shared/dev/clock.c

0001 /*  RTEMS Clock Tick Driver for Blackfin.  Uses Blackfin Core Timer.
0002  */
0003
0004 /*
0005  *  Copyright (c) 2008 Kallisti Labs, Los Gatos, CA, USA
0006  *             written by Allan Hessenflow <allanh@kallisti.com>
0007  *
0008  *  The license and distribution terms for this file may be
0009  *  found in the file LICENSE in this distribution or at
0010  *  http://www.rtems.org/license/LICENSE.
0011  */
0012
0013
0014 #include <rtems.h>
0015 #include <stdlib.h>
0016 #include <rtems/libio.h>
0017 #include <rtems/score/percpu.h>
0018 #include <rtems/score/thread.h>
0019 #include <bsp.h>
0020 #include <rtems/clockdrv.h>
0021
0022
0023 #include <libcpu/cecRegs.h>
0024 #include <libcpu/coreTimerRegs.h>
0025
0026 #if (BFIN_ON_SKYEYE)
0027 #define CLOCK_DRIVER_USE_FAST_IDLE 1
0028 #endif
0029
0030 volatile uint32_t Clock_driver_ticks;
0031
0032 static rtems_isr clockISR(rtems_vector_number vector) {
0033
0034   Clock_driver_ticks += 1;
0035
0036 #if CLOCK_DRIVER_USE_FAST_IDLE
0037   do {
0038     rtems_clock_tick();
0039   } while ( _Thread_Heir == _Thread_Executing && _Thread_Executing->is_idle );
0040 #else
0041   rtems_clock_tick();
0042 #endif
0043 }
0044
0045 /*
0046  *  Clock_exit
0047  *
0048  *  This routine allows the clock driver to exit by masking the interrupt and
0049  *  disabling the clock's counter.
0050  */
0051 static void Clock_exit(void)
0052 {
0053   *(uint32_t volatile *) TCNTL = 0;
0054 }
0055
0056 void _Clock_Initialize( void )
0057 {
0058   Clock_driver_ticks = 0;
0059
0060   set_vector(clockISR, CEC_CORE_TIMER_VECTOR, 1);
0061
0062   *(uint32_t volatile *) TCNTL = TCNTL_TMPWR | TCNTL_TAUTORLD;
0063   *(uint32_t volatile *) TSCALE = 0;
0064   *(uint32_t volatile *) TPERIOD = CCLK / 1000000 *
0065       rtems_configuration_get_microseconds_per_tick();
0066   *(uint32_t volatile *) TCNTL = TCNTL_TMPWR | TCNTL_TAUTORLD | TCNTL_TMREN;
0067
0068   atexit(Clock_exit);
0069 }