--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Handles hot and cold plug of persistent memory regions on pseries.
+ */
+
+#define pr_fmt(fmt) "pseries-pmem: " fmt
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/sched.h> /* for idle_task_exit */
+#include <linux/sched/hotplug.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <asm/prom.h>
+#include <asm/rtas.h>
+#include <asm/firmware.h>
+#include <asm/machdep.h>
+#include <asm/vdso_datapage.h>
+#include <asm/plpar_wrappers.h>
+#include <asm/topology.h>
+
+#include "pseries.h"
+#include "offline_states.h"
+
+static struct device_node *pmem_node;
+
+static ssize_t pmem_drc_add_node(u32 drc_index)
+{
+ struct device_node *dn;
+ int rc;
+
+ pr_debug("Attempting to add pmem node, drc index: %x\n", drc_index);
+
+ rc = dlpar_acquire_drc(drc_index);
+ if (rc) {
+ pr_err("Failed to acquire DRC, rc: %d, drc index: %x\n",
+ rc, drc_index);
+ return -EINVAL;
+ }
+
+ dn = dlpar_configure_connector(cpu_to_be32(drc_index), pmem_node);
+ if (!dn) {
+ pr_err("configure-connector failed for drc %x\n", drc_index);
+ dlpar_release_drc(drc_index);
+ return -EINVAL;
+ }
+
+ /* NB: The of reconfig notifier creates platform device from the node */
+ rc = dlpar_attach_node(dn, pmem_node);
+ if (rc) {
+ pr_err("Failed to attach node %s, rc: %d, drc index: %x\n",
+ dn->name, rc, drc_index);
+
+ if (dlpar_release_drc(drc_index))
+ dlpar_free_cc_nodes(dn);
+
+ return rc;
+ }
+
+ pr_info("Successfully added %pOF, drc index: %x\n", dn, drc_index);
+
+ return 0;
+}
+
+static ssize_t pmem_drc_remove_node(u32 drc_index)
+{
+ struct device_node *dn;
+ uint32_t index;
+ int rc;
+
+ for_each_child_of_node(pmem_node, dn) {
+ if (of_property_read_u32(dn, "ibm,my-drc-index", &index))
+ continue;
+ if (index == drc_index)
+ break;
+ }
+
+ if (!dn) {
+ pr_err("Attempting to remove unused DRC index %x\n", drc_index);
+ return -ENODEV;
+ }
+
+ pr_debug("Attempting to remove %pOF, drc index: %x\n", dn, drc_index);
+
+ /* * NB: tears down the ibm,pmemory device as a side-effect */
+ rc = dlpar_detach_node(dn);
+ if (rc)
+ return rc;
+
+ rc = dlpar_release_drc(drc_index);
+ if (rc) {
+ pr_err("Failed to release drc (%x) for CPU %s, rc: %d\n",
+ drc_index, dn->name, rc);
+ dlpar_attach_node(dn, pmem_node);
+ return rc;
+ }
+
+ pr_info("Successfully removed PMEM with drc index: %x\n", drc_index);
+
+ return 0;
+}
+
+int dlpar_hp_pmem(struct pseries_hp_errorlog *hp_elog)
+{
+ u32 count, drc_index;
+ int rc;
+
+ /* slim chance, but we might get a hotplug event while booting */
+ if (!pmem_node)
+ pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory");
+ if (!pmem_node) {
+ pr_err("Hotplug event for a pmem device, but none exists\n");
+ return -ENODEV;
+ }
+
+ if (hp_elog->id_type != PSERIES_HP_ELOG_ID_DRC_INDEX) {
+ pr_err("Unsupported hotplug event type %d\n",
+ hp_elog->id_type);
+ return -EINVAL;
+ }
+
+ count = hp_elog->_drc_u.drc_count;
+ drc_index = hp_elog->_drc_u.drc_index;
+
+ lock_device_hotplug();
+
+ if (hp_elog->action == PSERIES_HP_ELOG_ACTION_ADD) {
+ rc = pmem_drc_add_node(drc_index);
+ } else if (hp_elog->action == PSERIES_HP_ELOG_ACTION_REMOVE) {
+ rc = pmem_drc_remove_node(drc_index);
+ } else {
+ pr_err("Unsupported hotplug action (%d)\n", hp_elog->action);
+ rc = -EINVAL;
+ }
+
+ unlock_device_hotplug();
+ return rc;
+}
+
+const struct of_device_id drc_pmem_match[] = {
+ { .type = "ibm,persistent-memory", },
+ {}
+};
+
+static int pseries_pmem_init(void)
+{
+ pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory");
+ if (!pmem_node)
+ return 0;
+
+ /*
+ * The generic OF bus probe/populate handles creating platform devices
+ * from the child (ibm,pmemory) nodes. The generic code registers an of
+ * reconfig notifier to handle the hot-add/remove cases too.
+ */
+ of_platform_bus_probe(pmem_node, drc_pmem_match, NULL);
+
+ return 0;
+}
+machine_arch_initcall(pseries, pseries_pmem_init);
projects / mirror_ubuntu-focal-kernel.git / commitdiff