Apparently we need to explicitly stop the timers before reloading them. At

least this is what Linux does and it fixes a hang on the Olimex A10s boards.
While there, also preserve the clock selection when reloading the timer.

ok patrick@, jsg@, tom@

diff --git a/sys/arch/armv7/sunxi/sxitimer.c b/sys/arch/armv7/sunxi/sxitimer.c
index 4062b87..e882a4e 100644 (file)
--- a/sys/arch/armv7/sunxi/sxitimer.c
+++ b/sys/arch/armv7/sunxi/sxitimer.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: sxitimer.c,v 1.5 2016/02/01 23:31:34 jsg Exp $        */
+/*     $OpenBSD: sxitimer.c,v 1.6 2016/07/18 19:22:45 kettenis Exp $   */
 /*
  * Copyright (c) 2007,2009 Dale Rahn <drahn@openbsd.org>
  * Copyright (c) 2013 Raphael Graf <r@undefined.ch>
@@ -76,6 +76,8 @@
 #define        STATTIMER               1
 #define        CNTRTIMER               2
 
+#define TIMER_SYNC             3
+
 void   sxitimer_attach(struct device *, struct device *, void *);
 int    sxitimer_tickintr(void *);
 int    sxitimer_statintr(void *);
@@ -83,6 +85,7 @@ void  sxitimer_cpu_initclocks(void);
 void   sxitimer_setstatclockrate(int);
 uint64_t       sxitimer_readcnt64(void);
 uint32_t       sxitimer_readcnt32(void);
+void   sxitimer_sync(void);
 void   sxitimer_delay(u_int);
 
 u_int sxitimer_get_timecount(struct timecounter *);
@@ -267,6 +270,7 @@ int
 sxitimer_tickintr(void *frame)
 {
        uint32_t now, nextevent;
+       uint32_t val;
        int rc = 0;
 
        splassert(IPL_CLOCK);   
@@ -304,12 +308,21 @@ sxitimer_tickintr(void *frame)
                sxitimer_tick_nextevt = now;
        }
 
+       val = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
+           TIMER_CTRL(TICKTIMER));
+       bus_space_write_4(sxitimer_iot, sxitimer_ioh,
+           TIMER_CTRL(TICKTIMER), val & ~TIMER_ENABLE);
+
+       sxitimer_sync();
+
        bus_space_write_4(sxitimer_iot, sxitimer_ioh,
            TIMER_INTV(TICKTIMER), nextevent);
 
+       val = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
+           TIMER_CTRL(TICKTIMER));
        bus_space_write_4(sxitimer_iot, sxitimer_ioh,
            TIMER_CTRL(TICKTIMER),
-           TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
+           val | TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
 
        return rc;
 }
@@ -318,6 +331,7 @@ int
 sxitimer_statintr(void *frame)
 {
        uint32_t now, nextevent, r;
+       uint32_t val;
        int rc = 0;
 
        splassert(IPL_STATCLOCK);       
@@ -352,12 +366,21 @@ sxitimer_statintr(void *frame)
                sxitimer_stat_nextevt = now;
        }
 
+       val = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
+           TIMER_CTRL(STATTIMER));
+       bus_space_write_4(sxitimer_iot, sxitimer_ioh,
+           TIMER_CTRL(STATTIMER), val & ~TIMER_ENABLE);
+
+       sxitimer_sync();
+
        bus_space_write_4(sxitimer_iot, sxitimer_ioh,
            TIMER_INTV(STATTIMER), nextevent);
 
+       val = bus_space_read_4(sxitimer_iot, sxitimer_ioh,
+           TIMER_CTRL(STATTIMER));
        bus_space_write_4(sxitimer_iot, sxitimer_ioh,
            TIMER_CTRL(STATTIMER),
-           TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
+           val | TIMER_ENABLE | TIMER_RELOAD | TIMER_SINGLESHOT);
 
        return rc;
 }
@@ -390,6 +413,15 @@ sxitimer_readcnt32(void)
            TIMER_CURR(CNTRTIMER));
 }
 
+void
+sxitimer_sync(void)
+{
+       uint32_t now = sxitimer_readcnt32();
+
+       while ((now - sxitimer_readcnt32()) < TIMER_SYNC)
+               CPU_BUSY_CYCLE();
+}
+
 void
 sxitimer_delay(u_int usecs)
 {