[Intel-gfx] [PATCH 4/7] drm/i915/hwmon: Show device level energy usage

Badal Nilawar
2022-08-12T17:36:06Z

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>
---
.../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/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 2ce5bf94b220..416c77c89609 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -15,8 +15,10 @@
/*
* 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)) + \
@@ -28,12 +30,19 @@ 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 hwm_reg rg;
u32 power_max_initial_value;
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 921ae76099d3..d5d7f4a0bf4e 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.h
+++ b/drivers/gpu/drm/i915/i915_hwmon.h
@@ -17,4 +17,5 @@ struct drm_i915_private;
void i915_hwmon_register(struct drm_i915_private *i915);
void i915_hwmon_unregister(struct drm_i915_private *i915);

+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 4ba5f30b7901..18fcfc39ca2f 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)
--
2.25.1