Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 132 insertions, 0 deletions

diff --git a/arch/v850/kernel/highres_timer.c b/arch/v850/kernel/highres_timer.c
new file mode 100644
index 00000000000..b16ad1eaf96
--- /dev/null
+++ b/arch/v850/kernel/highres_timer.c
@@ -0,0 +1,132 @@
+/*
+ * arch/v850/kernel/highres_timer.c -- High resolution timing routines
+ *
+ *  Copyright (C) 2001,02,03  NEC Electronics Corporation
+ *  Copyright (C) 2001,02,03  Miles Bader <miles@gnu.org>
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License.  See the file COPYING in the main directory of this
+ * archive for more details.
+ *
+ * Written by Miles Bader <miles@gnu.org>
+ */
+
+#include <asm/system.h>
+#include <asm/v850e_timer_d.h>
+#include <asm/highres_timer.h>
+
+#define HIGHRES_TIMER_USEC_SHIFT   12
+
+/* Pre-calculated constant used for converting ticks to real time
+   units.  We initialize it to prevent it being put into BSS.  */
+static u32 highres_timer_usec_prescale = 1;
+
+void highres_timer_slow_tick_irq (void) __attribute__ ((noreturn));
+void highres_timer_slow_tick_irq (void)
+{
+	/* This is an interrupt handler, so it must be very careful to
+	   not to trash any registers.  At this point, the stack-pointer
+	   (r3) has been saved in the chip ram location ENTRY_SP by the
+	   interrupt vector, so we can use it as a scratch register; we
+	   must also restore it before returning.  */
+	asm ("ld.w	%0[r0], sp;"
+	     "add	1, sp;"
+	     "st.w	sp, %0[r0];"
+	     "ld.w	%1[r0], sp;" /* restore pre-irq stack-pointer */
+	     "reti"
+	     ::
+	      "i" (HIGHRES_TIMER_SLOW_TICKS_ADDR),
+	      "i" (ENTRY_SP_ADDR)
+	     : "memory");
+}
+
+void highres_timer_reset (void)
+{
+	V850E_TIMER_D_TMD (HIGHRES_TIMER_TIMER_D_UNIT) = 0;
+	HIGHRES_TIMER_SLOW_TICKS = 0;
+}
+
+void highres_timer_start (void)
+{
+	u32 fast_tick_rate;
+
+	/* Start hardware timer.  */
+	v850e_timer_d_configure (HIGHRES_TIMER_TIMER_D_UNIT,
+				 HIGHRES_TIMER_SLOW_TICK_RATE);
+
+	fast_tick_rate =
+		(V850E_TIMER_D_BASE_FREQ
+		 >> V850E_TIMER_D_DIVLOG2 (HIGHRES_TIMER_TIMER_D_UNIT));
+
+	/* The obvious way of calculating microseconds from fast ticks
+	   is to do:
+
+	     usec = fast_ticks * 10^6 / fast_tick_rate
+
+	   However, divisions are much slower than multiplications, and
+	   the above calculation can overflow, so we do this instead:
+
+	     usec = fast_ticks * (10^6 * 2^12 / fast_tick_rate) / 2^12
+
+           since we can pre-calculate (10^6 * (2^12 / fast_tick_rate))
+	   and use a shift for dividing by 2^12, this avoids division,
+	   and is almost as accurate (it differs by about 2 microseconds
+	   at the extreme value of the fast-tick counter's ranger).  */
+	highres_timer_usec_prescale = ((1000000 << HIGHRES_TIMER_USEC_SHIFT)
+				       / fast_tick_rate);
+
+	/* Enable the interrupt (which is hardwired to this use), and
+	   give it the highest priority.  */
+	V850E_INTC_IC (IRQ_INTCMD (HIGHRES_TIMER_TIMER_D_UNIT)) = 0;
+}
+
+void highres_timer_stop (void)
+{
+	/* Stop the timer.  */
+	V850E_TIMER_D_TMCD (HIGHRES_TIMER_TIMER_D_UNIT) =
+		V850E_TIMER_D_TMCD_CAE;
+	/* Disable its interrupt, just in case.  */
+	v850e_intc_disable_irq (IRQ_INTCMD (HIGHRES_TIMER_TIMER_D_UNIT));
+}
+
+inline void highres_timer_read_ticks (u32 *slow_ticks, u32 *fast_ticks)
+{
+	int flags;
+	u32 fast_ticks_1, fast_ticks_2, _slow_ticks;
+
+	local_irq_save (flags);
+	fast_ticks_1 = V850E_TIMER_D_TMD (HIGHRES_TIMER_TIMER_D_UNIT);
+	_slow_ticks = HIGHRES_TIMER_SLOW_TICKS;
+	fast_ticks_2 = V850E_TIMER_D_TMD (HIGHRES_TIMER_TIMER_D_UNIT);
+	local_irq_restore (flags);
+
+	if (fast_ticks_2 < fast_ticks_1)
+		_slow_ticks++;
+
+	*slow_ticks = _slow_ticks;
+	*fast_ticks = fast_ticks_2;
+}
+
+inline void highres_timer_ticks_to_timeval (u32 slow_ticks, u32 fast_ticks,
+					    struct timeval *tv)
+{
+	unsigned long sec, sec_rem, usec;
+
+	usec = ((fast_ticks * highres_timer_usec_prescale)
+		>> HIGHRES_TIMER_USEC_SHIFT);
+
+	sec = slow_ticks / HIGHRES_TIMER_SLOW_TICK_RATE;
+	sec_rem = slow_ticks % HIGHRES_TIMER_SLOW_TICK_RATE;
+
+	usec += sec_rem * (1000000 / HIGHRES_TIMER_SLOW_TICK_RATE);
+
+	tv->tv_sec = sec;
+	tv->tv_usec = usec;
+}
+
+void highres_timer_read (struct timeval *tv)
+{
+	u32 fast_ticks, slow_ticks;
+	highres_timer_read_ticks (&slow_ticks, &fast_ticks);
+	highres_timer_ticks_to_timeval (slow_ticks, fast_ticks, tv);
+}