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

Neil Armstrong
2019-10-14T14:17:28Z

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"

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>
---
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 999ce5e84d3c..a36cf33330fb 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -993,6 +993,9 @@ 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);
}

@@ -1303,6 +1306,8 @@ 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