Re: [PATCH v2] nvme: Add hardware monitoring support

[Chris Healy]

On an ARM64 system with Toshiba SSD:

Tested-by: Chris Healy <cphealy@xxxxxxxxx>

On Tue, Oct 29, 2019 at 3:32 PM Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> nvme devices report temperature information in the controller information
> (for limits) and in the smart log. Currently, the only means to retrieve
> this information is the nvme command line interface, which requires
> super-user privileges.
>
> At the same time, it would be desirable to use NVME temperature information
> for thermal control.
>
> This patch adds support to read NVME temperatures from the kernel using the
> hwmon API and adds temperature zones for NVME drives. The thermal subsystem
> can use this information to set thermal policies, and userspace can access
> it using libsensors and/or the "sensors" command.
>
> Example output from the "sensors" command:
>
> nvme0-pci-0100
> Adapter: PCI adapter
> Composite:    +39.0ÂC  (high = +85.0ÂC, crit = +85.0ÂC)
> Sensor 1:     +39.0ÂC
> Sensor 2:     +41.0ÂC
>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> v2: Use devm_kfree() to release memory in error path
>
>  drivers/nvme/host/Kconfig      |  10 ++
>  drivers/nvme/host/Makefile     |   1 +
>  drivers/nvme/host/core.c       |   5 +
>  drivers/nvme/host/nvme-hwmon.c | 163 +++++++++++++++++++++++++++++++++
>  drivers/nvme/host/nvme.h       |   8 ++
>  5 files changed, 187 insertions(+)
>  create mode 100644 drivers/nvme/host/nvme-hwmon.c
>
> diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig
> index 2b36f052bfb9..aeb49e16e386 100644
> --- a/drivers/nvme/host/Kconfig
> +++ b/drivers/nvme/host/Kconfig
> @@ -23,6 +23,16 @@ config NVME_MULTIPATH
>            /dev/nvmeXnY device will show up for each NVMe namespaces,
>            even if it is accessible through multiple controllers.
>
> +config NVME_HWMON
> +       bool "NVME hardware monitoring"
> +       depends on (NVME_CORE=y && HWMON=y) || (NVME_CORE=m && HWMON)
> +       help
> +         This provides support for NVME hardware monitoring. If enabled,
> +         a hardware monitoring device will be created for each NVME drive
> +         in the system.
> +
> +         If unsure, say N.
> +
>  config NVME_FABRICS
>         tristate
>
> diff --git a/drivers/nvme/host/Makefile b/drivers/nvme/host/Makefile
> index 8a4b671c5f0c..03de4797a877 100644
> --- a/drivers/nvme/host/Makefile
> +++ b/drivers/nvme/host/Makefile
> @@ -14,6 +14,7 @@ nvme-core-$(CONFIG_TRACING)           += trace.o
>  nvme-core-$(CONFIG_NVME_MULTIPATH)     += multipath.o
>  nvme-core-$(CONFIG_NVM)                        += lightnvm.o
>  nvme-core-$(CONFIG_FAULT_INJECTION_DEBUG_FS)   += fault_inject.o
> +nvme-core-$(CONFIG_NVME_HWMON)         += nvme-hwmon.o
>
>  nvme-y                                 += pci.o
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index fa7ba09dca77..fc1d4b146717 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -2796,6 +2796,9 @@ int nvme_init_identify(struct nvme_ctrl *ctrl)
>         ctrl->oncs = le16_to_cpu(id->oncs);
>         ctrl->mtfa = le16_to_cpu(id->mtfa);
>         ctrl->oaes = le32_to_cpu(id->oaes);
> +       ctrl->wctemp = le16_to_cpu(id->wctemp);
> +       ctrl->cctemp = le16_to_cpu(id->cctemp);
> +
>         atomic_set(&ctrl->abort_limit, id->acl + 1);
>         ctrl->vwc = id->vwc;
>         if (id->mdts)
> @@ -2897,6 +2900,8 @@ int nvme_init_identify(struct nvme_ctrl *ctrl)
>
>         ctrl->identified = true;
>
> +       nvme_hwmon_init(ctrl);
> +
>         return 0;
>
>  out_free:
> diff --git a/drivers/nvme/host/nvme-hwmon.c b/drivers/nvme/host/nvme-hwmon.c
> new file mode 100644
> index 000000000000..af5eda326ec6
> --- /dev/null
> +++ b/drivers/nvme/host/nvme-hwmon.c
> @@ -0,0 +1,163 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * NVM Express hardware monitoring support
> + * Copyright (c) 2019, Guenter Roeck
> + */
> +
> +#include <linux/hwmon.h>
> +
> +#include "nvme.h"
> +
> +struct nvme_hwmon_data {
> +       struct nvme_ctrl *ctrl;
> +       struct nvme_smart_log log;
> +};
> +
> +static int nvme_hwmon_get_smart_log(struct nvme_hwmon_data *data)
> +{
> +       return nvme_get_log(data->ctrl, NVME_NSID_ALL, NVME_LOG_SMART, 0,
> +                           &data->log, sizeof(data->log), 0);
> +}
> +
> +static int nvme_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
> +                          u32 attr, int channel, long *val)
> +{
> +       struct nvme_hwmon_data *data = dev_get_drvdata(dev);
> +       struct nvme_smart_log *log = &data->log;
> +       int err;
> +       int temp;
> +
> +       err = nvme_hwmon_get_smart_log(data);
> +       if (err)
> +               return err < 0 ? err : -EPROTO;
> +
> +       switch (attr) {
> +       case hwmon_temp_max:
> +               *val = (data->ctrl->wctemp - 273) * 1000;
> +               break;
> +       case hwmon_temp_crit:
> +               *val = (data->ctrl->cctemp - 273) * 1000;
> +               break;
> +       case hwmon_temp_input:
> +               if (!channel)
> +                       temp = le16_to_cpup((__le16 *)log->temperature);
> +               else
> +                       temp = le16_to_cpu(log->temp_sensor[channel - 1]);
> +               *val = (temp - 273) * 1000;
> +               break;
> +       case hwmon_temp_crit_alarm:
> +               *val = !!(log->critical_warning & NVME_SMART_CRIT_TEMPERATURE);
> +               break;
> +       default:
> +               err = -EOPNOTSUPP;
> +               break;
> +       }
> +       return err;
> +}
> +
> +static const char * const nvme_hwmon_sensor_names[] = {
> +       "Composite",
> +       "Sensor 1",
> +       "Sensor 2",
> +       "Sensor 3",
> +       "Sensor 4",
> +       "Sensor 5",
> +       "Sensor 6",
> +       "Sensor 7",
> +       "Sensor 8",
> +};
> +
> +static int nvme_hwmon_read_string(struct device *dev,
> +                                 enum hwmon_sensor_types type, u32 attr,
> +                                 int channel, const char **str)
> +{
> +       *str = nvme_hwmon_sensor_names[channel];
> +       return 0;
> +}
> +
> +static umode_t nvme_hwmon_is_visible(const void *_data,
> +                                    enum hwmon_sensor_types type,
> +                                    u32 attr, int channel)
> +{
> +       const struct nvme_hwmon_data *data = _data;
> +
> +       switch (attr) {
> +       case hwmon_temp_crit:
> +               if (!channel && data->ctrl->cctemp)
> +                       return 0444;
> +               break;
> +       case hwmon_temp_max:
> +               if (!channel && data->ctrl->wctemp)
> +                       return 0444;
> +               break;
> +       case hwmon_temp_crit_alarm:
> +               if (!channel)
> +                       return 0444;
> +               break;
> +       case hwmon_temp_input:
> +       case hwmon_temp_label:
> +               if (!channel || data->log.temp_sensor[channel - 1])
> +                       return 0444;
> +               break;
> +       default:
> +               break;
> +       }
> +       return 0;
> +}
> +
> +static const struct hwmon_channel_info *nvme_hwmon_info[] = {
> +       HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
> +       HWMON_CHANNEL_INFO(temp,
> +                          HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
> +                               HWMON_T_LABEL | HWMON_T_CRIT_ALARM,
> +                          HWMON_T_INPUT | HWMON_T_LABEL,
> +                          HWMON_T_INPUT | HWMON_T_LABEL,
> +                          HWMON_T_INPUT | HWMON_T_LABEL,
> +                          HWMON_T_INPUT | HWMON_T_LABEL,
> +                          HWMON_T_INPUT | HWMON_T_LABEL,
> +                          HWMON_T_INPUT | HWMON_T_LABEL,
> +                          HWMON_T_INPUT | HWMON_T_LABEL,
> +                          HWMON_T_INPUT | HWMON_T_LABEL),
> +       NULL
> +};
> +
> +static const struct hwmon_ops nvme_hwmon_ops = {
> +       .is_visible = nvme_hwmon_is_visible,
> +       .read = nvme_hwmon_read,
> +       .read_string = nvme_hwmon_read_string,
> +};
> +
> +static const struct hwmon_chip_info nvme_hwmon_chip_info = {
> +       .ops = &nvme_hwmon_ops,
> +       .info = nvme_hwmon_info,
> +};
> +
> +void nvme_hwmon_init(struct nvme_ctrl *ctrl)
> +{
> +       struct device *dev = ctrl->device;
> +       struct nvme_hwmon_data *data;
> +       struct device *hwmon;
> +       int err;
> +
> +       data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +       if (!data)
> +               return;
> +
> +       data->ctrl = ctrl;
> +
> +       err = nvme_hwmon_get_smart_log(data);
> +       if (err) {
> +               dev_warn(dev, "Failed to read smart log (error %d)\n", err);
> +               devm_kfree(dev, data);
> +               return;
> +       }
> +
> +       hwmon = devm_hwmon_device_register_with_info(dev, dev_name(dev),
> +                                                    data,
> +                                                    &nvme_hwmon_chip_info,
> +                                                    NULL);
> +       if (IS_ERR(hwmon)) {
> +               dev_warn(dev, "Failed to instantiate hwmon device\n");
> +               devm_kfree(dev, data);
> +       }
> +}
> diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
> index 22e8401352c2..e6460c1216bc 100644
> --- a/drivers/nvme/host/nvme.h
> +++ b/drivers/nvme/host/nvme.h
> @@ -231,6 +231,8 @@ struct nvme_ctrl {
>         u16 kas;
>         u8 npss;
>         u8 apsta;
> +       u16 wctemp;
> +       u16 cctemp;
>         u32 oaes;
>         u32 aen_result;
>         u32 ctratt;
> @@ -652,4 +654,10 @@ static inline struct nvme_ns *nvme_get_ns_from_dev(struct device *dev)
>         return dev_to_disk(dev)->private_data;
>  }
>
> +#if IS_ENABLED(CONFIG_NVME_HWMON)
> +void nvme_hwmon_init(struct nvme_ctrl *ctrl);
> +#else
> +static inline void nvme_hwmon_init(struct nvme_ctrl *ctrl) { }
> +#endif
> +
>  #endif /* _NVME_H */
> --
> 2.17.1
>