openrisc: Add library functions

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>

1 files changed, 104 insertions, 0 deletions

diff --git a/arch/openrisc/lib/timer.c b/arch/openrisc/lib/timer.c
new file mode 100644
index 00000000000..4e92a311590
--- /dev/null
+++ b/arch/openrisc/lib/timer.c
@@ -0,0 +1,104 @@
+/*
+ * (C) Copyright 2011, Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
+ * (C) Copyright 2011, Julius Baxter <julius@opencores.org>
+ * (C) Copyright 2003
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/system.h>
+#include <asm/openrisc_exc.h>
+
+static ulong timestamp;
+
+/* how many counter cycles in a jiffy */
+#define TIMER_COUNTER_CYCLES  (CONFIG_SYS_CLK_FREQ/CONFIG_SYS_OPENRISC_TMR_HZ)
+/* how many ms elapses between each timer interrupt */
+#define TIMER_TIMESTAMP_INC   (1000/CONFIG_SYS_OPENRISC_TMR_HZ)
+/* how many cycles per ms */
+#define TIMER_CYCLES_MS       (CONFIG_SYS_CLK_FREQ/1000)
+/* how many cycles per us */
+#define TIMER_CYCLES_US       (CONFIG_SYS_CLK_FREQ/1000000uL)
+
+void timer_isr(void)
+{
+	timestamp += TIMER_TIMESTAMP_INC;
+	mtspr(SPR_TTMR, SPR_TTMR_IE | SPR_TTMR_RT |
+		(TIMER_COUNTER_CYCLES & SPR_TTMR_TP));
+}
+
+int timer_init(void)
+{
+	/* Install timer exception handler */
+	exception_install_handler(EXC_TIMER, timer_isr);
+
+	/* Set up the timer for the first expiration. */
+	timestamp = 0;
+
+	mtspr(SPR_TTMR, SPR_TTMR_IE | SPR_TTMR_RT |
+		(TIMER_COUNTER_CYCLES & SPR_TTMR_TP));
+
+	/* Enable tick timer exception in supervisor register */
+	mtspr(SPR_SR, mfspr(SPR_SR) | SPR_SR_TEE);
+
+	return 0;
+}
+
+void reset_timer(void)
+{
+	timestamp = 0;
+
+	mtspr(SPR_TTMR, SPR_TTMR_IE | SPR_TTMR_RT |
+		(TIMER_COUNTER_CYCLES & SPR_TTMR_TP));
+}
+
+/*
+ * The timer value in ms is calculated by taking the
+ * value accumulated by full timer revolutions plus the value
+ * accumulated in this period
+ */
+ulong get_timer(ulong base)
+{
+	return timestamp + mfspr(SPR_TTCR)/TIMER_CYCLES_MS - base;
+}
+
+void set_timer(ulong t)
+{
+	reset_timer();
+	timestamp = t;
+}
+
+void __udelay(ulong usec)
+{
+	ulong elapsed = 0;
+	ulong tick;
+	ulong last_tick;
+
+	last_tick = mfspr(SPR_TTCR);
+	while ((elapsed / TIMER_CYCLES_US) < usec) {
+		tick = mfspr(SPR_TTCR);
+		if (tick >= last_tick)
+			elapsed += (tick - last_tick);
+		else
+			elapsed += TIMER_COUNTER_CYCLES - (last_tick - tick);
+		last_tick = tick;
+	}
+}