Re: [PATCH 3/3] k10temp: Add power sensor for family 19h

From: Guenter Roeck
Date: Thu Sep 02 2021 - 15:26:59 EST


On Thu, Sep 02, 2021 at 11:11:55PM +0530, Naveen Krishna Chatradhi wrote:
> On newer Fam19h server line of AMD processors a new channel
> is created to report and manage socket power limits.
>
> This patch creates hwmon_power sensor to report current power,
> power cap and max power cap of the socket.
> While at it, update the k10temp documentation
>
> Tested-by: suma hegde <suma.hegde@xxxxxxx>
> Signed-off-by: Naveen Krishna Chatradhi <nchatrad@xxxxxxx>
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>

Would it make sense to add this to fam15h_power instead ?
Just wondering, no strong opinion. That driver does seem to be
a bit messy, so it might be best to leave it alone.

One other question, though: We had to drop the amd_energy driver
because it opened up an attack surface. Is the power consumption
reported by this patch vague enough that this won't be a problem ?

Thanks,
Guenter

> ---
> Documentation/hwmon/k10temp.rst | 18 ++++++
> drivers/hwmon/k10temp.c | 106 ++++++++++++++++++++++++++++++++
> 2 files changed, 124 insertions(+)
>
> diff --git a/Documentation/hwmon/k10temp.rst b/Documentation/hwmon/k10temp.rst
> index 91b99adc6c48..d5a78a7b6ca5 100644
> --- a/Documentation/hwmon/k10temp.rst
> +++ b/Documentation/hwmon/k10temp.rst
> @@ -132,3 +132,21 @@ On Family 17h and Family 18h CPUs, additional temperature sensors may report
> Core Complex Die (CCD) temperatures. Up to 8 such temperatures are reported
> as temp{3..10}_input, labeled Tccd{1..8}. Actual support depends on the CPU
> variant.
> +
> +On Family 19h server line of CPUs, additionally driver may report socket
> +current power consumption with power cap and power cap max. This requires the
> +HSMP support exported in the amd_nb module.
> +
> +The power1_cap can be set to any value, SMU FW will limit the maximum cap to
> +the value reported by power1_cap_max entry. The SMU FW may not take any action
> +if the power1_cap is set to a value lesser than the minimum socket consumption.
> +
> +The following attributes may be reported.
> +
> +================ ===== ========================================================
> +Name Perm Description
> +================ ===== ========================================================
> +power1_input RO Socket current Power consumed
> +power1_cap RW Socket Power limit can be set between 0 and power1_cap_max
> +power1_cap_max RO Maximum powerlimit calculated and reported by the SMU FW
> +================ ===== ========================================================
> diff --git a/drivers/hwmon/k10temp.c b/drivers/hwmon/k10temp.c
> index 3618a924e78e..b993fdd94979 100644
> --- a/drivers/hwmon/k10temp.c
> +++ b/drivers/hwmon/k10temp.c
> @@ -105,6 +105,9 @@ struct k10temp_data {
> u32 show_temp;
> bool is_zen;
> u32 ccd_offset;
> + bool show_power;
> + char pwr_label[20];
> + u32 power_cap_max;
> };
>
> #define TCTL_BIT 0
> @@ -197,10 +200,14 @@ static int k10temp_read_labels(struct device *dev,
> enum hwmon_sensor_types type,
> u32 attr, int channel, const char **str)
> {
> + struct k10temp_data *data = dev_get_drvdata(dev);
> switch (type) {
> case hwmon_temp:
> *str = k10temp_temp_label[channel];
> break;
> + case hwmon_power:
> + *str = data->pwr_label;
> + break;
> default:
> return -EOPNOTSUPP;
> }
> @@ -254,12 +261,43 @@ static int k10temp_read_temp(struct device *dev, u32 attr, int channel,
> return 0;
> }
>
> +static int k10temp_read_power(struct device *dev, u32 attr, int channel, long *val)
> +{
> + struct k10temp_data *data = dev_get_drvdata(dev);
> + struct hsmp_message msg = { 0 };
> + int err;
> +
> + switch (attr) {
> + case hwmon_power_input:
> + msg.msg_id = HSMP_GET_SOCKET_POWER;
> + break;
> + case hwmon_power_cap:
> + msg.msg_id = HSMP_GET_SOCKET_POWER_LIMIT;
> + break;
> + case hwmon_power_cap_max:
> + /* power_cap_max does not change dynamically, hence return the cached value */
> + *val = data->power_cap_max * 1000;
> + return 0;
> + default:
> + return -EOPNOTSUPP;
> + }
> + msg.response_sz = 1;
> + err = hsmp_send_message(amd_pci_dev_to_node_id(data->pdev), &msg);
> + if (!err)
> + /* power metric is reported in micro watts. hence multiply by 1000 */
> + *val = msg.response[0] * 1000;
> +
> + return err;
> +}
> +
> static int k10temp_read(struct device *dev, enum hwmon_sensor_types type,
> u32 attr, int channel, long *val)
> {
> switch (type) {
> case hwmon_temp:
> return k10temp_read_temp(dev, attr, channel, val);
> + case hwmon_power:
> + return k10temp_read_power(dev, attr, channel, val);
> default:
> return -EOPNOTSUPP;
> }
> @@ -308,12 +346,45 @@ static umode_t k10temp_is_visible(const void *_data,
> return 0;
> }
> break;
> + case hwmon_power:
> + switch (attr) {
> + case hwmon_power_input:
> + case hwmon_power_cap_max:
> + case hwmon_power_label:
> + /* Show power attributes only if show_power is available */
> + if (data->show_power)
> + break;
> + return 0;
> + case hwmon_power_cap:
> + if (data->show_power)
> + return 0644;
> + return 0;
> + default:
> + return -EOPNOTSUPP;
> + }
> + break;
> default:
> return 0;
> }
> return 0444;
> }
>
> +static int k10temp_write(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long val)
> +{
> + struct hsmp_message msg = { 0 };
> + struct k10temp_data *data = dev_get_drvdata(dev);
> +
> + if (type == hwmon_power && attr == hwmon_power_cap) {
> + msg.response_sz = 1;
> + msg.num_args = 1;
> + msg.msg_id = HSMP_SET_SOCKET_POWER_LIMIT;
> + msg.args[0] = val / 1000;
> + return hsmp_send_message(amd_pci_dev_to_node_id(data->pdev), &msg);
> + }
> + return -EOPNOTSUPP;
> +}
> +
> static bool has_erratum_319(struct pci_dev *pdev)
> {
> u32 pkg_type, reg_dram_cfg;
> @@ -362,6 +433,9 @@ static const struct hwmon_channel_info *k10temp_info[] = {
> HWMON_T_INPUT | HWMON_T_LABEL,
> HWMON_T_INPUT | HWMON_T_LABEL,
> HWMON_T_INPUT | HWMON_T_LABEL),
> + HWMON_CHANNEL_INFO(power,
> + HWMON_P_INPUT | HWMON_P_LABEL |
> + HWMON_P_CAP | HWMON_P_CAP_MAX),
> NULL
> };
>
> @@ -369,6 +443,7 @@ static const struct hwmon_ops k10temp_hwmon_ops = {
> .is_visible = k10temp_is_visible,
> .read = k10temp_read,
> .read_string = k10temp_read_labels,
> + .write = k10temp_write,
> };
>
> static const struct hwmon_chip_info k10temp_chip_info = {
> @@ -390,6 +465,32 @@ static void k10temp_get_ccd_support(struct pci_dev *pdev,
> }
> }
>
> +static int k10temp_get_max_power(struct k10temp_data *data)
> +{
> + int err;
> + struct hsmp_message msg = { 0 };
> +
> + msg.msg_id = HSMP_GET_SOCKET_POWER_LIMIT_MAX;
> + msg.response_sz = 1;
> + err = hsmp_send_message(amd_pci_dev_to_node_id(data->pdev), &msg);
> + if (!err)
> + data->power_cap_max = msg.response[0];
> + return err;
> +}
> +
> +static void check_power_support(struct k10temp_data *data)
> +{
> + /* HSMP support is required to obtain power metrics */
> + if (!amd_nb_has_feature(AMD_NB_HSMP))
> + return;
> +
> + if (k10temp_get_max_power(data))
> + return;
> +
> + sprintf(data->pwr_label, "socket%d_pwr", amd_pci_dev_to_node_id(data->pdev));
> + data->show_power = true;
> +}
> +
> static int k10temp_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> {
> int unreliable = has_erratum_319(pdev);
> @@ -448,6 +549,11 @@ static int k10temp_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>
> switch (boot_cpu_data.x86_model) {
> case 0x0 ... 0x1: /* Zen3 SP3/TR */
> + case 0x30 ... 0x31:
> + check_power_support(data);
> + data->ccd_offset = 0x154;
> + k10temp_get_ccd_support(pdev, data, 8);
> + break;
> case 0x21: /* Zen3 Ryzen Desktop */
> case 0x50 ... 0x5f: /* Green Sardine */
> data->ccd_offset = 0x154;