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