[src/trunk]: src/sys/arch/arm/cortex - Add an isb before cnt[pv]_ctl read

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

details:   https://anonhg.NetBSD.org/src/rev/a35902575634
branches:  trunk
changeset: 1023263:a35902575634
user:      jmcneill <jmcneill%NetBSD.org@localhost>
date:      Mon Aug 30 22:53:37 2021 +0000

description:
- Add an isb before cnt[pv]_ctl read
- cntk_ctl is 64-bits
- Do not toggle CNTCTL_IMASK in intr handler, as this may be needed
  elsewhere.

diffstat:

 sys/arch/arm/cortex/gtmr.c |  44 ++++++++++++++++++++------------------------
 1 files changed, 20 insertions(+), 24 deletions(-)

diffs (115 lines):

diff -r 7f92b93abea4 -r a35902575634 sys/arch/arm/cortex/gtmr.c
--- a/sys/arch/arm/cortex/gtmr.c        Mon Aug 30 22:49:42 2021 +0000
+++ b/sys/arch/arm/cortex/gtmr.c        Mon Aug 30 22:53:37 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: gtmr.c,v 1.43 2021/01/18 23:43:34 jmcneill Exp $       */
+/*     $NetBSD: gtmr.c,v 1.44 2021/08/30 22:53:37 jmcneill Exp $       */
 
 /*-
  * Copyright (c) 2012 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: gtmr.c,v 1.43 2021/01/18 23:43:34 jmcneill Exp $");
+__KERNEL_RCSID(0, "$NetBSD: gtmr.c,v 1.44 2021/08/30 22:53:37 jmcneill Exp $");
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -41,6 +41,7 @@
 #include <sys/proc.h>
 #include <sys/systm.h>
 #include <sys/timetc.h>
+#include <sys/cpu.h>
 
 #include <prop/proplib.h>
 
@@ -195,6 +196,8 @@
 static uint32_t
 gtmr_read_ctl(struct gtmr_softc *sc)
 {
+       isb();
+
        if (sc->sc_physical)
                return gtmr_cntp_ctl_read();
        else
@@ -239,7 +242,8 @@
 gtmr_init_cpu_clock(struct cpu_info *ci)
 {
        struct gtmr_softc * const sc = &gtmr_sc;
-       uint32_t val;
+       uint32_t cntk;
+       uint64_t ctl;
 
        KASSERT(ci == curcpu());
 
@@ -249,29 +253,34 @@
         * Allow the virtual and physical counters to be accessed from
         * usermode. (PL0)
         */
-       val = gtmr_cntk_ctl_read();
-       val &= ~(CNTKCTL_PL0PTEN | CNTKCTL_PL0VTEN | CNTKCTL_EVNTEN);
+       cntk = gtmr_cntk_ctl_read();
+       cntk &= ~(CNTKCTL_PL0PTEN | CNTKCTL_PL0VTEN | CNTKCTL_EVNTEN);
        if (sc->sc_physical) {
-               val |= CNTKCTL_PL0PCTEN;
-               val &= ~CNTKCTL_PL0VCTEN;
+               cntk |= CNTKCTL_PL0PCTEN;
+               cntk &= ~CNTKCTL_PL0VCTEN;
        } else {
-               val |= CNTKCTL_PL0VCTEN;
-               val &= ~CNTKCTL_PL0PCTEN;
+               cntk |= CNTKCTL_PL0VCTEN;
+               cntk &= ~CNTKCTL_PL0PCTEN;
        }
-       gtmr_cntk_ctl_write(val);
+       gtmr_cntk_ctl_write(cntk);
        isb();
 
        /*
         * enable timer and stop masking the timer.
         */
-       gtmr_write_ctl(sc, CNTCTL_ENABLE);
+       ctl = gtmr_read_ctl(sc);
+       ctl &= ~CNTCTL_IMASK;
+       ctl |= CNTCTL_ENABLE;
+       gtmr_write_ctl(sc, ctl);
 
        /*
         * Get now and update the compare timer.
         */
        ci->ci_lastintr = gtmr_read_cntct(sc);
        gtmr_write_tval(sc, sc->sc_autoinc);
+
        splx(s);
+
        KASSERT(gtmr_read_cntct(sc) != 0);
 }
 
@@ -324,14 +333,6 @@
        struct cpu_info * const ci = curcpu();
        struct clockframe * const cf = arg;
        struct gtmr_softc * const sc = &gtmr_sc;
-       uint32_t ctl;
-
-       ctl = gtmr_read_ctl(sc);
-       if ((ctl & CNTCTL_ISTATUS) == 0)
-               return 0;
-
-       ctl |= CNTCTL_IMASK;
-       gtmr_write_ctl(sc, ctl);
 
        const uint64_t now = gtmr_read_cntct(sc);
        uint64_t delta = now - ci->ci_lastintr;
@@ -371,11 +372,6 @@
                gtmr_write_tval(sc, sc->sc_autoinc - delta);
        }
 
-       ctl = gtmr_read_ctl(sc);
-       ctl &= ~CNTCTL_IMASK;
-       ctl |= CNTCTL_ENABLE;
-       gtmr_write_ctl(sc, ctl);
-
        ci->ci_lastintr = now;
 
 #ifdef DIAGNOSTIC