/*
* LPC22XX/LPC21xx clock specific using the System Timer
*
* Set the Time0 to generate click for RTEMS
*/
/*
* Copyright (c) 2006 by Ray <rayx.cn@gmail.com>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#include <rtems.h>
#include <bsp.h>
#include <bsp/irq.h>
#include <lpc22xx.h>
#include <rtems/bspIo.h> /* for printk */
#include <rtems/timecounter.h>
void Clock_isr(rtems_irq_hdl_param arg);
static void clock_isr_on(const rtems_irq_connect_data *unused);
static void clock_isr_off(const rtems_irq_connect_data *unused);
static int clock_isr_is_on(const rtems_irq_connect_data *irq);
static rtems_timecounter_simple lpc22xx_tc;
static uint32_t lpc22xx_tc_get(rtems_timecounter_simple *tc)
{
return T0TC;
}
static bool lpc22xx_tc_is_pending(rtems_timecounter_simple *tc)
{
return (T0IR & 0x1) != 0;
}
static uint32_t lpc22xx_tc_get_timecount(struct timecounter *tc)
{
return rtems_timecounter_simple_upcounter_get(
tc,
lpc22xx_tc_get,
lpc22xx_tc_is_pending
);
}
/**
* When we get the clock interrupt
* - clear the interrupt bit?
* - restart the timer?
*/
static void lpc22xx_tc_at_tick(rtems_timecounter_simple *tc)
{
if (!(T0IR & 0x01))
return;
T0IR = 0x01;
VICVectAddr = 0x00;
}
static void lpc22xx_tc_tick(void)
{
rtems_timecounter_simple_upcounter_tick(
&lpc22xx_tc,
lpc22xx_tc_get,
lpc22xx_tc_at_tick
);
}
/* Replace the first value with the clock's interrupt name. */
rtems_irq_connect_data clock_isr_data = {
.name = LPC22xx_INTERRUPT_TIMER0,
.hdl = Clock_isr,
.handle = NULL,
.on = clock_isr_on,
.off = clock_isr_off,
.isOn = clock_isr_is_on,
};
/* use the /shared/dev/clock/clockimpl.h code template */
/**
* Installs the clock ISR. You shouldn't need to change this.
*/
#define Clock_driver_support_install_isr( _new ) \
BSP_install_rtems_irq_handler(&clock_isr_data)
/**
* Initialize the hardware for the clock
* - Set the frequency
* - enable it
* - clear any pending interrupts
*
* Since you may want the clock always running, you can
* enable interrupts here. If you do so, the clock_isr_on(),
* clock_isr_off(), and clock_isr_is_on() functions can be
* NOPs.
*
* set timer to generate interrupt every
* rtems_configuration_get_microseconds_per_tick()
* MR0/(LPC22xx_Fpclk/(PR0+1)) = 10/1000 = 0.01s
*/
#define Clock_driver_support_initialize_hardware() \
do { \
/* disable and clear timer 0, set to */ \
T0TCR &= 0; \
/* TC is incremented on every pclk.*/ \
T0PC = 0; \
/* initialize the timer period and prescaler */ \
T0MR0 = ((LPC22xx_Fpclk/1000 * \
rtems_configuration_get_microseconds_per_tick()) / 1000); \
/* generate interrupt when T0MR0 match T0TC and Reset Timer Count*/ \
T0MCR |= 0x03; \
/* No external match */ \
T0EMR = 0; \
/* enable timer0 */ \
T0TCR = 1; \
/* enable interrupt, skyeye will check this*/ \
T0IR |= 0x01; \
/* install timecounter */ \
rtems_timecounter_simple_install( \
&lpc22xx_tc, \
LPC22xx_Fpclk, \
T0MR0, \
lpc22xx_tc_get_timecount \
); \
} while (0)
/**
* Enables clock interrupt.
*
* If the interrupt is always on, this can be a NOP.
*/
static void clock_isr_on(const rtems_irq_connect_data *unused)
{
T0IR&=0x01;
}
/**
* Disables clock interrupts
*
* If the interrupt is always on, this can be a NOP.
*/
static void clock_isr_off(const rtems_irq_connect_data *unused)
{
T0IR=0x00;
}
/**
* Tests to see if clock interrupt is enabled, and returns 1 if so.
* If interrupt is not enabled, returns 0.
*
* If the interrupt is always on, this always returns 1.
*/
static int clock_isr_is_on(const rtems_irq_connect_data *irq)
{
return T0IR & 0x01; /* MR0 mask */
}
#define Clock_driver_timecounter_tick() lpc22xx_tc_tick()
/* Make sure to include this, and only at the end of the file */
#include "../../../shared/dev/clock/clockimpl.h"
