diff mbox series

[4/7] drm/i915/hwmon: Show device level energy usage

Message ID 20220927055020.3499420-5-badal.nilawar@intel.com (mailing list archive)
State Handled Elsewhere
Headers show
Series drm/i915: Add HWMON support | expand

Commit Message

Nilawar, Badal Sept. 27, 2022, 5:50 a.m. UTC 
From: Dale B Stimson <dale.b.stimson@intel.com>

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@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Riana Tauro <riana.tauro@intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
---
 .../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(-)

Comments

Rodrigo Vivi Sept. 30, 2022, 4:52 p.m. UTC | #1 
On Tue, Sep 27, 2022 at 11:20:17AM +0530, Badal Nilawar wrote:
> From: Dale B Stimson <dale.b.stimson@intel.com>
> 
> 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@intel.com>
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> Signed-off-by: Riana Tauro <riana.tauro@intel.com>
> Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
> Acked-by: Guenter Roeck <linux@roeck-us.net>
> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
> ---
>  .../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@lists.freedesktop.org
>  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@lists.freedesktop.org

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@lists.freedesktop.org

> +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
>
Andi Shyti Oct. 3, 2022, 9:13 p.m. UTC | #2 
Hi Badal,

[...]

> > 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@lists.freedesktop.org
> >  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@lists.freedesktop.org
> 
> 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@lists.freedesktop.org

same question here.

> > +Description:	RO. Energy input of device in microjoules.
> > +
> > +		Only supported for particular Intel i915 graphics platforms.

[...]

> > +/*
> > + * 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)

This function can just be void.

Andi

> > +{

[...]
Dixit, Ashutosh Oct. 13, 2022, 3:54 p.m. UTC | #3 
On Fri, 30 Sep 2022 09:52:28 -0700, Rodrigo Vivi wrote:
>

Hi Rodrigo,

> On Tue, Sep 27, 2022 at 11:20:17AM +0530, Badal Nilawar wrote:
> > From: Dale B Stimson <dale.b.stimson@intel.com>
> >
> > 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@intel.com>
> > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> > Signed-off-by: Riana Tauro <riana.tauro@intel.com>
> > Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
> > Acked-by: Guenter Roeck <linux@roeck-us.net>
> > Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> > Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
> > ---
> >  .../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@lists.freedesktop.org
> >  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@lists.freedesktop.org
>
> 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@lists.freedesktop.org

I have changed the contact to intel-gfx@lists.freedesktop.org in v9 for all
patches.

Thanks.
--
Ashutosh
Dixit, Ashutosh Oct. 13, 2022, 3:54 p.m. UTC | #4 
On Mon, 03 Oct 2022 14:13:10 -0700, Andi Shyti wrote:
>

Hi Andi,

> [...]
>
> > > 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@lists.freedesktop.org
> > >  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@lists.freedesktop.org
> >
> > 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@lists.freedesktop.org
>
> same question here.

These have all been changed to intel-gfx.

>
> > > +Description:	RO. Energy input of device in microjoules.
> > > +
> > > +		Only supported for particular Intel i915 graphics platforms.
>
> [...]
>
> > > +/*
> > > + * 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)
>
> This function can just be void.

Done.

Thanks.
--
Ashutosh
diff mbox series

Patch

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@lists.freedesktop.org
 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@lists.freedesktop.org
+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)