1/*
2 * Copyright (C) 2012 Intel Corporation
3 *    Author: Liu Jinsong <jinsong.liu@intel.com>
4 *    Author: Jiang Yunhong <yunhong.jiang@intel.com>
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
18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/init.h>
23#include <linux/types.h>
24#include <linux/acpi.h>
25#include <xen/acpi.h>
26#include <xen/interface/platform.h>
27#include <asm/xen/hypercall.h>
28
29#define PREFIX "ACPI:xen_memory_hotplug:"
30
31struct acpi_memory_info {
32	struct list_head list;
33	u64 start_addr;		/* Memory Range start physical addr */
34	u64 length;		/* Memory Range length */
35	unsigned short caching;	/* memory cache attribute */
36	unsigned short write_protect;	/* memory read/write attribute */
37				/* copied from buffer getting from _CRS */
38	unsigned int enabled:1;
39};
40
41struct acpi_memory_device {
42	struct acpi_device *device;
43	struct list_head res_list;
44};
45
46static bool acpi_hotmem_initialized __read_mostly;
47
48static int xen_hotadd_memory(int pxm, struct acpi_memory_info *info)
49{
50	int rc;
51	struct xen_platform_op op;
52
53	op.cmd = XENPF_mem_hotadd;
54	op.u.mem_add.spfn = info->start_addr >> PAGE_SHIFT;
55	op.u.mem_add.epfn = (info->start_addr + info->length) >> PAGE_SHIFT;
56	op.u.mem_add.pxm = pxm;
57
58	rc = HYPERVISOR_dom0_op(&op);
59	if (rc)
60		pr_err(PREFIX "Xen Hotplug Memory Add failed on "
61			"0x%lx -> 0x%lx, _PXM: %d, error: %d\n",
62			(unsigned long)info->start_addr,
63			(unsigned long)(info->start_addr + info->length),
64			pxm, rc);
65
66	return rc;
67}
68
69static int xen_acpi_memory_enable_device(struct acpi_memory_device *mem_device)
70{
71	int pxm, result;
72	int num_enabled = 0;
73	struct acpi_memory_info *info;
74
75	if (!mem_device)
76		return -EINVAL;
77
78	pxm = xen_acpi_get_pxm(mem_device->device->handle);
79	if (pxm < 0)
80		return pxm;
81
82	list_for_each_entry(info, &mem_device->res_list, list) {
83		if (info->enabled) { /* just sanity check...*/
84			num_enabled++;
85			continue;
86		}
87
88		if (!info->length)
89			continue;
90
91		result = xen_hotadd_memory(pxm, info);
92		if (result)
93			continue;
94		info->enabled = 1;
95		num_enabled++;
96	}
97
98	if (!num_enabled)
99		return -ENODEV;
100
101	return 0;
102}
103
104static acpi_status
105acpi_memory_get_resource(struct acpi_resource *resource, void *context)
106{
107	struct acpi_memory_device *mem_device = context;
108	struct acpi_resource_address64 address64;
109	struct acpi_memory_info *info, *new;
110	acpi_status status;
111
112	status = acpi_resource_to_address64(resource, &address64);
113	if (ACPI_FAILURE(status) ||
114	    (address64.resource_type != ACPI_MEMORY_RANGE))
115		return AE_OK;
116
117	list_for_each_entry(info, &mem_device->res_list, list) {
118		if ((info->caching == address64.info.mem.caching) &&
119		    (info->write_protect == address64.info.mem.write_protect) &&
120		    (info->start_addr + info->length == address64.address.minimum)) {
121			info->length += address64.address.address_length;
122			return AE_OK;
123		}
124	}
125
126	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
127	if (!new)
128		return AE_ERROR;
129
130	INIT_LIST_HEAD(&new->list);
131	new->caching = address64.info.mem.caching;
132	new->write_protect = address64.info.mem.write_protect;
133	new->start_addr = address64.address.minimum;
134	new->length = address64.address.address_length;
135	list_add_tail(&new->list, &mem_device->res_list);
136
137	return AE_OK;
138}
139
140static int
141acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
142{
143	acpi_status status;
144	struct acpi_memory_info *info, *n;
145
146	if (!list_empty(&mem_device->res_list))
147		return 0;
148
149	status = acpi_walk_resources(mem_device->device->handle,
150		METHOD_NAME__CRS, acpi_memory_get_resource, mem_device);
151
152	if (ACPI_FAILURE(status)) {
153		list_for_each_entry_safe(info, n, &mem_device->res_list, list)
154			kfree(info);
155		INIT_LIST_HEAD(&mem_device->res_list);
156		return -EINVAL;
157	}
158
159	return 0;
160}
161
162static int acpi_memory_get_device(acpi_handle handle,
163				  struct acpi_memory_device **mem_device)
164{
165	struct acpi_device *device = NULL;
166	int result = 0;
167
168	acpi_scan_lock_acquire();
169
170	acpi_bus_get_device(handle, &device);
171	if (acpi_device_enumerated(device))
172		goto end;
173
174	/*
175	 * Now add the notified device.  This creates the acpi_device
176	 * and invokes .add function
177	 */
178	result = acpi_bus_scan(handle);
179	if (result) {
180		pr_warn(PREFIX "ACPI namespace scan failed\n");
181		result = -EINVAL;
182		goto out;
183	}
184	device = NULL;
185	acpi_bus_get_device(handle, &device);
186	if (!acpi_device_enumerated(device)) {
187		pr_warn(PREFIX "Missing device object\n");
188		result = -EINVAL;
189		goto out;
190	}
191
192end:
193	*mem_device = acpi_driver_data(device);
194	if (!(*mem_device)) {
195		pr_err(PREFIX "driver data not found\n");
196		result = -ENODEV;
197		goto out;
198	}
199
200out:
201	acpi_scan_lock_release();
202	return result;
203}
204
205static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
206{
207	unsigned long long current_status;
208
209	/* Get device present/absent information from the _STA */
210	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
211				"_STA", NULL, &current_status)))
212		return -ENODEV;
213	/*
214	 * Check for device status. Device should be
215	 * present/enabled/functioning.
216	 */
217	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
218	      && (current_status & ACPI_STA_DEVICE_ENABLED)
219	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
220		return -ENODEV;
221
222	return 0;
223}
224
225static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
226{
227	pr_debug(PREFIX "Xen does not support memory hotremove\n");
228
229	return -ENOSYS;
230}
231
232static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
233{
234	struct acpi_memory_device *mem_device;
235	struct acpi_device *device;
236	u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
237
238	switch (event) {
239	case ACPI_NOTIFY_BUS_CHECK:
240		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
241			"\nReceived BUS CHECK notification for device\n"));
242		/* Fall Through */
243	case ACPI_NOTIFY_DEVICE_CHECK:
244		if (event == ACPI_NOTIFY_DEVICE_CHECK)
245			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
246			"\nReceived DEVICE CHECK notification for device\n"));
247
248		if (acpi_memory_get_device(handle, &mem_device)) {
249			pr_err(PREFIX "Cannot find driver data\n");
250			break;
251		}
252
253		ost_code = ACPI_OST_SC_SUCCESS;
254		break;
255
256	case ACPI_NOTIFY_EJECT_REQUEST:
257		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
258			"\nReceived EJECT REQUEST notification for device\n"));
259
260		acpi_scan_lock_acquire();
261		if (acpi_bus_get_device(handle, &device)) {
262			acpi_scan_lock_release();
263			pr_err(PREFIX "Device doesn't exist\n");
264			break;
265		}
266		mem_device = acpi_driver_data(device);
267		if (!mem_device) {
268			acpi_scan_lock_release();
269			pr_err(PREFIX "Driver Data is NULL\n");
270			break;
271		}
272
273		/*
274		 * TBD: implement acpi_memory_disable_device and invoke
275		 * acpi_bus_remove if Xen support hotremove in the future
276		 */
277		acpi_memory_disable_device(mem_device);
278		acpi_scan_lock_release();
279		break;
280
281	default:
282		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
283				  "Unsupported event [0x%x]\n", event));
284		/* non-hotplug event; possibly handled by other handler */
285		return;
286	}
287
288	(void) acpi_evaluate_ost(handle, event, ost_code, NULL);
289	return;
290}
291
292static int xen_acpi_memory_device_add(struct acpi_device *device)
293{
294	int result;
295	struct acpi_memory_device *mem_device = NULL;
296
297
298	if (!device)
299		return -EINVAL;
300
301	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
302	if (!mem_device)
303		return -ENOMEM;
304
305	INIT_LIST_HEAD(&mem_device->res_list);
306	mem_device->device = device;
307	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
308	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
309	device->driver_data = mem_device;
310
311	/* Get the range from the _CRS */
312	result = acpi_memory_get_device_resources(mem_device);
313	if (result) {
314		kfree(mem_device);
315		return result;
316	}
317
318	/*
319	 * For booting existed memory devices, early boot code has recognized
320	 * memory area by EFI/E820. If DSDT shows these memory devices on boot,
321	 * hotplug is not necessary for them.
322	 * For hot-added memory devices during runtime, it need hypercall to
323	 * Xen hypervisor to add memory.
324	 */
325	if (!acpi_hotmem_initialized)
326		return 0;
327
328	if (!acpi_memory_check_device(mem_device))
329		result = xen_acpi_memory_enable_device(mem_device);
330
331	return result;
332}
333
334static int xen_acpi_memory_device_remove(struct acpi_device *device)
335{
336	struct acpi_memory_device *mem_device = NULL;
337
338	if (!device || !acpi_driver_data(device))
339		return -EINVAL;
340
341	mem_device = acpi_driver_data(device);
342	kfree(mem_device);
343
344	return 0;
345}
346
347/*
348 * Helper function to check for memory device
349 */
350static acpi_status is_memory_device(acpi_handle handle)
351{
352	char *hardware_id;
353	acpi_status status;
354	struct acpi_device_info *info;
355
356	status = acpi_get_object_info(handle, &info);
357	if (ACPI_FAILURE(status))
358		return status;
359
360	if (!(info->valid & ACPI_VALID_HID)) {
361		kfree(info);
362		return AE_ERROR;
363	}
364
365	hardware_id = info->hardware_id.string;
366	if ((hardware_id == NULL) ||
367	    (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
368		status = AE_ERROR;
369
370	kfree(info);
371	return status;
372}
373
374static acpi_status
375acpi_memory_register_notify_handler(acpi_handle handle,
376				    u32 level, void *ctxt, void **retv)
377{
378	acpi_status status;
379
380	status = is_memory_device(handle);
381	if (ACPI_FAILURE(status))
382		return AE_OK;	/* continue */
383
384	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
385					     acpi_memory_device_notify, NULL);
386	/* continue */
387	return AE_OK;
388}
389
390static acpi_status
391acpi_memory_deregister_notify_handler(acpi_handle handle,
392				      u32 level, void *ctxt, void **retv)
393{
394	acpi_status status;
395
396	status = is_memory_device(handle);
397	if (ACPI_FAILURE(status))
398		return AE_OK;	/* continue */
399
400	status = acpi_remove_notify_handler(handle,
401					    ACPI_SYSTEM_NOTIFY,
402					    acpi_memory_device_notify);
403
404	return AE_OK;	/* continue */
405}
406
407static const struct acpi_device_id memory_device_ids[] = {
408	{ACPI_MEMORY_DEVICE_HID, 0},
409	{"", 0},
410};
411MODULE_DEVICE_TABLE(acpi, memory_device_ids);
412
413static struct acpi_driver xen_acpi_memory_device_driver = {
414	.name = "acpi_memhotplug",
415	.class = ACPI_MEMORY_DEVICE_CLASS,
416	.ids = memory_device_ids,
417	.ops = {
418		.add = xen_acpi_memory_device_add,
419		.remove = xen_acpi_memory_device_remove,
420		},
421};
422
423static int __init xen_acpi_memory_device_init(void)
424{
425	int result;
426	acpi_status status;
427
428	if (!xen_initial_domain())
429		return -ENODEV;
430
431	/* unregister the stub which only used to reserve driver space */
432	xen_stub_memory_device_exit();
433
434	result = acpi_bus_register_driver(&xen_acpi_memory_device_driver);
435	if (result < 0) {
436		xen_stub_memory_device_init();
437		return -ENODEV;
438	}
439
440	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
441				     ACPI_UINT32_MAX,
442				     acpi_memory_register_notify_handler,
443				     NULL, NULL, NULL);
444
445	if (ACPI_FAILURE(status)) {
446		pr_warn(PREFIX "walk_namespace failed\n");
447		acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
448		xen_stub_memory_device_init();
449		return -ENODEV;
450	}
451
452	acpi_hotmem_initialized = true;
453	return 0;
454}
455
456static void __exit xen_acpi_memory_device_exit(void)
457{
458	acpi_status status;
459
460	if (!xen_initial_domain())
461		return;
462
463	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
464				     ACPI_UINT32_MAX,
465				     acpi_memory_deregister_notify_handler,
466				     NULL, NULL, NULL);
467	if (ACPI_FAILURE(status))
468		pr_warn(PREFIX "walk_namespace failed\n");
469
470	acpi_bus_unregister_driver(&xen_acpi_memory_device_driver);
471
472	/*
473	 * stub reserve space again to prevent any chance of native
474	 * driver loading.
475	 */
476	xen_stub_memory_device_init();
477	return;
478}
479
480module_init(xen_acpi_memory_device_init);
481module_exit(xen_acpi_memory_device_exit);
482ACPI_MODULE_NAME("xen-acpi-memhotplug");
483MODULE_AUTHOR("Liu Jinsong <jinsong.liu@intel.com>");
484MODULE_DESCRIPTION("Xen Hotplug Mem Driver");
485MODULE_LICENSE("GPL");
486