[PATCH v2 0/2] Patches to fix remote wakeup on rk3288 dwc2 "host" port

[PATCH v2 0/2] Patches to fix remote wakeup on rk3288 dwc2 "host" port

[Douglas Anderson]

On the rk3288 USB host-only port (the one that's not the OTG-enabled
port) the PHY can get into a bad state when a wakeup is asserted (not
just a wakeup from full system suspend but also a wakeup from
autosuspend).

We can get the PHY out of its bad state by asserting its "port reset",
but unfortunately that seems to assert a reset onto the USB bus so it
could confuse things if we don't actually deenumerate / reenumerate the
device.

We can also get the PHY out of its bad state by fully resetting it using
the reset from the CRU (clock reset unit), which does a more full
reset.  The CRU-based reset appears to actually cause devices on the bus
to be removed and reinserted, which fixes the problem (albeit in a hacky
way).

It's unfortunate that we need to do a full re-enumeration of devices at
wakeup time, but this is better than alternative of letting the bus get
wedged.

I've tested this series atop a bit of a conglomeration of Heiko's github
"somewhat stable" branch (v4.3-rc3-876-g6509232) but with Greg KH's
usb-next merged in.

===

I've posted up a bunch of patches recently but tried to keep them in
separate series where it makes sense.  A summary of known patches:
All patches can be found with: https://patchwork.kernel.org/patch/<ID>/

ACKed (thanks!) and not yet landed:
 7453801  usb: dwc2: host: Fix ahbcfg for rk3066
 7467521  usb: dwc2: host: Fix remote wakeup when not in DWC2_L2

Important, not yet reviewed:
 7421171  [1/2] usb: dwc2: host: Fix missing device insertions

Fixes no known issues, not yet reviewed:
 7421181  [2/2] usb: dwc2: host: Clear interrupts before handling them

Optimization to reduce probe time (may require simple rebase):
 7348131  [1/5] usb: dwc2: Restore GUSBCFG in dwc2_get_hwparams()
 7348221  [2/5] usb: dwc2: reset dwc2 core before dwc2_get_hwparams()
 7348191  [3/5] CHROMIUM: usb: dwc2: Avoid double-reset at boot time
 7348211  [4/5] usb: dwc2: Speed dwc2_get_hwparams() on some host-only ports
 7348201  [5/5] usb: dwc2: reduce dwc2 driver probe time
 7355241  usb: dwc2: Avoid more calls to dwc2_core_reset()

This series:
 usb: dwc2: optionally assert phy "full reset" when waking up
 ARM: dts: rockchip: Point rk3288 dwc2 usb at the full PHY reset

Coming soon:
 RFT: usb: dwc2: bus suspend/resume that's not hibernate

Abandoned for now (can't get wakeup to work on mainline):
 6727091  [REPOST,1/3] USB: Export usb_wakeup_enabled_descendants()
 6727101  [REPOST,2/3] Documentation: dt-bindings: Add snps,need-phy-for-wake for dwc2 USB
 6727121  [REPOST,3/3] USB: dwc2: Don't turn off the usbphy in suspend if wakeup is enabled

Changes in v2:
- Use a full PHY reset for safety; no PHY changes needed for that.
- Cover letter explains outstanding patches

Doug Anderson (2):
  usb: dwc2: optionally assert phy "full reset" when waking up
  ARM: dts: rockchip: Point rk3288 dwc2 usb at the full PHY reset

 Documentation/devicetree/bindings/usb/dwc2.txt |  7 +++++++
 arch/arm/boot/dts/rk3288.dtsi                  |  5 +++++
 drivers/usb/dwc2/core.h                        |  5 +++++
 drivers/usb/dwc2/core_intr.c                   | 14 ++++++++++++++
 drivers/usb/dwc2/platform.c                    | 13 +++++++++++++
 5 files changed, 44 insertions(+)

-- 
2.6.0.rc2.230.g3dd15c0

[PATCH v2 2/2] ARM: dts: rockchip: Point rk3288 dwc2 usb at the full PHY reset

[Douglas Anderson]

From: Doug Anderson <dianders@chromium.org>

The "host1" port (AKA the dwc2 port that isn't the OTG port) on rk3288
has a hardware errata that causes everything to get confused when we get
a remote wakeup.  We'll use the reset that's in the CRU to reset the
port when it's in a bad state.

Note that we add the reset to both dwc2 controllers even though only one
has the errata in case we find some other use for this reset that's
unrelated to the current hardware errata.  Only the host port gets the
quirk property, though.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
Changes in v2:
- Use a full PHY reset for safety; no PHY changes needed for that.

 arch/arm/boot/dts/rk3288.dtsi | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm/boot/dts/rk3288.dtsi b/arch/arm/boot/dts/rk3288.dtsi
index 906e938fb6bf..58773beb283f 100644
--- a/arch/arm/boot/dts/rk3288.dtsi
+++ b/arch/arm/boot/dts/rk3288.dtsi
@@ -496,6 +496,9 @@
 		dr_mode = "host";
 		phys = <&usbphy2>;
 		phy-names = "usb2-phy";
+		resets = <&cru SRST_USBHOST1_PHY>;
+		reset-names = "phy-full-reset";
+		snps,need-phy-full-reset-on-wake;
 		status = "disabled";
 	};
 
@@ -513,6 +516,8 @@
 		g-use-dma;
 		phys = <&usbphy0>;
 		phy-names = "usb2-phy";
+		resets = <&cru SRST_USBOTG_PHY>;
+		reset-names = "phy-full-reset";
 		status = "disabled";
 	};
 
-- 
2.6.0.rc2.230.g3dd15c0