Fixed overflow issue in pps_gen_utc

5a4de885 · Vincent van Beveren · e3af54f4 · 5a4de885
Commit 5a4de885 authored Aug 04, 2023 by Vincent van Beveren
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pps_gen.c dev/pps_gen.c +9 -1

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--- a/dev/pps_gen.c
+++ b/dev/pps_gen.c
@@ -85,11 +85,19 @@ void shw_pps_gen_set_time(uint64_t seconds, uint32_t nanoseconds, int counter)
 static uint64_t pps_get_utc(void)
 {
 	uint64_t out;
-	uint32_t low, high;
+	uint32_t low, low2, high;

 	low = ppsg_read(CNTR_UTCLO);
 	high = ppsg_read(CNTR_UTCHI);

+	// check for wrap, if so, re-read registers
+	low2 = ppsg_read(CNTR_UTCLO);
+	if (low2 < low) 
+	{
+		high = ppsg_read(CNTR_UTCHI);
+		low = low2;
+	}
+
 	high &= 0xFF;		/* CNTR_UTCHI has only 8 bits defined -- rest are HDL don't care */

 	out = (uint64_t) low | (uint64_t) high << 32;