diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/pmem.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/pmem.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/pmem.c b/arch/powerpc/platforms/pseries/pmem.c new file mode 100644 index 000000000..3c290b9ed --- /dev/null +++ b/arch/powerpc/platforms/pseries/pmem.c @@ -0,0 +1,167 @@ +// 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); |