drm/i915/hwmon: expose fan speed

Add hwmon support for fan1_input attribute, which will expose fan speed
in RPM. With this in place we can monitor fan speed using lm-sensors tool.

$ sensors
i915-pci-0300
Adapter: PCI adapter
in0:         653.00 mV
fan1:        3833 RPM
power1:           N/A  (max =  43.00 W)
energy1:      32.02 kJ

v2: Handle overflow, add mutex protection and ABI documentation
    Aesthetic adjustments (Riana)
v3: Change rotations data type, ABI date and version
v4: Fix wakeref leak
    Drop switch case and simplify hwm_fan_xx() (Andi)
v5: Rework time calculation, aesthetic adjustments (Andy)
v6: Drop redundant overflow logic (Andy)
    Split fan_input_read() into dedicated helper (Badal)
v7: Fix undefined reference to __udivdi3 for i386 (Andy)

Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Riana Tauro <riana.tauro@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Badal Nilawar <badal.nilawar@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240823034548.2670032-1-raag.jadav@intel.com

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
index 92fe7c5c5ac1d1d981562d1b441f32a6bafdc1aa..be4141a7522f6b44e058c131b191d2234f74ceaa 100644 (file)
--- a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
+++ b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
@@ -75,3 +75,11 @@ Description: RO. Energy input of device or gt in microjoules.
                for the gt.
 
                Only supported for particular Intel i915 graphics platforms.
+
+What:          /sys/bus/pci/drivers/i915/.../hwmon/hwmon<i>/fan1_input
+Date:          November 2024
+KernelVersion: 6.12
+Contact:       intel-gfx@lists.freedesktop.org
+Description:   RO. Fan speed of device in RPM.
+
+               Only supported for particular Intel i915 graphics platforms.

diff --git a/drivers/gpu/drm/i915/gt/intel_gt_regs.h b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
index e42b3a5d4e63dd2b9908ea18ee4fcee9c821a41e..57a3c83d3655377f3482328fd1bdc19371c2e501 100644 (file)
--- a/drivers/gpu/drm/i915/gt/intel_gt_regs.h
+++ b/drivers/gpu/drm/i915/gt/intel_gt_regs.h
@@ -1553,6 +1553,8 @@
 #define VLV_RENDER_C0_COUNT                    _MMIO(0x138118)
 #define VLV_MEDIA_C0_COUNT                     _MMIO(0x13811c)
 
+#define PCU_PWM_FAN_SPEED                      _MMIO(0x138140)
+
 #define GEN12_RPSTAT1                          _MMIO(0x1381b4)
 #define   GEN12_VOLTAGE_MASK                   REG_GENMASK(10, 0)
 #define   GEN12_CAGF_MASK                      REG_GENMASK(19, 11)

diff --git a/drivers/gpu/drm/i915/i915_hwmon.c b/drivers/gpu/drm/i915/i915_hwmon.c
index 49db3e09826c70c2b9725ea4d25ea5e73c10c40a..17d30f6b84b0316a09ae9f0befbfb4c244592068 100644 (file)
--- a/drivers/gpu/drm/i915/i915_hwmon.c
+++ b/drivers/gpu/drm/i915/i915_hwmon.c
@@ -5,6 +5,7 @@
 
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
+#include <linux/jiffies.h>
 #include <linux/types.h>
 
 #include "i915_drv.h"
@@ -36,6 +37,7 @@ struct hwm_reg {
        i915_reg_t pkg_rapl_limit;
        i915_reg_t energy_status_all;
        i915_reg_t energy_status_tile;
+       i915_reg_t fan_speed;
 };
 
 struct hwm_energy_info {
@@ -43,11 +45,17 @@ struct hwm_energy_info {
        long accum_energy;                      /* Accumulated energy for energy1_input */
 };
 
+struct hwm_fan_info {
+       u32 reg_val_prev;
+       u64 time_prev;
+};
+
 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 */
+       struct hwm_fan_info fi;                 /*  Fan info for fan1_input */
        char name[12];
        int gt_n;
        bool reset_in_progress;
@@ -276,6 +284,7 @@ static const struct hwmon_channel_info * const hwm_info[] = {
        HWMON_CHANNEL_INFO(power, HWMON_P_MAX | HWMON_P_RATED_MAX | HWMON_P_CRIT),
        HWMON_CHANNEL_INFO(energy, HWMON_E_INPUT),
        HWMON_CHANNEL_INFO(curr, HWMON_C_CRIT),
+       HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
        NULL
 };
 
@@ -613,6 +622,69 @@ hwm_curr_write(struct hwm_drvdata *ddat, u32 attr, long val)
        }
 }
 
+static umode_t
+hwm_fan_is_visible(const struct hwm_drvdata *ddat, u32 attr)
+{
+       struct i915_hwmon *hwmon = ddat->hwmon;
+
+       if (attr == hwmon_fan_input && i915_mmio_reg_valid(hwmon->rg.fan_speed))
+               return 0444;
+
+       return 0;
+}
+
+static int
+hwm_fan_input_read(struct hwm_drvdata *ddat, long *val)
+{
+       struct i915_hwmon *hwmon = ddat->hwmon;
+       struct hwm_fan_info *fi = &ddat->fi;
+       u64 rotations, time_now, time;
+       intel_wakeref_t wakeref;
+       u32 reg_val;
+       int ret = 0;
+
+       wakeref = intel_runtime_pm_get(ddat->uncore->rpm);
+       mutex_lock(&hwmon->hwmon_lock);
+
+       reg_val = intel_uncore_read(ddat->uncore, hwmon->rg.fan_speed);
+       time_now = get_jiffies_64();
+
+       /*
+        * HW register value is accumulated count of pulses from
+        * PWM fan with the scale of 2 pulses per rotation.
+        */
+       rotations = (reg_val - fi->reg_val_prev) / 2;
+
+       time = jiffies_delta_to_msecs(time_now - fi->time_prev);
+       if (unlikely(!time)) {
+               ret = -EAGAIN;
+               goto exit;
+       }
+
+       /*
+        * Calculate fan speed in RPM by time averaging two subsequent
+        * readings in minutes.
+        * RPM = number of rotations * msecs per minute / time in msecs
+        */
+       *val = DIV_ROUND_UP_ULL(rotations * (MSEC_PER_SEC * 60), time);
+
+       fi->reg_val_prev = reg_val;
+       fi->time_prev = time_now;
+exit:
+       mutex_unlock(&hwmon->hwmon_lock);
+       intel_runtime_pm_put(ddat->uncore->rpm, wakeref);
+       return ret;
+}
+
+static int
+hwm_fan_read(struct hwm_drvdata *ddat, u32 attr, long *val)
+{
+       if (attr == hwmon_fan_input)
+               return hwm_fan_input_read(ddat, val);
+
+       return -EOPNOTSUPP;
+}
+
 static umode_t
 hwm_is_visible(const void *drvdata, enum hwmon_sensor_types type,
               u32 attr, int channel)
@@ -628,6 +700,8 @@ hwm_is_visible(const void *drvdata, enum hwmon_sensor_types type,
                return hwm_energy_is_visible(ddat, attr);
        case hwmon_curr:
                return hwm_curr_is_visible(ddat, attr);
+       case hwmon_fan:
+               return hwm_fan_is_visible(ddat, attr);
        default:
                return 0;
        }
@@ -648,6 +722,8 @@ hwm_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
                return hwm_energy_read(ddat, attr, val);
        case hwmon_curr:
                return hwm_curr_read(ddat, attr, val);
+       case hwmon_fan:
+               return hwm_fan_read(ddat, attr, val);
        default:
                return -EOPNOTSUPP;
        }
@@ -739,12 +815,14 @@ hwm_get_preregistration_info(struct drm_i915_private *i915)
                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;
+               hwmon->rg.fan_speed = PCU_PWM_FAN_SPEED;
        } 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;
                hwmon->rg.energy_status_tile = INVALID_MMIO_REG;
+               hwmon->rg.fan_speed = INVALID_MMIO_REG;
        }
 
        with_intel_runtime_pm(uncore->rpm, wakeref) {
@@ -755,6 +833,16 @@ 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);
+
+               /*
+                * Store the initial fan register value, so that we can use it for
+                * initial fan speed calculation.
+                */
+               if (i915_mmio_reg_valid(hwmon->rg.fan_speed)) {
+                       ddat->fi.reg_val_prev = intel_uncore_read(uncore,
+                                                                 hwmon->rg.fan_speed);
+                       ddat->fi.time_prev = get_jiffies_64();
+               }
        }
 
        hwmon->scl_shift_power = REG_FIELD_GET(PKG_PWR_UNIT, val_sku_unit);