Linux-2.6.12-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!
diff --git a/arch/v850/kernel/highres_timer.c b/arch/v850/kernel/highres_timer.c
new file mode 100644
index 0000000..b16ad1e
--- /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);
+}