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[/] [or1k/] [trunk/] [rtems-20020807/] [c/] [src/] [lib/] [libbsp/] [i386/] [i386ex/] [clock/] [ckinit.c] - Rev 1765
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/* Clock_initialize * * This routine initializes the Timer/Counter on the Intel * 386ex evaluation board. * * The tick frequency is 1 millisecond. * * Input parameters: NONE * * Output parameters: NONE * * 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. * * ckinit.c,v 1.11 1999/11/17 17:50:46 joel Exp */ #define TMR0 0xF040 #define TMR1 0xF041 #define TMR2 0xF042 #define TMRCON 0xF043 #define TMRCFG 0xF834 #include <bsp.h> #include <irq.h> #include <rtems/libio.h> #include <stdlib.h> rtems_unsigned32 Clock_isrs; /* ISRs until next tick */ static rtems_unsigned32 Clock_initial_isr_value; volatile rtems_unsigned32 Clock_driver_ticks; void Clock_exit( void ); /* * These are set by clock driver during its init */ rtems_device_major_number rtems_clock_major = ~0; rtems_device_major_number rtems_clock_minor = 0; /* * This is the ISR handler. */ void Clock_isr() { /* enable_tracing(); */ Clock_driver_ticks += 1; if ( Clock_isrs == 1 ) { rtems_clock_tick(); Clock_isrs = Clock_initial_isr_value; /* BSP_Configuration.microseconds_per_tick / 1000;*/ } else Clock_isrs -= 1; } void ClockOff(const rtems_irq_connect_data* unused) { outport_byte ( TMRCFG , 0x80 ); /* disable the counter timer */ } void ClockOn(const rtems_irq_connect_data* unused) { outport_byte ( TMRCFG , 0x00 ); /* enable the counter timer */ } int ClockIsOn(const rtems_irq_connect_data* unused) { return ((i8259s_cache & 0x1) == 0); } static rtems_irq_connect_data clockIrqData = {BSP_PERIODIC_TIMER, Clock_isr, ClockOn, ClockOff, ClockIsOn}; rtems_device_driver Clock_initialize( rtems_device_major_number major, rtems_device_minor_number minor, void *pargp ) { unsigned timer_counter_init_value; unsigned char clock_lsb, clock_msb; Clock_driver_ticks = 0; Clock_isrs = Clock_initial_isr_value = BSP_Configuration.microseconds_per_tick / 1000; /* ticks per clock_isr */ /* * configure the counter timer ( should be based on microsecs/tick ) * NB. The divisor(Clock_isrs) resolves the is the same number that appears in confdefs.h * when setting the microseconds_per_tick value. */ ClockOff ( &clockIrqData ); timer_counter_init_value = BSP_Configuration.microseconds_per_tick / Clock_isrs; clock_lsb = (unsigned char)timer_counter_init_value; clock_msb = timer_counter_init_value >> 8; outport_byte ( TMRCON , 0x34 ); outport_byte ( TMR0 , clock_lsb ); /* load LSB first */ outport_byte ( TMR0 , clock_msb ); /* then MSB */ if (!BSP_install_rtems_irq_handler (&clockIrqData)) { printk("Unable to initialize system clock\n"); rtems_fatal_error_occurred(1); } /* * make major/minor avail to others such as shared memory driver */ rtems_clock_major = major; rtems_clock_minor = minor; return RTEMS_SUCCESSFUL; } rtems_device_driver Clock_control( rtems_device_major_number major, rtems_device_minor_number minor, void *pargp ) { rtems_libio_ioctl_args_t *args = pargp; if (args == 0) goto done; /* * This is hokey, but until we get a defined interface * to do this, it will just be this simple... */ if (args->command == rtems_build_name('I', 'S', 'R', ' ')) { Clock_isr(); } else if (args->command == rtems_build_name('N', 'E', 'W', ' ')) { if (!BSP_install_rtems_irq_handler (&clockIrqData)) { printk("Error installing clock interrupt handler!\n"); rtems_fatal_error_occurred(1); } #ifdef DEBUG else printk("Clock installed AGAIN\n"); #endif } done: return RTEMS_SUCCESSFUL; } void Clock_exit() { ClockOff(&clockIrqData); BSP_remove_rtems_irq_handler (&clockIrqData); }