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 29 static struct device_node *pmem_node; 30 31 static 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 %pOF, rc: %d, drc index: %x\n", 56 dn, 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 69 static 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 %pOFn, rc: %d\n", 97 drc_index, dn, 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 } 106 107 int dlpar_hp_pmem(struct pseries_hp_errorlog *hp_elog) 108 { 109 u32 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 drc_index = hp_elog->_drc_u.drc_index; 127 128 lock_device_hotplug(); 129 130 if (hp_elog->action == PSERIES_HP_ELOG_ACTION_ADD) { 131 rc = pmem_drc_add_node(drc_index); 132 } else if (hp_elog->action == PSERIES_HP_ELOG_ACTION_REMOVE) { 133 rc = pmem_drc_remove_node(drc_index); 134 } else { 135 pr_err("Unsupported hotplug action (%d)\n", hp_elog->action); 136 rc = -EINVAL; 137 } 138 139 unlock_device_hotplug(); 140 return rc; 141 } 142 143 const struct of_device_id drc_pmem_match[] = { 144 { .type = "ibm,persistent-memory", }, 145 {} 146 }; 147 148 static int pseries_pmem_init(void) 149 { 150 pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory"); 151 if (!pmem_node) 152 return 0; 153 154 /* 155 * The generic OF bus probe/populate handles creating platform devices 156 * from the child (ibm,pmemory) nodes. The generic code registers an of 157 * reconfig notifier to handle the hot-add/remove cases too. 158 */ 159 of_platform_bus_probe(pmem_node, drc_pmem_match, NULL); 160 161 return 0; 162 } 163 machine_arch_initcall(pseries, pseries_pmem_init); 164