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/*
* This file contains the generic RTEMS clock driver the Hitachi SH 7750
*
* Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia
* Author: Victor V. Vengerov <vvv@oktet.ru>
*
* COPYRIGHT (c) 2001
* 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.rtems.com/license/LICENSE.
*/
#include <rtems.h>
#include <stdlib.h>
#include <rtems/libio.h>
#include <rtems/score/sh_io.h>
#include <rtems/score/sh.h>
#include <rtems/score/ispsh7750.h>
#include <rtems/score/iosh7750.h>
extern uint32_t bsp_clicks_per_second;
#ifndef CLOCKPRIO
#define CLOCKPRIO 10
#endif
/* Clock timer prescaler division ratio */
#define CLOCK_PRESCALER 4
#define TCR0_TPSC SH7750_TCR_TPSC_DIV4
/*
* The interrupt vector number associated with the clock tick device
* driver.
*/
#define CLOCK_VECTOR SH7750_EVT_TO_NUM(SH7750_EVT_TUNI0)
/*
* Clock_driver_ticks is a monotonically increasing counter of the
* number of clock ticks since the driver was initialized.
*/
volatile uint32_t Clock_driver_ticks;
static void Clock_exit( void );
static rtems_isr Clock_isr( rtems_vector_number vector );
/*
* These are set by clock driver during its init
*/
rtems_device_major_number rtems_clock_major = ~0;
rtems_device_minor_number rtems_clock_minor;
/*
* The previous ISR on this clock tick interrupt vector.
*/
rtems_isr_entry Old_ticker;
/*
* Isr Handler
*/
/* Clock_isr --
* Clock interrupt handling routine.
*
* PARAMETERS:
* vector - interrupt vector number
*
* RETURNS:
* none
*/
rtems_isr
Clock_isr(rtems_vector_number vector)
{
uint16_t tcr;
/* reset the timer underflow flag */
tcr = read16(SH7750_TCR0);
write16(tcr & ~SH7750_TCR_UNF, SH7750_TCR0);
/* Increment the clock interrupt counter */
Clock_driver_ticks++ ;
/* Invoke rtems clock service routine */
rtems_clock_tick();
}
/* Install_clock --
* Install a clock tick handler and reprograms the chip. This
* is used to initially establish the clock tick.
*
* PARAMETERS:
* clock_isr - Clock interrupt stay routine
*
* RETURNS:
* none
*
* SIDE EFFECTS:
* Establish clock interrupt handler, configure Timer 0 hardware
*/
void
Install_clock(rtems_isr_entry clock_isr)
{
int cpudiv = 1; /* CPU frequency divider */
int tidiv = 1; /* Timer input frequency divider */
uint32_t timer_divider; /* Calculated Timer Divider value */
uint8_t temp8;
uint16_t temp16;
/*
* Initialize the clock tick device driver variables
*/
Clock_driver_ticks = 0;
/* Get CPU frequency divider from clock unit */
switch (read16(SH7750_FRQCR) & SH7750_FRQCR_IFC)
{
case SH7750_FRQCR_IFCDIV1:
cpudiv = 1;
break;
case SH7750_FRQCR_IFCDIV2:
cpudiv = 2;
break;
case SH7750_FRQCR_IFCDIV3:
cpudiv = 3;
break;
case SH7750_FRQCR_IFCDIV4:
cpudiv = 4;
break;
case SH7750_FRQCR_IFCDIV6:
cpudiv = 6;
break;
case SH7750_FRQCR_IFCDIV8:
cpudiv = 8;
break;
default:
rtems_fatal_error_occurred( RTEMS_NOT_CONFIGURED);
}
/* Get peripheral module frequency divider from clock unit */
switch (read16(SH7750_FRQCR) & SH7750_FRQCR_PFC)
{
case SH7750_FRQCR_PFCDIV2:
tidiv = 2 * CLOCK_PRESCALER;
break;
case SH7750_FRQCR_PFCDIV3:
tidiv = 3 * CLOCK_PRESCALER;
break;
case SH7750_FRQCR_PFCDIV4:
tidiv = 4 * CLOCK_PRESCALER;
break;
case SH7750_FRQCR_PFCDIV6:
tidiv = 6 * CLOCK_PRESCALER;
break;
case SH7750_FRQCR_PFCDIV8:
tidiv = 8 * CLOCK_PRESCALER;
break;
default:
rtems_fatal_error_occurred( RTEMS_NOT_CONFIGURED);
}
timer_divider =
(bsp_clicks_per_second * cpudiv / (tidiv*1000000)) *
rtems_configuration_get_microseconds_per_tick();
/*
* Hardware specific initialization
*/
/* Stop the Timer 0 */
temp8 = read8(SH7750_TSTR);
temp8 &= ~SH7750_TSTR_STR0;
write8(temp8, SH7750_TSTR);
/* Establish interrupt handler */
rtems_interrupt_catch( Clock_isr, CLOCK_VECTOR, &Old_ticker );
/* Reset counter */
write32(timer_divider, SH7750_TCNT0);
/* Load divider */
write32(timer_divider, SH7750_TCOR0);
write16(
SH7750_TCR_UNIE | /* Enable Underflow Interrupt */
SH7750_TCR_CKEG_RAISE | /* Count on rising edge */
TCR0_TPSC, /* Timer prescaler ratio */
SH7750_TCR0);
/* Set clock interrupt priority */
temp16 = read16(SH7750_IPRA);
temp16 = (temp16 & ~SH7750_IPRA_TMU0) | (CLOCKPRIO << SH7750_IPRA_TMU0_S);
write16(temp16, SH7750_IPRA);
/* Start the Timer 0 */
temp8 = read8(SH7750_TSTR);
temp8 |= SH7750_TSTR_STR0;
write8(temp8, SH7750_TSTR);
/*
* Schedule the clock cleanup routine to execute if the application exits.
*/
atexit( Clock_exit );
}
/* Clock_exit --
* Clean up before the application exits
*
* PARAMETERS:
* none
*
* RETURNS:
* none
*
* SIDE EFFECTS:
* Stop Timer 0 counting, set timer 0 interrupt priority level to 0.
*/
void
Clock_exit(void)
{
uint8_t temp8 = 0;
uint16_t temp16 = 0;
/* turn off the timer interrupts */
/* Stop the Timer 0 */
temp8 = read8(SH7750_TSTR);
temp8 &= ~SH7750_TSTR_STR0;
write8(temp8, SH7750_TSTR);
/* Lower timer interrupt priority to 0 */
temp16 = read16(SH7750_IPRA);
temp16 = (temp16 & ~SH7750_IPRA_TMU0) | (0 << SH7750_IPRA_TMU0_S);
write16(temp16, SH7750_IPRA);
/* old vector shall not be installed */
}
/* Clock_initialize --
* Device driver entry point for clock tick driver initialization.
*
* PARAMETERS:
* major - clock major device number
* minor - clock minor device number
* pargp - driver initialize primitive argument, not used
*
* RETURNS:
* RTEMS_SUCCESSFUL
*/
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;
}
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