diff options
Diffstat (limited to 'kernel/time')
-rw-r--r-- | kernel/time/ntp.c | 71 |
1 files changed, 18 insertions, 53 deletions
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c index 238ce47ef09d..65223b7ed810 100644 --- a/kernel/time/ntp.c +++ b/kernel/time/ntp.c | |||
@@ -22,8 +22,9 @@ unsigned long tick_usec = TICK_USEC; /* USER_HZ period (usec) */ | |||
22 | unsigned long tick_nsec; /* ACTHZ period (nsec) */ | 22 | unsigned long tick_nsec; /* ACTHZ period (nsec) */ |
23 | static u64 tick_length, tick_length_base; | 23 | static u64 tick_length, tick_length_base; |
24 | 24 | ||
25 | /* Don't completely fail for HZ > 500. */ | 25 | #define MAX_TICKADJ 500 /* microsecs */ |
26 | int tickadj = 500/HZ ? : 1; /* microsecs */ | 26 | #define MAX_TICKADJ_SCALED (((u64)(MAX_TICKADJ * NSEC_PER_USEC) << \ |
27 | TICK_LENGTH_SHIFT) / HZ) | ||
27 | 28 | ||
28 | /* | 29 | /* |
29 | * phase-lock loop variables | 30 | * phase-lock loop variables |
@@ -40,7 +41,6 @@ long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */ | |||
40 | long time_freq; /* frequency offset (scaled ppm)*/ | 41 | long time_freq; /* frequency offset (scaled ppm)*/ |
41 | long time_reftime; /* time at last adjustment (s) */ | 42 | long time_reftime; /* time at last adjustment (s) */ |
42 | long time_adjust; | 43 | long time_adjust; |
43 | long time_next_adjust; | ||
44 | 44 | ||
45 | /** | 45 | /** |
46 | * ntp_clear - Clears the NTP state variables | 46 | * ntp_clear - Clears the NTP state variables |
@@ -160,46 +160,19 @@ void second_overflow(void) | |||
160 | time_adj = max(time_adj, ((MAXPHASE / HZ) << SHIFT_UPDATE) / MINSEC); | 160 | time_adj = max(time_adj, ((MAXPHASE / HZ) << SHIFT_UPDATE) / MINSEC); |
161 | time_offset -= time_adj; | 161 | time_offset -= time_adj; |
162 | tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE); | 162 | tick_length += (s64)time_adj << (TICK_LENGTH_SHIFT - SHIFT_UPDATE); |
163 | } | ||
164 | |||
165 | /* | ||
166 | * Returns how many microseconds we need to add to xtime this tick | ||
167 | * in doing an adjustment requested with adjtime. | ||
168 | */ | ||
169 | static long adjtime_adjustment(void) | ||
170 | { | ||
171 | long time_adjust_step; | ||
172 | |||
173 | time_adjust_step = time_adjust; | ||
174 | if (time_adjust_step) { | ||
175 | /* | ||
176 | * We are doing an adjtime thing. Prepare time_adjust_step to | ||
177 | * be within bounds. Note that a positive time_adjust means we | ||
178 | * want the clock to run faster. | ||
179 | * | ||
180 | * Limit the amount of the step to be in the range | ||
181 | * -tickadj .. +tickadj | ||
182 | */ | ||
183 | time_adjust_step = min(time_adjust_step, (long)tickadj); | ||
184 | time_adjust_step = max(time_adjust_step, (long)-tickadj); | ||
185 | } | ||
186 | return time_adjust_step; | ||
187 | } | ||
188 | 163 | ||
189 | /* in the NTP reference this is called "hardclock()" */ | 164 | if (unlikely(time_adjust)) { |
190 | void update_ntp_one_tick(void) | 165 | if (time_adjust > MAX_TICKADJ) { |
191 | { | 166 | time_adjust -= MAX_TICKADJ; |
192 | long time_adjust_step; | 167 | tick_length += MAX_TICKADJ_SCALED; |
193 | 168 | } else if (time_adjust < -MAX_TICKADJ) { | |
194 | time_adjust_step = adjtime_adjustment(); | 169 | time_adjust += MAX_TICKADJ; |
195 | if (time_adjust_step) | 170 | tick_length -= MAX_TICKADJ_SCALED; |
196 | /* Reduce by this step the amount of time left */ | 171 | } else { |
197 | time_adjust -= time_adjust_step; | 172 | time_adjust = 0; |
198 | 173 | tick_length += (s64)(time_adjust * NSEC_PER_USEC / | |
199 | /* Changes by adjtime() do not take effect till next tick. */ | 174 | HZ) << TICK_LENGTH_SHIFT; |
200 | if (time_next_adjust != 0) { | 175 | } |
201 | time_adjust = time_next_adjust; | ||
202 | time_next_adjust = 0; | ||
203 | } | 176 | } |
204 | } | 177 | } |
205 | 178 | ||
@@ -213,14 +186,7 @@ void update_ntp_one_tick(void) | |||
213 | */ | 186 | */ |
214 | u64 current_tick_length(void) | 187 | u64 current_tick_length(void) |
215 | { | 188 | { |
216 | u64 ret; | 189 | return tick_length; |
217 | |||
218 | /* calculate the finest interval NTP will allow. | ||
219 | */ | ||
220 | ret = tick_length; | ||
221 | ret += (u64)(adjtime_adjustment() * 1000) << TICK_LENGTH_SHIFT; | ||
222 | |||
223 | return ret; | ||
224 | } | 190 | } |
225 | 191 | ||
226 | 192 | ||
@@ -263,7 +229,7 @@ int do_adjtimex(struct timex *txc) | |||
263 | result = time_state; /* mostly `TIME_OK' */ | 229 | result = time_state; /* mostly `TIME_OK' */ |
264 | 230 | ||
265 | /* Save for later - semantics of adjtime is to return old value */ | 231 | /* Save for later - semantics of adjtime is to return old value */ |
266 | save_adjust = time_next_adjust ? time_next_adjust : time_adjust; | 232 | save_adjust = time_adjust; |
267 | 233 | ||
268 | #if 0 /* STA_CLOCKERR is never set yet */ | 234 | #if 0 /* STA_CLOCKERR is never set yet */ |
269 | time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */ | 235 | time_status &= ~STA_CLOCKERR; /* reset STA_CLOCKERR */ |
@@ -310,8 +276,7 @@ int do_adjtimex(struct timex *txc) | |||
310 | if (txc->modes & ADJ_OFFSET) { /* values checked earlier */ | 276 | if (txc->modes & ADJ_OFFSET) { /* values checked earlier */ |
311 | if (txc->modes == ADJ_OFFSET_SINGLESHOT) { | 277 | if (txc->modes == ADJ_OFFSET_SINGLESHOT) { |
312 | /* adjtime() is independent from ntp_adjtime() */ | 278 | /* adjtime() is independent from ntp_adjtime() */ |
313 | if ((time_next_adjust = txc->offset) == 0) | 279 | time_adjust = txc->offset; |
314 | time_adjust = 0; | ||
315 | } | 280 | } |
316 | else if (time_status & STA_PLL) { | 281 | else if (time_status & STA_PLL) { |
317 | ltemp = txc->offset; | 282 | ltemp = txc->offset; |