[linux-block.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/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);
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>
3cfa210b	22	#include <xen/xen.h>
92e3229d	23	#include <xen/interface/version.h>
394b40f6	24	#include <xen/xen-ops.h>
8b48463f	25	#include <asm/xen/hypercall.h>
92e3229d LJ	26
	27	#define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
	28	#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
	29	#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
	30	static DEFINE_MUTEX(xen_cpu_lock);
	31
	32	static int xen_acpi_pad_idle_cpus(unsigned int idle_nums)
	33	{
	34	struct xen_platform_op op;
	35
	36	op.cmd = XENPF_core_parking;
	37	op.u.core_parking.type = XEN_CORE_PARKING_SET;
	38	op.u.core_parking.idle_nums = idle_nums;
	39
cfafae94	40	return HYPERVISOR_platform_op(&op);
92e3229d LJ	41	}
	42
	43	static int xen_acpi_pad_idle_cpus_num(void)
	44	{
	45	struct xen_platform_op op;
	46
	47	op.cmd = XENPF_core_parking;
	48	op.u.core_parking.type = XEN_CORE_PARKING_GET;
	49
cfafae94	50	return HYPERVISOR_platform_op(&op)
92e3229d LJ	51	?: op.u.core_parking.idle_nums;
	52	}
	53
	54	/*
	55	* Query firmware how many CPUs should be idle
	56	* return -1 on failure
	57	*/
	58	static int acpi_pad_pur(acpi_handle handle)
	59	{
	60	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
	61	union acpi_object *package;
	62	int num = -1;
	63
	64	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_PUR", NULL, &buffer)))
	65	return num;
	66
	67	if (!buffer.length \|\| !buffer.pointer)
	68	return num;
	69
	70	package = buffer.pointer;
	71
	72	if (package->type == ACPI_TYPE_PACKAGE &&
	73	package->package.count == 2 &&
	74	package->package.elements[0].integer.value == 1) /* rev 1 */
	75	num = package->package.elements[1].integer.value;
	76
	77	kfree(buffer.pointer);
	78	return num;
	79	}
	80
92e3229d LJ	81	static void acpi_pad_handle_notify(acpi_handle handle)
	82	{
	83	int idle_nums;
772c5399 JL	84	struct acpi_buffer param = {
	85	.length = 4,
	86	.pointer = (void *)&idle_nums,
	87	};
	88
92e3229d LJ	89
	90	mutex_lock(&xen_cpu_lock);
	91	idle_nums = acpi_pad_pur(handle);
	92	if (idle_nums < 0) {
	93	mutex_unlock(&xen_cpu_lock);
	94	return;
	95	}
	96
	97	idle_nums = xen_acpi_pad_idle_cpus(idle_nums)
	98	?: xen_acpi_pad_idle_cpus_num();
	99	if (idle_nums >= 0)
772c5399 JL	100	acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY,
772c5399 JL	101	0, &param);
92e3229d LJ	102	mutex_unlock(&xen_cpu_lock);
	103	}
	104
	105	static void acpi_pad_notify(acpi_handle handle, u32 event,
	106	void *data)
	107	{
	108	switch (event) {
	109	case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
	110	acpi_pad_handle_notify(handle);
	111	break;
	112	default:
	113	pr_warn("Unsupported event [0x%x]\n", event);
	114	break;
	115	}
	116	}
	117
	118	static int acpi_pad_add(struct acpi_device *device)
	119	{
	120	acpi_status status;
	121
	122	strcpy(acpi_device_name(device), ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME);
	123	strcpy(acpi_device_class(device), ACPI_PROCESSOR_AGGREGATOR_CLASS);
	124
	125	status = acpi_install_notify_handler(device->handle,
	126	ACPI_DEVICE_NOTIFY, acpi_pad_notify, device);
	127	if (ACPI_FAILURE(status))
	128	return -ENODEV;
	129
	130	return 0;
	131	}
	132
51fac838	133	static int acpi_pad_remove(struct acpi_device *device)
92e3229d LJ	134	{
	135	mutex_lock(&xen_cpu_lock);
	136	xen_acpi_pad_idle_cpus(0);
	137	mutex_unlock(&xen_cpu_lock);
	138
	139	acpi_remove_notify_handler(device->handle,
	140	ACPI_DEVICE_NOTIFY, acpi_pad_notify);
	141	return 0;
	142	}
	143
	144	static const struct acpi_device_id pad_device_ids[] = {
	145	{"ACPI000C", 0},
	146	{"", 0},
	147	};
	148
	149	static struct acpi_driver acpi_pad_driver = {
	150	.name = "processor_aggregator",
	151	.class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
	152	.ids = pad_device_ids,
	153	.ops = {
	154	.add = acpi_pad_add,
	155	.remove = acpi_pad_remove,
	156	},
	157	};
	158
	159	static int __init xen_acpi_pad_init(void)
	160	{
	161	/* Only DOM0 is responsible for Xen acpi pad */
	162	if (!xen_initial_domain())
	163	return -ENODEV;
	164
	165	/* Only Xen4.2 or later support Xen acpi pad */
	166	if (!xen_running_on_version_or_later(4, 2))
	167	return -ENODEV;
	168
	169	return acpi_bus_register_driver(&acpi_pad_driver);
	170	}
	171	subsys_initcall(xen_acpi_pad_init);