163 lines
3.7 KiB
C
163 lines
3.7 KiB
C
// 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 <jinsong.liu@intel.com>
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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 void 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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}
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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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