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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libbsp/] [i386/] [i386ex/] [timer/] [timer.c] - Blame information for rev 773

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/*  Timer_init()
 *
 *  This routine initializes the timer on the FORCE CPU-386 board.
 *
 *  Input parameters:  NONE
 *
 *  Output parameters:  NONE
 *
 *  NOTE: This routine will not work if the optimizer is enabled
 *        for some compilers.  The multiple writes to the Z8036
 *        may be optimized away.
 *
 *        It is important that the timer start/stop overhead be
 *        determined when porting or modifying this code.
 *
 *  COPYRIGHT (c) 1989-1999.
 *  On-Line Applications Research Corporation (OAR).
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.OARcorp.com/rtems/license.html.
 *
 *  $Id: timer.c,v 1.2 2001-09-27 11:59:47 chris Exp $
 */
 
 
#include <rtems.h>
#include <bsp.h>
#include <stdlib.h>
 
int Ttimer_val;
rtems_boolean Timer_driver_Find_average_overhead;
 
extern void timerisr();
extern int ClockIsOn(const rtems_raw_irq_connect_data*);
 
#define TMR0      0xF040
#define TMR1      0xF041
#define TMR2      0xF042
#define TMRCON    0xF043
#define TMRCFG    0xF834
 
void TimerOn(const rtems_raw_irq_connect_data* used)
{
 
  Ttimer_val = 0;                           /* clear timer ISR count */
 
  outport_byte  ( TMRCON , 0xb0 ); /* select tmr2, stay in mode 0 */
  outport_byte  ( TMR1   , 0xfa ); /* set to 250 usec interval */
  outport_byte  ( TMR1   , 0x00 );
  outport_byte  ( TMRCON , 0x64 ); /* change to mode 2 ( starts timer ) */
                                   /* interrupts ARE enabled */
  /*  outport_byte( IERA, 0x41 );             enable interrupt */
  /*
   * enable interrrupt at i8259 level
   */
  BSP_irq_enable_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE);
}
 
void TimerOff(const rtems_raw_irq_connect_data* used)
{
    /*
     * disable interrrupt at i8259 level
     */
     BSP_irq_disable_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE);
     /* reset timer mode to standard (DOS) value */
}
 
static rtems_raw_irq_connect_data timer_raw_irq_data = {
  BSP_RT_TIMER3 + BSP_IRQ_VECTOR_BASE,
  timerisr,
  TimerOn,
  TimerOff,
  ClockIsOn
};
 
void Timer_exit()
{
 if (!i386_delete_idt_entry(&timer_raw_irq_data)) {
      printk("Timer_exit:Timer raw handler removal failed\n");
      rtems_fatal_error_occurred(1);
 }
}
 
void Timer_initialize()
{
 
  static rtems_boolean First = TRUE;
 
  if (First)
  {
    First = FALSE;
 
    atexit(Timer_exit); /* Try not to hose the system at exit. */
    if (!i386_set_idt_entry (&timer_raw_irq_data)) {
      printk("Timer_initialize: raw handler installation failed\n");
      rtems_fatal_error_occurred(1);
    }
  }
  /* wait for ISR to be called at least once */
  Ttimer_val = 0;
  while (Ttimer_val == 0)
    continue;
  Ttimer_val = 0;
}
 
#define AVG_OVERHEAD      3  /* It typically takes 3.0 microseconds */
                             /* (3 ticks) to start/stop the timer. */
#define LEAST_VALID       4  /* Don't trust a value lower than this */
 
int Read_timer()
{
  register rtems_unsigned32 clicks;
  register rtems_unsigned32 total;
 
/*  outport_byte( TBCR, 0x00 );  stop the timer -- not needed on intel */
 
  outport_byte ( TMRCON, 0x40 );   /* latch the count */
  inport_byte  ( TMR1,   clicks ); /* read the count */
 
  total = Ttimer_val + 250 - clicks;
 
/*  outport_byte( TBCR, 0x00 );   initial value */
/*  outport_byte( IERA, 0x40 );   disable interrupt */
 
  /* ??? Is "do not restore old vector" causing problems? */
 
  if ( Timer_driver_Find_average_overhead == 1 )
    return total;          /* in one microsecond units */
 
  else {
    if ( total < LEAST_VALID )
      return 0;            /* below timer resolution */
    return (total - AVG_OVERHEAD);
  }
}
 
rtems_status_code Empty_function( void )
{
  return RTEMS_SUCCESSFUL;
}
 
void Set_find_average_overhead(
  rtems_boolean find_flag
)
{
  Timer_driver_Find_average_overhead = find_flag;
}

Line No.	Rev	Author	Line
1	30	unneback	`/* Timer_init()`
2			`*`
3			`* This routine initializes the timer on the FORCE CPU-386 board.`
4			`*`
5			`* Input parameters: NONE`
6			`*`
7			`* Output parameters: NONE`
8			`*`
9			`* NOTE: This routine will not work if the optimizer is enabled`
10			`* for some compilers. The multiple writes to the Z8036`
11			`* may be optimized away.`
12			`*`
13			`* It is important that the timer start/stop overhead be`
14			`* determined when porting or modifying this code.`
15			`*`
16			`* COPYRIGHT (c) 1989-1999.`
17			`* On-Line Applications Research Corporation (OAR).`
18			`*`
19			`* The license and distribution terms for this file may be`
20			`* found in the file LICENSE in this distribution or at`
21			`* http://www.OARcorp.com/rtems/license.html.`
22			`*`
23			`* $Id: timer.c,v 1.2 2001-09-27 11:59:47 chris Exp $`
24			`*/`
25
26
27			`#include <rtems.h>`
28			`#include <bsp.h>`
29			`#include <stdlib.h>`
30
31			`int Ttimer_val;`
32			`rtems_boolean Timer_driver_Find_average_overhead;`
33
34			`extern void timerisr();`
35			`extern int ClockIsOn(const rtems_raw_irq_connect_data*);`
36
37			`#define TMR0 0xF040`
38			`#define TMR1 0xF041`
39			`#define TMR2 0xF042`
40			`#define TMRCON 0xF043`
41			`#define TMRCFG 0xF834`
42
43			`void TimerOn(const rtems_raw_irq_connect_data* used)`
44			`{`
45
46			`Ttimer_val = 0; /* clear timer ISR count */`
47
48			`outport_byte ( TMRCON , 0xb0 ); /* select tmr2, stay in mode 0 */`
49			`outport_byte ( TMR1 , 0xfa ); /* set to 250 usec interval */`
50			`outport_byte ( TMR1 , 0x00 );`
51			`outport_byte ( TMRCON , 0x64 ); /* change to mode 2 ( starts timer ) */`
52			`/* interrupts ARE enabled */`
53			`/* outport_byte( IERA, 0x41 ); enable interrupt */`
54			`/*`
55			`* enable interrrupt at i8259 level`
56			`*/`
57			`BSP_irq_enable_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE);`
58			`}`
59
60			`void TimerOff(const rtems_raw_irq_connect_data* used)`
61			`{`
62			`/*`
63			`* disable interrrupt at i8259 level`
64			`*/`
65			`BSP_irq_disable_at_i8259s(used->idtIndex - BSP_IRQ_VECTOR_BASE);`
66			`/* reset timer mode to standard (DOS) value */`
67			`}`
68
69			`static rtems_raw_irq_connect_data timer_raw_irq_data = {`
70			`BSP_RT_TIMER3 + BSP_IRQ_VECTOR_BASE,`
71			`timerisr,`
72			`TimerOn,`
73			`TimerOff,`
74			`ClockIsOn`
75			`};`
76
77			`void Timer_exit()`
78			`{`
79			`if (!i386_delete_idt_entry(&timer_raw_irq_data)) {`
80			`printk("Timer_exit:Timer raw handler removal failed\n");`
81			`rtems_fatal_error_occurred(1);`
82			`}`
83			`}`
84
85			`void Timer_initialize()`
86			`{`
87
88			`static rtems_boolean First = TRUE;`
89
90			`if (First)`
91			`{`
92			`First = FALSE;`
93
94			`atexit(Timer_exit); /* Try not to hose the system at exit. */`
95			`if (!i386_set_idt_entry (&timer_raw_irq_data)) {`
96			`printk("Timer_initialize: raw handler installation failed\n");`
97			`rtems_fatal_error_occurred(1);`
98			`}`
99			`}`
100			`/* wait for ISR to be called at least once */`
101			`Ttimer_val = 0;`
102			`while (Ttimer_val == 0)`
103			`continue;`
104			`Ttimer_val = 0;`
105			`}`
106
107			`#define AVG_OVERHEAD 3 /* It typically takes 3.0 microseconds */`
108			`/* (3 ticks) to start/stop the timer. */`
109			`#define LEAST_VALID 4 /* Don't trust a value lower than this */`
110
111			`int Read_timer()`
112			`{`
113			`register rtems_unsigned32 clicks;`
114			`register rtems_unsigned32 total;`
115
116			`/* outport_byte( TBCR, 0x00 ); stop the timer -- not needed on intel */`
117
118			`outport_byte ( TMRCON, 0x40 ); /* latch the count */`
119			`inport_byte ( TMR1, clicks ); /* read the count */`
120
121			`total = Ttimer_val + 250 - clicks;`
122
123			`/* outport_byte( TBCR, 0x00 ); initial value */`
124			`/* outport_byte( IERA, 0x40 ); disable interrupt */`
125
126			`/* ??? Is "do not restore old vector" causing problems? */`
127
128			`if ( Timer_driver_Find_average_overhead == 1 )`
129			`return total; /* in one microsecond units */`
130
131			`else {`
132			`if ( total < LEAST_VALID )`
133			`return 0; /* below timer resolution */`
134			`return (total - AVG_OVERHEAD);`
135			`}`
136			`}`
137
138			`rtems_status_code Empty_function( void )`
139			`{`
140			`return RTEMS_SUCCESSFUL;`
141			`}`
142
143			`void Set_find_average_overhead(`
144			`rtems_boolean find_flag`
145			`)`
146			`{`
147			`Timer_driver_Find_average_overhead = find_flag;`
148			`}`

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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libbsp/] [i386/] [i386ex/] [timer/] [timer.c] - Blame information for rev 773