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1 | #ifndef _LINUX_JIFFIES_H |
1 | #ifndef _LINUX_JIFFIES_H |
2 | #define _LINUX_JIFFIES_H |
2 | #define _LINUX_JIFFIES_H |
3 | 3 | ||
4 | #include |
4 | #include |
5 | #include |
5 | #include |
6 | #include |
6 | #include |
7 | #include |
7 | #include |
8 | //#include |
8 | //#include |
9 | //#include |
9 | //#include |
10 | 10 | ||
11 | 11 | ||
12 | #define HZ 100 |
12 | #define HZ 100 |
13 | #define CLOCK_TICK_RATE 1193182ul |
13 | #define CLOCK_TICK_RATE 1193182ul |
14 | 14 | ||
15 | /* |
15 | /* |
16 | * The following defines establish the engineering parameters of the PLL |
16 | * The following defines establish the engineering parameters of the PLL |
17 | * model. The HZ variable establishes the timer interrupt frequency, 100 Hz |
17 | * model. The HZ variable establishes the timer interrupt frequency, 100 Hz |
18 | * for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the |
18 | * for the SunOS kernel, 256 Hz for the Ultrix kernel and 1024 Hz for the |
19 | * OSF/1 kernel. The SHIFT_HZ define expresses the same value as the |
19 | * OSF/1 kernel. The SHIFT_HZ define expresses the same value as the |
20 | * nearest power of two in order to avoid hardware multiply operations. |
20 | * nearest power of two in order to avoid hardware multiply operations. |
21 | */ |
21 | */ |
22 | #if HZ >= 12 && HZ < 24 |
22 | #if HZ >= 12 && HZ < 24 |
23 | # define SHIFT_HZ 4 |
23 | # define SHIFT_HZ 4 |
24 | #elif HZ >= 24 && HZ < 48 |
24 | #elif HZ >= 24 && HZ < 48 |
25 | # define SHIFT_HZ 5 |
25 | # define SHIFT_HZ 5 |
26 | #elif HZ >= 48 && HZ < 96 |
26 | #elif HZ >= 48 && HZ < 96 |
27 | # define SHIFT_HZ 6 |
27 | # define SHIFT_HZ 6 |
28 | #elif HZ >= 96 && HZ < 192 |
28 | #elif HZ >= 96 && HZ < 192 |
29 | # define SHIFT_HZ 7 |
29 | # define SHIFT_HZ 7 |
30 | #elif HZ >= 192 && HZ < 384 |
30 | #elif HZ >= 192 && HZ < 384 |
31 | # define SHIFT_HZ 8 |
31 | # define SHIFT_HZ 8 |
32 | #elif HZ >= 384 && HZ < 768 |
32 | #elif HZ >= 384 && HZ < 768 |
33 | # define SHIFT_HZ 9 |
33 | # define SHIFT_HZ 9 |
34 | #elif HZ >= 768 && HZ < 1536 |
34 | #elif HZ >= 768 && HZ < 1536 |
35 | # define SHIFT_HZ 10 |
35 | # define SHIFT_HZ 10 |
36 | #elif HZ >= 1536 && HZ < 3072 |
36 | #elif HZ >= 1536 && HZ < 3072 |
37 | # define SHIFT_HZ 11 |
37 | # define SHIFT_HZ 11 |
38 | #elif HZ >= 3072 && HZ < 6144 |
38 | #elif HZ >= 3072 && HZ < 6144 |
39 | # define SHIFT_HZ 12 |
39 | # define SHIFT_HZ 12 |
40 | #elif HZ >= 6144 && HZ < 12288 |
40 | #elif HZ >= 6144 && HZ < 12288 |
41 | # define SHIFT_HZ 13 |
41 | # define SHIFT_HZ 13 |
42 | #else |
42 | #else |
43 | # error Invalid value of HZ. |
43 | # error Invalid value of HZ. |
44 | #endif |
44 | #endif |
45 | 45 | ||
46 | /* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can |
46 | /* Suppose we want to divide two numbers NOM and DEN: NOM/DEN, then we can |
47 | * improve accuracy by shifting LSH bits, hence calculating: |
47 | * improve accuracy by shifting LSH bits, hence calculating: |
48 | * (NOM << LSH) / DEN |
48 | * (NOM << LSH) / DEN |
49 | * This however means trouble for large NOM, because (NOM << LSH) may no |
49 | * This however means trouble for large NOM, because (NOM << LSH) may no |
50 | * longer fit in 32 bits. The following way of calculating this gives us |
50 | * longer fit in 32 bits. The following way of calculating this gives us |
51 | * some slack, under the following conditions: |
51 | * some slack, under the following conditions: |
52 | * - (NOM / DEN) fits in (32 - LSH) bits. |
52 | * - (NOM / DEN) fits in (32 - LSH) bits. |
53 | * - (NOM % DEN) fits in (32 - LSH) bits. |
53 | * - (NOM % DEN) fits in (32 - LSH) bits. |
54 | */ |
54 | */ |
55 | #define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \ |
55 | #define SH_DIV(NOM,DEN,LSH) ( (((NOM) / (DEN)) << (LSH)) \ |
56 | + ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN)) |
56 | + ((((NOM) % (DEN)) << (LSH)) + (DEN) / 2) / (DEN)) |
57 | 57 | ||
58 | /* LATCH is used in the interval timer and ftape setup. */ |
58 | /* LATCH is used in the interval timer and ftape setup. */ |
59 | #define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */ |
59 | #define LATCH ((CLOCK_TICK_RATE + HZ/2) / HZ) /* For divider */ |
60 | 60 | ||
61 | extern int register_refined_jiffies(long clock_tick_rate); |
61 | extern int register_refined_jiffies(long clock_tick_rate); |
62 | 62 | ||
63 | /* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */ |
63 | /* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */ |
64 | #define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ) |
64 | #define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ) |
65 | 65 | ||
66 | /* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */ |
66 | /* TICK_USEC is the time between ticks in usec assuming fake USER_HZ */ |
67 | #define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ) |
67 | #define TICK_USEC ((1000000UL + USER_HZ/2) / USER_HZ) |
68 | 68 | ||
69 | /* some arch's have a small-data section that can be accessed register-relative |
69 | /* some arch's have a small-data section that can be accessed register-relative |
70 | * but that can only take up to, say, 4-byte variables. jiffies being part of |
70 | * but that can only take up to, say, 4-byte variables. jiffies being part of |
71 | * an 8-byte variable may not be correctly accessed unless we force the issue |
71 | * an 8-byte variable may not be correctly accessed unless we force the issue |
72 | */ |
72 | */ |
73 | #define __jiffy_data __attribute__((section(".data"))) |
73 | #define __jiffy_data __attribute__((section(".data"))) |
74 | 74 | ||
75 | /* |
75 | /* |
76 | * The 64-bit value is not atomic - you MUST NOT read it |
76 | * The 64-bit value is not atomic - you MUST NOT read it |
77 | * without sampling the sequence number in jiffies_lock. |
77 | * without sampling the sequence number in jiffies_lock. |
78 | * get_jiffies_64() will do this for you as appropriate. |
78 | * get_jiffies_64() will do this for you as appropriate. |
79 | */ |
79 | */ |
80 | extern u64 jiffies_64; |
80 | extern u64 __jiffy_data jiffies_64; |
81 | extern unsigned long volatile jiffies; |
81 | extern unsigned long volatile __jiffy_data jiffies; |
82 | 82 | ||
83 | #if (BITS_PER_LONG < 64) |
83 | #if (BITS_PER_LONG < 64) |
84 | u64 get_jiffies_64(void); |
84 | u64 get_jiffies_64(void); |
85 | #else |
85 | #else |
86 | static inline u64 get_jiffies_64(void) |
86 | static inline u64 get_jiffies_64(void) |
87 | { |
87 | { |
88 | return (u64)jiffies; |
88 | return (u64)jiffies; |
89 | } |
89 | } |
90 | #endif |
90 | #endif |
91 | 91 | ||
92 | /* |
92 | /* |
93 | * These inlines deal with timer wrapping correctly. You are |
93 | * These inlines deal with timer wrapping correctly. You are |
94 | * strongly encouraged to use them |
94 | * strongly encouraged to use them |
95 | * 1. Because people otherwise forget |
95 | * 1. Because people otherwise forget |
96 | * 2. Because if the timer wrap changes in future you won't have to |
96 | * 2. Because if the timer wrap changes in future you won't have to |
97 | * alter your driver code. |
97 | * alter your driver code. |
98 | * |
98 | * |
99 | * time_after(a,b) returns true if the time a is after time b. |
99 | * time_after(a,b) returns true if the time a is after time b. |
100 | * |
100 | * |
101 | * Do this with "<0" and ">=0" to only test the sign of the result. A |
101 | * Do this with "<0" and ">=0" to only test the sign of the result. A |
102 | * good compiler would generate better code (and a really good compiler |
102 | * good compiler would generate better code (and a really good compiler |
103 | * wouldn't care). Gcc is currently neither. |
103 | * wouldn't care). Gcc is currently neither. |
104 | */ |
104 | */ |
105 | #define time_after(a,b) \ |
105 | #define time_after(a,b) \ |
106 | (typecheck(unsigned long, a) && \ |
106 | (typecheck(unsigned long, a) && \ |
107 | typecheck(unsigned long, b) && \ |
107 | typecheck(unsigned long, b) && \ |
108 | ((long)((b) - (a)) < 0)) |
108 | ((long)((b) - (a)) < 0)) |
109 | #define time_before(a,b) time_after(b,a) |
109 | #define time_before(a,b) time_after(b,a) |
110 | 110 | ||
111 | #define time_after_eq(a,b) \ |
111 | #define time_after_eq(a,b) \ |
112 | (typecheck(unsigned long, a) && \ |
112 | (typecheck(unsigned long, a) && \ |
113 | typecheck(unsigned long, b) && \ |
113 | typecheck(unsigned long, b) && \ |
114 | ((long)((a) - (b)) >= 0)) |
114 | ((long)((a) - (b)) >= 0)) |
115 | #define time_before_eq(a,b) time_after_eq(b,a) |
115 | #define time_before_eq(a,b) time_after_eq(b,a) |
116 | 116 | ||
117 | /* |
117 | /* |
118 | * Calculate whether a is in the range of [b, c]. |
118 | * Calculate whether a is in the range of [b, c]. |
119 | */ |
119 | */ |
120 | #define time_in_range(a,b,c) \ |
120 | #define time_in_range(a,b,c) \ |
121 | (time_after_eq(a,b) && \ |
121 | (time_after_eq(a,b) && \ |
122 | time_before_eq(a,c)) |
122 | time_before_eq(a,c)) |
123 | 123 | ||
124 | /* |
124 | /* |
125 | * Calculate whether a is in the range of [b, c). |
125 | * Calculate whether a is in the range of [b, c). |
126 | */ |
126 | */ |
127 | #define time_in_range_open(a,b,c) \ |
127 | #define time_in_range_open(a,b,c) \ |
128 | (time_after_eq(a,b) && \ |
128 | (time_after_eq(a,b) && \ |
129 | time_before(a,c)) |
129 | time_before(a,c)) |
130 | 130 | ||
131 | /* Same as above, but does so with platform independent 64bit types. |
131 | /* Same as above, but does so with platform independent 64bit types. |
132 | * These must be used when utilizing jiffies_64 (i.e. return value of |
132 | * These must be used when utilizing jiffies_64 (i.e. return value of |
133 | * get_jiffies_64() */ |
133 | * get_jiffies_64() */ |
134 | #define time_after64(a,b) \ |
134 | #define time_after64(a,b) \ |
135 | (typecheck(__u64, a) && \ |
135 | (typecheck(__u64, a) && \ |
136 | typecheck(__u64, b) && \ |
136 | typecheck(__u64, b) && \ |
137 | ((__s64)((b) - (a)) < 0)) |
137 | ((__s64)((b) - (a)) < 0)) |
138 | #define time_before64(a,b) time_after64(b,a) |
138 | #define time_before64(a,b) time_after64(b,a) |
139 | 139 | ||
140 | #define time_after_eq64(a,b) \ |
140 | #define time_after_eq64(a,b) \ |
141 | (typecheck(__u64, a) && \ |
141 | (typecheck(__u64, a) && \ |
142 | typecheck(__u64, b) && \ |
142 | typecheck(__u64, b) && \ |
143 | ((__s64)((a) - (b)) >= 0)) |
143 | ((__s64)((a) - (b)) >= 0)) |
144 | #define time_before_eq64(a,b) time_after_eq64(b,a) |
144 | #define time_before_eq64(a,b) time_after_eq64(b,a) |
145 | 145 | ||
146 | #define time_in_range64(a, b, c) \ |
146 | #define time_in_range64(a, b, c) \ |
147 | (time_after_eq64(a, b) && \ |
147 | (time_after_eq64(a, b) && \ |
148 | time_before_eq64(a, c)) |
148 | time_before_eq64(a, c)) |
149 | 149 | ||
150 | /* |
150 | /* |
151 | * These four macros compare jiffies and 'a' for convenience. |
151 | * These four macros compare jiffies and 'a' for convenience. |
152 | */ |
152 | */ |
153 | 153 | ||
154 | /* time_is_before_jiffies(a) return true if a is before jiffies */ |
154 | /* time_is_before_jiffies(a) return true if a is before jiffies */ |
155 | #define time_is_before_jiffies(a) time_after(jiffies, a) |
155 | #define time_is_before_jiffies(a) time_after(jiffies, a) |
156 | 156 | ||
157 | /* time_is_after_jiffies(a) return true if a is after jiffies */ |
157 | /* time_is_after_jiffies(a) return true if a is after jiffies */ |
158 | #define time_is_after_jiffies(a) time_before(jiffies, a) |
158 | #define time_is_after_jiffies(a) time_before(jiffies, a) |
159 | 159 | ||
160 | /* time_is_before_eq_jiffies(a) return true if a is before or equal to jiffies*/ |
160 | /* time_is_before_eq_jiffies(a) return true if a is before or equal to jiffies*/ |
161 | #define time_is_before_eq_jiffies(a) time_after_eq(jiffies, a) |
161 | #define time_is_before_eq_jiffies(a) time_after_eq(jiffies, a) |
162 | 162 | ||
163 | /* time_is_after_eq_jiffies(a) return true if a is after or equal to jiffies*/ |
163 | /* time_is_after_eq_jiffies(a) return true if a is after or equal to jiffies*/ |
164 | #define time_is_after_eq_jiffies(a) time_before_eq(jiffies, a) |
164 | #define time_is_after_eq_jiffies(a) time_before_eq(jiffies, a) |
165 | 165 | ||
166 | /* |
166 | /* |
167 | * Have the 32 bit jiffies value wrap 5 minutes after boot |
167 | * Have the 32 bit jiffies value wrap 5 minutes after boot |
168 | * so jiffies wrap bugs show up earlier. |
168 | * so jiffies wrap bugs show up earlier. |
169 | */ |
169 | */ |
170 | #define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ)) |
170 | #define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ)) |
171 | 171 | ||
172 | /* |
172 | /* |
173 | * Change timeval to jiffies, trying to avoid the |
173 | * Change timeval to jiffies, trying to avoid the |
174 | * most obvious overflows.. |
174 | * most obvious overflows.. |
175 | * |
175 | * |
176 | * And some not so obvious. |
176 | * And some not so obvious. |
177 | * |
177 | * |
178 | * Note that we don't want to return LONG_MAX, because |
178 | * Note that we don't want to return LONG_MAX, because |
179 | * for various timeout reasons we often end up having |
179 | * for various timeout reasons we often end up having |
180 | * to wait "jiffies+1" in order to guarantee that we wait |
180 | * to wait "jiffies+1" in order to guarantee that we wait |
181 | * at _least_ "jiffies" - so "jiffies+1" had better still |
181 | * at _least_ "jiffies" - so "jiffies+1" had better still |
182 | * be positive. |
182 | * be positive. |
183 | */ |
183 | */ |
184 | #define MAX_JIFFY_OFFSET ((LONG_MAX >> 1)-1) |
184 | #define MAX_JIFFY_OFFSET ((LONG_MAX >> 1)-1) |
185 | 185 | ||
186 | extern unsigned long preset_lpj; |
186 | extern unsigned long preset_lpj; |
187 | 187 | ||
188 | /* |
188 | /* |
189 | * We want to do realistic conversions of time so we need to use the same |
189 | * We want to do realistic conversions of time so we need to use the same |
190 | * values the update wall clock code uses as the jiffies size. This value |
190 | * values the update wall clock code uses as the jiffies size. This value |
191 | * is: TICK_NSEC (which is defined in timex.h). This |
191 | * is: TICK_NSEC (which is defined in timex.h). This |
192 | * is a constant and is in nanoseconds. We will use scaled math |
192 | * is a constant and is in nanoseconds. We will use scaled math |
193 | * with a set of scales defined here as SEC_JIFFIE_SC, USEC_JIFFIE_SC and |
193 | * with a set of scales defined here as SEC_JIFFIE_SC, USEC_JIFFIE_SC and |
194 | * NSEC_JIFFIE_SC. Note that these defines contain nothing but |
194 | * NSEC_JIFFIE_SC. Note that these defines contain nothing but |
195 | * constants and so are computed at compile time. SHIFT_HZ (computed in |
195 | * constants and so are computed at compile time. SHIFT_HZ (computed in |
196 | * timex.h) adjusts the scaling for different HZ values. |
196 | * timex.h) adjusts the scaling for different HZ values. |
197 | 197 | ||
198 | * Scaled math??? What is that? |
198 | * Scaled math??? What is that? |
199 | * |
199 | * |
200 | * Scaled math is a way to do integer math on values that would, |
200 | * Scaled math is a way to do integer math on values that would, |
201 | * otherwise, either overflow, underflow, or cause undesired div |
201 | * otherwise, either overflow, underflow, or cause undesired div |
202 | * instructions to appear in the execution path. In short, we "scale" |
202 | * instructions to appear in the execution path. In short, we "scale" |
203 | * up the operands so they take more bits (more precision, less |
203 | * up the operands so they take more bits (more precision, less |
204 | * underflow), do the desired operation and then "scale" the result back |
204 | * underflow), do the desired operation and then "scale" the result back |
205 | * by the same amount. If we do the scaling by shifting we avoid the |
205 | * by the same amount. If we do the scaling by shifting we avoid the |
206 | * costly mpy and the dastardly div instructions. |
206 | * costly mpy and the dastardly div instructions. |
207 | 207 | ||
208 | * Suppose, for example, we want to convert from seconds to jiffies |
208 | * Suppose, for example, we want to convert from seconds to jiffies |
209 | * where jiffies is defined in nanoseconds as NSEC_PER_JIFFIE. The |
209 | * where jiffies is defined in nanoseconds as NSEC_PER_JIFFIE. The |
210 | * simple math is: jiff = (sec * NSEC_PER_SEC) / NSEC_PER_JIFFIE; We |
210 | * simple math is: jiff = (sec * NSEC_PER_SEC) / NSEC_PER_JIFFIE; We |
211 | * observe that (NSEC_PER_SEC / NSEC_PER_JIFFIE) is a constant which we |
211 | * observe that (NSEC_PER_SEC / NSEC_PER_JIFFIE) is a constant which we |
212 | * might calculate at compile time, however, the result will only have |
212 | * might calculate at compile time, however, the result will only have |
213 | * about 3-4 bits of precision (less for smaller values of HZ). |
213 | * about 3-4 bits of precision (less for smaller values of HZ). |
214 | * |
214 | * |
215 | * So, we scale as follows: |
215 | * So, we scale as follows: |
216 | * jiff = (sec) * (NSEC_PER_SEC / NSEC_PER_JIFFIE); |
216 | * jiff = (sec) * (NSEC_PER_SEC / NSEC_PER_JIFFIE); |
217 | * jiff = ((sec) * ((NSEC_PER_SEC * SCALE)/ NSEC_PER_JIFFIE)) / SCALE; |
217 | * jiff = ((sec) * ((NSEC_PER_SEC * SCALE)/ NSEC_PER_JIFFIE)) / SCALE; |
218 | * Then we make SCALE a power of two so: |
218 | * Then we make SCALE a power of two so: |
219 | * jiff = ((sec) * ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) >> SCALE; |
219 | * jiff = ((sec) * ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) >> SCALE; |
220 | * Now we define: |
220 | * Now we define: |
221 | * #define SEC_CONV = ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) |
221 | * #define SEC_CONV = ((NSEC_PER_SEC << SCALE)/ NSEC_PER_JIFFIE)) |
222 | * jiff = (sec * SEC_CONV) >> SCALE; |
222 | * jiff = (sec * SEC_CONV) >> SCALE; |
223 | * |
223 | * |
224 | * Often the math we use will expand beyond 32-bits so we tell C how to |
224 | * Often the math we use will expand beyond 32-bits so we tell C how to |
225 | * do this and pass the 64-bit result of the mpy through the ">> SCALE" |
225 | * do this and pass the 64-bit result of the mpy through the ">> SCALE" |
226 | * which should take the result back to 32-bits. We want this expansion |
226 | * which should take the result back to 32-bits. We want this expansion |
227 | * to capture as much precision as possible. At the same time we don't |
227 | * to capture as much precision as possible. At the same time we don't |
228 | * want to overflow so we pick the SCALE to avoid this. In this file, |
228 | * want to overflow so we pick the SCALE to avoid this. In this file, |
229 | * that means using a different scale for each range of HZ values (as |
229 | * that means using a different scale for each range of HZ values (as |
230 | * defined in timex.h). |
230 | * defined in timex.h). |
231 | * |
231 | * |
232 | * For those who want to know, gcc will give a 64-bit result from a "*" |
232 | * For those who want to know, gcc will give a 64-bit result from a "*" |
233 | * operator if the result is a long long AND at least one of the |
233 | * operator if the result is a long long AND at least one of the |
234 | * operands is cast to long long (usually just prior to the "*" so as |
234 | * operands is cast to long long (usually just prior to the "*" so as |
235 | * not to confuse it into thinking it really has a 64-bit operand, |
235 | * not to confuse it into thinking it really has a 64-bit operand, |
236 | * which, buy the way, it can do, but it takes more code and at least 2 |
236 | * which, buy the way, it can do, but it takes more code and at least 2 |
237 | * mpys). |
237 | * mpys). |
238 | 238 | ||
239 | * We also need to be aware that one second in nanoseconds is only a |
239 | * We also need to be aware that one second in nanoseconds is only a |
240 | * couple of bits away from overflowing a 32-bit word, so we MUST use |
240 | * couple of bits away from overflowing a 32-bit word, so we MUST use |
241 | * 64-bits to get the full range time in nanoseconds. |
241 | * 64-bits to get the full range time in nanoseconds. |
242 | 242 | ||
243 | */ |
243 | */ |
244 | 244 | ||
245 | /* |
245 | /* |
246 | * Here are the scales we will use. One for seconds, nanoseconds and |
246 | * Here are the scales we will use. One for seconds, nanoseconds and |
247 | * microseconds. |
247 | * microseconds. |
248 | * |
248 | * |
249 | * Within the limits of cpp we do a rough cut at the SEC_JIFFIE_SC and |
249 | * Within the limits of cpp we do a rough cut at the SEC_JIFFIE_SC and |
250 | * check if the sign bit is set. If not, we bump the shift count by 1. |
250 | * check if the sign bit is set. If not, we bump the shift count by 1. |
251 | * (Gets an extra bit of precision where we can use it.) |
251 | * (Gets an extra bit of precision where we can use it.) |
252 | * We know it is set for HZ = 1024 and HZ = 100 not for 1000. |
252 | * We know it is set for HZ = 1024 and HZ = 100 not for 1000. |
253 | * Haven't tested others. |
253 | * Haven't tested others. |
254 | 254 | ||
255 | * Limits of cpp (for #if expressions) only long (no long long), but |
255 | * Limits of cpp (for #if expressions) only long (no long long), but |
256 | * then we only need the most signicant bit. |
256 | * then we only need the most signicant bit. |
257 | */ |
257 | */ |
258 | 258 | ||
259 | #define SEC_JIFFIE_SC (31 - SHIFT_HZ) |
259 | #define SEC_JIFFIE_SC (31 - SHIFT_HZ) |
260 | #if !((((NSEC_PER_SEC << 2) / TICK_NSEC) << (SEC_JIFFIE_SC - 2)) & 0x80000000) |
260 | #if !((((NSEC_PER_SEC << 2) / TICK_NSEC) << (SEC_JIFFIE_SC - 2)) & 0x80000000) |
261 | #undef SEC_JIFFIE_SC |
261 | #undef SEC_JIFFIE_SC |
262 | #define SEC_JIFFIE_SC (32 - SHIFT_HZ) |
262 | #define SEC_JIFFIE_SC (32 - SHIFT_HZ) |
263 | #endif |
263 | #endif |
264 | #define NSEC_JIFFIE_SC (SEC_JIFFIE_SC + 29) |
264 | #define NSEC_JIFFIE_SC (SEC_JIFFIE_SC + 29) |
265 | #define USEC_JIFFIE_SC (SEC_JIFFIE_SC + 19) |
- | |
266 | #define SEC_CONVERSION ((unsigned long)((((u64)NSEC_PER_SEC << SEC_JIFFIE_SC) +\ |
265 | #define SEC_CONVERSION ((unsigned long)((((u64)NSEC_PER_SEC << SEC_JIFFIE_SC) +\ |
267 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
266 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
268 | 267 | ||
269 | #define NSEC_CONVERSION ((unsigned long)((((u64)1 << NSEC_JIFFIE_SC) +\ |
268 | #define NSEC_CONVERSION ((unsigned long)((((u64)1 << NSEC_JIFFIE_SC) +\ |
270 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
269 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
271 | #define USEC_CONVERSION \ |
- | |
272 | ((unsigned long)((((u64)NSEC_PER_USEC << USEC_JIFFIE_SC) +\ |
- | |
273 | TICK_NSEC -1) / (u64)TICK_NSEC)) |
- | |
274 | /* |
- | |
275 | * USEC_ROUND is used in the timeval to jiffie conversion. See there |
- | |
276 | * for more details. It is the scaled resolution rounding value. Note |
- | |
277 | * that it is a 64-bit value. Since, when it is applied, we are already |
- | |
278 | * in jiffies (albit scaled), it is nothing but the bits we will shift |
- | |
279 | * off. |
- | |
280 | */ |
- | |
281 | #define USEC_ROUND (u64)(((u64)1 << USEC_JIFFIE_SC) - 1) |
- | |
282 | /* |
270 | /* |
283 | * The maximum jiffie value is (MAX_INT >> 1). Here we translate that |
271 | * The maximum jiffie value is (MAX_INT >> 1). Here we translate that |
284 | * into seconds. The 64-bit case will overflow if we are not careful, |
272 | * into seconds. The 64-bit case will overflow if we are not careful, |
285 | * so use the messy SH_DIV macro to do it. Still all constants. |
273 | * so use the messy SH_DIV macro to do it. Still all constants. |
286 | */ |
274 | */ |
287 | #if BITS_PER_LONG < 64 |
275 | #if BITS_PER_LONG < 64 |
288 | # define MAX_SEC_IN_JIFFIES \ |
276 | # define MAX_SEC_IN_JIFFIES \ |
289 | (long)((u64)((u64)MAX_JIFFY_OFFSET * TICK_NSEC) / NSEC_PER_SEC) |
277 | (long)((u64)((u64)MAX_JIFFY_OFFSET * TICK_NSEC) / NSEC_PER_SEC) |
290 | #else /* take care of overflow on 64 bits machines */ |
278 | #else /* take care of overflow on 64 bits machines */ |
291 | # define MAX_SEC_IN_JIFFIES \ |
279 | # define MAX_SEC_IN_JIFFIES \ |
292 | (SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 1) - 1) |
280 | (SH_DIV((MAX_JIFFY_OFFSET >> SEC_JIFFIE_SC) * TICK_NSEC, NSEC_PER_SEC, 1) - 1) |
293 | 281 | ||
294 | #endif |
282 | #endif |
295 | 283 | ||
296 | /* |
284 | /* |
297 | * Convert various time units to each other: |
285 | * Convert various time units to each other: |
298 | */ |
286 | */ |
299 | extern unsigned int jiffies_to_msecs(const unsigned long j); |
287 | extern unsigned int jiffies_to_msecs(const unsigned long j); |
300 | extern unsigned int jiffies_to_usecs(const unsigned long j); |
288 | extern unsigned int jiffies_to_usecs(const unsigned long j); |
301 | 289 | ||
302 | static inline u64 jiffies_to_nsecs(const unsigned long j) |
290 | static inline u64 jiffies_to_nsecs(const unsigned long j) |
303 | { |
291 | { |
304 | return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC; |
292 | return (u64)jiffies_to_usecs(j) * NSEC_PER_USEC; |
305 | } |
293 | } |
306 | 294 | ||
307 | extern unsigned long msecs_to_jiffies(const unsigned int m); |
295 | extern unsigned long msecs_to_jiffies(const unsigned int m); |
308 | extern unsigned long usecs_to_jiffies(const unsigned int u); |
296 | extern unsigned long usecs_to_jiffies(const unsigned int u); |
309 | extern unsigned long timespec_to_jiffies(const struct timespec *value); |
297 | extern unsigned long timespec_to_jiffies(const struct timespec *value); |
310 | extern void jiffies_to_timespec(const unsigned long jiffies, |
298 | extern void jiffies_to_timespec(const unsigned long jiffies, |
311 | struct timespec *value); |
299 | struct timespec *value); |
312 | extern unsigned long timeval_to_jiffies(const struct timeval *value); |
300 | extern unsigned long timeval_to_jiffies(const struct timeval *value); |
313 | extern void jiffies_to_timeval(const unsigned long jiffies, |
301 | extern void jiffies_to_timeval(const unsigned long jiffies, |
314 | struct timeval *value); |
302 | struct timeval *value); |
315 | 303 | ||
316 | extern clock_t jiffies_to_clock_t(unsigned long x); |
304 | extern clock_t jiffies_to_clock_t(unsigned long x); |
317 | static inline clock_t jiffies_delta_to_clock_t(long delta) |
305 | static inline clock_t jiffies_delta_to_clock_t(long delta) |
318 | { |
306 | { |
319 | return jiffies_to_clock_t(max(0L, delta)); |
307 | return jiffies_to_clock_t(max(0L, delta)); |
320 | } |
308 | } |
321 | 309 | ||
322 | extern unsigned long clock_t_to_jiffies(unsigned long x); |
310 | extern unsigned long clock_t_to_jiffies(unsigned long x); |
323 | extern u64 jiffies_64_to_clock_t(u64 x); |
311 | extern u64 jiffies_64_to_clock_t(u64 x); |
324 | extern u64 nsec_to_clock_t(u64 x); |
312 | extern u64 nsec_to_clock_t(u64 x); |
325 | extern u64 nsecs_to_jiffies64(u64 n); |
313 | extern u64 nsecs_to_jiffies64(u64 n); |
326 | extern unsigned long nsecs_to_jiffies(u64 n); |
314 | extern unsigned long nsecs_to_jiffies(u64 n); |
327 | - | ||
328 | - | ||
329 | static unsigned long round_jiffies_common(unsigned long j, bool force_up) |
- | |
330 | { |
- | |
331 | int rem; |
- | |
332 | unsigned long original = j; |
- | |
333 | - | ||
334 | rem = j % HZ; |
- | |
335 | - | ||
336 | /* |
- | |
337 | * If the target jiffie is just after a whole second (which can happen |
- | |
338 | * due to delays of the timer irq, long irq off times etc etc) then |
- | |
339 | * we should round down to the whole second, not up. Use 1/4th second |
- | |
340 | * as cutoff for this rounding as an extreme upper bound for this. |
- | |
341 | * But never round down if @force_up is set. |
- | |
342 | */ |
- | |
343 | if (rem < HZ/4 && !force_up) /* round down */ |
- | |
344 | j = j - rem; |
- | |
345 | else /* round up */ |
- | |
346 | j = j - rem + HZ; |
- | |
347 | - | ||
348 | if (j <= GetTimerTicks()) /* rounding ate our timeout entirely; */ |
- | |
349 | return original; |
- | |
350 | return j; |
- | |
351 | } |
- | |
352 | - | ||
353 | - | ||
354 | - | ||
355 | unsigned long round_jiffies_up_relative(unsigned long j); |
- | |
356 | 315 | ||
357 | #define TIMESTAMP_SIZE 30 |
316 | #define TIMESTAMP_SIZE 30 |
358 | 317 | ||
359 | #endif=>>>><>><>><>><>><>><>><>><>>>0">>><>><>><>><>>>>>>>>>>> |
318 | #endif>><>><>><>><>><>><>>>0">>><>><>><>><>>>>>>>>>>> |