380 return AE_CTRL_DEPTH;
384 void acpi_processor_install_hotplug_notify(void)
386 int action = INSTALL_NOTIFY_HANDLER;
387 acpi_walk_namespace(ACPI_TYPE_ANY,
390 processor_walk_namespace_cb, NULL, &action, NULL);
394 void acpi_processor_uninstall_hotplug_notify(void)
396 int action = UNINSTALL_NOTIFY_HANDLER;
397 acpi_walk_namespace(ACPI_TYPE_ANY,
400 processor_walk_namespace_cb, NULL, &action, NULL);
403 static const struct acpi_device_id processor_device_ids[] = {
404 {ACPI_PROCESSOR_OBJECT_HID, 0},
405 {ACPI_PROCESSOR_DEVICE_HID, 0},
408 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
410 static struct acpi_driver xen_acpi_processor_driver = {
412 .class = ACPI_PROCESSOR_CLASS,
413 .ids = processor_device_ids,
415 .add = xen_acpi_processor_add,
416 .remove = xen_acpi_processor_remove,
420 static int __init xen_acpi_processor_init(void)
424 if (!xen_initial_domain())
427 /* unregister the stub which only used to reserve driver space */
428 xen_stub_processor_exit();
430 result = acpi_bus_register_driver(&xen_acpi_processor_driver);
432 xen_stub_processor_init();
436 acpi_processor_install_hotplug_notify();
440 static void __exit xen_acpi_processor_exit(void)
442 if (!xen_initial_domain())
445 acpi_processor_uninstall_hotplug_notify();
447 acpi_bus_unregister_driver(&xen_acpi_processor_driver);
450 * stub reserve space again to prevent any chance of native
453 xen_stub_processor_init();
457 module_init(xen_acpi_processor_init);
458 module_exit(xen_acpi_processor_exit);
459 ACPI_MODULE_NAME("xen-acpi-cpuhotplug");
460 MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
461 MODULE_DESCRIPTION("Xen Hotplug CPU Driver");
462 MODULE_LICENSE("GPL");