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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [lib/] [libbsp/] [powerpc/] [score603e/] [clock/] [clock.c] - Rev 593
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/* * Clock Tick Device Driver * * This routine utilizes the Decrementer Register common to the PPC family. * * The tick frequency is directly programmed to the configured number of * microseconds per tick. * * COPYRIGHT (c) 1989-1997. * On-Line Applications Research Corporation (OAR). * Copyright assigned to U.S. Government, 1994. * * The license and distribution terms for this file may in * the file LICENSE in this distribution or at * http://www.OARcorp.com/rtems/license.html. * * $Id: clock.c,v 1.2 2001-09-27 12:01:03 chris Exp $ */ #include <stdlib.h> #include <bsp.h> #include <rtems/libio.h> #include <assert.h> /* * The Real Time Clock Counter Timer uses this trap type. */ #define CLOCK_VECTOR PPC_IRQ_DECREMENTER /* * Clock ticks since initialization */ volatile rtems_unsigned32 Clock_driver_ticks; /* * This is the value programmed into the count down timer. */ rtems_unsigned32 Clock_Decrementer_value; rtems_isr_entry Old_ticker; void Clock_exit( void ); /* * These are set by clock driver during its init */ rtems_device_major_number rtems_clock_major = ~0; rtems_device_minor_number rtems_clock_minor; #define PPC_Set_decrementer( _clicks ) \ do { \ asm volatile( "mtdec %0" : "=r" ((_clicks)) : "r" ((_clicks)) ); \ } while (0) /* * Clock_isr * * This is the clock tick interrupt handler. * * Input parameters: * vector - vector number * * Output parameters: NONE * * Return values: NONE * */ rtems_isr Clock_isr( rtems_vector_number vector, CPU_Interrupt_frame *frame ) { /* * Set the decrementer. */ PPC_Set_decrementer( Clock_Decrementer_value ); /* * The driver has seen another tick. */ Clock_driver_ticks += 1; /* * Real Time Clock counter/timer is set to automatically reload. */ rtems_clock_tick(); } /* * Install_clock * * This routine actually performs the hardware initialization for the clock. * * Input parameters: * clock_isr - clock interrupt service routine entry point * * Output parameters: NONE * * Return values: NONE * */ extern int CLOCK_SPEED; void Install_clock( rtems_isr_entry clock_isr ) { Clock_driver_ticks = 0; Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 ); PPC_Set_decrementer( Clock_Decrementer_value ); atexit( Clock_exit ); } /* * Clock_exit * * This routine allows the clock driver to exit by masking the interrupt and * disabling the clock's counter. * * Input parameters: NONE * * Output parameters: NONE * * Return values: NONE * */ void Clock_exit( void ) { /* nothing to do */; /* do not restore old vector */ } /* * Clock_initialize * * This routine initializes the clock driver. * * Input parameters: * major - clock device major number * minor - clock device minor number * parg - pointer to optional device driver arguments * * Output parameters: NONE * * Return values: * rtems_device_driver status code */ rtems_device_driver Clock_initialize( rtems_device_major_number major, rtems_device_minor_number minor, void *pargp ) { Clock_Decrementer_value = (int) &CPU_PPC_CLICKS_PER_MS * (BSP_Configuration.microseconds_per_tick / 1000); Install_clock( (rtems_isr_entry) Clock_isr ); /* * make major/minor avail to others such as shared memory driver */ rtems_clock_major = major; rtems_clock_minor = minor; return RTEMS_SUCCESSFUL; } /* * Clock_control * * This routine is the clock device driver control entry point. * * Input parameters: * major - clock device major number * minor - clock device minor number * parg - pointer to optional device driver arguments * * Output parameters: NONE * * Return values: * rtems_device_driver status code */ rtems_device_driver Clock_control( rtems_device_major_number major, rtems_device_minor_number minor, void *pargp ) { rtems_unsigned32 isrlevel; 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( CLOCK_VECTOR, pargp ); } else if (args->command == rtems_build_name('N', 'E', 'W', ' ')) { rtems_interrupt_disable( isrlevel ); (void) set_vector( args->buffer, CLOCK_VECTOR, 1 ); rtems_interrupt_enable( isrlevel ); } done: return RTEMS_SUCCESSFUL; }
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