[src/trunk]: src/sys/dev/usb xhci: shrink port reset delay

[jmcneill <jmcneill%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c888bb849bd7
branches:  trunk
changeset: 1024126:c888bb849bd7
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Sun Oct 10 20:10:12 2021 +0000

description:
xhci: shrink port reset delay

Instead of waiting for USB_PORT_ROOT_RESET_DELAY (250ms) before checking
the port reset status, poll the PORTSC register and return early if the
reset has completed.

diffstat:

 sys/dev/usb/xhci.c |  21 ++++++++++-----------
 1 files changed, 10 insertions(+), 11 deletions(-)

diffs (45 lines):

diff -r a921d66703c6 -r c888bb849bd7 sys/dev/usb/xhci.c
--- a/sys/dev/usb/xhci.c        Sun Oct 10 19:17:31 2021 +0000
+++ b/sys/dev/usb/xhci.c        Sun Oct 10 20:10:12 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: xhci.c,v 1.148 2021/08/17 22:00:32 andvar Exp $        */
+/*     $NetBSD: xhci.c,v 1.149 2021/10/10 20:10:12 jmcneill Exp $      */
 
 /*
  * Copyright (c) 2013 Jonathan A. Kollasch
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: xhci.c,v 1.148 2021/08/17 22:00:32 andvar Exp $");
+__KERNEL_RCSID(0, "$NetBSD: xhci.c,v 1.149 2021/10/10 20:10:12 jmcneill Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_usb.h"
@@ -4121,18 +4121,17 @@
                        /* XXX suspend */
                        break;
                case UHF_PORT_RESET:
-                       v &= ~(XHCI_PS_PED | XHCI_PS_PR);
                        xhci_op_write_4(sc, port, v | XHCI_PS_PR);
                        /* Wait for reset to complete. */
-                       usb_delay_ms(&sc->sc_bus, USB_PORT_ROOT_RESET_DELAY);
-                       if (sc->sc_dying) {
-                               return -1;
-                       }
-                       v = xhci_op_read_4(sc, port);
-                       if (v & XHCI_PS_PR) {
-                               xhci_op_write_4(sc, port, v & ~XHCI_PS_PR);
+                       for (i = 0; i < USB_PORT_ROOT_RESET_DELAY / 10; i++) {
+                               if (sc->sc_dying) {
+                                       return -1;
+                               }
+                               v = xhci_op_read_4(sc, port);
+                               if ((v & XHCI_PS_PR) == 0) {
+                                       break;
+                               }
                                usb_delay_ms(&sc->sc_bus, 10);
-                               /* XXX */
                        }
                        break;
                case UHF_PORT_POWER: