MFC 264019, 264041, 264048, 264049, 264050, 264051

  Add support for event timers whose clock frequency can change while running.

  Apparently all ARM configs build kern_et.c, but only a few of them also
  build kern_clocksource.c, un-break the build by not referencing functions in
  kern_clocksource if NO_EVENTTIMERS is defined.

  Add variable-frequency support to the arm mpcore eventtimer driver.

  mpcore_timer: Disable the timer and clear any pending bit, then setup the
  new counter register values, then restart the timer.  Also re-nest the parens
  properly for casting the result of converting time and frequency to a count.

1 files changed, 16 insertions, 0 deletions

diff --git a/sys/kern/kern_et.c b/sys/kern/kern_et.c
index d07316c..544e6e4 100644
--- a/sys/kern/kern_et.c
+++ b/sys/kern/kern_et.c
@@ -34,6 +34,8 @@ __FBSDID("$FreeBSD$");
 #include <sys/queue.h>
 #include <sys/timeet.h>
 
+#include "opt_timer.h"
+
 SLIST_HEAD(et_eventtimers_list, eventtimer);
 static struct et_eventtimers_list eventtimers = SLIST_HEAD_INITIALIZER(et_eventtimers);
 
@@ -113,6 +115,20 @@ et_deregister(struct eventtimer *et)
 }
 
 /*
+ * Change the frequency of the given timer.  If it is the active timer,
+ * reconfigure it on all CPUs (reschedules all current events based on the new
+ * timer frequency).
+ */
+void
+et_change_frequency(struct eventtimer *et, uint64_t newfreq)
+{
+
+#ifndef NO_EVENTTIMERS
+	cpu_et_frequency(et, newfreq);
+#endif
+}
+
+/*
  * Find free event timer hardware with specified parameters.
  */
 struct eventtimer *