usb: dwc2: make the scheduler handle excessive NAKs better

I'm seeing problems with a d-link dwcl-g122 wifi dongle that
someone sent me. There are reports of other wifi dongles with the
same/similar problem. The devices appear to be NAKing to the point
of confusing the dwc2 driver completely.

The attached patch helps with my d-link dwl-g122 - it's adapted
from the Raspberry Pi dwc_otg driver, which is a modified version
of the Synopsys vendor driver. The error recovery is still valid
after the patch, I think.

Cc: Dom Cobley <[e-mail]>
Signed-off-by: Nick Hudson <[e-mail]>
Signed-off-by: Paul Zimmerman <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/dwc2/hcd_intr.c

···
 					"hcint 0x%08x, intsts 0x%08x\n",
 					chan->hcint,
 					readl(hsotg->regs + GINTSTS));
+				goto error;
 			}
 		}
 	} else {
 		dev_info(hsotg->dev,
 			 "NYET/NAK/ACK/other in non-error case, 0x%08x\n",
 			 chan->hcint);
+error:
+		/* Failthrough: use 3-strikes rule */
+		qtd->error_count++;
+		dwc2_update_urb_state_abn(hsotg, chan, chnum, qtd->urb,
+					  qtd, DWC2_HC_XFER_XACT_ERR);
+		dwc2_hcd_save_data_toggle(hsotg, chan, chnum, qtd);
+		dwc2_halt_channel(hsotg, chan, qtd, DWC2_HC_XFER_XACT_ERR);
 	}
 }