diff mbox series

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

Message ID 20220825132118.784407-5-badal.nilawar@intel.com (mailing list archive)
State Handled Elsewhere
Headers show
Series drm/i915: Add HWMON support | expand

Commit Message

Nilawar, Badal Aug. 25, 2022, 1:21 p.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

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>
---
 .../ABI/testing/sysfs-driver-intel-i915-hwmon |   8 ++
 drivers/gpu/drm/i915/i915_hwmon.c             | 119 +++++++++++++++++-
 drivers/gpu/drm/i915/i915_hwmon.h             |   1 +
 drivers/gpu/drm/i915/intel_mchbar_regs.h      |   2 +
 4 files changed, 128 insertions(+), 2 deletions(-)

Comments

Dixit, Ashutosh Aug. 30, 2022, 3:14 a.m. UTC | #1 
On Thu, 25 Aug 2022 06:21:15 -0700, 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

A few things to delete below but since no other changes this is:

Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>

> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> index 9a2d10edfce8..03d71c6869d3 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:		June 2022
> +KernelVersion:	5.19

Need to update kernel version on all patches now at least to 6.0 if not
6.1.

> +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;
> +
> +	if (!i915_mmio_reg_valid(rgaddr))
> +		return -EOPNOTSUPP;

Delete two lines above. Something like this is only needed if we have
i915_hwmon_energy_status_get() which we are deleting
below. hwm_energy_is_visible() takes care of making the sysfs node
invisible when something cannot be supported and has the same check.

> +int
> +i915_hwmon_energy_status_get(struct drm_i915_private *i915, long *energy)
> +{
> +	struct i915_hwmon *hwmon = i915->hwmon;
> +	struct hwm_drvdata *ddat = &hwmon->ddat;
> +
> +	return hwm_energy(ddat, energy);
> +}

Let's delete this function, there are no users for it at present.

> diff --git a/drivers/gpu/drm/i915/i915_hwmon.h b/drivers/gpu/drm/i915/i915_hwmon.h
> index 7ca9cf2c34c9..4e5b6c149f3a 100644
> --- a/drivers/gpu/drm/i915/i915_hwmon.h
> +++ b/drivers/gpu/drm/i915/i915_hwmon.h
> @@ -17,4 +17,5 @@ static inline void i915_hwmon_register(struct drm_i915_private *i915) { };
>  static inline void i915_hwmon_unregister(struct drm_i915_private *i915) { };
>  #endif
>
> +int i915_hwmon_energy_status_get(struct drm_i915_private *i915, long *energy);

Delete.
Tvrtko Ursulin Sept. 13, 2022, 8:50 a.m. UTC | #2 
On 25/08/2022 14:21, 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
> 
> 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>
> ---
>   .../ABI/testing/sysfs-driver-intel-i915-hwmon |   8 ++
>   drivers/gpu/drm/i915/i915_hwmon.c             | 119 +++++++++++++++++-
>   drivers/gpu/drm/i915/i915_hwmon.h             |   1 +
>   drivers/gpu/drm/i915/intel_mchbar_regs.h      |   2 +
>   4 files changed, 128 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> index 9a2d10edfce8..03d71c6869d3 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:		June 2022
> +KernelVersion:	5.19

Date and kernel version will need updating throughout I think.

But why I am here actually is to ask if there are plans to make 
intel_gpu_top support this? It would be nice to have since it reports 
power for integrated.

Regards,

Tvrtko

> +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 922463da65bf..e35f125be242 100644
> --- a/drivers/gpu/drm/i915/i915_hwmon.c
> +++ b/drivers/gpu/drm/i915/i915_hwmon.c
> @@ -16,8 +16,10 @@
>   /*
>    * SF_* - scale factors for particular quantities according to hwmon spec.
>    * - power  - microwatts
> + * - energy - microjoules
>    */
>   #define SF_POWER	1000000
> +#define SF_ENERGY	1000000
>   
>   #define FIELD_SHIFT(__mask)				    \
>   	(BUILD_BUG_ON_ZERO(!__builtin_constant_p(__mask)) + \
> @@ -29,12 +31,19 @@ struct hwm_reg {
>   	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];
>   };
>   
> @@ -43,6 +52,7 @@ 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
> @@ -102,9 +112,72 @@ 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;
> +
> +	if (!i915_mmio_reg_valid(rgaddr))
> +		return -EOPNOTSUPP;
> +
> +	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;
> +}
> +
> +int
> +i915_hwmon_energy_status_get(struct drm_i915_private *i915, long *energy)
> +{
> +	struct i915_hwmon *hwmon = i915->hwmon;
> +	struct hwm_drvdata *ddat = &hwmon->ddat;
> +
> +	return hwm_energy(ddat, energy);
> +}
> +
>   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
>   };
>   
> @@ -199,6 +272,32 @@ 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)
> @@ -210,6 +309,8 @@ 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;
>   	}
> @@ -226,6 +327,8 @@ 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;
>   	}
> @@ -261,19 +364,23 @@ 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 = INVALID_MMIO_REG;
>   		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) {
> @@ -291,9 +398,17 @@ 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/i915_hwmon.h b/drivers/gpu/drm/i915/i915_hwmon.h
> index 7ca9cf2c34c9..4e5b6c149f3a 100644
> --- a/drivers/gpu/drm/i915/i915_hwmon.h
> +++ b/drivers/gpu/drm/i915/i915_hwmon.h
> @@ -17,4 +17,5 @@ static inline void i915_hwmon_register(struct drm_i915_private *i915) { };
>   static inline void i915_hwmon_unregister(struct drm_i915_private *i915) { };
>   #endif
>   
> +int i915_hwmon_energy_status_get(struct drm_i915_private *i915, long *energy);
>   #endif /* __I915_HWMON_H__ */
> diff --git a/drivers/gpu/drm/i915/intel_mchbar_regs.h b/drivers/gpu/drm/i915/intel_mchbar_regs.h
> index b74df11977c6..1014d0b7cc16 100644
> --- a/drivers/gpu/drm/i915/intel_mchbar_regs.h
> +++ b/drivers/gpu/drm/i915/intel_mchbar_regs.h
> @@ -191,7 +191,9 @@
>   
>   #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)
Dixit, Ashutosh Sept. 21, 2022, 12:24 a.m. UTC | #3 
On Tue, 13 Sep 2022 01:50:08 -0700, Tvrtko Ursulin wrote:
>

Hi Tvrtko,

> On 25/08/2022 14:21, Badal Nilawar wrote:
> > From: Dale B Stimson <dale.b.stimson@intel.com>
> >
> > diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
> > index 9a2d10edfce8..03d71c6869d3 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:		June 2022
> > +KernelVersion:	5.19
>
> Date and kernel version will need updating throughout I think.
>
> But why I am here actually is to ask if there are plans to make
> intel_gpu_top support this? It would be nice to have since it reports power
> for integrated.

There were no plans but now Riana has an IGT patch series which exposes a
unified inteface for rapl/hwmon (igfx/dgfx):

https://patchwork.freedesktop.org/series/108185/

So perhaps we can either have intel_gpu_top use this IGT lib or if it
doesn't, copy some functions to intel_gpu_top.

Thanks.
--
Ashutosh
Tvrtko Ursulin Sept. 21, 2022, 7:43 a.m. UTC | #4 
On 21/09/2022 01:24, Dixit, Ashutosh wrote:
> On Tue, 13 Sep 2022 01:50:08 -0700, Tvrtko Ursulin wrote:
>>
> 
> Hi Tvrtko,
> 
>> On 25/08/2022 14:21, Badal Nilawar wrote:
>>> From: Dale B Stimson <dale.b.stimson@intel.com>
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
>>> index 9a2d10edfce8..03d71c6869d3 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:		June 2022
>>> +KernelVersion:	5.19
>>
>> Date and kernel version will need updating throughout I think.
>>
>> But why I am here actually is to ask if there are plans to make
>> intel_gpu_top support this? It would be nice to have since it reports power
>> for integrated.
> 
> There were no plans but now Riana has an IGT patch series which exposes a
> unified inteface for rapl/hwmon (igfx/dgfx):
> 
> https://patchwork.freedesktop.org/series/108185/
> 
> So perhaps we can either have intel_gpu_top use this IGT lib or if it
> doesn't, copy some functions to intel_gpu_top.

Looks promising and would be nice yeah.

On the practicalities, first thing which comes to mind that probably it 
would need to be a separate library like igt_perf and igt_device_scan, 
since so far we have avoided linking intel_gpu_top with the whole lib_igt.

Regards,

Tvrtko
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 9a2d10edfce8..03d71c6869d3 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:		June 2022
+KernelVersion:	5.19
+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 922463da65bf..e35f125be242 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -16,8 +16,10 @@ 
 /*
  * SF_* - scale factors for particular quantities according to hwmon spec.
  * - power  - microwatts
+ * - energy - microjoules
  */
 #define SF_POWER	1000000
+#define SF_ENERGY	1000000
 
 #define FIELD_SHIFT(__mask)				    \
 	(BUILD_BUG_ON_ZERO(!__builtin_constant_p(__mask)) + \
@@ -29,12 +31,19 @@  struct hwm_reg {
 	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];
 };
 
@@ -43,6 +52,7 @@  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
@@ -102,9 +112,72 @@  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;
+
+	if (!i915_mmio_reg_valid(rgaddr))
+		return -EOPNOTSUPP;
+
+	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;
+}
+
+int
+i915_hwmon_energy_status_get(struct drm_i915_private *i915, long *energy)
+{
+	struct i915_hwmon *hwmon = i915->hwmon;
+	struct hwm_drvdata *ddat = &hwmon->ddat;
+
+	return hwm_energy(ddat, energy);
+}
+
 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
 };
 
@@ -199,6 +272,32 @@  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)
@@ -210,6 +309,8 @@  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;
 	}
@@ -226,6 +327,8 @@  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;
 	}
@@ -261,19 +364,23 @@  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 = INVALID_MMIO_REG;
 		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) {
@@ -291,9 +398,17 @@  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/i915_hwmon.h b/drivers/gpu/drm/i915/i915_hwmon.h
index 7ca9cf2c34c9..4e5b6c149f3a 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.h
+++ b/drivers/gpu/drm/i915/i915_hwmon.h
@@ -17,4 +17,5 @@  static inline void i915_hwmon_register(struct drm_i915_private *i915) { };
 static inline void i915_hwmon_unregister(struct drm_i915_private *i915) { };
 #endif
 
+int i915_hwmon_energy_status_get(struct drm_i915_private *i915, long *energy);
 #endif /* __I915_HWMON_H__ */
diff --git a/drivers/gpu/drm/i915/intel_mchbar_regs.h b/drivers/gpu/drm/i915/intel_mchbar_regs.h
index b74df11977c6..1014d0b7cc16 100644
--- a/drivers/gpu/drm/i915/intel_mchbar_regs.h
+++ b/drivers/gpu/drm/i915/intel_mchbar_regs.h
@@ -191,7 +191,9 @@ 
 
 #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)