168 lines
3.8 KiB
C
168 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Handles hot and cold plug of persistent memory regions on pseries.
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*/
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#define pr_fmt(fmt) "pseries-pmem: " fmt
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/delay.h>
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#include <linux/sched.h> /* for idle_task_exit */
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#include <linux/sched/hotplug.h>
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#include <linux/cpu.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <linux/slab.h>
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#include <asm/rtas.h>
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#include <asm/firmware.h>
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#include <asm/machdep.h>
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#include <asm/vdso_datapage.h>
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#include <asm/plpar_wrappers.h>
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#include <asm/topology.h>
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#include "pseries.h"
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static struct device_node *pmem_node;
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static ssize_t pmem_drc_add_node(u32 drc_index)
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{
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struct device_node *dn;
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int rc;
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pr_debug("Attempting to add pmem node, drc index: %x\n", drc_index);
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rc = dlpar_acquire_drc(drc_index);
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if (rc) {
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pr_err("Failed to acquire DRC, rc: %d, drc index: %x\n",
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rc, drc_index);
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return -EINVAL;
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}
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dn = dlpar_configure_connector(cpu_to_be32(drc_index), pmem_node);
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if (!dn) {
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pr_err("configure-connector failed for drc %x\n", drc_index);
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dlpar_release_drc(drc_index);
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return -EINVAL;
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}
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/* NB: The of reconfig notifier creates platform device from the node */
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rc = dlpar_attach_node(dn, pmem_node);
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if (rc) {
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pr_err("Failed to attach node %pOF, rc: %d, drc index: %x\n",
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dn, rc, drc_index);
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if (dlpar_release_drc(drc_index))
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dlpar_free_cc_nodes(dn);
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return rc;
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}
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pr_info("Successfully added %pOF, drc index: %x\n", dn, drc_index);
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return 0;
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}
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static ssize_t pmem_drc_remove_node(u32 drc_index)
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{
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struct device_node *dn;
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uint32_t index;
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int rc;
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for_each_child_of_node(pmem_node, dn) {
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if (of_property_read_u32(dn, "ibm,my-drc-index", &index))
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continue;
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if (index == drc_index)
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break;
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}
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if (!dn) {
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pr_err("Attempting to remove unused DRC index %x\n", drc_index);
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return -ENODEV;
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}
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pr_debug("Attempting to remove %pOF, drc index: %x\n", dn, drc_index);
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/* * NB: tears down the ibm,pmemory device as a side-effect */
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rc = dlpar_detach_node(dn);
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if (rc)
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return rc;
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rc = dlpar_release_drc(drc_index);
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if (rc) {
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pr_err("Failed to release drc (%x) for CPU %pOFn, rc: %d\n",
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drc_index, dn, rc);
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dlpar_attach_node(dn, pmem_node);
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return rc;
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}
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pr_info("Successfully removed PMEM with drc index: %x\n", drc_index);
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return 0;
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}
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int dlpar_hp_pmem(struct pseries_hp_errorlog *hp_elog)
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{
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u32 drc_index;
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int rc;
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/* slim chance, but we might get a hotplug event while booting */
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if (!pmem_node)
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pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory");
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if (!pmem_node) {
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pr_err("Hotplug event for a pmem device, but none exists\n");
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return -ENODEV;
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}
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if (hp_elog->id_type != PSERIES_HP_ELOG_ID_DRC_INDEX) {
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pr_err("Unsupported hotplug event type %d\n",
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hp_elog->id_type);
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return -EINVAL;
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}
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drc_index = hp_elog->_drc_u.drc_index;
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lock_device_hotplug();
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if (hp_elog->action == PSERIES_HP_ELOG_ACTION_ADD) {
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rc = pmem_drc_add_node(drc_index);
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} else if (hp_elog->action == PSERIES_HP_ELOG_ACTION_REMOVE) {
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rc = pmem_drc_remove_node(drc_index);
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} else {
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pr_err("Unsupported hotplug action (%d)\n", hp_elog->action);
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rc = -EINVAL;
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}
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unlock_device_hotplug();
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return rc;
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}
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static const struct of_device_id drc_pmem_match[] = {
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{ .type = "ibm,persistent-memory", },
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{}
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};
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static int pseries_pmem_init(void)
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{
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/*
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* Only supported on POWER8 and above.
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*/
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if (!cpu_has_feature(CPU_FTR_ARCH_207S))
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return 0;
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pmem_node = of_find_node_by_type(NULL, "ibm,persistent-memory");
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if (!pmem_node)
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return 0;
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/*
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* The generic OF bus probe/populate handles creating platform devices
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* from the child (ibm,pmemory) nodes. The generic code registers an of
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* reconfig notifier to handle the hot-add/remove cases too.
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*/
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of_platform_bus_probe(pmem_node, drc_pmem_match, NULL);
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return 0;
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}
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machine_arch_initcall(pseries, pseries_pmem_init);
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