On Tue, Aug 13, 2024 at 02:07:01PM -0400, Frank Li wrote: > 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. > Bjorn Andersson: Any follow up on this thread? Frank > 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> > >
