linux/drivers/xen/xen-acpi-pad.c
Thomas Gleixner 2025cf9e19 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms and conditions of the gnu general public license
  version 2 as published by the free software foundation this program
  is distributed in the hope it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 263 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:36:37 +02:00

164 lines
3.7 KiB
C

// 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, &param);
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);