On Sun, Aug 11, 2024 at 08:11:57PM -0700, Bjorn Andersson wrote: > The USB IP-block found in most Qualcomm platforms is modelled in the > Linux kernel as 3 different independent device drivers, but as shown by > the already existing layering violations in the Qualcomm glue driver > they can not be operated independently. > > With the current implementation, the glue driver registers the core and > has no way to know when this is done. As a result, e.g. the suspend > callbacks needs to guard against NULL pointer dereferences when trying > to peek into the struct dwc3 found in the drvdata of the child. > > Missing from the upstream Qualcomm USB support is handling of role > switching, in which the glue needs to be notified upon DRD mode changes. > Several attempts has been made through the years to register callbacks > etc, but they always fall short when it comes to handling of the core's > probe deferral on resources etc. > > Furhtermore, the DeviceTree binding is a direct representation of the > Linux driver model, and doesn't necessarily describe "the USB IP-block". > > This series therefor attempts to flatten the driver split, and operate > the glue and core out of the same platform_device instance. And in order > to do this, the DeviceTree representation of the IP block is flattened. Thanks, we faced the same problem. Can you cc me next time? Frank > > --- > Changes in v2: > - Rewrite after ACPI removal, multiport support and interrupt fixes > - Completely changed strategy for DeviceTree binding, as previous idea > of using snps,dwc3 as a generic fallback required unreasonable changes > to that binding. > - Abandoned idea of supporting both flattened and unflattened device > model in the one driver. As Johan pointed out, it will leave the race > condition holes and will make the code harder to understand. > Furthermore, the role switching logic that we intend to introduce > following this would have depended on the user updating their > DeviceTree blobs. > - Per above, introduced the dynamic DeviceTree rewrite > - Link to v1: https://lore.kernel.org/all/20231016-dwc3-refactor-v1-0-ab4a84165470@xxxxxxxxxxx/ > > --- > Bjorn Andersson (7): > dt-bindings: usb: snps,dwc3: Split core description > dt-bindings: usb: Introduce qcom,snps-dwc3 > of: dynamic: Don't discard children upon node attach > usb: dwc3: core: Expose core driver as library > usb: dwc3: qcom: Don't reply on drvdata during probe > usb: dwc3: qcom: Transition to flattened model > arm64: dts: qcom: sc8280x: Flatten the USB nodes > > .../devicetree/bindings/usb/qcom,dwc3.yaml | 13 +- > .../devicetree/bindings/usb/qcom,snps-dwc3.yaml | 608 +++++++++++++++++++++ > .../devicetree/bindings/usb/snps,dwc3-common.yaml | 417 ++++++++++++++ > .../devicetree/bindings/usb/snps,dwc3.yaml | 391 +------------ > arch/arm64/boot/dts/qcom/sa8295p-adp.dts | 12 +- > arch/arm64/boot/dts/qcom/sa8540p-ride.dts | 5 +- > arch/arm64/boot/dts/qcom/sc8280xp-crd.dts | 12 +- > .../dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts | 11 +- > arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 138 +++-- > drivers/of/dynamic.c | 1 - > drivers/usb/dwc3/core.c | 169 ++++-- > drivers/usb/dwc3/core.h | 3 + > drivers/usb/dwc3/dwc3-qcom.c | 323 ++++++++--- > 13 files changed, 1483 insertions(+), 620 deletions(-) > --- > base-commit: 864b1099d16fc7e332c3ad7823058c65f890486c > change-id: 20231016-dwc3-refactor-931e3b08a8b9 > > Best regards, > -- > Bjorn Andersson <quic_bjorande@xxxxxxxxxxx> >
