diff options
Diffstat (limited to 'c/src/lib/libbsp/m68k/idp/clock/ckinit.c')
| -rw-r--r-- | c/src/lib/libbsp/m68k/idp/clock/ckinit.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/m68k/idp/clock/ckinit.c b/c/src/lib/libbsp/m68k/idp/clock/ckinit.c new file mode 100644 index 0000000000..1d3c22d280 --- /dev/null +++ b/c/src/lib/libbsp/m68k/idp/clock/ckinit.c @@ -0,0 +1,199 @@ +/* Clock_init() + * + * + * This is modified by Doug McBride to get it to work for the MC68EC040 + * IDP board. The below comments are kept to show that some prior work + * was done in the area and the modifications performed was application + * specific for the IDP board to port it to. + * + * This routine initializes the mc68230 on the MC68EC040 board. + * The tick frequency is 40 milliseconds. + * + * Input parameters: NONE + * + * Output parameters: NONE + * + * 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. + * + * $Id$ + */ + +#include <stdlib.h> + +#include <bsp.h> +#include <rtems/libio.h> + +rtems_unsigned32 Clock_isrs; /* ISRs until next tick */ +volatile rtems_unsigned32 Clock_driver_ticks; + /* ticks since initialization */ +rtems_isr_entry Old_ticker; + +extern rtems_configuration_table Configuration; +extern void led_putnum(); +void Disable_clock(); + +#define CLOCK_VECTOR 0x4D + +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; + + +/* + * ISR Handler + * + * + * ((1ms * 6.5 MHz) / 2^5) = 203.125) where 6.5 MHz is the clock rate of the + * MC68230, 2^5 is the prescaler factor, and 1ms is the common interrupt + * interval for the Clock_isr routine. + * Therefore, 203 (decimal) is the number to program into the CPRH-L registers + * of the MC68230 for countdown. However, I have found that 193 instead of + * 203 provides greater accuracy -- why? The crystal should be more accurate + * than that + */ + +rtems_isr Clock_isr( + rtems_vector_number vector +) +{ + Clock_driver_ticks += 1; + /* acknowledge interrupt + TSR = 1; */ + MC68230_WRITE (TSR, 1); + + if ( Clock_isrs == 1 ) { + rtems_clock_tick(); + /* Cast to an integer so that 68EC040 IDP which doesn't have an FPU doesn't + have a heart attack -- if you use newlib1.6 or greater and get + libgcc.a for gcc with software floating point support, this is not + a problem */ + Clock_isrs = + (int)(BSP_Configuration.microseconds_per_tick / 1000); + } + else + Clock_isrs -= 1; +} + +void Disable_clock() +{ + /* Disable timer */ + MC68230_WRITE (TCR, 0x00); +} + +void Install_clock( clock_isr ) +rtems_isr_entry clock_isr; +{ + Clock_driver_ticks = 0; + Clock_isrs = (int)(Configuration.microseconds_per_tick / 1000); + + if ( Configuration.ticks_per_timeslice ) { +/* led_putnum('c'); * for debugging purposes */ + Old_ticker = (rtems_isr_entry) set_vector( clock_isr, CLOCK_VECTOR, 1 ); + + /* Disable timer for initialization */ + MC68230_WRITE (TCR, 0x00); + + /* some PI/T initialization stuff here -- see comment in the ckisr.c + file in this directory to understand why I use the values that I do */ + /* Set up the interrupt vector on the MC68230 chip: + TIVR = CLOCK_VECTOR; */ + MC68230_WRITE (TIVR, CLOCK_VECTOR); + + /* Set CPRH through CPRL to 193 (not 203) decimal for countdown--see ckisr.c + CPRH = 0x00; + CPRM = 0x00; + CPRL = 0xC1; */ + MC68230_WRITE (CPRH, 0x00); + MC68230_WRITE (CPRM, 0x00); + MC68230_WRITE (CPRL, 0xC1); + + /* Enable timer and use it as an external periodic interrupt generator + TCR = 0xA1; */ +/* led_putnum('a'); * for debugging purposes */ + MC68230_WRITE (TCR, 0xA1); + + /* + * Schedule the clock cleanup routine to execute if the application exits. + */ + atexit( Clock_exit ); + } +} + +/* The following was added for debugging purposes */ +void Clock_exit( void ) +{ + rtems_unsigned8 data; + + if ( Configuration.ticks_per_timeslice ) { + + /* disable timer + data = TCR; + TCR = (data & 0xFE); */ + MC68230_READ (TCR, data); + MC68230_WRITE (TCR, (data & 0xFE)); + + /* do not restore old vector */ + } +} + +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 == 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); + } + 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; +} + |