Re: [Intel-gfx] [PATCH 6/7] drm/i915/hwmon: Expose power1_max_interval

Andi Shyti
2022-10-03T21:32:46Z

Hi Badal,

> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> index f9d6d3b08bba..19b9fe3ef237 100644
> --- a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> +++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> @@ -26,6 +26,15 @@ Description: RO. Card default power limit (default TDP setting).
>
> Only supported for particular Intel i915 graphics platforms.
>
> +What: /sys/devices/.../hwmon/hwmon/power1_max_interval
> +Date: February 2023
> +KernelVersion: 6.2
> +Contact: dri-devel@lists.freedesktop.org

same question here.

> +Description: RW. Sustained power limit interval (Tau in PL1/Tau) in
> + milliseconds over which sustained power is averaged.
> +
> + Only supported for particular Intel i915 graphics platforms.
> +
> What: /sys/devices/.../hwmon/hwmon/power1_crit
> Date: February 2023
> KernelVersion: 6.2
> diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
> index 2394fa789793..641143956c45 100644
> --- a/drivers/gpu/drm/i915/i915_hwmon.c
> +++ b/drivers/gpu/drm/i915/i915_hwmon.c
> @@ -20,11 +20,13 @@
> * - power - microwatts
> * - curr - milliamperes
> * - energy - microjoules
> + * - time - milliseconds
> */
> #define SF_VOLTAGE 1000
> #define SF_POWER 1000000
> #define SF_CURR 1000
> #define SF_ENERGY 1000000
> +#define SF_TIME 1000
>
> struct hwm_reg {
> i915_reg_t gt_perf_status;
> @@ -53,6 +55,7 @@ struct i915_hwmon {
> struct hwm_reg rg;
> int scl_shift_power;
> int scl_shift_energy;
> + int scl_shift_time;
> };
>
> static void
> @@ -161,6 +164,115 @@ hwm_energy(struct hwm_drvdata *ddat, long *energy)
> return 0;
> }
>
> +static ssize_t
> +hwm_power1_max_interval_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct hwm_drvdata *ddat = dev_get_drvdata(dev);
> + struct i915_hwmon *hwmon = ddat->hwmon;
> + intel_wakeref_t wakeref;
> + u32 r, x, y, x_w = 2; /* 2 bits */
> + u64 tau4, out;
> +
> + with_intel_runtime_pm(ddat->uncore->rpm, wakeref)
> + r = intel_uncore_read(ddat->uncore, hwmon->rg.pkg_rapl_limit);
> +
> + x = REG_FIELD_GET(PKG_PWR_LIM_1_TIME_X, r);
> + y = REG_FIELD_GET(PKG_PWR_LIM_1_TIME_Y, r);
> + /*
> + * tau = 1.x * power(2,y), x = bits(23:22), y = bits(21:17)
> + * = (4 | x) << (y - 2)
> + * where (y - 2) ensures a 1.x fixed point representation of 1.x
> + * However because y can be < 2, we compute
> + * tau4 = (4 | x) << y
> + * but add 2 when doing the final right shift to account for units
> + */
> + tau4 = ((1 << x_w) | x) << y;
> + /* val in hwmon interface units (millisec) */
> + out = mul_u64_u32_shr(tau4, SF_TIME, hwmon->scl_shift_time + x_w);
> +
> + return sysfs_emit(buf, "%llu\n", out);
> +}
> +
> +static ssize_t
> +hwm_power1_max_interval_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct hwm_drvdata *ddat = dev_get_drvdata(dev);
> + struct i915_hwmon *hwmon = ddat->hwmon;
> + long val, max_win, ret;

you have some type mismatch here:

- val should be unsigned long
- max_win should be u64
- ret should be int

> + u32 x, y, rxy, x_w = 2; /* 2 bits */
> + u64 tau4, r;
> +
> +#define PKG_MAX_WIN_DEFAULT 0x12ull

could you please add a comment here?

> +
> + ret = kstrtoul(buf, 0, &val);
> + if (ret)
> + return ret;
> +
> + /*
> + * val must be < max in hwmon interface units. The steps below are
> + * explained in i915_power1_max_interval_show()
> + */
> + r = FIELD_PREP(PKG_MAX_WIN, PKG_MAX_WIN_DEFAULT);
> +
> + x = REG_FIELD_GET(PKG_MAX_WIN_X, r);
> + y = REG_FIELD_GET(PKG_MAX_WIN_Y, r);
> + tau4 = ((1 << x_w) | x) << y;
> + max_win = mul_u64_u32_shr(tau4, SF_TIME, hwmon->scl_shift_time + x_w);
> +
> + if (val > max_win)
> + return -EINVAL;
> +
> + /* val in hw units */
> + val = DIV_ROUND_CLOSEST_ULL((u64)val << hwmon->scl_shift_time, SF_TIME);
> + /* Convert to 1.x * power(2,y) */
> + if (!val)
> + return -EINVAL;
> + y = ilog2(val);
> + /* x = (val - (1 << y)) >> (y - 2); */

some leftover

> + x = (val - (1ul << y)) << x_w >> y;
> +
> + rxy = REG_FIELD_PREP(PKG_PWR_LIM_1_TIME_X, x) | REG_FIELD_PREP(PKG_PWR_LIM_1_TIME_Y, y);
> +
> + hwm_locked_with_pm_intel_uncore_rmw(ddat, hwmon->rg.pkg_rapl_limit,
> + PKG_PWR_LIM_1_TIME, rxy);
> + return count;
> +}
> +
> +static SENSOR_DEVICE_ATTR(power1_max_interval, 0664,
> + hwm_power1_max_interval_show,
> + hwm_power1_max_interval_store, 0);
> +
> +static struct attribute *hwm_attributes[] = {
> + &sensor_dev_attr_power1_max_interval.dev_attr.attr,
> + NULL
> +};
> +
> +static umode_t hwm_attributes_visible(struct kobject *kobj,
> + struct attribute *attr, int index)
> +{
> + struct device *dev = kobj_to_dev(kobj);
> + struct hwm_drvdata *ddat = dev_get_drvdata(dev);
> + struct i915_hwmon *hwmon = ddat->hwmon;
> +
> + if (attr == &sensor_dev_attr_power1_max_interval.dev_attr.attr)
> + return i915_mmio_reg_valid(hwmon->rg.pkg_rapl_limit) ? attr->mode : 0;
> + else
> + return 0;

please remove the else

Andi

> +}
> +
> +static const struct attribute_group hwm_attrgroup = {
> + .attrs = hwm_attributes,
> + .is_visible = hwm_attributes_visible,
> +};
> +
> +static const struct attribute_group *hwm_groups[] = {
> + &hwm_attrgroup,
> + NULL
> +};
> +
> static const struct hwmon_channel_info *hwm_info[] = {
> HWMON_CHANNEL_INFO(in, HWMON_I_INPUT),
> HWMON_CHANNEL_INFO(power, HWMON_P_MAX | HWMON_P_RATED_MAX | HWMON_P_CRIT),
> @@ -472,6 +584,7 @@ hwm_get_preregistration_info(struct drm_i915_private *i915)
>
> hwmon->scl_shift_power = REG_FIELD_GET(PKG_PWR_UNIT, val_sku_unit);
> hwmon->scl_shift_energy = REG_FIELD_GET(PKG_ENERGY_UNIT, val_sku_unit);
> + hwmon->scl_shift_time = REG_FIELD_GET(PKG_TIME_UNIT, val_sku_unit);
>
> /*
> * Initialize 'struct hwm_energy_info', i.e. set fields to the
> @@ -510,7 +623,7 @@ void i915_hwmon_register(struct drm_i915_private *i915)
> hwmon_dev = devm_hwmon_device_register_with_info(dev, ddat->name,
> ddat,
> &hwm_chip_info,
> - NULL);
> + hwm_groups);
> if (IS_ERR(hwmon_dev)) {
> i915->hwmon = NULL;
> return;
> diff --git a/drivers/gpu/drm/i915/intel_mchbar_regs.h b/drivers/gpu/drm/i915/intel_mchbar_regs.h
> index bd42fb66e297..64aa1e9be463 100644
> --- a/drivers/gpu/drm/i915/intel_mchbar_regs.h
> +++ b/drivers/gpu/drm/i915/intel_mchbar_regs.h
> @@ -194,6 +194,9 @@
> */
> #define PCU_PACKAGE_POWER_SKU _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5930)
> #define PKG_PKG_TDP GENMASK_ULL(14, 0)
> +#define PKG_MAX_WIN GENMASK_ULL(54, 48)
> +#define PKG_MAX_WIN_X GENMASK_ULL(54, 53)
> +#define PKG_MAX_WIN_Y GENMASK_ULL(52, 48)
>
> #define PCU_PACKAGE_POWER_SKU_UNIT _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5938)
> #define PKG_PWR_UNIT REG_GENMASK(3, 0)
> @@ -212,6 +215,10 @@
> #define RPE_MASK REG_GENMASK(15, 8)
> #define PCU_PACKAGE_RAPL_LIMIT _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x59a0)
> #define PKG_PWR_LIM_1 REG_GENMASK(14, 0)
> +#define PKG_PWR_LIM_1_EN REG_BIT(15)
> +#define PKG_PWR_LIM_1_TIME REG_GENMASK(23, 17)
> +#define PKG_PWR_LIM_1_TIME_X REG_GENMASK(23, 22)
> +#define PKG_PWR_LIM_1_TIME_Y REG_GENMASK(21, 17)
>
> /* snb MCH registers for priority tuning */
> #define MCH_SSKPD _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5d10)
> --
> 2.25.1