[src/trunk]: src/sys/arch/arm/cortex Various fixes / changes

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

details:   https://anonhg.NetBSD.org/src/rev/933cd9c40a4b
branches:  trunk
changeset: 458869:933cd9c40a4b
user:      skrll <skrll%NetBSD.org@localhost>
date:      Wed Aug 14 09:20:00 2019 +0000

description:
Various fixes / changes

- don't use prescaler
- improve AB_DEBUG output
- fix a9ptmr_delay to work with a decrementing counter!

Thanks to jmcneill@ for proving I'm an idiot

diffstat:

 sys/arch/arm/cortex/a9ptmr.c |  19 +++++++++++--------
 1 files changed, 11 insertions(+), 8 deletions(-)

diffs (69 lines):

diff -r 2a87e0952b77 -r 933cd9c40a4b sys/arch/arm/cortex/a9ptmr.c
--- a/sys/arch/arm/cortex/a9ptmr.c      Wed Aug 14 08:34:44 2019 +0000
+++ b/sys/arch/arm/cortex/a9ptmr.c      Wed Aug 14 09:20:00 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: a9ptmr.c,v 1.1 2019/08/10 17:03:59 skrll Exp $ */
+/*     $NetBSD: a9ptmr.c,v 1.2 2019/08/14 09:20:00 skrll Exp $ */
 
 /*-
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: a9ptmr.c,v 1.1 2019/08/10 17:03:59 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: a9ptmr.c,v 1.2 2019/08/14 09:20:00 skrll Exp $");
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -144,6 +144,7 @@
        sc->sc_ctl = a9ptmr_read(sc, TMR_CTL);
 
        sc->sc_prescaler = 1;
+#if 0
        /*
         * Let's hope the timer frequency isn't prime.
         */
@@ -154,14 +155,17 @@
                }
        }
        sc->sc_freq /= sc->sc_prescaler;
+#endif
 
-       aprint_debug_dev(sc->sc_dev, ": freq %d prescaler %d", sc->sc_freq,
+       aprint_debug(": freq %d prescaler %d", sc->sc_freq,
            sc->sc_prescaler);
        sc->sc_ctl = TMR_CTL_INT_ENABLE | TMR_CTL_AUTO_RELOAD | TMR_CTL_ENABLE;
        sc->sc_ctl |= __SHIFTIN(sc->sc_prescaler - 1, TMR_CTL_PRESCALER);
 
        sc->sc_load = (sc->sc_freq / hz) - 1;
 
+       aprint_debug(": load %d ", sc->sc_load);
+
        a9ptmr_init_cpu_clock(curcpu());
 
        aprint_naive("\n");
@@ -188,7 +192,6 @@
            curcpu()->ci_data.cpu_cc_freq / 2;
        KASSERT(freq != 0);
 
-
        const uint64_t counts_per_usec = freq / 1000000;
        uint32_t delta, usecs, last, curr;
 
@@ -200,11 +203,11 @@
        while (n > usecs) {
                curr = a9ptmr_read(sc, TMR_CTR);
 
-               /* Check to see if the timer has wrapped around. */
-               if (curr < last)
-                       delta += curr + (sc->sc_load - last);
+               /* Check to see if the timer has reloaded. */
+               if (curr > last)
+                       delta += (sc->sc_load - curr) + last;
                else
-                       delta += curr - last;
+                       delta += last - curr;
 
                last = curr;