[PATCH 4.9 099/134] usb: dwc3: gadget: Fix setting of DEPCFG.bInterval_m1

[Greg Kroah-Hartman]

From: Thinh Nguyen <thinh.ngu...@synopsys.com>

commit a1679af85b2ae35a2b78ad04c18bb069c37330cc upstream.

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: <sta...@vger.kernel.org>
Signed-off-by: Thinh Nguyen <thinh.ngu...@synopsys.com>
Link: 
https://lore.kernel.org/r/3f57026f993c0ce71498dbb06e49b3a47c4d0265.1612820995.git.thinh.ngu...@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 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
@@ -528,7 +528,17 @@ 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);
        }