[PATCH v2 12/14] dm: usb: initialize and scan multiple buses simultaneously with uthread

[Simon Glass]

Hi Jerome,

On Tue, 25 Feb 2025 at 09:35, Jerome Forissier
<jerome.forissier at linaro.org> wrote:
>
> Use the uthread framework to initialize and scan USB buses in parallel
> for better performance. The console output is slightly modified with a
> final per-bus report of the number of devices found, common to UTHREAD
> and !UTHREAD. The USB tests are updated accordingly.
>
> Tested on two platforms:
>
> 1. arm64 QEMU on a somewhat contrived example (4 USB buses, each with
> one audio device, one keyboard, one mouse and one tablet)
>
>  $ make qemu_arm64_defconfig
>  $ make -j$(nproc) CROSS_COMPILE="ccache aarch64-linux-gnu-"
>  $ qemu-system-aarch64 -M virt -nographic -cpu max -bios u-boot.bin \
>      $(for i in {1..4}; do echo -device qemu-xhci,id=xhci$i \
>          -device\ usb-{audio,kbd,mouse,tablet},bus=xhci$i.0; \
>      done)
>
> 2. i.MX93 EVK (imx93_11x11_evk_defconfig) with two USB hubs, each with
> one webcam and one ethernet adapter, resulting in the following device
> tree:
>
>  USB device tree:
>    1  Hub (480 Mb/s, 0mA)
>    |  u-boot EHCI Host Controller
>    |
>    +-2  Hub (480 Mb/s, 100mA)
>      |  GenesysLogic USB2.1 Hub
>      |
>      +-3  Vendor specific (480 Mb/s, 350mA)
>      |    Realtek USB 10/100/1000 LAN 001000001
>      |
>      +-4   (480 Mb/s, 500mA)
>            HD Pro Webcam C920 8F7CD51F
>
>    1  Hub (480 Mb/s, 0mA)
>    |  u-boot EHCI Host Controller
>    |
>    +-2  Hub (480 Mb/s, 100mA)
>      |   USB 2.0 Hub
>      |
>      +-3  Vendor specific (480 Mb/s, 200mA)
>      |    Realtek USB 10/100/1000 LAN 000001
>      |
>      +-4   (480 Mb/s, 500mA)
>           Generic OnLan-CS30 201801010008
>
> Note that i.MX was tested on top of the downstream repository [1] since
> USB doesn't work in the upstream master branch.
>
> [1] https://github.com/nxp-imx/uboot-imx/tree/lf-6.6.52-2.2.0
>     commit 6c4545203d12 ("LF-13928 update key for capsule")
>
> The time spent in usb_init() ("usb start" command) is reported on
> the console. Here are the results:
>
>         | CONFIG_UTHREAD=n | CONFIG_UTHREAD=y
> --------+------------------+-----------------
> QEMU    |          5628 ms |          2212 ms
> i.MX93  |          4591 ms |          2441 ms
>
> Signed-off-by: Jerome Forissier <jerome.forissier at linaro.org>
> ---
>  drivers/usb/host/usb-uclass.c | 92 ++++++++++++++++++++++++++++-------
>  test/boot/bootdev.c           | 14 +++---
>  test/boot/bootflow.c          |  2 +-
>  3 files changed, 83 insertions(+), 25 deletions(-)

What happens to output produced by a thread? Does it get stored
somewhere and written when the thread completes, or do the threads
intermingle their output?

I'm not sure if you saw my email about using a state machine for USB.
If so, could you please point me to your reply?

Regards,
Simon