[mirror_ubuntu-bionic-kernel.git] / drivers / xen / xen-acpi-pad.c

/*
 * xen-acpi-pad.c - Xen pad interface
 *
 * Copyright (c) 2012, Intel Corporation.
 *    Author: Liu, Jinsong <jinsong.liu@intel.com>
 *
 * 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.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/acpi.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);
Commit	Line	Data
92e3229d LJ	1	/*
	2	* xen-acpi-pad.c - Xen pad interface
	3	*
	4	* Copyright (c) 2012, Intel Corporation.
	5	* Author: Liu, Jinsong <jinsong.liu@intel.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms and conditions of the GNU General Public License,
	9	* version 2, as published by the Free Software Foundation.
	10	*
	11	* This program is distributed in the hope it will be useful, but WITHOUT
	12	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	13	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	14	* more details.
	15	*/
	16
283c0972 JP	17	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
283c0972 JP	18
92e3229d LJ	19	#include <linux/kernel.h>
92e3229d LJ	20	#include <linux/types.h>
8b48463f	21	#include <linux/acpi.h>
92e3229d	22	#include <xen/interface/version.h>
394b40f6	23	#include <xen/xen-ops.h>
8b48463f	24	#include <asm/xen/hypercall.h>
92e3229d LJ	25
	26	#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
	27	#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
	28	#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
	29	static DEFINE_MUTEX(xen_cpu_lock);
	30
	31	static int xen_acpi_pad_idle_cpus(unsigned int idle_nums)
	32	{
	33	struct xen_platform_op op;
	34
	35	op.cmd = XENPF_core_parking;
	36	op.u.core_parking.type = XEN_CORE_PARKING_SET;
	37	op.u.core_parking.idle_nums = idle_nums;
	38
cfafae94	39	return HYPERVISOR_platform_op(&op);
92e3229d LJ	40	}
	41
	42	static int xen_acpi_pad_idle_cpus_num(void)
	43	{
	44	struct xen_platform_op op;
	45
	46	op.cmd = XENPF_core_parking;
	47	op.u.core_parking.type = XEN_CORE_PARKING_GET;
	48
cfafae94	49	return HYPERVISOR_platform_op(&op)
92e3229d LJ	50	?: op.u.core_parking.idle_nums;
	51	}
	52
	53	/*
	54	* Query firmware how many CPUs should be idle
	55	* return -1 on failure
	56	*/
	57	static int acpi_pad_pur(acpi_handle handle)
	58	{
	59	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
	60	union acpi_object *package;
	61	int num = -1;
	62
	63	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
	64	return num;
	65
	66	if (!buffer.length \|\| !buffer.pointer)
	67	return num;
	68
	69	package = buffer.pointer;
	70
	71	if (package->type == ACPI_TYPE_PACKAGE &&
	72	package->package.count == 2 &&
	73	package->package.elements[0].integer.value == 1) /* rev 1 */
	74	num = package->package.elements[1].integer.value;
	75
	76	kfree(buffer.pointer);
	77	return num;
	78	}
	79
92e3229d LJ	80	static void acpi_pad_handle_notify(acpi_handle handle)
	81	{
	82	int idle_nums;
772c5399 JL	83	struct acpi_buffer param = {
	84	.length = 4,
	85	.pointer = (void *)&idle_nums,
	86	};
	87
92e3229d LJ	88
	89	mutex_lock(&xen_cpu_lock);
	90	idle_nums = acpi_pad_pur(handle);
	91	if (idle_nums < 0) {
	92	mutex_unlock(&xen_cpu_lock);
	93	return;
	94	}
	95
	96	idle_nums = xen_acpi_pad_idle_cpus(idle_nums)
	97	?: xen_acpi_pad_idle_cpus_num();
	98	if (idle_nums >= 0)
772c5399 JL	99	acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY,
772c5399 JL	100	0, &param);
92e3229d LJ	101	mutex_unlock(&xen_cpu_lock);
	102	}
	103
	104	static void acpi_pad_notify(acpi_handle handle, u32 event,
	105	void *data)
	106	{
	107	switch (event) {
	108	case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
	109	acpi_pad_handle_notify(handle);
	110	break;
	111	default:
	112	pr_warn("Unsupported event [0x%x]\n", event);
	113	break;
	114	}
	115	}
	116
	117	static int acpi_pad_add(struct acpi_device *device)
	118	{
	119	acpi_status status;
	120
	121	strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
	122	strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
	123
	124	status = acpi_install_notify_handler(device->handle,
	125	ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
	126	if (ACPI_FAILURE(status))
	127	return -ENODEV;
	128
	129	return 0;
	130	}
	131
51fac838	132	static int acpi_pad_remove(struct acpi_device *device)
92e3229d LJ	133	{
	134	mutex_lock(&xen_cpu_lock);
	135	xen_acpi_pad_idle_cpus(0);
	136	mutex_unlock(&xen_cpu_lock);
	137
	138	acpi_remove_notify_handler(device->handle,
	139	ACPI_DEVICE_NOTIFY, acpi_pad_notify);
	140	return 0;
	141	}
	142
	143	static const struct acpi_device_id pad_device_ids[] = {
	144	{"ACPI000C", 0},
	145	{"", 0},
	146	};
	147
	148	static struct acpi_driver acpi_pad_driver = {
	149	.name = "processor_aggregator",
	150	.class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
	151	.ids = pad_device_ids,
	152	.ops = {
	153	.add = acpi_pad_add,
	154	.remove = acpi_pad_remove,
	155	},
	156	};
	157
	158	static int __init xen_acpi_pad_init(void)
	159	{
	160	/* Only DOM0 is responsible for Xen acpi pad */
	161	if (!xen_initial_domain())
	162	return -ENODEV;
	163
	164	/* Only Xen4.2 or later support Xen acpi pad */
	165	if (!xen_running_on_version_or_later(4, 2))
	166	return -ENODEV;
	167
	168	return acpi_bus_register_driver(&acpi_pad_driver);
	169	}
	170	subsys_initcall(xen_acpi_pad_init);