[PATCH v2 0/3] arm64: g12-common: parkmode_disable_ss_quirk on DWC3 controller

[PATCH v2 0/3] arm64: g12-common: parkmode_disable_ss_quirk on DWC3 controller

[Neil Armstrong]

In certain circumstances, the XHCI SuperSpeed instance in park mode
can fail to recover, thus on Amlogic G12A/G12B/SM1 SoCs when there is high
load on the single XHCI SuperSpeed instance, the controller can crash like:
xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint command.
xhci-hcd xhci-hcd.0.auto: Host halt failed, -110
xhci-hcd xhci-hcd.0.auto: xHCI host controller not responding, assume dead
xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint command.
hub 2-1.1:1.0: hub_ext_port_status failed (err = -22)
xhci-hcd xhci-hcd.0.auto: HC died; cleaning up
usb 2-1.1-port1: cannot reset (err = -22)

Setting the PARKMODE_DISABLE_SS bit in the DWC3_USB3_GUCTL1 mitigates
the issue. The bit is described as :
"When this bit is set to '1' all SS bus instances in park mode are disabled"

The bug has been reproduced by Jun Li <lijun.kernel@gmail.com> and confirmed
by Thinh Nguyen <Thinh.Nguyen@synopsys.com> with the explanation:
> The GUCTL1.PARKMODE_DISABLE_SS is only available in dwc_usb3 controller 
> running in host mode. This should not be set for other IPs.
> This can be disabled by default based on IP, but I recommend to have a 
> property to enable this feature for devices that need this.

Changes since v1 at [1]:
- added rob review tag
- added Thinh Nguyen in commit log

[1] https://lore.kernel.org/linux-amlogic/20191014141718.22603-1-narmstrong@baylibre.com

Neil Armstrong (3):
  doc: dt: bindings: usb: dwc3: Update entries for disabling SS
    instances in park mode
  usb: dwc3: gadget: Add support for disabling SS instances in park mode
  arm64: dts: g12-common: add parkmode_disable_ss_quirk on DWC3
    controller

 Documentation/devicetree/bindings/usb/dwc3.txt    | 2 ++
 arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi | 1 +
 drivers/usb/dwc3/core.c                           | 5 +++++
 drivers/usb/dwc3/core.h                           | 4 ++++
 4 files changed, 12 insertions(+)

-- 
2.22.0

[PATCH v2 1/3] doc: dt: bindings: usb: dwc3: Update entries for disabling SS instances in park mode

[Neil Armstrong]

This patch updates the documentation with the information related
to the quirks that needs to be added for disabling all SuperSpeed XHCI
instances in park mode.

Cc: Dongjin Kim <tobetter@gmail.com>
Cc: Jianxin Pan <jianxin.pan@amlogic.com>
Cc: Thinh Nguyen <thinhn@synopsys.com>
Cc: Jun Li <lijun.kernel@gmail.com>
Reported-by: Tim <elatllat@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/usb/dwc3.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
index 66780a47ad85..c977a3ba2f35 100644
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ b/Documentation/devicetree/bindings/usb/dwc3.txt
@@ -75,6 +75,8 @@ Optional properties:
 			from P0 to P1/P2/P3 without delay.
  - snps,dis-tx-ipgap-linecheck-quirk: when set, disable u2mac linestate check
 			during HS transmit.
+ - snps,parkmode-disable-ss-quirk: when set, all SuperSpeed bus instances in
+			park mode are disabled.
  - snps,dis_metastability_quirk: when set, disable metastability workaround.
 			CAUTION: use only if you are absolutely sure of it.
  - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal
-- 
2.22.0

[PATCH v2 2/3] usb: dwc3: gadget: Add support for disabling SS instances in park mode

[Neil Armstrong]

In certain circumstances, the XHCI SuperSpeed instance in park mode
can fail to recover, thus on Amlogic G12A/G12B/SM1 SoCs when there is high
load on the single XHCI SuperSpeed instance, the controller can crash like:
 xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint command.
 xhci-hcd xhci-hcd.0.auto: Host halt failed, -110
 xhci-hcd xhci-hcd.0.auto: xHCI host controller not responding, assume dead
 xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint command.
 hub 2-1.1:1.0: hub_ext_port_status failed (err = -22)
 xhci-hcd xhci-hcd.0.auto: HC died; cleaning up
 usb 2-1.1-port1: cannot reset (err = -22)

Setting the PARKMODE_DISABLE_SS bit in the DWC3_USB3_GUCTL1 mitigates
the issue. The bit is described as :
"When this bit is set to '1' all SS bus instances in park mode are disabled"

Synopsys explains in [1]:
The GUCTL1.PARKMODE_DISABLE_SS is only available in
dwc_usb3 controller running in host mode.
This should not be set for other IPs.
This can be disabled by default based on IP, but I recommend to have a
property to enable this feature for devices that need this.

[1] https://lore.kernel.org/linux-usb/45212db9-e366-2669-5c0a-3c5bd06287f6@synopsys.com

CC: Dongjin Kim <tobetter@gmail.com>
Cc: Jianxin Pan <jianxin.pan@amlogic.com>
Cc: Thinh Nguyen <thinhn@synopsys.com>
Cc: Jun Li <lijun.kernel@gmail.com>
Reported-by: Tim <elatllat@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/usb/dwc3/core.c | 5 +++++
 drivers/usb/dwc3/core.h | 4 ++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 2991e5056600..2cb441e2e51b 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1030,6 +1030,9 @@ static int dwc3_core_init(struct dwc3 *dwc)
 		if (dwc->dis_tx_ipgap_linecheck_quirk)
 			reg |= DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS;
 
+		if (dwc->parkmode_disable_ss_quirk)
+			reg |= DWC3_GUCTL1_PARKMODE_DISABLE_SS;
+
 		dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
 	}
 
@@ -1340,6 +1343,8 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 				"snps,dis-del-phy-power-chg-quirk");
 	dwc->dis_tx_ipgap_linecheck_quirk = device_property_read_bool(dev,
 				"snps,dis-tx-ipgap-linecheck-quirk");
+	dwc->parkmode_disable_ss_quirk = device_property_read_bool(dev,
+				"snps,parkmode-disable-ss-quirk");
 
 	dwc->tx_de_emphasis_quirk = device_property_read_bool(dev,
 				"snps,tx_de_emphasis_quirk");
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 1c8b349379af..5fb557f24d38 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -249,6 +249,7 @@
 #define DWC3_GUCTL_HSTINAUTORETRY	BIT(14)
 
 /* Global User Control 1 Register */
+#define DWC3_GUCTL1_PARKMODE_DISABLE_SS	BIT(17)
 #define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS	BIT(28)
 #define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW	BIT(24)
 
@@ -1022,6 +1023,8 @@ struct dwc3_scratchpad_array {
  *			change quirk.
  * @dis_tx_ipgap_linecheck_quirk: set if we disable u2mac linestate
  *			check during HS transmit.
+ * @parkmode_disable_ss_quirk: set if we need to disable all SuperSpeed
+ *			instances in park mode.
  * @tx_de_emphasis_quirk: set if we enable Tx de-emphasis quirk
  * @tx_de_emphasis: Tx de-emphasis value
  * 	0	- -6dB de-emphasis
@@ -1213,6 +1216,7 @@ struct dwc3 {
 	unsigned		dis_u2_freeclk_exists_quirk:1;
 	unsigned		dis_del_phy_power_chg_quirk:1;
 	unsigned		dis_tx_ipgap_linecheck_quirk:1;
+	unsigned		parkmode_disable_ss_quirk:1;
 
 	unsigned		tx_de_emphasis_quirk:1;
 	unsigned		tx_de_emphasis:2;
-- 
2.22.0

[PATCH v2 3/3] arm64: dts: g12-common: add parkmode_disable_ss_quirk on DWC3 controller

[Neil Armstrong]

When high load on the DWC3 SuperSpee port, the controller crashed as:
[  221.141621] xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint command.
[  221.157631] xhci-hcd xhci-hcd.0.auto: Host halt failed, -110
[  221.157635] xhci-hcd xhci-hcd.0.auto: xHCI host controller not responding, assume dead
[  221.159901] xhci-hcd xhci-hcd.0.auto: xHCI host not responding to stop endpoint command.
[  221.159961] hub 2-1.1:1.0: hub_ext_port_status failed (err = -22)
[  221.160076] xhci-hcd xhci-hcd.0.auto: HC died; cleaning up
[  221.165946] usb 2-1.1-port1: cannot reset (err = -22)

Setting the parkmode_disable_ss_quirk quirk fixes the issue.

CC: Dongjin Kim <tobetter@gmail.com>
Cc: Jianxin Pan <jianxin.pan@amlogic.com>
Reported-by: Tim <elatllat@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi b/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi
index 3f39e020f74e..4b002e799e5c 100644
--- a/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-g12-common.dtsi
@@ -2381,6 +2381,7 @@
 				dr_mode = "host";
 				snps,dis_u2_susphy_quirk;
 				snps,quirk-frame-length-adjustment;
+				snps,parkmode-disable-ss-quirk;
 			};
 		};
 
-- 
2.22.0