tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2
3/*
4 * Handles hot and cold plug of persistent memory regions on pseries.
5 */
6
7#define pr_fmt(fmt) "pseries-pmem: " fmt
8
9#include <linux/kernel.h>
10#include <linux/interrupt.h>
11#include <linux/delay.h>
12#include <linux/sched.h> /* for idle_task_exit */
13#include <linux/sched/hotplug.h>
14#include <linux/cpu.h>
15#include <linux/of.h>
16#include <linux/of_platform.h>
17#include <linux/slab.h>
18#include <asm/prom.h>
19#include <asm/rtas.h>
20#include <asm/firmware.h>
21#include <asm/machdep.h>
22#include <asm/vdso_datapage.h>
23#include <asm/plpar_wrappers.h>
24#include <asm/topology.h>
25
26#include "pseries.h"
27#include "offline_states.h"
28
29static struct device_node *pmem_node;
30
31static ssize_t pmem_drc_add_node(u32 drc_index)
32{
33 struct device_node *dn;
34 int rc;
35
36 pr_debug("Attempting to add pmem node, drc index: %x\n", drc_index);
37
38 rc = dlpar_acquire_drc(drc_index);
39 if (rc) {
40 pr_err("Failed to acquire DRC, rc: %d, drc index: %x\n",
41 rc, drc_index);
42 return -EINVAL;
43 }
44
45 dn = dlpar_configure_connector(cpu_to_be32(drc_index), pmem_node);
46 if (!dn) {
47 pr_err("configure-connector failed for drc %x\n", drc_index);
48 dlpar_release_drc(drc_index);
49 return -EINVAL;
50 }
51
52 /* NB: The of reconfig notifier creates platform device from the node */
53 rc = dlpar_attach_node(dn, pmem_node);
54 if (rc) {
55 pr_err("Failed to attach node %s, rc: %d, drc index: %x\n",
56 dn->name, rc, drc_index);
57
58 if (dlpar_release_drc(drc_index))
59 dlpar_free_cc_nodes(dn);
60
61 return rc;
62 }
63
64 pr_info("Successfully added %pOF, drc index: %x\n", dn, drc_index);
65
66 return 0;
67}
68
69static ssize_t pmem_drc_remove_node(u32 drc_index)
70{
71 struct device_node *dn;
72 uint32_t index;
73 int rc;
74
75 for_each_child_of_node(pmem_node, dn) {
76 if (of_property_read_u32(dn, "ibm,my-drc-index", &index))
77 continue;
78 if (index == drc_index)
79 break;
80 }
81
82 if (!dn) {
83 pr_err("Attempting to remove unused DRC index %x\n", drc_index);
84 return -ENODEV;
85 }
86
87 pr_debug("Attempting to remove %pOF, drc index: %x\n", dn, drc_index);
88
89 /* * NB: tears down the ibm,pmemory device as a side-effect */
90 rc = dlpar_detach_node(dn);
91 if (rc)
92 return rc;
93
94 rc = dlpar_release_drc(drc_index);
95 if (rc) {
96 pr_err("Failed to release drc (%x) for CPU %s, rc: %d\n",
97 drc_index, dn->name, rc);
98 dlpar_attach_node(dn, pmem_node);
99 return rc;
100 }
101
102 pr_info("Successfully removed PMEM with drc index: %x\n", drc_index);
103
104 return 0;
105}
106
107int dlpar_hp_pmem(struct pseries_hp_errorlog *hp_elog)
108{
109 u32 count, drc_index;
110 int rc;
111
112 /* slim chance, but we might get a hotplug event while booting */
113 if (!pmem_node)
114 pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory");
115 if (!pmem_node) {
116 pr_err("Hotplug event for a pmem device, but none exists\n");
117 return -ENODEV;
118 }
119
120 if (hp_elog->id_type != PSERIES_HP_ELOG_ID_DRC_INDEX) {
121 pr_err("Unsupported hotplug event type %d\n",
122 hp_elog->id_type);
123 return -EINVAL;
124 }
125
126 count = hp_elog->_drc_u.drc_count;
127 drc_index = hp_elog->_drc_u.drc_index;
128
129 lock_device_hotplug();
130
131 if (hp_elog->action == PSERIES_HP_ELOG_ACTION_ADD) {
132 rc = pmem_drc_add_node(drc_index);
133 } else if (hp_elog->action == PSERIES_HP_ELOG_ACTION_REMOVE) {
134 rc = pmem_drc_remove_node(drc_index);
135 } else {
136 pr_err("Unsupported hotplug action (%d)\n", hp_elog->action);
137 rc = -EINVAL;
138 }
139
140 unlock_device_hotplug();
141 return rc;
142}
143
144const struct of_device_id drc_pmem_match[] = {
145 { .type = "ibm,persistent-memory", },
146 {}
147};
148
149static int pseries_pmem_init(void)
150{
151 pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory");
152 if (!pmem_node)
153 return 0;
154
155 /*
156 * The generic OF bus probe/populate handles creating platform devices
157 * from the child (ibm,pmemory) nodes. The generic code registers an of
158 * reconfig notifier to handle the hot-add/remove cases too.
159 */
160 of_platform_bus_probe(pmem_node, drc_pmem_match, NULL);
161
162 return 0;
163}
164machine_arch_initcall(pseries, pseries_pmem_init);