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-rw-r--r--kernel/time/ntp.c23
1 files changed, 17 insertions, 6 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index c88b5910e7a..5fd9b946977 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -42,12 +42,13 @@ long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
42long time_freq; /* frequency offset (scaled ppm)*/ 42long time_freq; /* frequency offset (scaled ppm)*/
43static long time_reftime; /* time at last adjustment (s) */ 43static long time_reftime; /* time at last adjustment (s) */
44long time_adjust; 44long time_adjust;
45static long ntp_tick_adj;
45 46
46static void ntp_update_frequency(void) 47static void ntp_update_frequency(void)
47{ 48{
48 u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ) 49 u64 second_length = (u64)(tick_usec * NSEC_PER_USEC * USER_HZ)
49 << TICK_LENGTH_SHIFT; 50 << TICK_LENGTH_SHIFT;
50 second_length += (s64)CLOCK_TICK_ADJUST << TICK_LENGTH_SHIFT; 51 second_length += (s64)ntp_tick_adj << TICK_LENGTH_SHIFT;
51 second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC); 52 second_length += (s64)time_freq << (TICK_LENGTH_SHIFT - SHIFT_NSEC);
52 53
53 tick_length_base = second_length; 54 tick_length_base = second_length;
@@ -342,14 +343,16 @@ int do_adjtimex(struct timex *txc)
342 freq_adj = shift_right(freq_adj, time_constant * 2 + 343 freq_adj = shift_right(freq_adj, time_constant * 2 +
343 (SHIFT_PLL + 2) * 2 - SHIFT_NSEC); 344 (SHIFT_PLL + 2) * 2 - SHIFT_NSEC);
344 if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) { 345 if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp > MAXSEC)) {
346 u64 utemp64;
345 temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL); 347 temp64 = time_offset << (SHIFT_NSEC - SHIFT_FLL);
346 if (time_offset < 0) { 348 if (time_offset < 0) {
347 temp64 = -temp64; 349 utemp64 = -temp64;
348 do_div(temp64, mtemp); 350 do_div(utemp64, mtemp);
349 freq_adj -= temp64; 351 freq_adj -= utemp64;
350 } else { 352 } else {
351 do_div(temp64, mtemp); 353 utemp64 = temp64;
352 freq_adj += temp64; 354 do_div(utemp64, mtemp);
355 freq_adj += utemp64;
353 } 356 }
354 } 357 }
355 freq_adj += time_freq; 358 freq_adj += time_freq;
@@ -400,3 +403,11 @@ leave: if ((time_status & (STA_UNSYNC|STA_CLOCKERR)) != 0)
400 notify_cmos_timer(); 403 notify_cmos_timer();
401 return(result); 404 return(result);
402} 405}
406
407static int __init ntp_tick_adj_setup(char *str)
408{
409 ntp_tick_adj = simple_strtol(str, NULL, 0);
410 return 1;
411}
412
413__setup("ntp_tick_adj=", ntp_tick_adj_setup);