Re: [PATCH 1/3] hwmon: Add amd_energy driver to report energy counters

[Naveen Krishna Ch <naveenkrishna.ch@gmail.com>]

Hi Guenter

On Wed, 6 May 2020 at 21:54, Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Fri, May 01, 2020 at 11:20:01PM +0530, Naveen Krishna Chatradhi wrote:
> > This patch adds hwmon based amd_energy driver support for
> > family 17h processors from AMD.
> >
> > The driver provides following interface to the userspace
> > 1. Reports the per core consumption
> >       * file: "energy%d_input", label: "Ecore%03d"
> > 2. Reports per socket energy consumption
> >       * file: "energy%d_input", label: "Esocket%d"
> > 3. To, increase the wrap around time of the socket energy
> >    counters, a 64bit accumultor is implemented.
> > 4. Reports scaled energy value in Joules.
> >
> > Cc: Guenter Roeck <linux@roeck-us.net>
> > Signed-off-by: Naveen Krishna Chatradhi <nchatrad@amd.com>
> > ---
> > Changes in v5:
> > 1. To improve wrap around time. A kernel thread is implemented
> >    to accumulate the socket energy counters into a 64bit.
> > 2. Address other comments from Guenter.
> >
> >  drivers/hwmon/Kconfig      |  10 ++
> >  drivers/hwmon/Makefile     |   1 +
> >  drivers/hwmon/amd_energy.c | 329 +++++++++++++++++++++++++++++++++++++
> >  3 files changed, 340 insertions(+)
> >  create mode 100644 drivers/hwmon/amd_energy.c
> >
> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > index 4c62f900bf7e..e165e10c49ef 100644
> > --- a/drivers/hwmon/Kconfig
> > +++ b/drivers/hwmon/Kconfig
> > @@ -324,6 +324,16 @@ config SENSORS_FAM15H_POWER
> >         This driver can also be built as a module. If so, the module
> >         will be called fam15h_power.
> >
> > +config SENSORS_AMD_ENERGY
> > +     tristate "AMD RAPL MSR based Energy driver"
> > +     depends on X86
> > +     help
> > +       If you say yes here you get support for core and package energy
> > +       sensors, based on RAPL MSR for AMD family 17h and above CPUs.
> > +
> > +       This driver can also be built as a module. If so, the module
> > +       will be called as amd_energy.
> > +
> >  config SENSORS_APPLESMC
> >       tristate "Apple SMC (Motion sensor, light sensor, keyboard backlight)"
> >       depends on INPUT && X86
> > diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> > index b0b9c8e57176..318f89dc7133 100644
> > --- a/drivers/hwmon/Makefile
> > +++ b/drivers/hwmon/Makefile
> > @@ -45,6 +45,7 @@ obj-$(CONFIG_SENSORS_ADT7411)       += adt7411.o
> >  obj-$(CONFIG_SENSORS_ADT7462)        += adt7462.o
> >  obj-$(CONFIG_SENSORS_ADT7470)        += adt7470.o
> >  obj-$(CONFIG_SENSORS_ADT7475)        += adt7475.o
> > +obj-$(CONFIG_SENSORS_AMD_ENERGY) += amd_energy.o
> >  obj-$(CONFIG_SENSORS_APPLESMC)       += applesmc.o
> >  obj-$(CONFIG_SENSORS_ARM_SCMI)       += scmi-hwmon.o
> >  obj-$(CONFIG_SENSORS_ARM_SCPI)       += scpi-hwmon.o
> > diff --git a/drivers/hwmon/amd_energy.c b/drivers/hwmon/amd_energy.c
> > new file mode 100644
> > index 000000000000..16364576f067
> > --- /dev/null
> > +++ b/drivers/hwmon/amd_energy.c
> > @@ -0,0 +1,329 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +/*
> > + * Copyright (C) 2020 Advanced Micro Devices, Inc.
> > + */
> > +#include <asm/cpu_device_id.h>
> > +
> > +#include <linux/bits.h>
> > +#include <linux/cpu.h>
> > +#include <linux/cpumask.h>
> > +#include <linux/device.h>
> > +#include <linux/hwmon.h>
> > +#include <linux/kernel.h>
> > +#include <linux/kthread.h>
> > +#include <linux/list.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/processor.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +#include <linux/types.h>
> > +
> > +#define DRVNAME                      "amd_energy"
> > +
> > +#define ENERGY_PWR_UNIT_MSR  0xC0010299
> > +#define ENERGY_CORE_MSR              0xC001029A
> > +#define ENERGY_PKG_MSR               0xC001029B
> > +
> > +#define AMD_ENERGY_UNIT_MASK 0x01F00
> > +
> > +struct amd_energy_data {
> > +     struct hwmon_channel_info energy_info;
> > +     const struct hwmon_channel_info *info[2];
> > +     struct hwmon_chip_info chip;
> > +     /* Lock around the accumulator */
> > +     struct mutex lock;
> > +     /* Energy Status Units */
> > +     u64 energy_units;
> > +     /* An accumulator for each socket */
> > +     u64 *energy_ctrs;
> > +     u64 *prev_value;
> > +};
> > +
> > +/* */
> > +struct task_struct *wrap_accumulate;
>
> declare as static
>
> > +static int nr_cpus, nr_socks;
> > +
> > +static int amd_energy_read_labels(struct device *dev,
> > +                               enum hwmon_sensor_types type,
> > +                              u32 attr, int channel,
> > +                              const char **str)
>
> indentation is off here.
>
> > +{
> > +     char *buf = devm_kcalloc(dev, 10, sizeof(char), GFP_KERNEL);
> > +
>
> This allocates 10 bytes each time the function is called, ie each time
> the "sensors" command is executed (or, more specifically, each time
> the sysfs attribute is read).
>
> On a side note, using devm_kcalloc() to allocate a string is really
> not necessary / useful.
>
> > +     if (channel >= nr_cpus)
> > +             scnprintf(buf, 9, "Esocket%u", channel - nr_cpus);
> > +     else
> > +             scnprintf(buf, 9, "Ecore%03u", channel);
>
> For scnprintf(), the length parameter includes the trailing '\0'.
> So it is safe to pass 10 as length here.
>
> > +
> > +     *str = buf;
> > +
> > +     return 0;
> > +}
> > +
> > +static int get_energy_units(struct amd_energy_data *data)
> > +{
> > +     u64 rapl_units;
> > +     int ret;
> > +
> > +     ret = rdmsrl_safe(ENERGY_PWR_UNIT_MSR, &rapl_units);
> > +     if (ret)
> > +             return ret;
> > +
> > +     data->energy_units = (rapl_units & AMD_ENERGY_UNIT_MASK) >> 8;
> > +     return 0;
> > +}
> > +
> > +static int read_accumulate(struct amd_energy_data *data)
> > +{
> > +     int ret, cu;
> > +     u64 input = 0;
> > +
> > +     for (cu = 0; cu < nr_socks; cu++) {
> > +             int cpu;
> > +
> > +             cpu = cpumask_first_and(cpu_online_mask,
> > +                                     cpumask_of_node(cu));
> > +
> > +             ret = rdmsrl_safe_on_cpu(cpu, ENERGY_PKG_MSR, &input);
> > +             if (ret)
> > +                     return ret;
> > +
> > +             if (input > data->prev_value[cu])
> > +                     data->energy_ctrs[cu] +=
> > +                             input - data->prev_value[cu];
> > +             else
> > +                     data->energy_ctrs[cu] +=
> > +                             UINT_MAX - data->prev_value[cu] + input;
> > +
> > +             data->prev_value[cu] = input;
> > +     }
> > +             return 0;
> > +}
> > +
> > +static int amd_energy_read(struct device *dev,
> > +                        enum hwmon_sensor_types type,
> > +                        u32 attr, int channel, long *val)
> > +{
> > +     struct amd_energy_data *data = dev_get_drvdata(dev);
> > +     int ret, cpu;
> > +     u32 reg;
> > +     u64 input;
> > +
> > +     if (channel >= nr_cpus) {
> > +             reg = ENERGY_PKG_MSR;
> > +             cpu = cpumask_first_and(cpu_online_mask,
> > +                                     cpumask_of_node
> > +                                     (channel - nr_cpus));
> > +     } else {
> > +             reg = ENERGY_CORE_MSR;
> > +             cpu = channel;
> > +     }
> > +
> > +     if (!cpu_online(cpu))
> > +             return -ENODEV;
> > +
> > +     if (data->energy_units == 0 && get_energy_units(data))
> > +             return -EAGAIN;
> > +
> > +     mutex_lock(&data->lock);
> > +     ret = rdmsrl_safe_on_cpu(cpu, reg, &input);
> > +     if (ret)
> > +             return -EAGAIN;
> > +
> > +     /* Accumulation is for sockets only */
> > +     if (channel >= nr_cpus)
> > +             input += data->energy_ctrs[channel - nr_cpus];
> > +
> > +     /* Energy consumed = (1/(2^ESU) * RAW * 1000000UL) Joules */
> > +     *val = (long)input * div64_ul(1000000UL,
> > +                                   BIT(data->energy_units));
> > +     mutex_unlock(&data->lock);
> > +
> > +     return 0;
> > +}
> > +
> > +static umode_t amd_energy_is_visible(const void *_data,
> > +                                  enum hwmon_sensor_types type,
> > +                                  u32 attr, int channel)
> > +{
> > +     return 0444;
> > +}
> > +
> > +static int socket_accumulator(void *p)
> > +{
> > +     struct amd_energy_data *data = (struct amd_energy_data *)p;
> > +
> > +     while (!kthread_should_stop()) {
> > +             mutex_lock(&data->lock);
> > +             read_accumulate(data);
> > +             mutex_unlock(&data->lock);
> > +
> > +             set_current_state(TASK_INTERRUPTIBLE);
> > +             if (kthread_should_stop())
> > +                     break;
> > +
> > +             /*
> > +              * On a 240W system, the Socket Energy status
> > +              * register may wrap around in
> > +              * 2^32*15.3 e-6/240 = 273.8041 secs (~4.5 mins)
> > +              *
> > +              * let us accumulate for every 100secs
> > +              */
> > +             schedule_timeout(msecs_to_jiffies(100000));
> > +     }
> > +     return 0;
> > +}
> > +
> > +static const struct hwmon_ops amd_energy_ops = {
> > +     .is_visible = amd_energy_is_visible,
> > +     .read = amd_energy_read,
> > +     .read_string = amd_energy_read_labels,
> > +};
> > +
> > +static int amd_create_sensor(struct device *dev,
> > +                          struct amd_energy_data *data,
> > +                          u8 type, u32 config)
> > +{
> > +     int i;
> > +     u32 *s_config;
> > +
> > +     struct hwmon_channel_info *info = &data->energy_info;
> > +
> > +     nr_socks = num_possible_nodes();
> > +     nr_cpus = num_present_cpus();
> > +
> > +     s_config = devm_kcalloc(dev, nr_cpus + nr_socks,
> > +                             sizeof(u32), GFP_KERNEL);
> > +     if (!s_config)
> > +             return -ENOMEM;
> > +
> > +     data->energy_ctrs = devm_kcalloc(dev, nr_socks,
> > +                                      sizeof(u64), GFP_KERNEL);
> > +     if (!data->energy_ctrs)
> > +             return -ENOMEM;
> > +
> > +     data->prev_value = devm_kcalloc(dev, nr_socks,
> > +                                     sizeof(u64), GFP_KERNEL);
> > +     if (!data->prev_value)
> > +             return -ENOMEM;
> > +
> > +     info->type = type;
> > +     info->config = s_config;
> > +
> > +     for (i = 0; i < nr_cpus + nr_socks; i++)
> > +             s_config[i] = config;
> > +
> > +     return 0;
> > +}
> > +
> > +static int amd_energy_probe(struct platform_device *pdev)
> > +{
> > +     struct device *hwmon_dev;
> > +     struct amd_energy_data *data;
> > +     struct device *dev = &pdev->dev;
> > +     int ret;
> > +
> > +     data = devm_kzalloc(dev,
> > +                         sizeof(struct amd_energy_data), GFP_KERNEL);
> > +     if (!data)
> > +             return -ENOMEM;
> > +
> > +     data->chip.ops = &amd_energy_ops;
> > +     data->chip.info = data->info;
> > +
> > +     /* Populate per-core energy reporting */
> > +     data->info[0] = &data->energy_info;
> > +     amd_create_sensor(dev, data,  hwmon_energy,
> > +                       HWMON_E_INPUT | HWMON_E_LABEL);
> > +
> > +     mutex_init(&data->lock);
> > +
> > +     ret = get_energy_units(data);
> > +     if (ret)
> > +             return ret;
> > +
> > +     hwmon_dev = devm_hwmon_device_register_with_info(dev, DRVNAME,
> > +                                                      data,
> > +                                                      &data->chip,
> > +                                                      NULL);
> > +     if (IS_ERR(hwmon_dev))
> > +             return PTR_ERR(hwmon_dev);
> > +
> > +     wrap_accumulate = kthread_run(socket_accumulator, data,
> > +                                   "%s", dev_name(hwmon_dev));
> > +     if (IS_ERR(wrap_accumulate))
> > +             return PTR_ERR(wrap_accumulate);
> > +
> > +     return 0;
>
>         return PTR_ERR_OR_ZERO(wrap_accumulate);
>
> > +}
> > +
> > +static int amd_energy_remove(struct platform_device *pdev)
> > +{
> > +     if (wrap_accumulate)
> > +             kthread_stop(wrap_accumulate);
> > +
> > +     return 0;
> > +}
> > +
> > +static const struct platform_device_id amd_energy_ids[] = {
> > +     { .name = DRVNAME, },
> > +     {}
> > +};
> > +MODULE_DEVICE_TABLE(platform, amd_energy_ids);
> > +
> > +static struct platform_driver amd_energy_driver = {
> > +     .probe = amd_energy_probe,
> > +     .remove = amd_energy_remove,
> > +     .id_table = amd_energy_ids,
> > +     .driver = {
> > +             .name = DRVNAME,
> > +     },
> > +};
> > +
> > +static struct platform_device *amd_energy_platdev;
> > +
> > +static const struct x86_cpu_id cpu_ids[] __initconst = {
> > +     X86_MATCH_VENDOR_FAM(AMD, 0x17, NULL),
> > +     X86_MATCH_VENDOR_FAM(AMD, 0x19, NULL),
> > +     {}
> > +};
> > +MODULE_DEVICE_TABLE(x86cpu, cpu_ids);
> > +
> > +static int __init amd_energy_init(void)
> > +{
> > +     int ret;
> > +
> > +     if (!x86_match_cpu(cpu_ids))
> > +             return -ENODEV;
> > +
> > +     ret = platform_driver_register(&amd_energy_driver);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     amd_energy_platdev = platform_device_alloc(DRVNAME, 0);
> > +     if (!amd_energy_platdev)
> > +             return -ENOMEM;
> > +
> > +     ret = platform_device_add(amd_energy_platdev);
> > +     if (ret) {
> > +             platform_device_unregister(amd_energy_platdev);
> > +             return ret;
> > +     }
> > +
> > +     return ret;
> > +}
> > +
> > +static void __exit amd_energy_exit(void)
> > +{
> > +     platform_device_unregister(amd_energy_platdev);
> > +     platform_driver_unregister(&amd_energy_driver);
> > +}
> > +
> > +module_init(amd_energy_init);
> > +module_exit(amd_energy_exit);
> > +
> > +MODULE_DESCRIPTION("Driver for AMD Energy reporting from RAPL MSR via HWMON interface");
> > +MODULE_AUTHOR("Naveen Krishna Chatradhi <nchatrad@amd.com>");
> > +MODULE_LICENSE("GPL");

Thank you for reviewing the code, will address and resubmit.

-- 
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(: Nav :)