1 // SPDX-License-Identifier: GPL-2.0
4 * Handles hot and cold plug of persistent memory regions on pseries.
7 #define pr_fmt(fmt) "pseries-pmem: " fmt
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>
16 #include <linux/of_platform.h>
17 #include <linux/slab.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>
28 static struct device_node *pmem_node;
30 static ssize_t pmem_drc_add_node(u32 drc_index)
32 struct device_node *dn;
35 pr_debug("Attempting to add pmem node, drc index: %x\n", drc_index);
37 rc = dlpar_acquire_drc(drc_index);
39 pr_err("Failed to acquire DRC, rc: %d, drc index: %x\n",
44 dn = dlpar_configure_connector(cpu_to_be32(drc_index), pmem_node);
46 pr_err("configure-connector failed for drc %x\n", drc_index);
47 dlpar_release_drc(drc_index);
51 /* NB: The of reconfig notifier creates platform device from the node */
52 rc = dlpar_attach_node(dn, pmem_node);
54 pr_err("Failed to attach node %pOF, rc: %d, drc index: %x\n",
57 if (dlpar_release_drc(drc_index))
58 dlpar_free_cc_nodes(dn);
63 pr_info("Successfully added %pOF, drc index: %x\n", dn, drc_index);
68 static ssize_t pmem_drc_remove_node(u32 drc_index)
70 struct device_node *dn;
74 for_each_child_of_node(pmem_node, dn) {
75 if (of_property_read_u32(dn, "ibm,my-drc-index", &index))
77 if (index == drc_index)
82 pr_err("Attempting to remove unused DRC index %x\n", drc_index);
86 pr_debug("Attempting to remove %pOF, drc index: %x\n", dn, drc_index);
88 /* * NB: tears down the ibm,pmemory device as a side-effect */
89 rc = dlpar_detach_node(dn);
93 rc = dlpar_release_drc(drc_index);
95 pr_err("Failed to release drc (%x) for CPU %pOFn, rc: %d\n",
97 dlpar_attach_node(dn, pmem_node);
101 pr_info("Successfully removed PMEM with drc index: %x\n", drc_index);
106 int dlpar_hp_pmem(struct pseries_hp_errorlog *hp_elog)
111 /* slim chance, but we might get a hotplug event while booting */
113 pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory");
115 pr_err("Hotplug event for a pmem device, but none exists\n");
119 if (hp_elog->id_type != PSERIES_HP_ELOG_ID_DRC_INDEX) {
120 pr_err("Unsupported hotplug event type %d\n",
125 drc_index = hp_elog->_drc_u.drc_index;
127 lock_device_hotplug();
129 if (hp_elog->action == PSERIES_HP_ELOG_ACTION_ADD) {
130 rc = pmem_drc_add_node(drc_index);
131 } else if (hp_elog->action == PSERIES_HP_ELOG_ACTION_REMOVE) {
132 rc = pmem_drc_remove_node(drc_index);
134 pr_err("Unsupported hotplug action (%d)\n", hp_elog->action);
138 unlock_device_hotplug();
142 const struct of_device_id drc_pmem_match[] = {
143 { .type = "ibm,persistent-memory", },
147 static int pseries_pmem_init(void)
150 * Only supported on POWER8 and above.
152 if (!cpu_has_feature(CPU_FTR_ARCH_207S))
155 pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory");
160 * The generic OF bus probe/populate handles creating platform devices
161 * from the child (ibm,pmemory) nodes. The generic code registers an of
162 * reconfig notifier to handle the hot-add/remove cases too.
164 of_platform_bus_probe(pmem_node, drc_pmem_match, NULL);
168 machine_arch_initcall(pseries, pseries_pmem_init);