diff options
Diffstat (limited to 'drivers/xen/xen-acpi-pad.c')
| -rw-r--r-- | drivers/xen/xen-acpi-pad.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/xen/xen-acpi-pad.c b/drivers/xen/xen-acpi-pad.c new file mode 100644 index 000000000..ccd801202 --- /dev/null +++ b/drivers/xen/xen-acpi-pad.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * xen-acpi-pad.c - Xen pad interface + * + * Copyright (c) 2012, Intel Corporation. + * Author: Liu, Jinsong <jinsong.liu@intel.com> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/acpi.h> +#include <xen/xen.h> +#include <xen/interface/version.h> +#include <xen/xen-ops.h> +#include <asm/xen/hypercall.h> + +#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad" +#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator" +#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80 +static DEFINE_MUTEX(xen_cpu_lock); + +static int xen_acpi_pad_idle_cpus(unsigned int idle_nums) +{ + struct xen_platform_op op; + + op.cmd = XENPF_core_parking; + op.u.core_parking.type = XEN_CORE_PARKING_SET; + op.u.core_parking.idle_nums = idle_nums; + + return HYPERVISOR_platform_op(&op); +} + +static int xen_acpi_pad_idle_cpus_num(void) +{ + struct xen_platform_op op; + + op.cmd = XENPF_core_parking; + op.u.core_parking.type = XEN_CORE_PARKING_GET; + + return HYPERVISOR_platform_op(&op) + ?: op.u.core_parking.idle_nums; +} + +/* + * Query firmware how many CPUs should be idle + * return -1 on failure + */ +static int acpi_pad_pur(acpi_handle handle) +{ + struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL}; + union acpi_object *package; + int num = -1; + + if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer))) + return num; + + if (!buffer.length || !buffer.pointer) + return num; + + package = buffer.pointer; + + if (package->type == ACPI_TYPE_PACKAGE && + package->package.count == 2 && + package->package.elements[0].integer.value == 1) /* rev 1 */ + num = package->package.elements[1].integer.value; + + kfree(buffer.pointer); + return num; +} + +static void acpi_pad_handle_notify(acpi_handle handle) +{ + int idle_nums; + struct acpi_buffer param = { + .length = 4, + .pointer = (void *)&idle_nums, + }; + + + mutex_lock(&xen_cpu_lock); + idle_nums = acpi_pad_pur(handle); + if (idle_nums < 0) { + mutex_unlock(&xen_cpu_lock); + return; + } + + idle_nums = xen_acpi_pad_idle_cpus(idle_nums) + ?: xen_acpi_pad_idle_cpus_num(); + if (idle_nums >= 0) + acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY, + 0, ¶m); + mutex_unlock(&xen_cpu_lock); +} + +static void acpi_pad_notify(acpi_handle handle, u32 event, + void *data) +{ + switch (event) { + case ACPI_PROCESSOR_AGGREGATOR_NOTIFY: + acpi_pad_handle_notify(handle); + break; + default: + pr_warn("Unsupported event [0x%x]\n", event); + break; + } +} + +static int acpi_pad_add(struct acpi_device *device) +{ + acpi_status status; + + strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME); + strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS); + + status = acpi_install_notify_handler(device->handle, + ACPI_DEVICE_NOTIFY, acpi_pad_notify, device); + if (ACPI_FAILURE(status)) + return -ENODEV; + + return 0; +} + +static int acpi_pad_remove(struct acpi_device *device) +{ + mutex_lock(&xen_cpu_lock); + xen_acpi_pad_idle_cpus(0); + mutex_unlock(&xen_cpu_lock); + + acpi_remove_notify_handler(device->handle, + ACPI_DEVICE_NOTIFY, acpi_pad_notify); + return 0; +} + +static const struct acpi_device_id pad_device_ids[] = { + {"ACPI000C", 0}, + {"", 0}, +}; + +static struct acpi_driver acpi_pad_driver = { + .name = "processor_aggregator", + .class = ACPI_PROCESSOR_AGGREGATOR_CLASS, + .ids = pad_device_ids, + .ops = { + .add = acpi_pad_add, + .remove = acpi_pad_remove, + }, +}; + +static int __init xen_acpi_pad_init(void) +{ + /* Only DOM0 is responsible for Xen acpi pad */ + if (!xen_initial_domain()) + return -ENODEV; + + /* Only Xen4.2 or later support Xen acpi pad */ + if (!xen_running_on_version_or_later(4, 2)) + return -ENODEV; + + return acpi_bus_register_driver(&acpi_pad_driver); +} +subsys_initcall(xen_acpi_pad_init); |