usb: dwc3: Enable AutoRetry feature in the controller

By default when core sees any transaction error (CRC or overflow) it
replies with terminating retry ACK (Retry=1 and Nump == 0).

Enabling this Auto Retry feature in controller will make the core send
a non-terminanting ACK upon such transaction errors. That is, ACK TP
with Retry=1 and Nump != 0.

Doing so will give controller a chance to recover from transient error
conditions.

Reference from below Linux commit,

commit <b138e23d3dff> ("usb: dwc3: core: Enable AutoRetry feature
in the controller")

Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index b399c9bea9913b76bc231b1ea7fa30c38f9c39f2..d7f666ba3c27f8b4542f44ffcfd249f23e2184cb 100644 (file)
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -997,6 +997,15 @@ int dwc3_init(struct dwc3 *dwc)
                dwc3_writel(dwc->regs, DWC3_GUCTL1, reg);
        }
 
+       if (dwc->dr_mode == USB_DR_MODE_HOST ||
+           dwc->dr_mode == USB_DR_MODE_OTG) {
+               reg = dwc3_readl(dwc->regs, DWC3_GUCTL);
+
+               reg |= DWC3_GUCTL_HSTINAUTORETRY;
+
+               dwc3_writel(dwc->regs, DWC3_GUCTL, reg);
+       }
+
        ret = dwc3_core_init_mode(dwc);
        if (ret)
                goto mode_fail;

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index ca72b490dfd017872429c3ae31a926695cf9b3be..d1f8606b84946d801c7dd1fd5d2dc21f795bd08d 100644 (file)
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -161,6 +161,9 @@
 #define DWC3_GCTL_GBLHIBERNATIONEN     (1 << 1)
 #define DWC3_GCTL_DSBLCLKGTNG          (1 << 0)
 
+/* Global User Control Register */
+#define DWC3_GUCTL_HSTINAUTORETRY      BIT(14)
+
 /* Global User Control 1 Register */
 #define DWC3_GUCTL1_TX_IPGAP_LINECHECK_DIS     BIT(28)
 #define DWC3_GUCTL1_DEV_L1_EXIT_BY_HW  BIT(24)