diff options
Diffstat (limited to 'c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c')
| -rw-r--r-- | c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c b/c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c new file mode 100644 index 0000000000..dbcf7c2396 --- /dev/null +++ b/c/src/lib/libbsp/m68k/gen68360/clock/ckinit.c @@ -0,0 +1,149 @@ +/* + * This routine initializes the MC68360 Periodic Interval Timer + * + * The PIT has rather poor resolution, but it is easy to set up + * and requires no housekeeping once it is going. + * + * Based on the `gen68302' board support package, and covered by the + * original distribution terms. + * + * W. Eric Norum + * Saskatchewan Accelerator Laboratory + * University of Saskatchewan + * Saskatoon, Saskatchewan, CANADA + * eric@skatter.usask.ca + * + * $Id$ + */ + +/* + * Input parameters: NONE + * + * Output parameters: NONE + * + * COPYRIGHT (c) 1989, 1990, 1991, 1992, 1993, 1994. + * On-Line Applications Research Corporation (OAR). + * All rights assigned to U.S. Government, 1994. + * + * This material may be reproduced by or for the U.S. Government pursuant + * to the copyright license under the clause at DFARS 252.227-7013. This + * notice must appear in all copies of this file and its derivatives. + */ + +#include <stdlib.h> /* for atexit() */ +#include <bsp.h> +#include <rtems/libio.h> +#include "mc68360.h" + +#define CLOCK_VECTOR 120 +#define CLOCK_IRQ_LEVEL 6 + +/* + * Clock_driver_ticks is a monotonically increasing counter of the + * number of clock ticks since the driver was initialized. + */ +volatile rtems_unsigned32 Clock_driver_ticks; + +/* + * These are set by clock driver during its init + */ + +rtems_device_major_number rtems_clock_major = ~0; +rtems_device_minor_number rtems_clock_minor; + +/* + * Periodic interval timer interrupt handler + */ +rtems_isr +Clock_isr (rtems_vector_number vector) +{ + Clock_driver_ticks++; + rtems_clock_tick(); +} + +void +Clock_exit (void) +{ + if (BSP_Configuration.ticks_per_timeslice ) { + /* + * Turn off periodic interval timer + */ + m360.pitr &= ~0xFF; + } +} + +static void +Install_clock (rtems_isr_entry clock_isr) +{ + Clock_driver_ticks = 0; + if ( BSP_Configuration.ticks_per_timeslice ) { + int pitr; + + /* + * Choose periodic interval timer register value + * For a 25 MHz external clock the basic clock rate is + * 40 nsec * 128 * 4 = 20.48 usec/tick + */ + pitr = ((BSP_Configuration.microseconds_per_tick * 100) + 1023) / 2048; + if (pitr >= 256) { + pitr = (pitr + 255) / 512; + if (pitr >= 256) + pitr = 255; + else if (pitr == 0) + pitr = 1; + pitr |= 0x100; + } + else if (pitr == 0) { + pitr = 1; + } + m360.pitr &= ~0x1FF; + m360.picr = (CLOCK_IRQ_LEVEL << 8) | CLOCK_VECTOR; + set_vector (clock_isr, CLOCK_VECTOR, 1); + m360.pitr |= pitr; + atexit (Clock_exit); + } +} + +rtems_device_driver +Clock_initialize( + rtems_device_major_number major, + rtems_device_minor_number minor, + void *pargp +) +{ + Install_clock (Clock_isr); + + /* + * 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_unsigned32 isrlevel; + rtems_libio_ioctl_args_t *args = pargp; + + if (args) { + /* + * 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); + } + 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 ); + } + } + return RTEMS_SUCCESSFUL; +} |