linux-kernel - Re: [PATCH] ACPI / LPIT: Add Low Power Idle Table (LPIT) support

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Message-ID: <1507163979.53049.122.camel@linux.intel.com>
Date:   Wed, 04 Oct 2017 17:39:39 -0700
From:   Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>, Lv <lv.zheng@...el.com>,
        Len Brown <lenb@...nel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI / LPIT: Add Low Power Idle Table (LPIT) support

On Thu, 2017-10-05 at 02:10 +0200, Rafael J. Wysocki wrote:
> On Thu, Oct 5, 2017 at 1:43 AM, Srinivas Pandruvada
> <srinivas.pandruvada@...ux.intel.com> wrote:
> > 
> > Added functionality to read LPIT table, which provides:
> > 
> > - Sysfs interface to read residency counters via
> > /sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
> > /sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
> > 
> > 

[...]

> > +int lpit_read_residency_count_address(u64 *address)
> > +{
> > +       if (!residency_info_mem.gaddr.address)
> > +               return -EINVAL;
> > +
> > +       *address = residency_info_mem.gaddr.address;
> > +
> > +       return 0;
> > +}
> 
> I don't see users of this.  Are there any?
The user will be pmc_core_driver which will go through platform x86
drivers tree. Also some mei drivers will also need.


[...]

> > 
> > --- /dev/null+++ b/include/acpi/acpi_lpit.h
> > @@ -0,0 +1,34 @@
> > +/*
> > + * acpi_lpit.h - LPIT table processing functions interface
> > + *
> > + * Copyright (C) 2017 Intel Corporation. All rights reserved.
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > version
> > + * 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that 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.
> > + */
> > +
> > +#ifndef ACPI_LPIT_H
> > +#define ACPI_LPIT_H
> > +
> > +#ifdef CONFIG_ACPI_LPIT
> > +
> > +void acpi_init_lpit(void);
> > +int lpit_read_residency_count_address(u64 *address);
> > +
> > +#else
> > +
> > +static inline void acpi_init_lpit(void) { }
> > +
> > +static inline int lpit_read_residency_count_address(u64 *address)
> > +{
> > +       return -EINVAL;
> > +}
> > +
> > +#endif
> > +#endif
> 
> The above can go into internal.h or sleep.h in drivers/acpi/ IMO.
> There's not need to export it.
The pmc core driver is in drivers/platform/x86. Do you want to include
a local file from there?


Thanks,
Srinivas