[PATCH v1] drm/xe/hwmon: expose fan speed

Poosa, Karthik karthik.poosa at intel.com
Thu Mar 6 14:51:45 UTC 2025


On 24-02-2025 13:16, Raag Jadav wrote:
> On Fri, Feb 21, 2025 at 08:32:01PM +0530, Poosa, Karthik wrote:
>> On 10-02-2025 15:35, Raag Jadav wrote:
>>> Add hwmon support for fan1_input, fan2_input and fan3_input attributes,
>>> which will expose fan speed of respective channels in RPM when supported
>>> by hardware. With this in place we can monitor fan speed using lm-sensors
>>> tool.
>>>
>>> Signed-off-by: Raag Jadav <raag.jadav at intel.com>
>>> ---
>>>    .../ABI/testing/sysfs-driver-intel-xe-hwmon   |  24 ++++
>>>    drivers/gpu/drm/xe/regs/xe_pcode_regs.h       |   3 +
>>>    drivers/gpu/drm/xe/xe_hwmon.c                 | 124 +++++++++++++++++-
>>>    drivers/gpu/drm/xe/xe_pcode_api.h             |   3 +
>>>    4 files changed, 153 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Documentation/ABI/testing/sysfs-driver-intel-xe-hwmon b/Documentation/ABI/testing/sysfs-driver-intel-xe-hwmon
>>> index 9bce281314df..adbb9bce15a5 100644
>>> --- a/Documentation/ABI/testing/sysfs-driver-intel-xe-hwmon
>>> +++ b/Documentation/ABI/testing/sysfs-driver-intel-xe-hwmon
>>> @@ -124,3 +124,27 @@ Contact:	intel-xe at lists.freedesktop.org
>>>    Description:	RO. VRAM temperature in millidegree Celsius.
>>>    		Only supported for particular Intel Xe graphics platforms.
>>> +
>>> +What:		/sys/bus/pci/drivers/xe/.../hwmon/hwmon<i>/fan1_input
>>> +Date:		March 2025
>>> +KernelVersion:	6.14
>>> +Contact:	intel-xe at lists.freedesktop.org
>>> +Description:	RO. Fan 1 speed in RPM.
>>> +
>>> +		Only supported for particular Intel Xe graphics platforms.
>>> +
>>> +What:		/sys/bus/pci/drivers/xe/.../hwmon/hwmon<i>/fan2_input
>>> +Date:		March 2025
>>> +KernelVersion:	6.14
>>> +Contact:	intel-xe at lists.freedesktop.org
>>> +Description:	RO. Fan 2 speed in RPM.
>>> +
>>> +		Only supported for particular Intel Xe graphics platforms.
>>> +
>>> +What:		/sys/bus/pci/drivers/xe/.../hwmon/hwmon<i>/fan3_input
>>> +Date:		March 2025
>>> +KernelVersion:	6.14
>>> +Contact:	intel-xe at lists.freedesktop.org
>>> +Description:	RO. Fan 3 speed in RPM.
>>> +
>>> +		Only supported for particular Intel Xe graphics platforms.
>>> diff --git a/drivers/gpu/drm/xe/regs/xe_pcode_regs.h b/drivers/gpu/drm/xe/regs/xe_pcode_regs.h
>>> index 8846eb9ce2a4..c7d5d782e3f9 100644
>>> --- a/drivers/gpu/drm/xe/regs/xe_pcode_regs.h
>>> +++ b/drivers/gpu/drm/xe/regs/xe_pcode_regs.h
>>> @@ -21,6 +21,9 @@
>>>    #define BMG_PACKAGE_POWER_SKU			XE_REG(0x138098)
>>>    #define BMG_PACKAGE_POWER_SKU_UNIT		XE_REG(0x1380dc)
>>>    #define BMG_PACKAGE_ENERGY_STATUS		XE_REG(0x138120)
>>> +#define BMG_FAN_1_SPEED				XE_REG(0x138140)
>>> +#define BMG_FAN_2_SPEED				XE_REG(0x138170)
>>> +#define BMG_FAN_3_SPEED				XE_REG(0x1381a0)
>> Can you rename macros without having platform names, as this register is
>> available for both DG2 and BMG, like FAN_1_SPEED.
> Are you sure if we want to break the convention here?

I think we should, as the offset is not for a single platform.
You can also check if future platforms would continue to use the same 
offset.

>
>>>    #define BMG_VRAM_TEMPERATURE			XE_REG(0x1382c0)
>>>    #define BMG_PACKAGE_TEMPERATURE			XE_REG(0x138434)
>>>    #define BMG_PACKAGE_RAPL_LIMIT			XE_REG(0x138440)
>>> diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
>>> index 7f327e334212..f1f95655d9fb 100644
>>> --- a/drivers/gpu/drm/xe/xe_hwmon.c
>>> +++ b/drivers/gpu/drm/xe/xe_hwmon.c
>>> @@ -5,6 +5,7 @@
>>>    #include <linux/hwmon-sysfs.h>
>>>    #include <linux/hwmon.h>
>>> +#include <linux/jiffies.h>
>>>    #include <linux/types.h>
>>>    #include <linux/units.h>
>>> @@ -27,6 +28,7 @@ enum xe_hwmon_reg {
>>>    	REG_PKG_POWER_SKU_UNIT,
>>>    	REG_GT_PERF_STATUS,
>>>    	REG_PKG_ENERGY_STATUS,
>>> +	REG_FAN_SPEED,
>>>    };
>>>    enum xe_hwmon_reg_operation {
>>> @@ -42,6 +44,13 @@ enum xe_hwmon_channel {
>>>    	CHANNEL_MAX,
>>>    };
>>> +enum xe_fan_channel {
>>> +	FAN_1,
>>> +	FAN_2,
>>> +	FAN_3,
>>> +	FAN_MAX,
>>> +};
>>> +
>>>    /*
>>>     * SF_* - scale factors for particular quantities according to hwmon spec.
>>>     */
>>> @@ -61,6 +70,16 @@ struct xe_hwmon_energy_info {
>>>    	long accum_energy;
>>>    };
>>> +/**
>>> + * struct xe_hwmon_fan_info - to cache previous fan reading
>>> + */
>>> +struct xe_hwmon_fan_info {
>>> +	/** @reg_val_prev: previous fan reg val */
>>> +	u32 reg_val_prev;
>>> +	/** @time_prev: previous timestamp */
>>> +	u64 time_prev;
>>> +};
>>> +
>>>    /**
>>>     * struct xe_hwmon - xe hwmon data structure
>>>     */
>>> @@ -79,6 +98,8 @@ struct xe_hwmon {
>>>    	int scl_shift_time;
>>>    	/** @ei: Energy info for energyN_input */
>>>    	struct xe_hwmon_energy_info ei[CHANNEL_MAX];
>>> +	/** @fi: Fan info for fanN_input */
>>> +	struct xe_hwmon_fan_info fi[FAN_MAX];
>>>    };
>>>    static struct xe_reg xe_hwmon_get_reg(struct xe_hwmon *hwmon, enum xe_hwmon_reg hwmon_reg,
>>> @@ -144,6 +165,16 @@ static struct xe_reg xe_hwmon_get_reg(struct xe_hwmon *hwmon, enum xe_hwmon_reg
>>>    			return PCU_CR_PACKAGE_ENERGY_STATUS;
>>>    		}
>>>    		break;
>>> +	case REG_FAN_SPEED:
>>> +		if (xe->info.platform == XE_BATTLEMAGE || xe->info.platform == XE_DG2) {
>>> +			if (channel == FAN_1)
>>> +				return BMG_FAN_1_SPEED;
>>> +			else if (channel == FAN_2)
>>> +				return BMG_FAN_2_SPEED;
>>> +			else if (channel == FAN_3)
>>> +				return BMG_FAN_3_SPEED;
>>> +		}
>>> +		break;
>>>    	default:
>>>    		drm_warn(&xe->drm, "Unknown xe hwmon reg id: %d\n", hwmon_reg);
>>>    		break;
>>> @@ -454,6 +485,7 @@ static const struct hwmon_channel_info * const hwmon_info[] = {
>>>    	HWMON_CHANNEL_INFO(curr, HWMON_C_LABEL, HWMON_C_CRIT | HWMON_C_LABEL),
>>>    	HWMON_CHANNEL_INFO(in, HWMON_I_INPUT | HWMON_I_LABEL, HWMON_I_INPUT | HWMON_I_LABEL),
>>>    	HWMON_CHANNEL_INFO(energy, HWMON_E_INPUT | HWMON_E_LABEL, HWMON_E_INPUT | HWMON_E_LABEL),
>>> +	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT, HWMON_F_INPUT, HWMON_F_INPUT),
>>>    	NULL
>>>    };
>>> @@ -480,6 +512,14 @@ static int xe_hwmon_pcode_write_i1(const struct xe_hwmon *hwmon, u32 uval)
>>>    			      (uval & POWER_SETUP_I1_DATA_MASK));
>>>    }
>>> +static int xe_hwmon_pcode_read_num_fans(const struct xe_hwmon *hwmon, u32 *uval)
>>> +{
>>> +	struct xe_tile *root_tile = xe_device_get_root_tile(hwmon->xe);
>>> +
>>> +	return xe_pcode_read(root_tile, PCODE_MBOX(FAN_SPEED_CONTROL,
>>> +			     FSC_READ_NUM_FANS, 0), uval, NULL);
>>> +}
>>> +
>>>    static int xe_hwmon_power_curr_crit_read(struct xe_hwmon *hwmon, int channel,
>>>    					 long *value, u32 scale_factor)
>>>    {
>>> @@ -705,6 +745,77 @@ xe_hwmon_energy_read(struct xe_hwmon *hwmon, u32 attr, int channel, long *val)
>>>    	}
>>>    }
>>> +static umode_t
>>> +xe_hwmon_fan_is_visible(struct xe_hwmon *hwmon, u32 attr, int channel)
>>> +{
>>> +	struct xe_device *xe = hwmon->xe;
>>> +	u32 uval;
>>> +
>>> +	switch (attr) {
>>> +	case hwmon_fan_input:
>>> +		if (xe_hwmon_pcode_read_num_fans(hwmon, &uval))
>>> +			return 0;
>>> +
>>> +		/* Platforms that don't return correct value */
>> This can be rephrased to - "Platforms that don't support fan pcode mailbox
>> cmds"
> We wouldn't be at this point if it was not supported.

Does DG2 return incorrect value ?

AFAIK, FSC_READ_NUM_FANS is not supported on DG2.

>
>>> +		if (xe->info.platform == XE_DG2)
>>> +			uval = 2;
>>> +
>>> +		return channel < uval ? 0444 : 0;
>>> +	default:
>>> +		return 0;
>>> +	}
>>> +}
> Raag


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