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 28 static struct device_node *pmem_node; 29 30 static ssize_t pmem_drc_add_node(u32 drc_index) 31 { 32 struct device_node *dn; 33 int rc; 34 35 pr_debug("Attempting to add pmem node, drc index: %x\n", drc_index); 36 37 rc = dlpar_acquire_drc(drc_index); 38 if (rc) { 39 pr_err("Failed to acquire DRC, rc: %d, drc index: %x\n", 40 rc, drc_index); 41 return -EINVAL; 42 } 43 44 dn = dlpar_configure_connector(cpu_to_be32(drc_index), pmem_node); 45 if (!dn) { 46 pr_err("configure-connector failed for drc %x\n", drc_index); 47 dlpar_release_drc(drc_index); 48 return -EINVAL; 49 } 50 51 /* NB: The of reconfig notifier creates platform device from the node */ 52 rc = dlpar_attach_node(dn, pmem_node); 53 if (rc) { 54 pr_err("Failed to attach node %pOF, rc: %d, drc index: %x\n", 55 dn, rc, drc_index); 56 57 if (dlpar_release_drc(drc_index)) 58 dlpar_free_cc_nodes(dn); 59 60 return rc; 61 } 62 63 pr_info("Successfully added %pOF, drc index: %x\n", dn, drc_index); 64 65 return 0; 66 } 67 68 static ssize_t pmem_drc_remove_node(u32 drc_index) 69 { 70 struct device_node *dn; 71 uint32_t index; 72 int rc; 73 74 for_each_child_of_node(pmem_node, dn) { 75 if (of_property_read_u32(dn, "ibm,my-drc-index", &index)) 76 continue; 77 if (index == drc_index) 78 break; 79 } 80 81 if (!dn) { 82 pr_err("Attempting to remove unused DRC index %x\n", drc_index); 83 return -ENODEV; 84 } 85 86 pr_debug("Attempting to remove %pOF, drc index: %x\n", dn, drc_index); 87 88 /* * NB: tears down the ibm,pmemory device as a side-effect */ 89 rc = dlpar_detach_node(dn); 90 if (rc) 91 return rc; 92 93 rc = dlpar_release_drc(drc_index); 94 if (rc) { 95 pr_err("Failed to release drc (%x) for CPU %pOFn, rc: %d\n", 96 drc_index, dn, rc); 97 dlpar_attach_node(dn, pmem_node); 98 return rc; 99 } 100 101 pr_info("Successfully removed PMEM with drc index: %x\n", drc_index); 102 103 return 0; 104 } 105 106 int dlpar_hp_pmem(struct pseries_hp_errorlog *hp_elog) 107 { 108 u32 drc_index; 109 int rc; 110 111 /* slim chance, but we might get a hotplug event while booting */ 112 if (!pmem_node) 113 pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory"); 114 if (!pmem_node) { 115 pr_err("Hotplug event for a pmem device, but none exists\n"); 116 return -ENODEV; 117 } 118 119 if (hp_elog->id_type != PSERIES_HP_ELOG_ID_DRC_INDEX) { 120 pr_err("Unsupported hotplug event type %d\n", 121 hp_elog->id_type); 122 return -EINVAL; 123 } 124 125 drc_index = hp_elog->_drc_u.drc_index; 126 127 lock_device_hotplug(); 128 129 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); 133 } else { 134 pr_err("Unsupported hotplug action (%d)\n", hp_elog->action); 135 rc = -EINVAL; 136 } 137 138 unlock_device_hotplug(); 139 return rc; 140 } 141 142 const struct of_device_id drc_pmem_match[] = { 143 { .type = "ibm,persistent-memory", }, 144 {} 145 }; 146 147 static int pseries_pmem_init(void) 148 { 149 /* 150 * Only supported on POWER8 and above. 151 */ 152 if (!cpu_has_feature(CPU_FTR_ARCH_207S)) 153 return 0; 154 155 pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory"); 156 if (!pmem_node) 157 return 0; 158 159 /* 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. 163 */ 164 of_platform_bus_probe(pmem_node, drc_pmem_match, NULL); 165 166 return 0; 167 } 168 machine_arch_initcall(pseries, pseries_pmem_init); 169