Re: [PATCH v2] accel/ivpu: Add support for limiting NPU frequency

[Karol Wachowski <karol.wachowski@linux.intel.com>]

On 4/8/2026 3:08 PM, Andrzej Kacprowski wrote:
> Add configurable frequency limits to allow users to constrain the NPU
> operating frequency range for power and thermal management. This support
> requires firmware API version 3.34.0 or newer.
> 
> New sysfs interface:
> 
> The freq/ subdirectory contains the following attributes:
> 
> - hw_min_freq: Minimum frequency supported by hardware (read-only)
> - hw_max_freq: Maximum frequency supported by hardware (read-only)
> - hw_efficient_freq: Hardware's optimal operating frequency (read-only)
> - current_freq: Current NPU frequency in MHz (read-only)
> - set_min_freq: Configure minimum operating frequency (50XX+ devices)
> - set_max_freq: Configure maximum operating frequency (50XX+ devices)
> 
> Legacy attributes npu_max_frequency_mhz and npu_current_frequency_mhz
> are maintained for backward compatibility.
> 
> Implementation details:
> 
> - Frequency configuration is communicated to firmware via JSM messages
> - User-specified frequency values are clamped to hardware limits
> - Power-efficient frequency (pn_ratio) is adjusted dynamically to stay
>   within the configured range
> - Frequency configuration is initialized during device boot
> - The JSM API header is updated to version 3.34.0 to support the new
>   VPU_JSM_MSG_FREQ_CONFIG firmware message
> 
> Added description for the sysfs attributes in the Documentation/ABI.
> 
> Signed-off-by: Andrzej Kacprowski <andrzej.kacprowski@linux.intel.com>
> ---
> Changes in v2:
> - Added sysfs attribute documentation in Documentation/ABI.
> - Updated MAINTAINERS to include the new documentation files.
> 
>  Documentation/ABI/obsolete/sysfs-driver-ivpu |  30 +++
>  Documentation/ABI/testing/sysfs-driver-ivpu  |  65 +++++++
>  MAINTAINERS                                  |   2 +
>  drivers/accel/ivpu/ivpu_drv.c                |   8 +-
>  drivers/accel/ivpu/ivpu_hw.h                 |  16 +-
>  drivers/accel/ivpu/ivpu_hw_btrs.c            | 112 ++++++++---
>  drivers/accel/ivpu/ivpu_hw_btrs.h            |  10 +-
>  drivers/accel/ivpu/ivpu_jsm_msg.c            |  18 +-
>  drivers/accel/ivpu/ivpu_jsm_msg.h            |   4 +-
>  drivers/accel/ivpu/ivpu_sysfs.c              | 186 ++++++++++++++++---
>  drivers/accel/ivpu/vpu_jsm_api.h             |  34 +++-
>  11 files changed, 420 insertions(+), 65 deletions(-)
>  create mode 100644 Documentation/ABI/obsolete/sysfs-driver-ivpu
>  create mode 100644 Documentation/ABI/testing/sysfs-driver-ivpu
> 
> diff --git a/Documentation/ABI/obsolete/sysfs-driver-ivpu b/Documentation/ABI/obsolete/sysfs-driver-ivpu
> new file mode 100644
> index 000000000000..16f6a0b22406
> --- /dev/null
> +++ b/Documentation/ABI/obsolete/sysfs-driver-ivpu
> @@ -0,0 +1,30 @@
> +What:		/sys/bus/pci/drivers/intel_vpu/.../sched_mode
> +Date:		October 2024
> +KernelVersion:	6.12
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:	Current NPU scheduling mode. Returns one of the following strings:
> +		- "HW" - Hardware Scheduler mode
> +		- "OS" - Operating System Scheduler mode
> +		Read-only.
> +		Deprecated since the "OS" scheduling mode is not usable
> +		and will be removed from future versions of the driver.
> +		Will be removed in 2027
> +
> +What:		/sys/bus/pci/drivers/intel_vpu/.../npu_max_frequency_mhz

This says npu_max_frequency_mhz

> +Date:		April 2025
> +KernelVersion:	6.15
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:	Legacy alias for /sys/bus/pci/drivers/intel_vpu/.../freq/hw_min_freq.

But this is hw_min_freq - supposed to be hw_max_freq

> +		Shows maximum frequency in MHz of the NPU's data processing unit.
> +		Read-only.
> +		Will be removed in 2027
> +
> +What:		/sys/bus/pci/drivers/intel_vpu/.../npu_current_frequency_mhz
> +Date:		April 2025
> +KernelVersion:	6.15
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:	Legacy alias for /sys/bus/pci/drivers/intel_vpu/.../freq/current_freq.
> +		Shows current frequency in MHz of the NPU's data processing unit.
> +		The value is read only when the device is active; otherwise it returns 0.
> +		Read-only.
> +		Will be removed in 2027

...

> diff --git a/drivers/accel/ivpu/ivpu_jsm_msg.h b/drivers/accel/ivpu/ivpu_jsm_msg.h
> index a74f5a0b0d93..ead7d07d300f 100644
> --- a/drivers/accel/ivpu/ivpu_jsm_msg.h
> +++ b/drivers/accel/ivpu/ivpu_jsm_msg.h
> @@ -1,6 +1,6 @@
>  /* SPDX-License-Identifier: GPL-2.0-only */
>  /*
> - * Copyright (C) 2020-2024 Intel Corporation
> + * Copyright (C) 2020-2026 Intel Corporation
>   */
>  
>  #ifndef __IVPU_JSM_MSG_H__
> @@ -45,5 +45,7 @@ int ivpu_jsm_dct_enable(struct ivpu_device *vdev, u32 active_us, u32 inactive_us
>  int ivpu_jsm_dct_disable(struct ivpu_device *vdev);
>  int ivpu_jsm_state_dump(struct ivpu_device *vdev);
>  int ivpu_jsm_state_dump_no_reply(struct ivpu_device *vdev);
> +int ivpu_jsm_msg_freq_config(struct ivpu_device *vdev, u16 min_ratio, u16 pn_ratio, u16 max_ratio);
> +int ivpu_jsm_msg_freq_config(struct ivpu_device *vdev, u16 min_ratio, u16 pn_ratio, u16 max_ratio);

This got added twice.

...

Karol