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@xxxxxxxxx>
Reviewed-by: Riana Tauro <riana.tauro@xxxxxxxxx>
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
---
.../ABI/testing/sysfs-driver-intel-i915-hwmon | 8 ++
drivers/gpu/drm/i915/gt/intel_gt_regs.h | 2 +
drivers/gpu/drm/i915/i915_hwmon.c | 88 +++++++++++++++++++
3 files changed, 98 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-i915-hwmon
index 92fe7c5c5ac1..be4141a7522f 100644
--- 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@xxxxxxxxxxxxxxxxxxxxx
+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 e42b3a5d4e63..57a3c83d3655 100644
--- 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 49db3e09826c..17d30f6b84b0 100644
--- 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();
+ }
