drivers: usb: udc: stm32: implement proper isochronous support for ST USB IP #105151
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nashif merged 3 commits intozephyrproject-rtos:mainfrom Mar 24, 2026
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erwango
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Would appreciate review/+1 from an USB maintainer: @jfischer-no / @tmon-nordic / @josuah if one of you could please take a look 🙂 |
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@tmon-nordic PTAL again |
Move options such that all generic options go toghether, followed by hardware-specific ones and wrap the HW-specific options in dedicated menus. Signed-off-by: Mathieu Choplain <mathieu.choplain-ext@st.com>
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Update the copyright notice to use SPDX-FileCopyrightText. While at it, add STMicroelectronics to the list of copyright holders as we have made numerous contributions to this driver recently. Signed-off-by: Mathieu Choplain <mathieu.choplain-ext@st.com>
Implement proper support for isochronous operation when "st,stm32-usb" IP is used. Previously, the driver did not take into account specificities of this IP regarding isochronous endpoints resulting in invalid transfers. Signed-off-by: Mathieu Choplain <mathieu.choplain-ext@st.com>
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Fixed the typo reported by @gautierg-st and added STMicroelectronics to the copyright list of the driver in a preliminary commit while at it. |
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The ST USB IP (compatible
st,stm32-usb) supports two different modes of operation for each endpoint:EP0 IN/EP0 OUT) uses a single USB SRAM buffer and a singlebuffer descriptorregister to perform transfersEP1 OUT) uses two USB SRAM buffers and twobuffer descriptorregisters to perform transfersUnlike others, isochronous endpoints must be double-buffered which requires special handling that, up until now, was not implemented in the driver. As such, it was possible to incorrectly configure the IP which could result in e.g. wrong data being sent to the USB bus.
Update the UDC driver to properly support isochronous operation with this IP. To this end, and due to stack architecture, three new Kconfig options are introduced:
UDC_STM32_STUSB_ISOCHRONOUS_SUPPORT: enables overall isochronous supportUDC_STM32_STUSB_ISO_OUT_EP_NUM/UDC_STM32_STUSB_ISO_IN_EP_NUM: used to reserve a fixed number of endpoints for isochronous operation (in either direction)EPn <OUT/IN>as not supporting isochronous mode onceEPn <IN/OUT>has been configured in bulk/interrupt modeEPn <OUT/IN>as not being available (no mode supported) onceEPn <IN/OUT>has been configured in isochronous modeTested OK on STM32H573I-DK with
samples/subsys/usb/uac2_explicit_feedback(requires additional patches not provided here)