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// 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/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"
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 %pOF, rc: %d, drc index: %x\n",
dn, 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 %pOFn, rc: %d\n",
drc_index, dn, 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 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;
}
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;
}
static const struct of_device_id drc_pmem_match[] = {
{ .type = "ibm,persistent-memory", },
{}
};
static int pseries_pmem_init(void)
{
/*
* Only supported on POWER8 and above.
*/
if (!cpu_has_feature(CPU_FTR_ARCH_207S))
return 0;
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);
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