usb: dwc3: core: 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.

Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

2 files changed, 19 insertions, 0 deletions

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 64ba664d467c..88c80fcc39f5 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -985,6 +985,22 @@ static int dwc3_core_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);
+
+                /*
+                 * Enable Auto retry Feature to make the controller operating in
+                 * Host mode on seeing transaction errors(CRC errors or internal
+                 * overrun scenerios) on IN transfers to reply to the device
+                 * with a non-terminating retry ACK (i.e, an ACK transcation
+                 * packet with Retry=1 & Nump != 0)
+                 */
+                reg |= DWC3_GUCTL_HSTINAUTORETRY;
+
+                dwc3_writel(dwc->regs, DWC3_GUCTL, reg);
+        }
+
         /*
          * Must config both number of packets and max burst settings to enable
          * RX and/or TX threshold.
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 5f14fb7121b1..5bfb62533e0f 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -238,6 +238,9 @@
 #define DWC3_GCTL_GBLHIBERNATIONEN      BIT(1)
 #define DWC3_GCTL_DSBLCLKGTNG           BIT(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)