drivers/staging/csr/csr_time.h

   1 #ifndef CSR_TIME_H__
   2 #define CSR_TIME_H__
   3 /*****************************************************************************
   4
   5             (c) Cambridge Silicon Radio Limited 2010
   6             All rights reserved and confidential information of CSR
   7
   8             Refer to LICENSE.txt included with this source for details
   9             on the license terms.
  10
  11 *****************************************************************************/
  12
  13 #include "csr_types.h"
  14
  15 #ifdef __cplusplus
  16 extern "C" {
  17 #endif
  18
  19 /*******************************************************************************
  20
  21     NAME
  22         CsrTime
  23
  24     DESCRIPTION
  25         Type to hold a value describing the current system time, which is a
  26         measure of time elapsed since some arbitrarily defined fixed time
  27         reference, usually associated with system startup.
  28
  29 *******************************************************************************/
  30 typedef u32 CsrTime;
  31
  32
  33 /*******************************************************************************
  34
  35     NAME
  36         CsrTimeUtc
  37
  38     DESCRIPTION
  39         Type to hold a value describing a UTC wallclock time expressed in
  40         seconds and milliseconds elapsed since midnight January 1st 1970.
  41
  42 *******************************************************************************/
  43 typedef struct
  44 {
  45     u32 sec;
  46     u16 msec;
  47 } CsrTimeUtc;
  48
  49
  50 /*******************************************************************************
  51
  52     NAME
  53         CsrTimeGet
  54
  55     DESCRIPTION
  56         Returns the current system time in a low and a high part. The low part
  57         is expressed in microseconds. The high part is incremented when the low
  58         part wraps to provide an extended range.
  59
  60         The caller may provide a NULL pointer as the high parameter. In this case
  61         the function just returns the low part and ignores the high parameter.
  62
  63         Although the time is expressed in microseconds the actual resolution is
  64         platform dependent and can be less. It is recommended that the
  65         resolution is at least 10 milliseconds.
  66
  67     PARAMETERS
  68         high - Pointer to variable that will receive the high part of the
  69                current system time. Passing NULL is valid.
  70
  71     RETURNS
  72         Low part of current system time in microseconds.
  73
  74 *******************************************************************************/
  75 CsrTime CsrTimeGet(CsrTime *high);
  76
  77
  78 /*******************************************************************************
  79
  80     NAME
  81         CsrTimeUtcGet
  82
  83     DESCRIPTION
  84         Get the current system wallclock time, and optionally the current system
  85         time in a low and a high part as would have been returned by
  86         CsrTimeGet.
  87
  88         Although CsrTimeUtc is expressed in seconds and milliseconds, the actual
  89         resolution is platform dependent, and can be less. It is recommended
  90         that the resolution is at least 1 second.
  91
  92     PARAMETERS
  93         tod - Pointer to variable that will receive the current system
  94               wallclock time.
  95         low - The low part of the current system time in microseconds. Passing
  96               NULL is valid.
  97         high - The high part of the current system time in microseconds. Passing
  98                NULL is valid.
  99
 100 *******************************************************************************/
 101 void CsrTimeUtcGet(CsrTimeUtc *tod, CsrTime *low, CsrTime *high);
 102
 103
 104 /*------------------------------------------------------------------*/
 105 /* CsrTime Macros */
 106 /*------------------------------------------------------------------*/
 107
 108 /*----------------------------------------------------------------------------*
 109  *  NAME
 110  *      CsrTimeAdd
 111  *
 112  *  DESCRIPTION
 113  *      Add two time values. Adding the numbers can overflow the range of a
 114  *      CsrTime, so the user must be cautious.
 115  *
 116  *  RETURNS
 117  *      CsrTime - the sum of "t1" and "t2".
 118  *
 119  *----------------------------------------------------------------------------*/
 120 #define CsrTimeAdd(t1, t2) ((t1) + (t2))
 121
 122 /*----------------------------------------------------------------------------*
 123  *  NAME
 124  *      CsrTimeSub
 125  *
 126  *  DESCRIPTION
 127  *      Subtract two time values. Subtracting the numbers can provoke an
 128  *      underflow, so the user must be cautious.
 129  *
 130  *  RETURNS
 131  *      CsrTime - "t1" - "t2".
 132  *
 133  *----------------------------------------------------------------------------*/
 134 #define CsrTimeSub(t1, t2)    ((s32) (t1) - (s32) (t2))
 135
 136 /*----------------------------------------------------------------------------*
 137  *  NAME
 138  *      CsrTimeEq
 139  *
 140  *  DESCRIPTION
 141  *      Compare two time values.
 142  *
 143  *  RETURNS
 144  *      !0 if "t1" equal "t2", else 0.
 145  *
 146  *----------------------------------------------------------------------------*/
 147 #define CsrTimeEq(t1, t2) ((t1) == (t2))
 148
 149 /*----------------------------------------------------------------------------*
 150  *  NAME
 151  *      CsrTimeGt
 152  *
 153  *  DESCRIPTION
 154  *      Compare two time values.
 155  *
 156  *  RETURNS
 157  *      !0 if "t1" is greater than "t2", else 0.
 158  *
 159  *----------------------------------------------------------------------------*/
 160 #define CsrTimeGt(t1, t2) (CsrTimeSub((t1), (t2)) > 0)
 161
 162 /*----------------------------------------------------------------------------*
 163  *  NAME
 164  *      CsrTimeGe
 165  *
 166  *  DESCRIPTION
 167  *      Compare two time values.
 168  *
 169  *  RETURNS
 170  *      !0 if "t1" is greater than, or equal to "t2", else 0.
 171  *
 172  *----------------------------------------------------------------------------*/
 173 #define CsrTimeGe(t1, t2) (CsrTimeSub((t1), (t2)) >= 0)
 174
 175 /*----------------------------------------------------------------------------*
 176  *  NAME
 177  *      CsrTimeLt
 178  *
 179  *  DESCRIPTION
 180  *      Compare two time values.
 181  *
 182  *  RETURNS
 183  *      !0 if "t1" is less than "t2", else 0.
 184  *
 185  *----------------------------------------------------------------------------*/
 186 #define CsrTimeLt(t1, t2) (CsrTimeSub((t1), (t2)) < 0)
 187
 188 /*----------------------------------------------------------------------------*
 189  *  NAME
 190  *      CsrTimeLe
 191  *
 192  *  DESCRIPTION
 193  *      Compare two time values.
 194  *
 195  *  RETURNS
 196  *      !0 if "t1" is less than, or equal to "t2", else 0.
 197  *
 198  *----------------------------------------------------------------------------*/
 199 #define CsrTimeLe(t1, t2) (CsrTimeSub((t1), (t2)) <= 0)
 200
 201 #ifdef __cplusplus
 202 }
 203 #endif
 204
 205 #endif