From: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
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@xxxxxxx>
Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
---
drivers/usb/dwc3/core.c | 9 +++++++++
drivers/usb/dwc3/core.h | 3 +++
2 files changed, 12 insertions(+)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index dc92f471c1..aab6c34c2d 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -995,6 +995,15 @@ 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 b510d8a983..2adcaf0029 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -160,6 +160,9 @@
#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)
--
2.17.1
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