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SubjectRE: [PATCH 3/3] Xen pad logic and notification
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Konrad Rzeszutek Wilk wrote:
> On Fri, Feb 17, 2012 at 08:58:38AM +0000, Liu, Jinsong wrote:
>>> From fee39804d2634dfba7b369dc82dac19b57400f84 Mon Sep 17 00:00:00
>>> 2001
>> From: Liu, Jinsong <jinsong.liu@intel.com>
>> Date: Sat, 18 Feb 2012 00:46:29 +0800
>> Subject: [PATCH 3/3] Xen pad logic and notification
>>
>> This patch implement Xen pad logic, and when getting pad device
>> notification, it hypercalls to Xen hypervisor for core parking.
>
> CC-ing linux-acpi@vger.kernel.org and Len Brown.
>
>>
>> Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com> ---
>> drivers/xen/xen_acpi_pad.c | 189
>> ++++++++++++++++++++++++++++++++++++++
>> include/xen/interface/platform.h | 14 +++ 2 files changed, 203
>> insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/xen/xen_acpi_pad.c b/drivers/xen/xen_acpi_pad.c
>> index 63ab2fb..ba66d51 100644
>> --- a/drivers/xen/xen_acpi_pad.c
>> +++ b/drivers/xen/xen_acpi_pad.c
>> @@ -1,8 +1,197 @@
>> +/*
>> + * 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. + */
>> +
>> +#include <linux/kernel.h>
>> +#include <linux/types.h>
>> +#include <acpi/acpi_bus.h>
>> +#include <acpi/acpi_drivers.h>
>> +
>> +#include <asm/xen/hypercall.h>
>> +
>> +#define ACPI_PROCESSOR_AGGREGATOR_CLASS "xen_acpi_pad"
>> +#define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Xen Processor
>> Aggregator" +#define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
>> +static DEFINE_MUTEX(xen_cpu_lock);
>> +
>> +static int xen_acpi_pad_idle_cpus(int *num_cpus)
>> +{
>> + int ret;
>> +
>> + struct xen_platform_op op = {
>> + .cmd = XENPF_core_parking,
>> + .interface_version = XENPF_INTERFACE_VERSION,
>> + };
>> +
>> + /* set cpu nums expected to be idled */
>> + op.u.core_parking.type = XEN_CORE_PARKING_SET;
>> + op.u.core_parking.idle_nums = (uint32_t)*num_cpus;
>> + ret = HYPERVISOR_dom0_op(&op);
>> + if (ret)
>> + return ret;
>> +
>> + /*
>> + * get cpu nums actually be idled
>> + * cannot get it by using hypercall once (shared with _SET)
>> + * because of the characteristic of Xen continue_hypercall_on_cpu
>> + */ + op.u.core_parking.type = XEN_CORE_PARKING_GET;
>> + ret = HYPERVISOR_dom0_op(&op);
>> + if (ret)
>> + return ret;
>> +
>> + *num_cpus = op.u.core_parking.idle_nums;
>> + return 0;
>> +}
>> +
>> +/*
>> + * Query firmware how many CPUs should be idle
>> + * return -1 on failure
>> + */
>> +static int xen_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;
>> +}
>> +
>> +/* Notify firmware how many CPUs are idle */
>> +static void xen_acpi_pad_ost(acpi_handle handle, int stat,
>> + uint32_t idle_cpus) +{
>> + union acpi_object params[3] = {
>> + {.type = ACPI_TYPE_INTEGER,},
>> + {.type = ACPI_TYPE_INTEGER,},
>> + {.type = ACPI_TYPE_BUFFER,},
>> + };
>> + struct acpi_object_list arg_list = {3, params};
>> +
>> + params[0].integer.value = ACPI_PROCESSOR_AGGREGATOR_NOTIFY;
>> + params[1].integer.value = stat;
>> + params[2].buffer.length = 4;
>> + params[2].buffer.pointer = (void *)&idle_cpus;
>> + acpi_evaluate_object(handle, "_OST", &arg_list, NULL); +}
>> +
>> +static void xen_acpi_pad_handle_notify(acpi_handle handle) +{
>> + int ret, num_cpus;
>> +
>> + mutex_lock(&xen_cpu_lock);
>> + num_cpus = xen_acpi_pad_pur(handle);
>> + if (num_cpus < 0) {
>> + mutex_unlock(&xen_cpu_lock);
>> + return;
>> + }
>> +
>> + ret = xen_acpi_pad_idle_cpus(&num_cpus);
>> + if (ret) {
>> + mutex_unlock(&xen_cpu_lock);
>> + return;
>> + }
>> +
>> + xen_acpi_pad_ost(handle, 0, num_cpus);
>> + mutex_unlock(&xen_cpu_lock);
>> +}
>> +
>> +static void xen_acpi_pad_notify(acpi_handle handle, u32 event,
>> + void *data) +{
>> + switch (event) {
>> + case ACPI_PROCESSOR_AGGREGATOR_NOTIFY:
>> + xen_acpi_pad_handle_notify(handle);
>> + break;
>> + default:
>> + printk(KERN_WARNING "Unsupported event [0x%x]\n", event);
>> + break; + }
>> +}
>> +
>> +static int xen_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,
>> xen_acpi_pad_notify, device); + if (ACPI_FAILURE(status)) + return
>> -ENODEV; + + return 0;
>> +}
>> +
>> +static int xen_acpi_pad_remove(struct acpi_device *device, + int
>> type) +{
>> + int num_cpus = 0;
>> +
>> + mutex_lock(&xen_cpu_lock);
>> + xen_acpi_pad_idle_cpus(&num_cpus);
>> + mutex_unlock(&xen_cpu_lock);
>> +
>> + acpi_remove_notify_handler(device->handle,
>> + ACPI_DEVICE_NOTIFY, xen_acpi_pad_notify);
>> + return 0;
>> +}
>> +
>> +static const struct acpi_device_id xen_pad_device_ids[] = {
>> + {"ACPI000C", 0}, + {"", 0},
>> +};
>> +
>> +static struct acpi_driver xen_acpi_pad_driver = {
>> + .name = "xen_processor_aggregator",
>> + .class = ACPI_PROCESSOR_AGGREGATOR_CLASS,
>> + .ids = xen_pad_device_ids,
>> + .ops = {
>> + .add = xen_acpi_pad_add,
>> + .remove = xen_acpi_pad_remove,
>> + },
>> +};
>> +
>> int xen_acpi_pad_init(void)
>> {
>> +#ifdef CONFIG_ACPI_PROCESSOR_AGGREGATOR
>
> How does that work when the the driver is booted under baremetal?
> Won't it kick out the native ACPI_PROCESSOR_AGGREGATOR_CLASS
> (acpi_pad.c) ?
>
> What about if the other ACPI_PROCESSOR_AGGREGATOR_CLASS gets called
> first? Won't this fail?
>
> Or is the acpi_bus_register_driver smart enough to process more than
> one ACPI bus device?

When driver booted under baremetal, xen_acpi_pad.c would be disabled and native acpi_pad.c logic would work.

Thanks,
Jinsong

>
>> + return acpi_bus_register_driver(&xen_acpi_pad_driver); +#else
>> return 0;
>> +#endif
>> }
>>
>> void xen_acpi_pad_exit(void)
>> {
>> +#ifdef CONFIG_ACPI_PROCESSOR_AGGREGATOR
>> + acpi_bus_unregister_driver(&xen_acpi_pad_driver); +#endif
>> }
>> diff --git a/include/xen/interface/platform.h
>> b/include/xen/interface/platform.h index c168468..56ec72a 100644 ---
>> a/include/xen/interface/platform.h +++
>> b/include/xen/interface/platform.h @@ -297,6 +297,19 @@ struct
>> xenpf_set_processor_pminfo { };
>> DEFINE_GUEST_HANDLE_STRUCT(xenpf_set_processor_pminfo);
>>
>> +#define XENPF_core_parking 60
>> +
>> +#define XEN_CORE_PARKING_SET 1
>> +#define XEN_CORE_PARKING_GET 2
>> +struct xenpf_core_parking {
>> + /* IN variables */
>> + uint32_t type;
>> + /* IN variables: set cpu nums expected to be idled */
>> + /* OUT variables: get cpu nums actually be idled */ + uint32_t
>> idle_nums; +};
>> +DEFINE_GUEST_HANDLE_STRUCT(xenpf_core_parking);
>> +
>> struct xen_platform_op {
>> uint32_t cmd;
>> uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
>> @@ -312,6 +325,7 @@ struct xen_platform_op {
>> struct xenpf_change_freq change_freq;
>> struct xenpf_getidletime getidletime;
>> struct xenpf_set_processor_pminfo set_pminfo;
>> + struct xenpf_core_parking core_parking;
>> uint8_t pad[128];
>> } u;
>> };
>> --
>> 1.7.1



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