165 lines
4.7 KiB
C
165 lines
4.7 KiB
C
#include <jiffies.h>
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#define HZ_TO_MSEC_MUL32 0xA0000000
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#define HZ_TO_MSEC_ADJ32 0x0
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#define HZ_TO_MSEC_SHR32 28
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#define HZ_TO_MSEC_MUL64 0xA000000000000000
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#define HZ_TO_MSEC_ADJ64 0x0
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#define HZ_TO_MSEC_SHR64 60
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#define MSEC_TO_HZ_MUL32 0xCCCCCCCD
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#define MSEC_TO_HZ_ADJ32 0x733333333
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#define MSEC_TO_HZ_SHR32 35
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#define MSEC_TO_HZ_MUL64 0xCCCCCCCCCCCCCCCD
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#define MSEC_TO_HZ_ADJ64 0x73333333333333333
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#define MSEC_TO_HZ_SHR64 67
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#define HZ_TO_MSEC_NUM 10
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#define HZ_TO_MSEC_DEN 1
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#define MSEC_TO_HZ_NUM 1
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#define MSEC_TO_HZ_DEN 10
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#define HZ_TO_USEC_MUL32 0x9C400000
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#define HZ_TO_USEC_ADJ32 0x0
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#define HZ_TO_USEC_SHR32 18
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#define HZ_TO_USEC_MUL64 0x9C40000000000000
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#define HZ_TO_USEC_ADJ64 0x0
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#define HZ_TO_USEC_SHR64 50
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#define USEC_TO_HZ_MUL32 0xD1B71759
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#define USEC_TO_HZ_ADJ32 0x1FFF2E48E8A7
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#define USEC_TO_HZ_SHR32 45
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#define USEC_TO_HZ_MUL64 0xD1B71758E219652C
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#define USEC_TO_HZ_ADJ64 0x1FFF2E48E8A71DE69AD4
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#define USEC_TO_HZ_SHR64 77
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#define HZ_TO_USEC_NUM 10000
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#define HZ_TO_USEC_DEN 1
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#define USEC_TO_HZ_NUM 1
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#define USEC_TO_HZ_DEN 10000
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#define MSEC_PER_SEC 1000L
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#define USEC_PER_MSEC 1000L
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#define NSEC_PER_USEC 1000L
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#define NSEC_PER_MSEC 1000000L
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#define USEC_PER_SEC 1000000L
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#define NSEC_PER_SEC 1000000000L
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#define FSEC_PER_SEC 1000000000000000LL
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unsigned int jiffies_to_msecs(const unsigned long j)
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{
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#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
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return (MSEC_PER_SEC / HZ) * j;
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#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
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return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
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#else
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# if BITS_PER_LONG == 32
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return (HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
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# else
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return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
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# endif
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#endif
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}
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unsigned int jiffies_to_usecs(const unsigned long j)
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{
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#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
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return (USEC_PER_SEC / HZ) * j;
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#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
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return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
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#else
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# if BITS_PER_LONG == 32
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return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
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# else
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return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
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# endif
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#endif
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}
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/*
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* When we convert to jiffies then we interpret incoming values
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* the following way:
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*
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* - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
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*
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* - 'too large' values [that would result in larger than
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* MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
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*
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* - all other values are converted to jiffies by either multiplying
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* the input value by a factor or dividing it with a factor
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*
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* We must also be careful about 32-bit overflows.
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*/
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unsigned long msecs_to_jiffies(const unsigned int m)
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{
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/*
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* Negative value, means infinite timeout:
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*/
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if ((int)m < 0)
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return MAX_JIFFY_OFFSET;
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#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
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/*
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* HZ is equal to or smaller than 1000, and 1000 is a nice
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* round multiple of HZ, divide with the factor between them,
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* but round upwards:
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*/
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return (m + (MSEC_PER_SEC / HZ) - 1) / (MSEC_PER_SEC / HZ);
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#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
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/*
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* HZ is larger than 1000, and HZ is a nice round multiple of
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* 1000 - simply multiply with the factor between them.
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*
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* But first make sure the multiplication result cannot
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* overflow:
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*/
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if (m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
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return MAX_JIFFY_OFFSET;
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return m * (HZ / MSEC_PER_SEC);
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#else
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/*
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* Generic case - multiply, round and divide. But first
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* check that if we are doing a net multiplication, that
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* we wouldn't overflow:
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*/
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if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
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return MAX_JIFFY_OFFSET;
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return (MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32)
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>> MSEC_TO_HZ_SHR32;
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#endif
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}
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unsigned long usecs_to_jiffies(const unsigned int u)
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{
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if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
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return MAX_JIFFY_OFFSET;
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#if HZ <= USEC_PER_SEC && !(USEC_PER_SEC % HZ)
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return (u + (USEC_PER_SEC / HZ) - 1) / (USEC_PER_SEC / HZ);
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#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
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return u * (HZ / USEC_PER_SEC);
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#else
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return (USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)
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>> USEC_TO_HZ_SHR32;
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#endif
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}
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unsigned long
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timespec_to_jiffies(const struct timespec *value)
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{
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unsigned long sec = value->tv_sec;
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long nsec = value->tv_nsec + TICK_NSEC - 1;
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if (sec >= MAX_SEC_IN_JIFFIES){
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sec = MAX_SEC_IN_JIFFIES;
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nsec = 0;
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}
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return (((u64)sec * SEC_CONVERSION) +
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(((u64)nsec * NSEC_CONVERSION) >>
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(NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
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}
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