[PATCH v5 00/12] Fix USB suspend on TI J7200 (cdns3-ti, cdns3, xhci)

[Théo Lebrun]

Currently, system-wide suspend is broken on J7200 because of a
controller reset. The TI wrapper does not get re-initialised at resume
and the first register access from cdns core fails.

We address that in a few ways:
 - In cdns3-ti, if a reset has occured at resume, we reconfigure the HW.
 - We pass the XHCI_RESET_ON_RESUME quirk, meaning the XHCI core expects
   a resume.
 - We add a xhci->lost_power flag.

The previous revision had one big issue: we had to know if
reset-on-resume was true, at probe-time. This is where the main
difference with previous revisions is. We now pass the information from
wrapper devices back up into XHCI. The xhci->lost_power flag gets its
default value from the XHCI_RESET_ON_RESUME quirk. It however allows
wrappers to signal *at resume* if they still expect a reset.

That means wrappers that are unsure if they will reset should:
 - (1) set the quirk at probe and,
 - (2) potentially set xhci->lost_power to false at resume.

We implement that for cdns3, by piggybacking on the host role ->resume()
callback already receives the information from its caller.

Have a nice day,
Théo

Signed-off-by: Théo Lebrun <theo.lebrun@xxxxxxxxxxx>
---
Changes in v5:
- dt-bindings: take Reviewed-by Rob and Conor for the first
  patch: "dt-bindings: usb: ti,j721e-usb: fix compatible list".
- cdns3-ti:
  - We now do have HW init code inside cdns_ti_reset_and_init_hw().
  - It gets called at probe unconditionally and from ->runtime_resume()
    if a reset is detected (using the W1 register).
  - Auxdata patches have been reworked now that there is default auxdata
    since commit b50a2da03bd9 ("usb: cdns3-ti: Add workaround for
    Errata i2409"). We now have a patch that moves auxdata to match
    data: "usb: cdns3-ti: grab auxdata from match data".
- cdns3/xhci: those are three new patches.
  - First, we rename "hibernated" to "lost_power" in arguments to
    the role ->resume() callbacks.
  - Then we add the xhci->lost_power flag, and only have it always copy
    the value from XHCI_RESET_ON_RESUME.
  - Finally, we set the flag from the host role driver.
- Link to v4: https://lore.kernel.org/lkml/20240307-j7200-usb-suspend-v4-0-5ec7615431f3@xxxxxxxxxxx/

Changes in v4:
- dt-bindings: usb: ti,j721e-usb:
  - Remove ti,am64-usb single compatible entry.
  - Reverse ordering of compatible pair j721e + am64
    (becoming am64 + j721e).
  - Add j7200 + j721e compatible pair (versus only j7200). It is the
    same thing as am64: only the integration differs with base j721e
    compatible.
  - NOT taking trailers from Conor as patches changed substantially.
- arm64: dts: ti: j3-j7200:
  - Use j7200 + j721e compatible pair (versus only j7200 previously).
- arm64: dts: ti: j3-am64:
  - Fix to use am64 + j721e compatible pair (versus only am64).
    This is a new patch.
- Link to v3: https://lore.kernel.org/r/20240223-j7200-usb-suspend-v3-0-b41c9893a130@xxxxxxxxxxx

Changes in v3:
- dt-bindings: use an enum to list compatibles instead of the previous
  odd construct. This is done in a separate patch from the one adding
  J7200 compatible.
- dt-bindings: dropped Acked-by Conor as the changes were modified a lot.
- Add runtime PM back. Put the init sequence in ->runtime_resume(). It
  gets called at probe for all compatibles and at resume for J7200.
- Introduce a cdns_ti_match_data struct rather than rely on compatible
  from code.
- Reorder code changes. Add infrastructure based on match data THEN add
  compatible and its match data.
- DTSI: use only J7200 compatible rather than both J7200 then J721E.
- Link to v2: https://lore.kernel.org/r/20231120-j7200-usb-suspend-v2-0-038c7e4a3df4@xxxxxxxxxxx

Changes in v2:
- Remove runtime PM from cdns3-ti; it brings nothing. That means our
  cdns3-ti suspend/resume patch is simpler; there is no need to handle
  runtime PM at suspend/resume.
- Do not add cdns3 host role suspend/resume callbacks; they are not
  needed as core detects reset on resume & calls cdns_drd_host_on when
  needed.
- cdns3-ti: Move usb2_refclk_rate_code assignment closer to the value
  computation.
- cdns3/host.c: do not pass XHCI_SUSPEND_RESUME_CLKS quirk to xHCI; it
  is unneeded on our platform.
- Link to v1: https://lore.kernel.org/r/20231113-j7200-usb-suspend-v1-0-ad1ee714835c@xxxxxxxxxxx

---
Théo Lebrun (12):
      dt-bindings: usb: ti,j721e-usb: fix compatible list
      dt-bindings: usb: ti,j721e-usb: add ti,j7200-usb compatible
      usb: cdns3-ti: move reg writes to separate function
      usb: cdns3-ti: run HW init at resume() if HW was reset
      usb: cdns3: add quirk to platform data for reset-on-resume
      usb: cdns3-ti: grab auxdata from match data
      usb: cdns3-ti: add J7200 support with reset-on-resume behavior
      usb: cdns3: rename hibernated argument of role->resume() to lost_power
      xhci: introduce xhci->lost_power flag
      usb: cdns3: host: transmit lost_power signal from wrapper to XHCI
      arm64: dts: ti: k3-j7200: use J7200-specific USB compatible
      arm64: dts: ti: k3-am64: add USB fallback compatible to J721E

 .../devicetree/bindings/usb/ti,j721e-usb.yaml      |   5 +-
 arch/arm64/boot/dts/ti/k3-am64-main.dtsi           |   2 +-
 arch/arm64/boot/dts/ti/k3-j7200-main.dtsi          |   2 +-
 drivers/usb/cdns3/cdns3-gadget.c                   |   4 +-
 drivers/usb/cdns3/cdns3-ti.c                       | 151 ++++++++++++++-------
 drivers/usb/cdns3/cdnsp-gadget.c                   |   2 +-
 drivers/usb/cdns3/core.h                           |   3 +-
 drivers/usb/cdns3/host.c                           |  13 ++
 drivers/usb/host/xhci.c                            |   8 +-
 drivers/usb/host/xhci.h                            |   6 +
 10 files changed, 136 insertions(+), 60 deletions(-)
---
base-commit: c33ffdb70cc6df4105160f991288e7d2567d7ffa
change-id: 20240726-s2r-cdns-4b180cd960ff

Best regards,
-- 
Théo Lebrun <theo.lebrun@xxxxxxxxxxx>