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(dn, "ibm,my-drc-index", &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, "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, "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(pmem_node, drc_pmem_match, NULL); 164 165 return 0; 166 } 167 machine_arch_initcall(pseries, pseries_pmem_init); 168