[src/trunk]: src/sys/arch/arm/cortex Move isb's to before reading count. Cha...

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

details:   https://anonhg.NetBSD.org/src/rev/284705aa046f
branches:  trunk
changeset: 336866:284705aa046f
user:      matt <matt%NetBSD.org@localhost>
date:      Tue Mar 24 15:53:39 2015 +0000

description:
Move isb's to before reading count.  Change interrupt to level.

diffstat:

 sys/arch/arm/cortex/gtmr.c |  26 +++++++++++---------------
 1 files changed, 11 insertions(+), 15 deletions(-)

diffs (95 lines):

diff -r 363902d3c31c -r 284705aa046f sys/arch/arm/cortex/gtmr.c
--- a/sys/arch/arm/cortex/gtmr.c        Tue Mar 24 08:58:41 2015 +0000
+++ b/sys/arch/arm/cortex/gtmr.c        Tue Mar 24 15:53:39 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: gtmr.c,v 1.11 2015/03/24 08:58:41 matt Exp $   */
+/*     $NetBSD: gtmr.c,v 1.12 2015/03/24 15:53:39 matt Exp $   */
 
 /*-
  * Copyright (c) 2012 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: gtmr.c,v 1.11 2015/03/24 08:58:41 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: gtmr.c,v 1.12 2015/03/24 15:53:39 matt Exp $");
 
 #include <sys/param.h>
 #include <sys/bus.h>
@@ -128,7 +128,7 @@
            device_xname(self), "missing interrupts");
 
        sc->sc_global_ih = intr_establish(mpcaa->mpcaa_irq, IPL_CLOCK,
-           IST_EDGE | IST_MPSAFE, gtmr_intr, NULL);
+           IST_LEVEL | IST_MPSAFE, gtmr_intr, NULL);
        if (sc->sc_global_ih == NULL)
                panic("%s: unable to register timer interrupt", __func__);
        aprint_normal_dev(self, "interrupting on irq %d\n",
@@ -170,8 +170,8 @@
        /*
         * Get now and update the compare timer.
         */
+       arm_isb();
        ci->ci_lastintr = armreg_cntv_ct_read();
-       arm_isb();
        armreg_cntv_tval_write(sc->sc_autoinc);
 #if 0
        printf("%s: %s: delta cval = %"PRIu64"\n",
@@ -187,19 +187,19 @@
 
        s = splsched();
 
+       arm_isb();
        uint64_t now64;
        uint64_t start64 = armreg_cntv_ct_read();
-       arm_isb();
        do {
+               arm_isb();
                now64 = armreg_cntv_ct_read();
-               arm_isb();
        } while (start64 == now64);
        start64 = now64;
        uint64_t end64 = start64 + 64;
        uint32_t start32 = armreg_pmccntr_read();
        do {
+               arm_isb();
                now64 = armreg_cntv_ct_read();
-               arm_isb();
        } while (end64 != now64);
        uint32_t end32 = armreg_pmccntr_read();
 
@@ -245,9 +245,9 @@
         */
        const uint64_t incr_per_us = (freq >> 20) + (freq >> 24);
 
-       const uint64_t delta = n * incr_per_us;
+       arm_isb();
        const uint64_t base = armreg_cntv_ct_read();
-       arm_isb();
+       const uint64_t delta = n * incr_per_us;
        const uint64_t finish = base + delta;
 
        while (armreg_cntv_ct_read() < finish) {
@@ -284,10 +284,9 @@
        struct clockframe * const cf = arg;
        struct gtmr_softc * const sc = &gtmr_sc;
 
-       const uint64_t now = armreg_cntv_ct_read();
-
        arm_isb();
 
+       const uint64_t now = armreg_cntv_ct_read();
        uint64_t delta = now - ci->ci_lastintr;
 
 #ifdef DIAGNOSTIC
@@ -340,9 +339,6 @@
 static u_int
 gtmr_get_timecount(struct timecounter *tc)
 {
-       u_int now = (u_int) armreg_cntp_ct_read();
-
        arm_isb();      // we want the time NOW, not some instructions later.
-
-       return now;
+       return (u_int) armreg_cntp_ct_read();
 }