[637df35] | 1 | /* Clock_initialize |
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| 2 | * |
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| 3 | * This routine initializes the 8254 timer under GO32. |
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| 4 | * The tick frequency is 1 millisecond. |
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| 5 | * |
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| 6 | * Input parameters: NONE |
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| 7 | * |
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| 8 | * Output parameters: NONE |
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| 9 | * |
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| 10 | * $Id$ |
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| 11 | */ |
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| 12 | |
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| 13 | #include <bsp.h> |
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| 14 | #include <clockdrv.h> |
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| 15 | #include <stdlib.h> |
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| 16 | |
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| 17 | volatile rtems_unsigned32 Clock_driver_ticks; |
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| 18 | rtems_unsigned32 Clock_isrs_per_tick; /* ISRs per tick */ |
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| 19 | rtems_unsigned32 Clock_isrs; /* ISRs until next tick */ |
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| 20 | rtems_isr_entry Old_ticker; |
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| 21 | |
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| 22 | rtems_device_driver Clock_initialize( |
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| 23 | rtems_device_major_number major, |
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| 24 | rtems_device_minor_number minor, |
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| 25 | void *pargp, |
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| 26 | rtems_id tid, |
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| 27 | rtems_unsigned32 *rval |
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| 28 | ) |
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| 29 | { |
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| 30 | Install_clock( Clock_isr ); |
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| 31 | } |
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| 32 | |
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| 33 | void ReInstall_clock( |
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| 34 | rtems_isr_entry clock_isr |
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| 35 | ) |
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| 36 | { |
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| 37 | rtems_unsigned32 isrlevel = 0; |
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| 38 | |
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| 39 | rtems_interrupt_disable( isrlevel ); |
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| 40 | (void) set_vector( clock_isr, 0x8, 1 ); |
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| 41 | rtems_interrupt_enable( isrlevel ); |
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| 42 | } |
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| 43 | |
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| 44 | void Install_clock( |
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| 45 | rtems_isr_entry clock_isr |
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| 46 | ) |
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| 47 | { |
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| 48 | unsigned int microseconds_per_isr; |
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| 49 | |
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| 50 | #if 0 |
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| 51 | /* Initialize clock from on-board real time clock. This breaks the */ |
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| 52 | /* test code which assumes which assumes the application will do it. */ |
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| 53 | { |
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| 54 | rtems_time_of_day Now; |
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| 55 | extern void init_rtc( void ); |
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| 56 | extern long rtc_read( rtems_time_of_day * tod ); |
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| 57 | init_rtc(); |
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| 58 | if ( rtc_read( &Now ) >= 0 ) |
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| 59 | clock_set( &Now ); |
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| 60 | } |
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| 61 | #endif |
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| 62 | |
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| 63 | /* Start by assuming hardware counter is large enough, then */ |
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| 64 | /* scale it until it actually fits. */ |
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| 65 | Clock_driver_ticks = 0; |
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| 66 | Clock_isrs_per_tick = 1; |
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| 67 | |
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| 68 | if ( BSP_Configuration.microseconds_per_tick == 0 ) |
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| 69 | microseconds_per_isr = 10000; /* default 10 ms */ |
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| 70 | else |
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| 71 | microseconds_per_isr = BSP_Configuration.microseconds_per_tick; |
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| 72 | while ( US_TO_TICK(microseconds_per_isr) > 65535 ) { |
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| 73 | Clock_isrs_per_tick *= 10; |
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| 74 | microseconds_per_isr /= 10; |
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| 75 | } |
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| 76 | |
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| 77 | /* Initialize count in ckisr.c */ |
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| 78 | Clock_isrs = Clock_isrs_per_tick; |
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| 79 | |
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| 80 | #if 0 |
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| 81 | /* This was dropped in the last revision. Its a nice thing to know. */ |
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| 82 | TICKS_PER_SECOND = 1000000 / (Clock_isrs_per_tick * microseconds_per_isr); |
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| 83 | #endif |
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| 84 | |
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| 85 | if ( BSP_Configuration.ticks_per_timeslice ) { |
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| 86 | /* 105/88 approximates TIMER_TICK*1e-6 */ |
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| 87 | unsigned int count = US_TO_TICK( microseconds_per_isr ); |
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| 88 | |
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| 89 | Old_ticker = (rtems_isr_entry) set_vector( clock_isr, 0x8, 1 ); |
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| 90 | outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN ); |
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| 91 | outport_byte( TIMER_CNTR0, count >> 0 & 0xff ); |
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| 92 | outport_byte( TIMER_CNTR0, count >> 8 & 0xff ); |
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| 93 | } |
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| 94 | atexit( Clock_exit ); |
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| 95 | } |
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| 96 | |
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| 97 | void Clock_exit( void ) |
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| 98 | { |
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| 99 | if ( BSP_Configuration.ticks_per_timeslice ) { |
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| 100 | extern void rtc_set_dos_date( void ); |
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| 101 | |
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| 102 | /* reset to DOS value: */ |
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| 103 | outport_byte( TIMER_MODE, TIMER_SEL0|TIMER_16BIT|TIMER_RATEGEN ); |
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| 104 | outport_byte( TIMER_CNTR0, 0 ); |
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| 105 | outport_byte( TIMER_CNTR0, 0 ); |
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| 106 | |
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| 107 | /* reset time-of-day */ |
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| 108 | rtc_set_dos_date(); |
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| 109 | |
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| 110 | /* re-enable old handler: assume it was one of ours */ |
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| 111 | set_vector( (rtems_isr_entry)Old_ticker, 0x8, 1 ); |
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| 112 | } |
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| 113 | } |
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| 114 | |
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| 115 | |
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| 116 | #if 0 && defined(pentium) |
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| 117 | /* This can be used to get extremely accurate timing on a pentium. */ |
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| 118 | /* It isn't supported. [bryce] */ |
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| 119 | #define HZ 90.0 |
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| 120 | volatile long long Last_RDTSC; |
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| 121 | #define RDTSC()\ |
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| 122 | ({ long long _now; __asm __volatile (".byte 0x0F,0x31":"=A"(_now)); _now; }) |
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| 123 | long long Kernel_Time_ns( void ) |
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| 124 | { |
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| 125 | extern rtems_unsigned32 _TOD_Ticks_per_second; |
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| 126 | unsigned isrs_per_second = Clock_isrs_per_tick * _TOD_Ticks_per_second; |
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| 127 | long long now; |
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| 128 | int flags; |
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| 129 | disable_intr( flags ); |
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| 130 | now = 1e9 * Clock_driver_ticks / isrs_per_second |
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| 131 | + (RDTSC() - Last_RDTSC) * (1000.0/HZ); |
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| 132 | enable_intr( flags ); |
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| 133 | return now; |
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| 134 | } |
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| 135 | #endif |
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