[Intel-gfx] [PATCH 4/4] drm/i915/hwmon: Add HWMON energy support
Badal Nilawar
badal.nilawar at intel.com
Mon Jun 20 20:46:49 UTC 2022
From: Dale B Stimson <dale.b.stimson at intel.com>
As part of the System Managemenent Interface (SMI), use the HWMON
subsystem to display energy utilization
v2:
- Updated the date and kernel version in feature description
Signed-off-by: Dale B Stimson <dale.b.stimson at intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
Signed-off-by: Riana Tauro <riana.tauro at intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar at intel.com>
---
.../ABI/testing/sysfs-driver-intel-i915-hwmon | 16 ++
drivers/gpu/drm/i915/i915_hwmon.c | 174 +++++++++++++++++-
drivers/gpu/drm/i915/i915_hwmon.h | 1 +
drivers/gpu/drm/i915/intel_mchbar_regs.h | 2 +
4 files changed, 185 insertions(+), 8 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
index 945f472dd4a2..2e87d7422b73 100644
--- a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
+++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
@@ -25,3 +25,19 @@ Contact: dri-devel at 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 at lists.freedesktop.org
+Description: RO. Energy input of device in microjoules.
+
+ The returned textual representation is an unsigned integer
+ number that can be stored in 64-bits. Warning: The hardware
+ register is 32-bits wide and can overflow by wrapping around.
+ A single wrap-around between calls to read this value can
+ be detected and will be accounted for in the returned value.
+ At a power consumption of 1 watt, the 32-bit hardware register
+ would wrap-around approximately every 3 days.
+
+ 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 75935a55f573..77d68f17316a 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -19,8 +19,10 @@
/*
* 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)) + \
@@ -32,12 +34,20 @@ struct i915_hwmon_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;
+ i915_reg_t energy_status_tile;
+};
+
+struct i915_energy_info {
+ u32 energy_counter_overflow;
+ u32 energy_counter_prev;
};
struct i915_hwmon_drvdata {
struct i915_hwmon *hwmon;
struct intel_uncore *uncore;
struct device *hwmon_dev;
+ struct i915_energy_info ei; /* Energy info for energy1_input */
char name[12];
};
@@ -51,6 +61,7 @@ struct i915_hwmon {
u32 power_max_initial_value;
int scl_shift_power;
+ int scl_shift_energy;
};
static void
@@ -121,6 +132,136 @@ _field_scale_and_write(struct i915_hwmon_drvdata *ddat, i915_reg_t rgadr,
bits_to_clear, bits_to_set);
}
+/*
+ * _i915_energy1_input_sub - A custom function to obtain energy1_input.
+ * Use a custom function instead of the usual hwmon helpers in order to
+ * guarantee 64-bits of result to user-space.
+ * Units are microjoules.
+ *
+ * The underlying hardware register is 32-bits and is subject to overflow.
+ * This function compensates for overflow of the 32-bit register by detecting
+ * wrap-around and incrementing an overflow counter.
+ * This only works if the register is sampled often enough to avoid
+ * missing an instance of overflow - achieved either by repeated
+ * queries through the API, or via a possible timer (future - TBD) that
+ * ensures values are read often enough to catch all overflows.
+ *
+ * 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
+ */
+static int
+_i915_energy1_input_sub(struct i915_hwmon_drvdata *ddat, u64 *energy)
+{
+ struct intel_uncore *uncore = ddat->uncore;
+ struct i915_hwmon *hwmon = ddat->hwmon;
+ struct i915_energy_info *pei = &ddat->ei;
+ int nshift = hwmon->scl_shift_energy;
+ intel_wakeref_t wakeref;
+ u32 reg_value;
+ u64 vlo;
+ u64 vhi;
+ i915_reg_t rgaddr;
+
+ 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_value = intel_uncore_read(uncore, rgaddr);
+
+ /*
+ * The u32 register concatenated with the u32 overflow counter
+ * gives an effective energy counter size of 64-bits. However, the
+ * computations below are done modulo 2^96 to avoid overflow during
+ * scaling in the conversion to microjoules.
+ *
+ * The low-order 64-bits of the resulting quantity are returned to
+ * the caller in units of microjoules, encoded into a decimal string.
+ *
+ * For a power of 1000 watts, 64 bits in units of microjoules will
+ * overflow after 584 years.
+ */
+
+ if (pei->energy_counter_prev > reg_value)
+ pei->energy_counter_overflow++;
+
+ pei->energy_counter_prev = reg_value;
+
+ /*
+ * 64-bit variables vlo and vhi are used for the scaling process.
+ * The 96-bit counter value is composed from the two 64-bit variables
+ * vhi and vlo thusly: counter == vhi << 32 + vlo .
+ * The 32-bits of overlap between the two variables is convenient for
+ * handling overflows out of vlo.
+ */
+
+ vlo = reg_value;
+ vhi = pei->energy_counter_overflow;
+
+ mutex_unlock(&hwmon->hwmon_lock);
+
+ vlo = SF_ENERGY * vlo;
+
+ /* Prepare to round to nearest */
+ if (nshift > 0)
+ vlo += 1 << (nshift - 1);
+
+ /*
+ * Anything in the upper-32 bits of vlo gets added into vhi here,
+ * and then cleared from vlo.
+ */
+ vhi = (SF_ENERGY * vhi) + (vlo >> 32);
+ vlo &= 0xffffffffULL;
+
+ /*
+ * Apply the right shift.
+ * - vlo shifted by itself.
+ * - vlo receiving what's shifted out of vhi.
+ * - vhi shifted by itself
+ */
+ vlo = vlo >> nshift;
+ vlo |= (vhi << (32 - nshift)) & 0xffffffffULL;
+ vhi = vhi >> nshift;
+
+ /* Combined to get a 64-bit result in vlo. */
+ vlo |= (vhi << 32);
+
+ *energy = vlo;
+
+ return 0;
+}
+
+static ssize_t
+i915_energy1_input_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct i915_hwmon_drvdata *ddat = dev_get_drvdata(dev);
+ ssize_t ret = 0;
+ u64 energy;
+
+ if (!_i915_energy1_input_sub(ddat, &energy))
+ ret = sysfs_emit(buf, "%llu\n", energy);
+
+ return ret;
+}
+
+int
+i915_energy_status_get(struct drm_i915_private *i915, u64 *energy)
+{
+ struct i915_hwmon *hwmon = i915->hwmon;
+ struct i915_hwmon_drvdata *ddat = &hwmon->ddat;
+
+ return _i915_energy1_input_sub(ddat, energy);
+}
+
static ssize_t
i915_power1_max_default_show(struct device *dev, struct device_attribute *attr,
char *buf)
@@ -141,9 +282,12 @@ i915_power1_max_default_show(struct device *dev, struct device_attribute *attr,
static SENSOR_DEVICE_ATTR(power1_max_default, 0444,
i915_power1_max_default_show, NULL, 0);
+static SENSOR_DEVICE_ATTR(energy1_input, 0444,
+ i915_energy1_input_show, NULL, 0);
static struct attribute *hwmon_attributes[] = {
&sensor_dev_attr_power1_max_default.dev_attr.attr,
+ &sensor_dev_attr_energy1_input.dev_attr.attr,
NULL
};
@@ -153,17 +297,15 @@ static umode_t hwmon_attributes_visible(struct kobject *kobj,
struct device *dev = kobj_to_dev(kobj);
struct i915_hwmon_drvdata *ddat = dev_get_drvdata(dev);
struct drm_i915_private *i915 = ddat->uncore->i915;
- i915_reg_t rgadr;
+ struct i915_hwmon *hwmon = ddat->hwmon;
- if (attr == &sensor_dev_attr_power1_max_default.dev_attr.attr)
+ if (attr == &sensor_dev_attr_energy1_input.dev_attr.attr)
+ return i915_mmio_reg_valid(hwmon->rg.energy_status_all) ?
+ attr->mode : 0;
+ else if (attr == &sensor_dev_attr_power1_max_default.dev_attr.attr)
return IS_DGFX(i915) ? attr->mode : 0;
else
return 0;
-
- if (!i915_mmio_reg_valid(rgadr))
- return 0;
-
- return attr->mode;
}
static const struct attribute_group hwmon_attrgroup = {
@@ -356,6 +498,8 @@ i915_hwmon_get_preregistration_info(struct drm_i915_private *i915)
{
struct i915_hwmon *hwmon = i915->hwmon;
struct intel_uncore *uncore = &i915->uncore;
+ struct i915_hwmon_drvdata *ddat = &hwmon->ddat;
+ struct i915_energy_info *pei;
intel_wakeref_t wakeref;
u32 val_sku_unit;
@@ -364,11 +508,15 @@ i915_hwmon_get_preregistration_info(struct drm_i915_private *i915)
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;
+ hwmon->rg.energy_status_tile = INVALID_MMIO_REG;
} 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;
+ hwmon->rg.energy_status_tile = INVALID_MMIO_REG;
}
@@ -387,8 +535,18 @@ i915_hwmon_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);
+ pei = &ddat->ei;
+ pei->energy_counter_overflow = 0;
+
+ if (i915_mmio_reg_valid(hwmon->rg.energy_status_all))
+ pei->energy_counter_prev =
+ intel_uncore_read(uncore, hwmon->rg.energy_status_all);
+ else
+ pei->energy_counter_prev = 0;
}
+
+ 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);
}
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 1e7e2516a981..5a15c84e4721 100644
--- a/drivers/gpu/drm/i915/i915_hwmon.h
+++ b/drivers/gpu/drm/i915/i915_hwmon.h
@@ -18,4 +18,5 @@ struct i915_hwmon;
void i915_hwmon_register(struct drm_i915_private *i915);
void i915_hwmon_unregister(struct drm_i915_private *i915);
+int i915_energy_status_get(struct drm_i915_private *i915, u64 *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 a3eccdee0ca4..3f2fc62ebb68 100644
--- a/drivers/gpu/drm/i915/intel_mchbar_regs.h
+++ b/drivers/gpu/drm/i915/intel_mchbar_regs.h
@@ -193,7 +193,9 @@
#define GEN6_RP_STATE_LIMITS _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5994)
#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_RP_STATE_CAP _MMIO(MCHBAR_MIRROR_BASE_SNB + 0x5998)
#define RP0_CAP_MASK REG_GENMASK(7, 0)
--
2.25.1
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