[RFC PATCH 1/5] x86: tsc: add tsc to art helpers

[Felipe Balbi <felipe.balbi@linux.intel.com>]

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
---
 arch/x86/include/asm/tsc.h |  2 ++
 arch/x86/kernel/tsc.c      | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 8a0c25c6bf09..b7a9f4385a82 100644
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -32,6 +32,8 @@ static inline cycles_t get_cycles(void)
 
 extern struct system_counterval_t convert_art_to_tsc(u64 art);
 extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
+extern void get_tsc_ns(struct system_counterval_t *tsc_counterval, u64 *tsc_ns);
+extern u64 get_art_ns_now(void);
 
 extern void tsc_early_init(void);
 extern void tsc_init(void);
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 0b29e58f288e..333fffc1db7c 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1215,6 +1215,38 @@ struct system_counterval_t convert_art_to_tsc(u64 art)
 }
 EXPORT_SYMBOL(convert_art_to_tsc);
 
+void get_tsc_ns(struct system_counterval_t *tsc_counterval, u64 *tsc_ns)
+{
+	u64 tmp, res, rem;
+	u64 cycles;
+
+	tsc_counterval->cycles = clocksource_tsc.read(NULL);
+	cycles = tsc_counterval->cycles;
+	tsc_counterval->cs = art_related_clocksource;
+
+	rem = do_div(cycles, tsc_khz);
+
+	res = cycles * USEC_PER_SEC;
+	tmp = rem * USEC_PER_SEC;
+
+	do_div(tmp, tsc_khz);
+	res += tmp;
+
+	*tsc_ns = res;
+}
+EXPORT_SYMBOL(get_tsc_ns);
+
+u64 get_art_ns_now(void)
+{
+	struct system_counterval_t tsc_cycles;
+	u64 tsc_ns;
+
+	get_tsc_ns(&tsc_cycles, &tsc_ns);
+
+	return tsc_ns;
+}
+EXPORT_SYMBOL(get_art_ns_now);
+
 /**
  * convert_art_ns_to_tsc() - Convert ART in nanoseconds to TSC.
  * @art_ns: ART (Always Running Timer) in unit of nanoseconds
-- 
2.22.0