1/*
2 * pseries Memory Hotplug infrastructure.
3 *
4 * Copyright (C) 2008 Badari Pulavarty, IBM Corporation
5 *
6 *      This program is free software; you can redistribute it and/or
7 *      modify it under the terms of the GNU General Public License
8 *      as published by the Free Software Foundation; either version
9 *      2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/of.h>
13#include <linux/memblock.h>
14#include <linux/vmalloc.h>
15#include <linux/memory.h>
16
17#include <asm/firmware.h>
18#include <asm/machdep.h>
19#include <asm/pSeries_reconfig.h>
20#include <asm/sparsemem.h>
21
22static unsigned long get_memblock_size(void)
23{
24	struct device_node *np;
25	unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
26	struct resource r;
27
28	np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
29	if (np) {
30		const __be64 *size;
31
32		size = of_get_property(np, "ibm,lmb-size", NULL);
33		if (size)
34			memblock_size = be64_to_cpup(size);
35		of_node_put(np);
36	} else  if (machine_is(pseries)) {
37		/* This fallback really only applies to pseries */
38		unsigned int memzero_size = 0;
39
40		np = of_find_node_by_path("/memory@0");
41		if (np) {
42			if (!of_address_to_resource(np, 0, &r))
43				memzero_size = resource_size(&r);
44			of_node_put(np);
45		}
46
47		if (memzero_size) {
48			/* We now know the size of memory@0, use this to find
49			 * the first memoryblock and get its size.
50			 */
51			char buf[64];
52
53			sprintf(buf, "/memory@%x", memzero_size);
54			np = of_find_node_by_path(buf);
55			if (np) {
56				if (!of_address_to_resource(np, 0, &r))
57					memblock_size = resource_size(&r);
58				of_node_put(np);
59			}
60		}
61	}
62	return memblock_size;
63}
64
65/* WARNING: This is going to override the generic definition whenever
66 * pseries is built-in regardless of what platform is active at boot
67 * time. This is fine for now as this is the only "option" and it
68 * should work everywhere. If not, we'll have to turn this into a
69 * ppc_md. callback
70 */
71unsigned long memory_block_size_bytes(void)
72{
73	return get_memblock_size();
74}
75
76static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
77{
78	unsigned long start, start_pfn;
79	struct zone *zone;
80	int ret;
81
82	start_pfn = base >> PAGE_SHIFT;
83
84	if (!pfn_valid(start_pfn)) {
85		memblock_remove(base, memblock_size);
86		return 0;
87	}
88
89	zone = page_zone(pfn_to_page(start_pfn));
90
91	/*
92	 * Remove section mappings and sysfs entries for the
93	 * section of the memory we are removing.
94	 *
95	 * NOTE: Ideally, this should be done in generic code like
96	 * remove_memory(). But remove_memory() gets called by writing
97	 * to sysfs "state" file and we can't remove sysfs entries
98	 * while writing to it. So we have to defer it to here.
99	 */
100	ret = __remove_pages(zone, start_pfn, memblock_size >> PAGE_SHIFT);
101	if (ret)
102		return ret;
103
104	/*
105	 * Update memory regions for memory remove
106	 */
107	memblock_remove(base, memblock_size);
108
109	/*
110	 * Remove htab bolted mappings for this section of memory
111	 */
112	start = (unsigned long)__va(base);
113	ret = remove_section_mapping(start, start + memblock_size);
114
115	/* Ensure all vmalloc mappings are flushed in case they also
116	 * hit that section of memory
117	 */
118	vm_unmap_aliases();
119
120	return ret;
121}
122
123static int pseries_remove_memory(struct device_node *np)
124{
125	const char *type;
126	const unsigned int *regs;
127	unsigned long base;
128	unsigned int lmb_size;
129	int ret = -EINVAL;
130
131	/*
132	 * Check to see if we are actually removing memory
133	 */
134	type = of_get_property(np, "device_type", NULL);
135	if (type == NULL || strcmp(type, "memory") != 0)
136		return 0;
137
138	/*
139	 * Find the bae address and size of the memblock
140	 */
141	regs = of_get_property(np, "reg", NULL);
142	if (!regs)
143		return ret;
144
145	base = *(unsigned long *)regs;
146	lmb_size = regs[3];
147
148	ret = pseries_remove_memblock(base, lmb_size);
149	return ret;
150}
151
152static int pseries_add_memory(struct device_node *np)
153{
154	const char *type;
155	const unsigned int *regs;
156	unsigned long base;
157	unsigned int lmb_size;
158	int ret = -EINVAL;
159
160	/*
161	 * Check to see if we are actually adding memory
162	 */
163	type = of_get_property(np, "device_type", NULL);
164	if (type == NULL || strcmp(type, "memory") != 0)
165		return 0;
166
167	/*
168	 * Find the base and size of the memblock
169	 */
170	regs = of_get_property(np, "reg", NULL);
171	if (!regs)
172		return ret;
173
174	base = *(unsigned long *)regs;
175	lmb_size = regs[3];
176
177	/*
178	 * Update memory region to represent the memory add
179	 */
180	ret = memblock_add(base, lmb_size);
181	return (ret < 0) ? -EINVAL : 0;
182}
183
184static int pseries_drconf_memory(unsigned long *base, unsigned int action)
185{
186	unsigned long memblock_size;
187	int rc;
188
189	memblock_size = get_memblock_size();
190	if (!memblock_size)
191		return -EINVAL;
192
193	if (action == PSERIES_DRCONF_MEM_ADD) {
194		rc = memblock_add(*base, memblock_size);
195		rc = (rc < 0) ? -EINVAL : 0;
196	} else if (action == PSERIES_DRCONF_MEM_REMOVE) {
197		rc = pseries_remove_memblock(*base, memblock_size);
198	} else {
199		rc = -EINVAL;
200	}
201
202	return rc;
203}
204
205static int pseries_memory_notifier(struct notifier_block *nb,
206				unsigned long action, void *node)
207{
208	int err = 0;
209
210	switch (action) {
211	case PSERIES_RECONFIG_ADD:
212		err = pseries_add_memory(node);
213		break;
214	case PSERIES_RECONFIG_REMOVE:
215		err = pseries_remove_memory(node);
216		break;
217	case PSERIES_DRCONF_MEM_ADD:
218	case PSERIES_DRCONF_MEM_REMOVE:
219		err = pseries_drconf_memory(node, action);
220		break;
221	}
222	return notifier_from_errno(err);
223}
224
225static struct notifier_block pseries_mem_nb = {
226	.notifier_call = pseries_memory_notifier,
227};
228
229static int __init pseries_memory_hotplug_init(void)
230{
231	if (firmware_has_feature(FW_FEATURE_LPAR))
232		pSeries_reconfig_notifier_register(&pseries_mem_nb);
233
234	return 0;
235}
236machine_device_initcall(pseries, pseries_memory_hotplug_init);
237