[src/trunk]: src/sys/arch/arm/marvell Rework mvsoctmr(4), improving timekeepi...

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

details:   https://anonhg.NetBSD.org/src/rev/11c1869ce573
branches:  trunk
changeset: 765895:11c1869ce573
user:      jakllsch <jakllsch%NetBSD.org@localhost>
date:      Thu Jun 09 13:43:44 2011 +0000

description:
Rework mvsoctmr(4), improving timekeeping accuracy

Inconveniently the Marvell hardware only counts down.
We need to reverse this for timecounter(9), and we need
to do it in a very lightweight way.

 - use Timer0 for the clock interrupt
 - use Timer1 for timecounter(9) and delay(9)
 - drop statclock due to lack of timers (does anyone actually use this?)

diffstat:

 sys/arch/arm/marvell/mvsoctmr.c |  82 +++++++++--------------------------------
 1 files changed, 18 insertions(+), 64 deletions(-)

diffs (189 lines):

diff -r a637a3b4ddae -r 11c1869ce573 sys/arch/arm/marvell/mvsoctmr.c
--- a/sys/arch/arm/marvell/mvsoctmr.c   Thu Jun 09 13:41:40 2011 +0000
+++ b/sys/arch/arm/marvell/mvsoctmr.c   Thu Jun 09 13:43:44 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mvsoctmr.c,v 1.1 2010/10/03 05:49:24 kiyohara Exp $    */
+/*     $NetBSD: mvsoctmr.c,v 1.2 2011/06/09 13:43:44 jakllsch Exp $    */
 /*
  * Copyright (c) 2007, 2008 KIYOHARA Takashi
  * All rights reserved.
@@ -25,7 +25,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: mvsoctmr.c,v 1.1 2010/10/03 05:49:24 kiyohara Exp $");
+__KERNEL_RCSID(0, "$NetBSD: mvsoctmr.c,v 1.2 2011/06/09 13:43:44 jakllsch Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -60,18 +60,12 @@
 static void mvsoctmr_attach(device_t, device_t, void *);
 
 static int clockhandler(void *);
-static int statclockhandler(void *);
 
 static u_int mvsoctmr_get_timecount(struct timecounter *);
 
 static void mvsoctmr_cntl(struct mvsoctmr_softc *, int, u_int, int, int);
 
-#ifndef STATHZ
-#define STATHZ 64
-#endif
-
 static struct mvsoctmr_softc *mvsoctmr_sc;
-static uint32_t clock_ticks, statclock_ticks;
 static struct timecounter mvsoctmr_timecounter = {
        mvsoctmr_get_timecount, /* get_timecount */
        0,                      /* no poll_pps */
@@ -82,7 +76,6 @@
        NULL,                   /* prev */
        NULL,                   /* next */
 };
-static volatile uint32_t mvsoctmr_base;
 
 CFATTACH_DECL_NEW(mvsoctmr, sizeof(struct mvsoctmr_softc),
     mvsoctmr_match, mvsoctmr_attach, NULL, NULL);
@@ -121,6 +114,9 @@
        if (bus_space_subregion(mva->mva_iot, mva->mva_ioh,
            mva->mva_offset, mva->mva_size, &sc->sc_ioh))
                panic("%s: Cannot map registers", device_xname(self));
+
+       mvsoctmr_timecounter.tc_name = device_xname(self);
+       mvsoctmr_cntl(sc, MVSOCTMR_TIMER1, 0xffffffff, 1, 1);
 }
 
 /*
@@ -133,48 +129,20 @@
 {
        struct clockframe *frame = arg;
 
-       atomic_add_32(&mvsoctmr_base, clock_ticks);
-
        hardclock(frame);
 
        return 1;
 }
 
 /*
- * statclockhandler:
- *
- *     Handle the statclock interrupt.
- */
-static int
-statclockhandler(void *arg)
-{
-       struct clockframe *frame = arg;
-
-       statclock(frame);
-
-       return 1;
-}
-
-
-/*
  * setstatclockrate:
  *
  *     Set the rate of the statistics clock.
- *
- *     We assume that hz is either stathz or profhz, and that neither
- *     will change after being set by cpu_initclocks().  We could
- *     recalculate the intervals here, but that would be a pain.
  */
 /* ARGSUSED */
 void
 setstatclockrate(int newhz)
 {
-       struct mvsoctmr_softc *sc = mvsoctmr_sc;
-       const int en = 1, autoen = 1;
-
-       statclock_ticks = mvTclk / newhz;
-
-       mvsoctmr_cntl(sc, MVSOCTMR_TIMER1, statclock_ticks, en, autoen);
 }
 
 /*
@@ -188,32 +156,26 @@
        struct mvsoctmr_softc *sc;
        void *clock_ih;
        const int en = 1, autoen = 1;
+       uint32_t timer0_tval;
 
        sc = mvsoctmr_sc;
        if (sc == NULL)
                panic("cpu_initclocks: mvsoctmr not found");
 
-       stathz = profhz = STATHZ;
+       mvsoctmr_timecounter.tc_priv = sc;
        mvsoctmr_timecounter.tc_frequency = mvTclk;
-       clock_ticks = mvTclk / hz;
 
-       mvsoctmr_cntl(sc, MVSOCTMR_TIMER0, clock_ticks, en, autoen);
+       timer0_tval = (mvTclk * 2) / (u_long) hz;
+       timer0_tval = (timer0_tval / 2) + (timer0_tval & 1);
+
+       mvsoctmr_cntl(sc, MVSOCTMR_TIMER0, timer0_tval, en, autoen);
+       mvsoctmr_cntl(sc, MVSOCTMR_TIMER1, 0xffffffff, en, autoen);
 
        clock_ih = mvsoc_bridge_intr_establish(MVSOC_MLMB_MLMBI_CPUTIMER0INTREQ,
            IPL_CLOCK, clockhandler, NULL);
        if (clock_ih == NULL)
                panic("cpu_initclocks: unable to register timer interrupt");
 
-       if (stathz) {
-               setstatclockrate(stathz);
-               clock_ih = mvsoc_bridge_intr_establish(
-                   MVSOC_MLMB_MLMBI_CPUTIMER1INTREQ, IPL_HIGH,
-                   statclockhandler, NULL);
-               if (clock_ih == NULL)
-                       panic("cpu_initclocks:"
-                           " unable to register statclock timer interrupt");
-       }
-
        tc_init(&mvsoctmr_timecounter);
 }
 
@@ -237,7 +199,7 @@
         * counted.
         */
        initial_tick = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
-           MVSOCTMR_TIMER(MVSOCTMR_TIMER0));
+           MVSOCTMR_TIMER(MVSOCTMR_TIMER1));
 
        if (n <= UINT_MAX / mvTclk) {
                /*
@@ -255,9 +217,9 @@
 
        while (remaining > 0) {
                cur_tick = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
-                   MVSOCTMR_TIMER(MVSOCTMR_TIMER0));
+                   MVSOCTMR_TIMER(MVSOCTMR_TIMER1));
                if (cur_tick > initial_tick)
-                       remaining -= clock_ticks - cur_tick + initial_tick;
+                       remaining -= 0xffffffff - cur_tick + initial_tick;
                else
                        remaining -= (initial_tick - cur_tick);
                initial_tick = cur_tick;
@@ -267,20 +229,12 @@
 static u_int
 mvsoctmr_get_timecount(struct timecounter *tc)
 {
-       struct mvsoctmr_softc *sc = mvsoctmr_sc;
-       uint32_t counter, base;
-       u_int intrstat;
+       struct mvsoctmr_softc *sc = tc->tc_priv;
 
-       intrstat = disable_interrupts(I32_bit);
-       base = mvsoctmr_base;
-       counter = bus_space_read_4(sc->sc_iot, sc->sc_ioh,
-           MVSOCTMR_TIMER(MVSOCTMR_TIMER0));
-       restore_interrupts(intrstat);
-
-       return base - counter;
+       return 0xffffffff - bus_space_read_4(sc->sc_iot, sc->sc_ioh,
+           MVSOCTMR_TIMER(MVSOCTMR_TIMER1));
 }
 
-
 static void
 mvsoctmr_cntl(struct mvsoctmr_softc *sc, int num, u_int ticks, int en,
              int autoen)