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Date:   Sun, 20 Feb 2022 22:34:03 +0800
From:   Huang Rui <ray.huang@amd.com>
To:     Shuah Khan <skhan@linuxfoundation.org>
Cc:     "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
        "Sharma, Deepak" <Deepak.Sharma@amd.com>,
        "Deucher, Alexander" <Alexander.Deucher@amd.com>,
        "Limonciello, Mario" <Mario.Limonciello@amd.com>,
        Steven Noonan <steven@valvesoftware.com>,
        "Fontenot, Nathan" <Nathan.Fontenot@amd.com>,
        "Su, Jinzhou (Joe)" <Jinzhou.Su@amd.com>,
        "Du, Xiaojian" <Xiaojian.Du@amd.com>,
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        "Meng, Li (Jassmine)" <Li.Meng@amd.com>,
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        Ingo Molnar <mingo@kernel.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Giovanni Gherdovich <ggherdovich@suse.cz>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RESEND v6 5/9] cpupower: Introduce ACPI CPPC library
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On Sat, Feb 19, 2022 at 07:53:52AM +0800, Shuah Khan wrote:
> On 2/16/22 12:35 AM, Huang Rui wrote:
> > Kernel ACPI subsytem introduced the sysfs attributes for acpi cppc
> > library in below path:
> > 
> > /sys/devices/system/cpu/cpuX/acpi_cppc/
> > 
> > And these attributes will be used for AMD P-State driver to provide some
> > performance and frequency values.
> > 
> > Signed-off-by: Huang Rui <ray.huang@amd.com>
> > ---
> >   tools/power/cpupower/Makefile        |  6 +--
> >   tools/power/cpupower/lib/acpi_cppc.c | 59 ++++++++++++++++++++++++++++
> >   tools/power/cpupower/lib/acpi_cppc.h | 21 ++++++++++
> >   3 files changed, 83 insertions(+), 3 deletions(-)
> >   create mode 100644 tools/power/cpupower/lib/acpi_cppc.c
> >   create mode 100644 tools/power/cpupower/lib/acpi_cppc.h
> > 
> > diff --git a/tools/power/cpupower/Makefile b/tools/power/cpupower/Makefile
> > index 3b1594447f29..e9b6de314654 100644
> > --- a/tools/power/cpupower/Makefile
> > +++ b/tools/power/cpupower/Makefile
> > @@ -143,9 +143,9 @@ UTIL_HEADERS = utils/helpers/helpers.h utils/idle_monitor/cpupower-monitor.h \
> >   	utils/helpers/bitmask.h \
> >   	utils/idle_monitor/idle_monitors.h utils/idle_monitor/idle_monitors.def
> >   
> > -LIB_HEADERS = 	lib/cpufreq.h lib/cpupower.h lib/cpuidle.h
> > -LIB_SRC = 	lib/cpufreq.c lib/cpupower.c lib/cpuidle.c
> > -LIB_OBJS = 	lib/cpufreq.o lib/cpupower.o lib/cpuidle.o
> > +LIB_HEADERS = 	lib/cpufreq.h lib/cpupower.h lib/cpuidle.h lib/acpi_cppc.h
> > +LIB_SRC = 	lib/cpufreq.c lib/cpupower.c lib/cpuidle.c lib/acpi_cppc.c
> > +LIB_OBJS = 	lib/cpufreq.o lib/cpupower.o lib/cpuidle.o lib/acpi_cppc.o
> >   LIB_OBJS :=	$(addprefix $(OUTPUT),$(LIB_OBJS))
> >   
> >   override CFLAGS +=	-pipe
> > diff --git a/tools/power/cpupower/lib/acpi_cppc.c b/tools/power/cpupower/lib/acpi_cppc.c
> > new file mode 100644
> > index 000000000000..a07a8922eca2
> > --- /dev/null
> > +++ b/tools/power/cpupower/lib/acpi_cppc.c
> > @@ -0,0 +1,59 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +#include <stdio.h>
> > +#include <errno.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +#include <sys/types.h>
> > +#include <sys/stat.h>
> > +#include <fcntl.h>
> > +#include <unistd.h>
> > +
> > +#include "cpupower_intern.h"
> > +#include "acpi_cppc.h"
> > +
> > +/* ACPI CPPC sysfs access ***********************************************/
> > +
> > +static int acpi_cppc_read_file(unsigned int cpu, const char *fname,
> > +			       char *buf, size_t buflen)
> > +{
> > +	char path[SYSFS_PATH_MAX];
> > +
> > +	snprintf(path, sizeof(path), PATH_TO_CPU "cpu%u/acpi_cppc/%s",
> > +		 cpu, fname);
> > +	return cpupower_read_sysfs(path, buf, buflen);
> > +}
> > +
> > +static const char *acpi_cppc_value_files[] = {
> > +	[HIGHEST_PERF] = "highest_perf",
> > +	[LOWEST_PERF] = "lowest_perf",
> > +	[NOMINAL_PERF] = "nominal_perf",
> > +	[LOWEST_NONLINEAR_PERF] = "lowest_nonlinear_perf",
> > +	[LOWEST_FREQ] = "lowest_freq",
> > +	[NOMINAL_FREQ] = "nominal_freq",
> > +	[REFERENCE_PERF] = "reference_perf",
> > +	[WRAPAROUND_TIME] = "wraparound_time"
> > +};
> > +
> > +unsigned long acpi_cppc_get_data(unsigned cpu, enum acpi_cppc_value which)
> 
> unsigned int cpu
> 
> > +{
> > +	unsigned long long value;
> > +	unsigned int len;
> > +	char linebuf[MAX_LINE_LEN];
> > +	char *endp;
> > +
> > +	if (which >= MAX_CPPC_VALUE_FILES)
> > +		return 0;
> > +
> > +	len = acpi_cppc_read_file(cpu, acpi_cppc_value_files[which],
> > +				  linebuf, sizeof(linebuf));
> > +	if (len == 0)
> > +		return 0;
> > +
> > +	value = strtoull(linebuf, &endp, 0);
> > +
> > +	if (endp == linebuf || errno == ERANGE)
> > +		return 0;
> > +
> > +	return value;
> > +}
> > diff --git a/tools/power/cpupower/lib/acpi_cppc.h b/tools/power/cpupower/lib/acpi_cppc.h
> > new file mode 100644
> > index 000000000000..576291155224
> > --- /dev/null
> > +++ b/tools/power/cpupower/lib/acpi_cppc.h
> > @@ -0,0 +1,21 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +
> > +#ifndef __ACPI_CPPC_H__
> > +#define __ACPI_CPPC_H__
> > +
> > +enum acpi_cppc_value {
> > +	HIGHEST_PERF,
> > +	LOWEST_PERF,
> > +	NOMINAL_PERF,
> > +	LOWEST_NONLINEAR_PERF,
> > +	LOWEST_FREQ,
> > +	NOMINAL_FREQ,
> > +	REFERENCE_PERF,
> > +	WRAPAROUND_TIME,
> > +	MAX_CPPC_VALUE_FILES
> > +};
> > +
> > +extern unsigned long acpi_cppc_get_data(unsigned cpu,
> 
> extern prototype in .h?

Will remove "extern" in .h file.

Thanks,
Ray