Intel Integrated Sensor Hub (ISH)

Overview

Intel Integrated Sensor Hub (ISH) is a lower-power/always-on co-processor inside many Intel Processors. It helps offload sensor processing tasks from the core processor for better power saving.

Hardware

  • LMT MinuteIA Core:

    • 16KB instruction cache and 16KB data cache.

    • 640KB SRAM space for code and data - implemented as L2 SRAM.

    • 8KB AON RF space for code resident during deep D0i2/3 PG states.

  • Interface-to-Sensor peripherals (I2C, SPI, UART, I3C, GPIO, DMA).

  • Inter Process Communications (IPC) to core processor and other IP processors.

Supported Features

In addition to the standard architecture devices (HPET, local and I/O APICs, etc.), Zephyr supports the following ISH-specific SoC devices:

  • HSUART

Programming and Debugging

Use the following procedures for booting an ISH image on a ADL RVP board for Chrome.

Build Zephyr application

  1. Build a Zephyr application; for instance, to build the hello_world application for ISH 5.4.1 on Intel ADL Processor:

    # From the root of the zephyr repository
west build -b intel_ish_5_4_1 samples/hello_world

    Note

    A Zephyr image file named ish_fw.bin is automatically created in the build directory after the application is built.

Run ish_fw.bin on ADL RVP board for Chrome

  • Power on the ADL RVP board.

  • Log in Chrome OS. (Note: the user must have root access right, see Developer Mode)

  • Re-mount the root filesystem as read-write:

$ mount -o remount,rw /

  • If re-mount fails, execute below commands to Remove rootfs verification:

$ /usr/share/vboot/bin/make_dev_ssd.sh --remove_rootfs_verification --partitions
$ reboot

  • Go to the ISH firmware direcoty:

$ cd /lib/firmware/intel

  • Relace the file adlrvp_ish.bin with zephyr image built out, ish_fw.bin.

  • Reboot, then observe Zephyr log output via ISH UART0.