riscv_mtimer: modify riscv_mtimer_current to reduce precision lost

Signed-off-by: liaoao <[email protected]>
leo11261 · Sep 12, 2024 · c6fa87b · c6fa87b
1 parent 8b4b66e
commit c6fa87b
Showing 1 changed file with 4 additions and 3 deletions.
diff --git a/arch/risc-v/src/common/riscv_mtimer.c b/arch/risc-v/src/common/riscv_mtimer.c
@@ -319,10 +319,11 @@ static int riscv_mtimer_current(struct oneshot_lowerhalf_s *lower,
   struct riscv_mtimer_lowerhalf_s *priv =
     (struct riscv_mtimer_lowerhalf_s *)lower;
   uint64_t mtime = riscv_mtimer_get_mtime(priv);
-  uint64_t nsec = mtime / (priv->freq / USEC_PER_SEC) * NSEC_PER_USEC;
+  uint64_t left;
 
-  ts->tv_sec  = nsec / NSEC_PER_SEC;
-  ts->tv_nsec = nsec % NSEC_PER_SEC;
+  ts->tv_sec  = mtime / priv->freq;
+  left        = mtime - ts->tv_sec * priv->freq;
+  ts->tv_nsec = NSEC_PER_SEC * left / priv->freq;
 
   return 0;
 }