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/of_address.h>
14 #include <linux/memblock.h>
15 #include <linux/vmalloc.h>
16 #include <linux/memory.h>
17 #include <linux/memory_hotplug.h>
18 
19 #include <asm/firmware.h>
20 #include <asm/machdep.h>
21 #include <asm/prom.h>
22 #include <asm/sparsemem.h>
23 
24 static unsigned long get_memblock_size(void)
25 {
26 	struct device_node *np;
27 	unsigned int memblock_size = MIN_MEMORY_BLOCK_SIZE;
28 	struct resource r;
29 
30 	np = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
31 	if (np) {
32 		const __be64 *size;
33 
34 		size = of_get_property(np, "ibm,lmb-size", NULL);
35 		if (size)
36 			memblock_size = be64_to_cpup(size);
37 		of_node_put(np);
38 	} else  if (machine_is(pseries)) {
39 		/* This fallback really only applies to pseries */
40 		unsigned int memzero_size = 0;
41 
42 		np = of_find_node_by_path("/memory@0");
43 		if (np) {
44 			if (!of_address_to_resource(np, 0, &r))
45 				memzero_size = resource_size(&r);
46 			of_node_put(np);
47 		}
48 
49 		if (memzero_size) {
50 			/* We now know the size of memory@0, use this to find
51 			 * the first memoryblock and get its size.
52 			 */
53 			char buf[64];
54 
55 			sprintf(buf, "/memory@%x", memzero_size);
56 			np = of_find_node_by_path(buf);
57 			if (np) {
58 				if (!of_address_to_resource(np, 0, &r))
59 					memblock_size = resource_size(&r);
60 				of_node_put(np);
61 			}
62 		}
63 	}
64 	return memblock_size;
65 }
66 
67 /* WARNING: This is going to override the generic definition whenever
68  * pseries is built-in regardless of what platform is active at boot
69  * time. This is fine for now as this is the only "option" and it
70  * should work everywhere. If not, we'll have to turn this into a
71  * ppc_md. callback
72  */
73 unsigned long memory_block_size_bytes(void)
74 {
75 	return get_memblock_size();
76 }
77 
78 #ifdef CONFIG_MEMORY_HOTREMOVE
79 static int pseries_remove_memory(u64 start, u64 size)
80 {
81 	int ret;
82 
83 	/* Remove htab bolted mappings for this section of memory */
84 	start = (unsigned long)__va(start);
85 	ret = remove_section_mapping(start, start + size);
86 
87 	/* Ensure all vmalloc mappings are flushed in case they also
88 	 * hit that section of memory
89 	 */
90 	vm_unmap_aliases();
91 
92 	return ret;
93 }
94 
95 static int pseries_remove_memblock(unsigned long base, unsigned int memblock_size)
96 {
97 	unsigned long block_sz, start_pfn;
98 	int sections_per_block;
99 	int i, nid;
100 
101 	start_pfn = base >> PAGE_SHIFT;
102 
103 	if (!pfn_valid(start_pfn)) {
104 		memblock_remove(base, memblock_size);
105 		return 0;
106 	}
107 
108 	block_sz = memory_block_size_bytes();
109 	sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
110 	nid = memory_add_physaddr_to_nid(base);
111 
112 	for (i = 0; i < sections_per_block; i++) {
113 		remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
114 		base += MIN_MEMORY_BLOCK_SIZE;
115 	}
116 
117 	/* Update memory regions for memory remove */
118 	memblock_remove(base, memblock_size);
119 	return 0;
120 }
121 
122 static int pseries_remove_mem_node(struct device_node *np)
123 {
124 	const char *type;
125 	const unsigned int *regs;
126 	unsigned long base;
127 	unsigned int lmb_size;
128 	int ret = -EINVAL;
129 
130 	/*
131 	 * Check to see if we are actually removing memory
132 	 */
133 	type = of_get_property(np, "device_type", NULL);
134 	if (type == NULL || strcmp(type, "memory") != 0)
135 		return 0;
136 
137 	/*
138 	 * Find the bae address and size of the memblock
139 	 */
140 	regs = of_get_property(np, "reg", NULL);
141 	if (!regs)
142 		return ret;
143 
144 	base = *(unsigned long *)regs;
145 	lmb_size = regs[3];
146 
147 	pseries_remove_memblock(base, lmb_size);
148 	return 0;
149 }
150 #else
151 static inline int pseries_remove_memblock(unsigned long base,
152 					  unsigned int memblock_size)
153 {
154 	return -EOPNOTSUPP;
155 }
156 static inline int pseries_remove_mem_node(struct device_node *np)
157 {
158 	return -EOPNOTSUPP;
159 }
160 #endif /* CONFIG_MEMORY_HOTREMOVE */
161 
162 static int pseries_add_mem_node(struct device_node *np)
163 {
164 	const char *type;
165 	const unsigned int *regs;
166 	unsigned long base;
167 	unsigned int lmb_size;
168 	int ret = -EINVAL;
169 
170 	/*
171 	 * Check to see if we are actually adding memory
172 	 */
173 	type = of_get_property(np, "device_type", NULL);
174 	if (type == NULL || strcmp(type, "memory") != 0)
175 		return 0;
176 
177 	/*
178 	 * Find the base and size of the memblock
179 	 */
180 	regs = of_get_property(np, "reg", NULL);
181 	if (!regs)
182 		return ret;
183 
184 	base = *(unsigned long *)regs;
185 	lmb_size = regs[3];
186 
187 	/*
188 	 * Update memory region to represent the memory add
189 	 */
190 	ret = memblock_add(base, lmb_size);
191 	return (ret < 0) ? -EINVAL : 0;
192 }
193 
194 static int pseries_update_drconf_memory(struct of_prop_reconfig *pr)
195 {
196 	struct of_drconf_cell *new_drmem, *old_drmem;
197 	unsigned long memblock_size;
198 	u32 entries;
199 	u32 *p;
200 	int i, rc = -EINVAL;
201 
202 	memblock_size = get_memblock_size();
203 	if (!memblock_size)
204 		return -EINVAL;
205 
206 	p = (u32 *)of_get_property(pr->dn, "ibm,dynamic-memory", NULL);
207 	if (!p)
208 		return -EINVAL;
209 
210 	/* The first int of the property is the number of lmb's described
211 	 * by the property. This is followed by an array of of_drconf_cell
212 	 * entries. Get the niumber of entries and skip to the array of
213 	 * of_drconf_cell's.
214 	 */
215 	entries = *p++;
216 	old_drmem = (struct of_drconf_cell *)p;
217 
218 	p = (u32 *)pr->prop->value;
219 	p++;
220 	new_drmem = (struct of_drconf_cell *)p;
221 
222 	for (i = 0; i < entries; i++) {
223 		if ((old_drmem[i].flags & DRCONF_MEM_ASSIGNED) &&
224 		    (!(new_drmem[i].flags & DRCONF_MEM_ASSIGNED))) {
225 			rc = pseries_remove_memblock(old_drmem[i].base_addr,
226 						     memblock_size);
227 			break;
228 		} else if ((!(old_drmem[i].flags & DRCONF_MEM_ASSIGNED)) &&
229 			   (new_drmem[i].flags & DRCONF_MEM_ASSIGNED)) {
230 			rc = memblock_add(old_drmem[i].base_addr,
231 					  memblock_size);
232 			rc = (rc < 0) ? -EINVAL : 0;
233 			break;
234 		}
235 	}
236 
237 	return rc;
238 }
239 
240 static int pseries_memory_notifier(struct notifier_block *nb,
241 				   unsigned long action, void *node)
242 {
243 	struct of_prop_reconfig *pr;
244 	int err = 0;
245 
246 	switch (action) {
247 	case OF_RECONFIG_ATTACH_NODE:
248 		err = pseries_add_mem_node(node);
249 		break;
250 	case OF_RECONFIG_DETACH_NODE:
251 		err = pseries_remove_mem_node(node);
252 		break;
253 	case OF_RECONFIG_UPDATE_PROPERTY:
254 		pr = (struct of_prop_reconfig *)node;
255 		if (!strcmp(pr->prop->name, "ibm,dynamic-memory"))
256 			err = pseries_update_drconf_memory(pr);
257 		break;
258 	}
259 	return notifier_from_errno(err);
260 }
261 
262 static struct notifier_block pseries_mem_nb = {
263 	.notifier_call = pseries_memory_notifier,
264 };
265 
266 static int __init pseries_memory_hotplug_init(void)
267 {
268 	if (firmware_has_feature(FW_FEATURE_LPAR))
269 		of_reconfig_notifier_register(&pseries_mem_nb);
270 
271 #ifdef CONFIG_MEMORY_HOTREMOVE
272 	ppc_md.remove_memory = pseries_remove_memory;
273 #endif
274 
275 	return 0;
276 }
277 machine_device_initcall(pseries, pseries_memory_hotplug_init);
278