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/rtas.h> |
19 | #include <asm/firmware.h> |
20 | #include <asm/machdep.h> |
21 | #include <asm/vdso_datapage.h> |
22 | #include <asm/plpar_wrappers.h> |
23 | #include <asm/topology.h> |
24 | |
25 | #include "pseries.h" |
26 | |
27 | static struct device_node *pmem_node; |
28 | |
29 | static ssize_t pmem_drc_add_node(u32 drc_index) |
30 | { |
31 | struct device_node *dn; |
32 | int rc; |
33 | |
34 | pr_debug("Attempting to add pmem node, drc index: %x\n" , drc_index); |
35 | |
36 | rc = dlpar_acquire_drc(drc_index); |
37 | if (rc) { |
38 | pr_err("Failed to acquire DRC, rc: %d, drc index: %x\n" , |
39 | rc, drc_index); |
40 | return -EINVAL; |
41 | } |
42 | |
43 | dn = dlpar_configure_connector(cpu_to_be32(drc_index), pmem_node); |
44 | if (!dn) { |
45 | pr_err("configure-connector failed for drc %x\n" , drc_index); |
46 | dlpar_release_drc(drc_index); |
47 | return -EINVAL; |
48 | } |
49 | |
50 | /* NB: The of reconfig notifier creates platform device from the node */ |
51 | rc = dlpar_attach_node(dn, pmem_node); |
52 | if (rc) { |
53 | pr_err("Failed to attach node %pOF, rc: %d, drc index: %x\n" , |
54 | dn, rc, drc_index); |
55 | |
56 | if (dlpar_release_drc(drc_index)) |
57 | dlpar_free_cc_nodes(dn); |
58 | |
59 | return rc; |
60 | } |
61 | |
62 | pr_info("Successfully added %pOF, drc index: %x\n" , dn, drc_index); |
63 | |
64 | return 0; |
65 | } |
66 | |
67 | static ssize_t pmem_drc_remove_node(u32 drc_index) |
68 | { |
69 | struct device_node *dn; |
70 | uint32_t index; |
71 | int rc; |
72 | |
73 | for_each_child_of_node(pmem_node, dn) { |
74 | if (of_property_read_u32(np: dn, propname: "ibm,my-drc-index" , out_value: &index)) |
75 | continue; |
76 | if (index == drc_index) |
77 | break; |
78 | } |
79 | |
80 | if (!dn) { |
81 | pr_err("Attempting to remove unused DRC index %x\n" , drc_index); |
82 | return -ENODEV; |
83 | } |
84 | |
85 | pr_debug("Attempting to remove %pOF, drc index: %x\n" , dn, drc_index); |
86 | |
87 | /* * NB: tears down the ibm,pmemory device as a side-effect */ |
88 | rc = dlpar_detach_node(dn); |
89 | if (rc) |
90 | return rc; |
91 | |
92 | rc = dlpar_release_drc(drc_index); |
93 | if (rc) { |
94 | pr_err("Failed to release drc (%x) for CPU %pOFn, rc: %d\n" , |
95 | drc_index, dn, rc); |
96 | dlpar_attach_node(dn, pmem_node); |
97 | return rc; |
98 | } |
99 | |
100 | pr_info("Successfully removed PMEM with drc index: %x\n" , drc_index); |
101 | |
102 | return 0; |
103 | } |
104 | |
105 | int dlpar_hp_pmem(struct pseries_hp_errorlog *hp_elog) |
106 | { |
107 | u32 drc_index; |
108 | int rc; |
109 | |
110 | /* slim chance, but we might get a hotplug event while booting */ |
111 | if (!pmem_node) |
112 | pmem_node = of_find_node_by_type(NULL, type: "ibm,persistent-memory" ); |
113 | if (!pmem_node) { |
114 | pr_err("Hotplug event for a pmem device, but none exists\n" ); |
115 | return -ENODEV; |
116 | } |
117 | |
118 | if (hp_elog->id_type != PSERIES_HP_ELOG_ID_DRC_INDEX) { |
119 | pr_err("Unsupported hotplug event type %d\n" , |
120 | hp_elog->id_type); |
121 | return -EINVAL; |
122 | } |
123 | |
124 | drc_index = hp_elog->_drc_u.drc_index; |
125 | |
126 | lock_device_hotplug(); |
127 | |
128 | if (hp_elog->action == PSERIES_HP_ELOG_ACTION_ADD) { |
129 | rc = pmem_drc_add_node(drc_index); |
130 | } else if (hp_elog->action == PSERIES_HP_ELOG_ACTION_REMOVE) { |
131 | rc = pmem_drc_remove_node(drc_index); |
132 | } else { |
133 | pr_err("Unsupported hotplug action (%d)\n" , hp_elog->action); |
134 | rc = -EINVAL; |
135 | } |
136 | |
137 | unlock_device_hotplug(); |
138 | return rc; |
139 | } |
140 | |
141 | static const struct of_device_id drc_pmem_match[] = { |
142 | { .type = "ibm,persistent-memory" , }, |
143 | {} |
144 | }; |
145 | |
146 | static int pseries_pmem_init(void) |
147 | { |
148 | /* |
149 | * Only supported on POWER8 and above. |
150 | */ |
151 | if (!cpu_has_feature(CPU_FTR_ARCH_207S)) |
152 | return 0; |
153 | |
154 | pmem_node = of_find_node_by_type(NULL, type: "ibm,persistent-memory" ); |
155 | if (!pmem_node) |
156 | return 0; |
157 | |
158 | /* |
159 | * The generic OF bus probe/populate handles creating platform devices |
160 | * from the child (ibm,pmemory) nodes. The generic code registers an of |
161 | * reconfig notifier to handle the hot-add/remove cases too. |
162 | */ |
163 | of_platform_bus_probe(root: pmem_node, matches: drc_pmem_match, NULL); |
164 | |
165 | return 0; |
166 | } |
167 | machine_arch_initcall(pseries, pseries_pmem_init); |
168 | |