[src/trunk]: src/sys/arch/arm/cortex Simplify gtmr_delay and don't mix and ma...

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

details:   https://anonhg.NetBSD.org/src/rev/8d821f646062
branches:  trunk
changeset: 323507:8d821f646062
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Sun Jun 17 22:42:41 2018 +0000

description:
Simplify gtmr_delay and don't mix and match usage of the physical and
virtual timers (always use the virtual timer).

diffstat:

 sys/arch/arm/cortex/gtmr.c |  28 ++++++++++------------------
 1 files changed, 10 insertions(+), 18 deletions(-)

diffs (74 lines):

diff -r 0db3a1354862 -r 8d821f646062 sys/arch/arm/cortex/gtmr.c
--- a/sys/arch/arm/cortex/gtmr.c        Sun Jun 17 18:10:18 2018 +0000
+++ b/sys/arch/arm/cortex/gtmr.c        Sun Jun 17 22:42:41 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: gtmr.c,v 1.29 2018/06/09 01:17:35 jakllsch Exp $       */
+/*     $NetBSD: gtmr.c,v 1.30 2018/06/17 22:42:41 jmcneill Exp $       */
 
 /*-
  * Copyright (c) 2012 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: gtmr.c,v 1.29 2018/06/09 01:17:35 jakllsch Exp $");
+__KERNEL_RCSID(0, "$NetBSD: gtmr.c,v 1.30 2018/06/17 22:42:41 jmcneill Exp $");
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -89,7 +89,6 @@
 
 stable_read(gtmr_cntv_cval);
 stable_read(gtmr_cntvct);
-stable_read(gtmr_cntpct);
 
 static int gtmr_match(device_t, cfdata_t, void *);
 static void gtmr_attach(device_t, device_t, void *);
@@ -177,8 +176,6 @@
            device_xname(self), "CNTV_CVAL read retry max");
        evcnt_attach_dynamic(&gtmr_cntvct_read_ev, EVCNT_TYPE_MISC, NULL,
            device_xname(self), "CNTVCT read retry max");
-       evcnt_attach_dynamic(&gtmr_cntpct_read_ev, EVCNT_TYPE_MISC, NULL,
-           device_xname(self), "CNTPCT read retry max");
 
        if (mpcaa->mpcaa_irq != -1) {
                sc->sc_global_ih = intr_establish(mpcaa->mpcaa_irq, IPL_CLOCK,
@@ -256,24 +253,19 @@
        KASSERT(freq != 0);
 
        const unsigned int incr_per_us = howmany(freq, 1000000);
-       unsigned int delta = 0, usecs = 0;
+       int64_t ticks = (int64_t)n * incr_per_us;
 
        arm_isb();
-       uint64_t last = gtmr_cntpct_stable_read(sc);
+       uint64_t last = gtmr_cntvct_stable_read(sc);
 
-       while (n > usecs) {
+       while (ticks > 0) {
                arm_isb();
-               uint64_t curr = gtmr_cntpct_stable_read(sc);
-               if (curr < last)
-                       delta += curr + (UINT64_MAX - last);
+               uint64_t curr = gtmr_cntvct_stable_read(sc);
+               if (curr > last)
+                       ticks -= (curr - last);
                else
-                       delta += curr - last;
-
+                       ticks -= (UINT64_MAX - curr + last);
                last = curr;
-               if (delta >= incr_per_us) {
-                       usecs += delta / incr_per_us;
-                       delta %= incr_per_us;
-               }
        }
 }
 
@@ -347,5 +339,5 @@
 {
        struct gtmr_softc * const sc = tc->tc_priv;
        arm_isb();      // we want the time NOW, not some instructions later.
-       return (u_int) gtmr_cntpct_stable_read(sc);
+       return (u_int) gtmr_cntvct_stable_read(sc);
 }