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authorSascha Hauer <s.hauer@pengutronix.de>2007-07-05 18:01:15 +0200
committerSascha Hauer <sha@octopus.labnet.pengutronix.de>2007-07-05 18:01:15 +0200
commit390c9283abc6dd9ea94bad9d82287f100d713822 (patch)
treee2d963f51d402854dd3089274c898d114980c163 /common/clock.c
parentbfa43fe81aa3845e0188e5d4757bf5658e24233d (diff)
downloadbarebox-390c9283abc6dd9ea94bad9d82287f100d713822.tar.gz
svn_rev_031
add clocksource stuff from kernel and first implementation (imx) (WIP)
Diffstat (limited to 'common/clock.c')
-rw-r--r--common/clock.c84
1 files changed, 84 insertions, 0 deletions
diff --git a/common/clock.c b/common/clock.c
new file mode 100644
index 0000000..2e4e9d7
--- /dev/null
+++ b/common/clock.c
@@ -0,0 +1,84 @@
+#include <common.h>
+#include <asm-generic/div64.h>
+#include <clock.h>
+
+static struct clocksource *current_clock;
+static uint64_t time_ns;
+
+/**
+ * get_time_ns - get current timestamp in nanoseconds
+ */
+uint64_t get_time_ns(void)
+{
+ struct clocksource *cs = current_clock;
+ uint64_t cycle_now, cycle_delta;
+ uint64_t ns_offset;
+
+ /* read clocksource: */
+ cycle_now = cs->read();
+
+ /* calculate the delta since the last call: */
+ cycle_delta = (cycle_now - cs->cycle_last) & cs->mask;
+
+ /* convert to nanoseconds: */
+ ns_offset = cyc2ns(cs, cycle_delta);
+
+ cs->cycle_last = cycle_now;
+
+ time_ns += ns_offset;
+ return time_ns;
+}
+
+/**
+ * clocksource_hz2mult - calculates mult from hz and shift
+ * @hz: Clocksource frequency in Hz
+ * @shift_constant: Clocksource shift factor
+ *
+ * Helper functions that converts a hz counter
+ * frequency to a timsource multiplier, given the
+ * clocksource shift value
+ */
+uint32_t clocksource_hz2mult(uint32_t hz, uint32_t shift_constant)
+{
+ /* hz = cyc/(Billion ns)
+ * mult/2^shift = ns/cyc
+ * mult = ns/cyc * 2^shift
+ * mult = 1Billion/hz * 2^shift
+ * mult = 1000000000 * 2^shift / hz
+ * mult = (1000000000<<shift) / hz
+ */
+ uint64_t tmp = ((uint64_t)1000000000) << shift_constant;
+
+ tmp += hz/2; /* round for do_div */
+ do_div(tmp, hz);
+
+ return (uint32_t)tmp;
+}
+
+int is_timeout(uint64_t start_ns, uint64_t time_offset_ns)
+{
+ if (start_ns + time_offset_ns < get_time_ns())
+ return 1;
+ else
+ return 0;
+}
+
+void udelay(unsigned long usecs)
+{
+ uint64_t start = get_time_ns();
+
+ while(!is_timeout(start, usecs * 1000));
+}
+
+void mdelay(unsigned long msecs)
+{
+ uint64_t start = get_time_ns();
+
+ while(!is_timeout(start, msecs * 1000000));
+}
+
+int init_clock(struct clocksource *cs)
+{
+ current_clock = cs;
+ return 0;
+}