[PATCH v3 00/12] usb: dwc3: qcom: Flatten dwc3 structure

Bjorn Andersson
2025-01-14T05:05:45Z

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 proper 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.

To avoid littering the dwc3-qcom driver with the migration code - which
we should be able to drop again in a LTS or two - this is now placed in
drivers/of/overlays.

A patch to convert a single platform - sc8280xp - is included in the
series. The broader conversion will be submitted in a follow up series.

---
Changes in v3:
- Replaced the handcoded migration logic of compatible, reg, interrupts,
phys with overlays.
- Move the migration logic (and overlays) to a new drivers/of/overlays
directory and apply this at postcore, so that it takes effect prior to
the relevant platform_devices are created
- struct dwc3 is embedded in the glue context, rather than having a
separate object allocated
- The hack of using of_address_to_resource() to avoid platform_resource
being stale is removed (thanks to applying migration at postcore)
- Link to v2: https://lore.kernel.org/r/20240811-dwc3-refactor-v2-0-91f370d61ad2@quicinc.com

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@quicinc.com/

---
Bjorn Andersson (12):
dt-bindings: usb: snps,dwc3: Split core description
dt-bindings: usb: Introduce qcom,snps-dwc3
of: dynamic: Add of_changeset_add_prop_copy()
of: overlays: Introduce dwc3 flattening overlay
of: overlays: dwc3-flattening: Add Qualcomm Arm32 overlays
of: overlays: dwc3-flattening: Add Qualcomm Arm64 board overlays
of: overlays: dwc3-flattening: Provide overlay symbols
usb: dwc3: core: Expose core driver as library
usb: dwc3: core: Don't touch resets and clocks
usb: dwc3: qcom: Don't rely 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 | 618 ++++++++
.../devicetree/bindings/usb/snps,dwc3-common.yaml | 415 ++++++
.../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 +-
.../boot/dts/qcom/sc8280xp-huawei-gaokun3.dts | 10 +-
.../dts/qcom/sc8280xp-lenovo-thinkpad-x13s.dts | 11 +-
.../boot/dts/qcom/sc8280xp-microsoft-arcata.dts | 10 +-
.../boot/dts/qcom/sc8280xp-microsoft-blackrock.dts | 18 +-
arch/arm64/boot/dts/qcom/sc8280xp.dtsi | 157 +-
drivers/of/Kconfig | 2 +
drivers/of/Makefile | 2 +
drivers/of/dynamic.c | 20 +
drivers/of/overlays/Kconfig | 15 +
drivers/of/overlays/Makefile | 3 +
drivers/of/overlays/dwc3-flattening/Makefile | 94 ++
.../of/overlays/dwc3-flattening/dwc3-flattening.c | 1552 ++++++++++++++++++++
.../of/overlays/dwc3-flattening/dwc3-flattening.h | 188 +++
.../overlays/dwc3-flattening/dwc3-qcom_apq8094.dts | 32 +
.../overlays/dwc3-flattening/dwc3-qcom_apq8096.dts | 60 +
.../dwc3-qcom_apq8096_inforce_ifc6640.dts | 58 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq4018.dts | 36 +
.../dwc3-qcom_ipq4018_8dev_jalapeno.dts | 38 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq4019.dts | 38 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq5018.dts | 28 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq5332.dts | 32 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq5424.dts | 58 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq6018.dts | 54 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq8064.dts | 40 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq8074.dts | 58 +
.../overlays/dwc3-flattening/dwc3-qcom_ipq9574.dts | 29 +
.../overlays/dwc3-flattening/dwc3-qcom_msm8953.dts | 32 +
.../overlays/dwc3-flattening/dwc3-qcom_msm8992.dts | 32 +
.../overlays/dwc3-flattening/dwc3-qcom_msm8994.dts | 32 +
.../overlays/dwc3-flattening/dwc3-qcom_msm8996.dts | 58 +
.../dwc3-qcom_msm8996_oneplus_oneplus3.dts | 56 +
.../dwc3-qcom_msm8996_oneplus_oneplus3t.dts | 56 +
.../dwc3-qcom_msm8996_sony_dora_row.dts | 57 +
.../dwc3-qcom_msm8996_sony_kagura_row.dts | 57 +
.../dwc3-qcom_msm8996_sony_keyaki_row.dts | 57 +
.../dwc3-qcom_msm8996_xiaomi_gemini.dts | 56 +
.../dwc3-qcom_msm8996_xiaomi_natrium.dts | 56 +
.../dwc3-qcom_msm8996_xiaomi_scorpio.dts | 56 +
.../overlays/dwc3-flattening/dwc3-qcom_msm8998.dts | 34 +
.../dwc3-qcom_msm8998_fxtec_pro1.dts | 35 +
.../dwc3-qcom_msm8998_oneplus_cheeseburger.dts | 32 +
.../dwc3-qcom_msm8998_oneplus_dumpling.dts | 32 +
.../dwc3-qcom_msm8998_sony_xperia_lilac.dts | 35 +
.../dwc3-qcom_msm8998_sony_xperia_maple.dts | 35 +
.../dwc3-qcom_msm8998_sony_xperia_poplar.dts | 35 +
.../dwc3-qcom_msm8998_xiaomi_sagit.dts | 32 +
.../overlays/dwc3-flattening/dwc3-qcom_qcm2290.dts | 32 +
.../overlays/dwc3-flattening/dwc3-qcom_qcm6490.dts | 63 +
.../overlays/dwc3-flattening/dwc3-qcom_qcs404.dts | 56 +
.../overlays/dwc3-flattening/dwc3-qcom_qcs615.dts | 62 +
.../overlays/dwc3-flattening/dwc3-qcom_qcs8300.dts | 62 +
.../overlays/dwc3-flattening/dwc3-qcom_qdu1000.dts | 38 +
.../overlays/dwc3-flattening/dwc3-qcom_qru1000.dts | 38 +
.../overlays/dwc3-flattening/dwc3-qcom_sa8155p.dts | 71 +
.../overlays/dwc3-flattening/dwc3-qcom_sa8540p.dts | 129 ++
.../overlays/dwc3-flattening/dwc3-qcom_sa8775p.dts | 90 ++
.../dwc3-flattening/dwc3-qcom_sar2130p.dts | 39 +
.../overlays/dwc3-flattening/dwc3-qcom_sc7180.dts | 39 +
.../overlays/dwc3-flattening/dwc3-qcom_sc7280.dts | 63 +
.../overlays/dwc3-flattening/dwc3-qcom_sc8180x.dts | 109 ++
.../dwc3-flattening/dwc3-qcom_sc8280xp.dts | 129 ++
.../dwc3-qcom_sc8280xp_microsoft_blackrock.dts | 121 ++
.../overlays/dwc3-flattening/dwc3-qcom_sda660.dts | 59 +
.../overlays/dwc3-flattening/dwc3-qcom_sdm450.dts | 33 +
.../overlays/dwc3-flattening/dwc3-qcom_sdm630.dts | 57 +
.../overlays/dwc3-flattening/dwc3-qcom_sdm632.dts | 32 +
.../overlays/dwc3-flattening/dwc3-qcom_sdm636.dts | 59 +
.../overlays/dwc3-flattening/dwc3-qcom_sdm660.dts | 57 +
.../overlays/dwc3-flattening/dwc3-qcom_sdm670.dts | 36 +
.../overlays/dwc3-flattening/dwc3-qcom_sdm845.dts | 64 +
.../dwc3-qcom_sdm845_lenovo_yoga_c630.dts | 67 +
.../dwc3-flattening/dwc3-qcom_sdm845_lg_judyln.dts | 67 +
.../dwc3-flattening/dwc3-qcom_sdm845_lg_judyp.dts | 67 +
.../dwc3-qcom_sdm845_qcom_sdm845_mtp.dts | 67 +
.../dwc3-qcom_sdm845_samsung_starqltechn.dts | 67 +
.../dwc3-qcom_sdm845_samsung_w737.dts | 67 +
.../dwc3-qcom_sdm845_shift_axolotl.dts | 67 +
.../dwc3-qcom_sdm845_thundercomm_db845c.dts | 67 +
.../dwc3-qcom_sdm845_xiaomi_beryllium.dts | 67 +
.../dwc3-qcom_sdm845_xiaomi_beryllium_ebbg.dts | 67 +
.../overlays/dwc3-flattening/dwc3-qcom_sdx55.dts | 38 +
.../overlays/dwc3-flattening/dwc3-qcom_sdx65.dts | 38 +
.../overlays/dwc3-flattening/dwc3-qcom_sdx75.dts | 36 +
.../overlays/dwc3-flattening/dwc3-qcom_sm4250.dts | 37 +
.../dwc3-qcom_sm4250_oneplus_billie2.dts | 35 +
.../overlays/dwc3-flattening/dwc3-qcom_sm6115.dts | 37 +
.../dwc3-qcom_sm6115_lenovo_j606f.dts | 35 +
.../overlays/dwc3-flattening/dwc3-qcom_sm6125.dts | 36 +
.../overlays/dwc3-flattening/dwc3-qcom_sm6350.dts | 39 +
.../overlays/dwc3-flattening/dwc3-qcom_sm6375.dts | 36 +
.../overlays/dwc3-flattening/dwc3-qcom_sm7125.dts | 39 +
.../overlays/dwc3-flattening/dwc3-qcom_sm7225.dts | 39 +
.../overlays/dwc3-flattening/dwc3-qcom_sm7325.dts | 60 +
.../overlays/dwc3-flattening/dwc3-qcom_sm8150.dts | 67 +
.../overlays/dwc3-flattening/dwc3-qcom_sm8250.dts | 67 +
.../dwc3-qcom_sm8250_xiaomi_elish.dts | 64 +
.../overlays/dwc3-flattening/dwc3-qcom_sm8350.dts | 67 +
.../dwc3-qcom_sm8350_microsoft_surface_duo2.dts | 67 +
.../dwc3-qcom_sm8350_qcom_sm8350_hdk.dts | 69 +
.../dwc3-qcom_sm8350_qcom_sm8350_mtp.dts | 67 +
.../dwc3-qcom_sm8350_sony_pdx214_generic.dts | 67 +
.../dwc3-qcom_sm8350_sony_pdx215_generic.dts | 67 +
.../overlays/dwc3-flattening/dwc3-qcom_sm8450.dts | 39 +
.../overlays/dwc3-flattening/dwc3-qcom_sm8550.dts | 39 +
.../overlays/dwc3-flattening/dwc3-qcom_sm8650.dts | 39 +
.../dwc3-flattening/dwc3-qcom_x1e80100.dts | 153 ++
.../dwc3-qcom_x1e80100_hp_omnibook_x14.dts | 149 ++
drivers/usb/dwc3/core.c | 167 ++-
drivers/usb/dwc3/dwc3-qcom.c | 149 +-
drivers/usb/dwc3/glue.h | 22 +
include/linux/of.h | 3 +
118 files changed, 8389 insertions(+), 670 deletions(-)
---
base-commit: 6ecd20965bdc21b265a0671ccf36d9ad8043f5ab
change-id: 20231016-dwc3-refactor-931e3b08a8b9

Best regards,
--
Bjorn Andersson <bjorn.andersson@oss.qualcomm.com>