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/lmb.h>
14 #include <asm/firmware.h>
15 #include <asm/machdep.h>
16 #include <asm/pSeries_reconfig.h>
17 
18 static int pseries_remove_memory(struct device_node *np)
19 {
20 	const char *type;
21 	const unsigned int *my_index;
22 	const unsigned int *regs;
23 	u64 start_pfn, start;
24 	struct zone *zone;
25 	int ret = -EINVAL;
26 
27 	/*
28 	 * Check to see if we are actually removing memory
29 	 */
30 	type = of_get_property(np, "device_type", NULL);
31 	if (type == NULL || strcmp(type, "memory") != 0)
32 		return 0;
33 
34 	/*
35 	 * Find the memory index and size of the removing section
36 	 */
37 	my_index = of_get_property(np, "ibm,my-drc-index", NULL);
38 	if (!my_index)
39 		return ret;
40 
41 	regs = of_get_property(np, "reg", NULL);
42 	if (!regs)
43 		return ret;
44 
45 	start_pfn = section_nr_to_pfn(*my_index & 0xffff);
46 	zone = page_zone(pfn_to_page(start_pfn));
47 
48 	/*
49 	 * Remove section mappings and sysfs entries for the
50 	 * section of the memory we are removing.
51 	 *
52 	 * NOTE: Ideally, this should be done in generic code like
53 	 * remove_memory(). But remove_memory() gets called by writing
54 	 * to sysfs "state" file and we can't remove sysfs entries
55 	 * while writing to it. So we have to defer it to here.
56 	 */
57 	ret = __remove_pages(zone, start_pfn, regs[3] >> PAGE_SHIFT);
58 	if (ret)
59 		return ret;
60 
61 	/*
62 	 * Update memory regions for memory remove
63 	 */
64 	lmb_remove(start_pfn << PAGE_SHIFT, regs[3]);
65 
66 	/*
67 	 * Remove htab bolted mappings for this section of memory
68 	 */
69 	start = (unsigned long)__va(start_pfn << PAGE_SHIFT);
70 	ret = remove_section_mapping(start, start + regs[3]);
71 	return ret;
72 }
73 
74 static int pseries_add_memory(struct device_node *np)
75 {
76 	const char *type;
77 	const unsigned int *my_index;
78 	const unsigned int *regs;
79 	u64 start_pfn;
80 	int ret = -EINVAL;
81 
82 	/*
83 	 * Check to see if we are actually adding memory
84 	 */
85 	type = of_get_property(np, "device_type", NULL);
86 	if (type == NULL || strcmp(type, "memory") != 0)
87 		return 0;
88 
89 	/*
90 	 * Find the memory index and size of the added section
91 	 */
92 	my_index = of_get_property(np, "ibm,my-drc-index", NULL);
93 	if (!my_index)
94 		return ret;
95 
96 	regs = of_get_property(np, "reg", NULL);
97 	if (!regs)
98 		return ret;
99 
100 	start_pfn = section_nr_to_pfn(*my_index & 0xffff);
101 
102 	/*
103 	 * Update memory region to represent the memory add
104 	 */
105 	lmb_add(start_pfn << PAGE_SHIFT, regs[3]);
106 	return 0;
107 }
108 
109 static int pseries_memory_notifier(struct notifier_block *nb,
110 				unsigned long action, void *node)
111 {
112 	int err = NOTIFY_OK;
113 
114 	switch (action) {
115 	case PSERIES_RECONFIG_ADD:
116 		if (pseries_add_memory(node))
117 			err = NOTIFY_BAD;
118 		break;
119 	case PSERIES_RECONFIG_REMOVE:
120 		if (pseries_remove_memory(node))
121 			err = NOTIFY_BAD;
122 		break;
123 	default:
124 		err = NOTIFY_DONE;
125 		break;
126 	}
127 	return err;
128 }
129 
130 static struct notifier_block pseries_mem_nb = {
131 	.notifier_call = pseries_memory_notifier,
132 };
133 
134 static int __init pseries_memory_hotplug_init(void)
135 {
136 	if (firmware_has_feature(FW_FEATURE_LPAR))
137 		pSeries_reconfig_notifier_register(&pseries_mem_nb);
138 
139 	return 0;
140 }
141 machine_device_initcall(pseries, pseries_memory_hotplug_init);
142