From a1679af85b2ae35a2b78ad04c18bb069c37330cc Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Mon, 8 Feb 2021 13:53:10 -0800
Subject: [PATCH] usb: dwc3: gadget: Fix setting of DEPCFG.bInterval_m1
Git-commit: a1679af85b2ae35a2b78ad04c18bb069c37330cc
Patch-mainline: v5.12-rc1
References: git-fixes

[ backport note: adjusted the gadget object access (from dwc->gadget->speed
  to dwc->gadget.speed) for 5.3.x kernel base -- tiwai ]

Valid range for DEPCFG.bInterval_m1 is from 0 to 13, and it must be set
to 0 when the controller operates in full-speed. See the programming
guide for DEPCFG command section 3.2.2.1 (v3.30a).

Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/3f57026f993c0ce71498dbb06e49b3a47c4d0265.1612820995.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/dwc3/gadget.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -593,7 +593,17 @@ static int dwc3_gadget_set_ep_config(str
 		params.param0 |= DWC3_DEPCFG_FIFO_NUMBER(dep->number >> 1);
 
 	if (desc->bInterval) {
-		params.param1 |= DWC3_DEPCFG_BINTERVAL_M1(desc->bInterval - 1);
+		u8 bInterval_m1;
+
+		/*
+		 * Valid range for DEPCFG.bInterval_m1 is from 0 to 13, and it
+		 * must be set to 0 when the controller operates in full-speed.
+		 */
+		bInterval_m1 = min_t(u8, desc->bInterval - 1, 13);
+		if (dwc->gadget.speed == USB_SPEED_FULL)
+			bInterval_m1 = 0;
+
+		params.param1 |= DWC3_DEPCFG_BINTERVAL_M1(bInterval_m1);
 		dep->interval = 1 << (desc->bInterval - 1);
 	}