Synopsis Designware USB3 IP earlier than v3.00a which is configured in silicon
with DWC_USB3_SUSPEND_ON_DISCONNECT_EN=1, would need a specific quirk to prevent
xhci host controller from dying when device is disconnected.

Since DWC_USB3_SUSPEND_ON_DISCONNECT_EN is an IP configuration whose state
cannot be checked from software in runtime, it has to be enabled via platform
data or device tree.

Signed-off-by: Sneeker Yeh <sneeker....@tw.fujitsu.com>
---
 Documentation/devicetree/bindings/usb/dwc3.txt |   17 +++++++++++++++++
 drivers/usb/dwc3/core.c                        |    6 ++++++
 drivers/usb/dwc3/core.h                        |    1 +
 drivers/usb/dwc3/host.c                        |    4 ++++
 drivers/usb/dwc3/platform_data.h               |    1 +
 5 files changed, 29 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt 
b/Documentation/devicetree/bindings/usb/dwc3.txt
index cd7f045..1b78b29 100644
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ b/Documentation/devicetree/bindings/usb/dwc3.txt
@@ -37,6 +37,23 @@ Optional properties:
  - snps,is-utmi-l1-suspend: true when DWC3 asserts output signal
                        utmi_l1_suspend_n, false when asserts utmi_sleep_n
  - snps,hird-threshold: HIRD threshold
+ - snps,has_suspend_on_disconnect: true when IP is configured in silicon with
+                       DWC_USB3_SUSPEND_ON_DISCONNECT_EN=1, it can inject a
+                       specific quirk to prevent xhci host controller from
+                       dying when usb device is disconnected from root hub.
+                       Since DWC_USB3_SUSPEND_ON_DISCONNECT_EN is an IP
+                       configuration whose state cannot be checked from
+                       software in runtime, it has to be enabled via platform
+                       data or device tree.
+
+                       xhci host dying symptom here is caused by that
+                       DWC_USB3_SUSPEND_ON_DISCONNECT_EN=1
+                       configuration makes IP auto-suspended after PORTCSC is
+                       cleared when usb device detached, then an asynchronous
+                       disconnection procedure might fail using endpoint
+                       command that suspened IP won't have any response to.
+
+                       this issue is fixed when IP version >= 3.00a.
 
 This is usually a subnode to DWC3 glue to which it is connected.
 
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 25ddc39..fbceab1 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -838,6 +838,9 @@ static int dwc3_probe(struct platform_device *pdev)
                                "snps,tx_de_emphasis_quirk");
                of_property_read_u8(node, "snps,tx_de_emphasis",
                                &tx_de_emphasis);
+
+               dwc->suspend_on_disconnect_quirk = of_property_read_bool(node,
+                               "snps,has_suspend_on_disconnect");
        } else if (pdata) {
                dwc->maximum_speed = pdata->maximum_speed;
                dwc->has_lpm_erratum = pdata->has_lpm_erratum;
@@ -864,6 +867,9 @@ static int dwc3_probe(struct platform_device *pdev)
                dwc->tx_de_emphasis_quirk = pdata->tx_de_emphasis_quirk;
                if (pdata->tx_de_emphasis)
                        tx_de_emphasis = pdata->tx_de_emphasis;
+
+               dwc->suspend_on_disconnect_quirk =
+                       pdata->has_suspend_on_disconnect;
        }
 
        /* default to superspeed if no maximum_speed passed */
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 8090249..d7458ff 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -832,6 +832,7 @@ struct dwc3 {
 
        unsigned                tx_de_emphasis_quirk:1;
        unsigned                tx_de_emphasis:2;
+       unsigned                suspend_on_disconnect_quirk:1;
 };
 
 /* -------------------------------------------------------------------------- 
*/
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index 12bfd3c..9c42074 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -53,6 +53,10 @@ int dwc3_host_init(struct dwc3 *dwc)
        pdata.usb3_lpm_capable = 1;
 #endif
 
+       if ((dwc->revision < DWC3_REVISION_300A) &&
+           dwc->suspend_on_disconnect_quirk)
+               pdata.delay_portcsc_clear = 1;
+
        ret = platform_device_add_data(xhci, &pdata, sizeof(pdata));
        if (ret) {
                dev_err(dwc->dev, "couldn't add platform data to xHCI 
device\n");
diff --git a/drivers/usb/dwc3/platform_data.h b/drivers/usb/dwc3/platform_data.h
index a3a3b6d..69562f1 100644
--- a/drivers/usb/dwc3/platform_data.h
+++ b/drivers/usb/dwc3/platform_data.h
@@ -44,4 +44,5 @@ struct dwc3_platform_data {
 
        unsigned tx_de_emphasis_quirk:1;
        unsigned tx_de_emphasis:2;
+       unsigned has_suspend_on_disconnect:1;
 };
-- 
1.7.9.5

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