On Tue, Sep 27, 2022 at 11:20:17AM +0530, Badal Nilawar wrote:
> From: Dale B Stimson <dale.b.stimson@xxxxxxxxx>
>
> Use i915 HWMON to display device level energy input.
>
> v2: Updated the date and kernel version in feature description
> v3:
> - Cleaned up hwm_energy function and removed unused function
> i915_hwmon_energy_status_get (Ashutosh)
> v4: KernelVersion: 6.2, Date: February 2023 in doc (Tvrtko)
>
> Signed-off-by: Dale B Stimson <dale.b.stimson@xxxxxxxxx>
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
> Signed-off-by: Riana Tauro <riana.tauro@xxxxxxxxx>
> Signed-off-by: Badal Nilawar <badal.nilawar@xxxxxxxxx>
> Acked-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx>
> Reviewed-by: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
> ---
> .../ABI/testing/sysfs-driver-intel-i915-hwmon | 8 ++
> drivers/gpu/drm/i915/i915_hwmon.c | 107 +++++++++++++++++-
> drivers/gpu/drm/i915/intel_mchbar_regs.h | 2 +
> 3 files changed, 115 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> index 16e697b1db3d..7525db243d74 100644
> --- a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> +++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> @@ -25,3 +25,11 @@ Contact: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Description: RO. Card default power limit (default TDP setting).
>
> Only supported for particular Intel i915 graphics platforms.
> +
> +What: /sys/devices/.../hwmon/hwmon<i>/energy1_input
> +Date: February 2023
> +KernelVersion: 6.2
> +Contact: dri-devel@xxxxxxxxxxxxxxxxxxxxx
I'm sorry for being late on the review here, and I know that others
already looked at the date and other details here in this doc.
So I'm curious why we have decided for the dri-devel mailing list
and not for the intel-gfx since intel-gfx is the only one we have
listed for i915 dir in the MAINTAINERS file:
L: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> +Description: RO. Energy input of device in microjoules.
> +
> + Only supported for particular Intel i915 graphics platforms.
> diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
> index 53d34a7a86f7..9a49521b358a 100644
> --- a/drivers/gpu/drm/i915/i915_hwmon.c
> +++ b/drivers/gpu/drm/i915/i915_hwmon.c
> @@ -17,21 +17,30 @@
> * SF_* - scale factors for particular quantities according to hwmon spec.
> * - voltage - millivolts
> * - power - microwatts
> + * - energy - microjoules
> */
> #define SF_VOLTAGE 1000
> #define SF_POWER 1000000
> +#define SF_ENERGY 1000000
>
> struct hwm_reg {
> i915_reg_t gt_perf_status;
> i915_reg_t pkg_power_sku_unit;
> i915_reg_t pkg_power_sku;
> i915_reg_t pkg_rapl_limit;
> + i915_reg_t energy_status_all;
> +};
> +
> +struct hwm_energy_info {
> + u32 reg_val_prev;
> + long accum_energy; /* Accumulated energy for energy1_input */
> };
>
> struct hwm_drvdata {
> struct i915_hwmon *hwmon;
> struct intel_uncore *uncore;
> struct device *hwmon_dev;
> + struct hwm_energy_info ei; /* Energy info for energy1_input */
> char name[12];
> };
>
> @@ -40,6 +49,7 @@ struct i915_hwmon {
> struct mutex hwmon_lock; /* counter overflow logic and rmw */
> struct hwm_reg rg;
> int scl_shift_power;
> + int scl_shift_energy;
> };
>
> static void
> @@ -98,9 +108,60 @@ hwm_field_scale_and_write(struct hwm_drvdata *ddat, i915_reg_t rgadr,
> bits_to_clear, bits_to_set);
> }
>
> +/*
> + * hwm_energy - Obtain energy value
> + *
> + * The underlying energy hardware register is 32-bits and is subject to
> + * overflow. How long before overflow? For example, with an example
> + * scaling bit shift of 14 bits (see register *PACKAGE_POWER_SKU_UNIT) and
> + * a power draw of 1000 watts, the 32-bit counter will overflow in
> + * approximately 4.36 minutes.
> + *
> + * Examples:
> + * 1 watt: (2^32 >> 14) / 1 W / (60 * 60 * 24) secs/day -> 3 days
> + * 1000 watts: (2^32 >> 14) / 1000 W / 60 secs/min -> 4.36 minutes
> + *
> + * The function significantly increases overflow duration (from 4.36
> + * minutes) by accumulating the energy register into a 'long' as allowed by
> + * the hwmon API. Using x86_64 128 bit arithmetic (see mul_u64_u32_shr()),
> + * a 'long' of 63 bits, SF_ENERGY of 1e6 (~20 bits) and
> + * hwmon->scl_shift_energy of 14 bits we have 57 (63 - 20 + 14) bits before
> + * energy1_input overflows. This at 1000 W is an overflow duration of 278 years.
> + */
> +static int
> +hwm_energy(struct hwm_drvdata *ddat, long *energy)
> +{
> + struct intel_uncore *uncore = ddat->uncore;
> + struct i915_hwmon *hwmon = ddat->hwmon;
> + struct hwm_energy_info *ei = &ddat->ei;
> + intel_wakeref_t wakeref;
> + i915_reg_t rgaddr;
> + u32 reg_val;
> +
> + rgaddr = hwmon->rg.energy_status_all;
> +
> + mutex_lock(&hwmon->hwmon_lock);
> +
> + with_intel_runtime_pm(uncore->rpm, wakeref)
> + reg_val = intel_uncore_read(uncore, rgaddr);
> +
> + if (reg_val >= ei->reg_val_prev)
> + ei->accum_energy += reg_val - ei->reg_val_prev;
> + else
> + ei->accum_energy += UINT_MAX - ei->reg_val_prev + reg_val;
> + ei->reg_val_prev = reg_val;
> +
> + *energy = mul_u64_u32_shr(ei->accum_energy, SF_ENERGY,
> + hwmon->scl_shift_energy);
> + mutex_unlock(&hwmon->hwmon_lock);
> +
> + return 0;
> +}
> +
> 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_CHANNEL_INFO(energy, HWMON_E_INPUT),
> NULL
> };
>
> @@ -192,6 +253,32 @@ hwm_power_write(struct hwm_drvdata *ddat, u32 attr, int chan, long val)
> }
> }
>
> +static umode_t
> +hwm_energy_is_visible(const struct hwm_drvdata *ddat, u32 attr)
> +{
> + struct i915_hwmon *hwmon = ddat->hwmon;
> + i915_reg_t rgaddr;
> +
> + switch (attr) {
> + case hwmon_energy_input:
> + rgaddr = hwmon->rg.energy_status_all;
> + return i915_mmio_reg_valid(rgaddr) ? 0444 : 0;
> + default:
> + return 0;
> + }
> +}
> +
> +static int
> +hwm_energy_read(struct hwm_drvdata *ddat, u32 attr, long *val)
> +{
> + switch (attr) {
> + case hwmon_energy_input:
> + return hwm_energy(ddat, val);
> + default:
> + return -EOPNOTSUPP;
> + }
> +}
> +
> static umode_t
> hwm_is_visible(const void *drvdata, enum hwmon_sensor_types type,
> u32 attr, int channel)
> @@ -203,6 +290,8 @@ hwm_is_visible(const void *drvdata, enum hwmon_sensor_types type,
> return hwm_in_is_visible(ddat, attr);
> case hwmon_power:
> return hwm_power_is_visible(ddat, attr, channel);
> + case hwmon_energy:
> + return hwm_energy_is_visible(ddat, attr);
> default:
> return 0;
> }
> @@ -219,6 +308,8 @@ hwm_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
> return hwm_in_read(ddat, attr, val);
> case hwmon_power:
> return hwm_power_read(ddat, attr, channel, val);
> + case hwmon_energy:
> + return hwm_energy_read(ddat, attr, val);
> default:
> return -EOPNOTSUPP;
> }
> @@ -254,19 +345,23 @@ hwm_get_preregistration_info(struct drm_i915_private *i915)
> {
> struct i915_hwmon *hwmon = i915->hwmon;
> struct intel_uncore *uncore = &i915->uncore;
> + struct hwm_drvdata *ddat = &hwmon->ddat;
> intel_wakeref_t wakeref;
> u32 val_sku_unit;
> + long energy;
>
> if (IS_DG1(i915) || IS_DG2(i915)) {
> hwmon->rg.gt_perf_status = GEN12_RPSTAT1;
> hwmon->rg.pkg_power_sku_unit = PCU_PACKAGE_POWER_SKU_UNIT;
> hwmon->rg.pkg_power_sku = PCU_PACKAGE_POWER_SKU;
> hwmon->rg.pkg_rapl_limit = PCU_PACKAGE_RAPL_LIMIT;
> + hwmon->rg.energy_status_all = PCU_PACKAGE_ENERGY_STATUS;
> } else {
> hwmon->rg.gt_perf_status = INVALID_MMIO_REG;
> hwmon->rg.pkg_power_sku_unit = INVALID_MMIO_REG;
> hwmon->rg.pkg_power_sku = INVALID_MMIO_REG;
> hwmon->rg.pkg_rapl_limit = INVALID_MMIO_REG;
> + hwmon->rg.energy_status_all = INVALID_MMIO_REG;
> }
>
> with_intel_runtime_pm(uncore->rpm, wakeref) {
> @@ -280,9 +375,17 @@ hwm_get_preregistration_info(struct drm_i915_private *i915)
> } else {
> val_sku_unit = 0;
> }
> -
> - hwmon->scl_shift_power = REG_FIELD_GET(PKG_PWR_UNIT, val_sku_unit);
> }
> +
> + 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);
> +
> + /*
> + * Initialize 'struct hwm_energy_info', i.e. set fields to the
> + * first value of the energy register read
> + */
> + if (i915_mmio_reg_valid(hwmon->rg.energy_status_all))
> + hwm_energy(ddat, &energy);
> }
>
> void i915_hwmon_register(struct drm_i915_private *i915)
> diff --git a/drivers/gpu/drm/i915/intel_mchbar_regs.h b/drivers/gpu/drm/i915/intel_mchbar_regs.h
> index d7e2e4711792..bd42fb66e297 100644
> --- a/drivers/gpu/drm/i915/intel_mchbar_regs.h
> +++ b/drivers/gpu/drm/i915/intel_mchbar_regs.h
> @@ -197,7 +197,9 @@
>
> #define PCU_PACKAGE_POWER_SKU_UNIT _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5938)
> #define PKG_PWR_UNIT REG_GENMASK(3, 0)
> +#define PKG_ENERGY_UNIT REG_GENMASK(12, 8)
> #define PKG_TIME_UNIT REG_GENMASK(19, 16)
> +#define PCU_PACKAGE_ENERGY_STATUS _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x593c)
>
> #define GEN6_GT_PERF_STATUS _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5948)
> #define GEN6_RP_STATE_LIMITS _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5994)
> --
> 2.25.1
>
