usb: dwc3: Device SoftReset PHY synchonization delay

PATCH Superseded Felipe Balbi 1 participant 1 message Jan 8, 2018 USB

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Felipe Balbi

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2018-01-08 11:59 UTC #0 lore raw

PATCH 1/15 usb: dwc3: Device SoftReset PHY synchonization delay

Hi,

Quoted 23 lines · Thinh Nguyen

From DWC_usb31 databook section 1.3.2, once DWC3_DCTL_CSFTRST bit is cleared, we must wait at least 50ms before accessing the PHY domain (synchronization delay).
Signed-off-by Thinh Nguyen <[email protected]>
---
 drivers/usb/dwc3/core.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)
drivers/usb/dwc3/core.c +1 -1
index 07832509584f..7d21f21707f5 100644
@@ -228,12 +228,23 @@ static int dwc3_core_soft_reset(struct dwc3 *dwc)
 	do {
 		reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 		if (!(reg & DWC3_DCTL_CSFTRST))
-			return 0;
+			goto done;
 
 		udelay(1);
 	} while (--retries);
 

drivers/usb/dwc3/core.c static int dwc3_core_soft_reset(struct dwc3 *dwc) · line 245

Quoted 10 lines

drivers/usb/dwc3/core.c +9 -0

 	return -ETIMEDOUT;
+
+done:
+	/*
+	 * For DWC_usb31 controller, once DWC3_DCTL_CSFTRST bit is cleared,
+	 * we must wait at least 50ms before accessing the PHY domain
+	 * (synchronization delay). DWC_usb31 Databook section 1.3.2.
+	 */
+	if (dwc3_is_usb31(dwc))
+		mdelay(50);

we don't have any locks held. Why are you busy looping for an entire 50ms? Why don't you msleep() here?