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drm/i915/hwmon: Show device level energy usage
authorDale B Stimson <dale.b.stimson@intel.com>
Thu, 13 Oct 2022 15:45:23 +0000 (08:45 -0700)
committerAnshuman Gupta <anshuman.gupta@intel.com>
Mon, 17 Oct 2022 09:23:50 +0000 (14:53 +0530)
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)
v5: Change contact to intel-gfx (Rodrigo)
    Change return type of hwm_energy to void (Andi)

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>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221013154526.2105579-5-ashutosh.dixit@intel.com
Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
drivers/gpu/drm/i915/i915_hwmon.c
drivers/gpu/drm/i915/intel_mchbar_regs.h

index e0b1af4..aa00c55 100644 (file)
@@ -25,3 +25,11 @@ Contact:     intel-gfx@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:       intel-gfx@lists.freedesktop.org
+Description:   RO. Energy input of device in microjoules.
+
+               Only supported for particular Intel i915 graphics platforms.
index db25441..d8d30da 100644 (file)
  * 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 +108,58 @@ 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 void
+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);
+}
+
 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
 };
 
@@ -195,6 +254,33 @@ 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:
+               hwm_energy(ddat, val);
+               return 0;
+       default:
+               return -EOPNOTSUPP;
+       }
+}
+
+static umode_t
 hwm_is_visible(const void *drvdata, enum hwmon_sensor_types type,
               u32 attr, int channel)
 {
@@ -205,6 +291,8 @@ 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;
        }
@@ -221,6 +309,8 @@ 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;
        }
@@ -256,8 +346,10 @@ 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 = 0;
+       long energy;
 
        /* Available for all Gen12+/dGfx */
        hwmon->rg.gt_perf_status = GEN12_RPSTAT1;
@@ -266,10 +358,12 @@ hwm_get_preregistration_info(struct drm_i915_private *i915)
                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.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 +374,17 @@ hwm_get_preregistration_info(struct drm_i915_private *i915)
                if (i915_mmio_reg_valid(hwmon->rg.pkg_power_sku_unit))
                        val_sku_unit = intel_uncore_read(uncore,
                                                         hwmon->rg.pkg_power_sku_unit);
-
-               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)
index d7e2e47..decd411 100644 (file)
 
 #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)