forked from Imagelibrary/rtems
160 lines
4.7 KiB
C
160 lines
4.7 KiB
C
/*
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* LPC22XX/LPC21xx clock specific using the System Timer
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* Copyright (c) 2006 by Ray <rayx.cn@gmail.com>
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* Set the Time0 to generate click for RTEMS
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*
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* This is hardware specific part of the clock driver. At the end of this
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* file, the generic part of the driver is #included.
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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*
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* http://www.rtems.com/license/LICENSE.
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*
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*
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* $Id$
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*/
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#include <rtems.h>
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#include <bsp.h>
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#include <irq.h>
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#include <lpc22xx.h>
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#include <rtems/bspIo.h> /* for printk */
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/* this is defined in ../../../shared/clockdrv_shell.h */
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rtems_isr Clock_isr(rtems_vector_number vector);
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static void clock_isr_on(const rtems_irq_connect_data *unused);
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static void clock_isr_off(const rtems_irq_connect_data *unused);
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static int clock_isr_is_on(const rtems_irq_connect_data *irq);
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/* Replace the first value with the clock's interrupt name. */
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rtems_irq_connect_data clock_isr_data = {LPC22xx_INTERRUPT_TIMER0,
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(rtems_irq_hdl)Clock_isr,
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clock_isr_on,
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clock_isr_off,
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clock_isr_is_on,
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3, /* unused for ARM cpus */
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0 }; /* unused for ARM cpus */
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/* If you follow the code, this is never used, so any value
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* should work
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*/
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#define CLOCK_VECTOR 0
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/* use the /shared/clockdrv_shell.h code template */
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/**
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* When we get the clock interrupt
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* - clear the interrupt bit?
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* - restart the timer?
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*/
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#define Clock_driver_support_at_tick() \
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do { \
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if (!(T0IR & 0x01)) return; \
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T0IR = 0x01; \
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VICVectAddr = 0x00;\
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} while(0)
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/**
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* Installs the clock ISR. You shouldn't need to change this.
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*/
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#define Clock_driver_support_install_isr( _new, _old ) \
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do { \
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(_old) = NULL; \
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BSP_install_rtems_irq_handler(&clock_isr_data); \
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} while(0)
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/**
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* Initialize the hardware for the clock
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* - Set the frequency
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* - enable it
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* - clear any pending interrupts
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*
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* Since you may want the clock always running, you can
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* enable interrupts here. If you do so, the clock_isr_on(),
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* clock_isr_off(), and clock_isr_is_on() functions can be
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* NOPs.
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*/
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/* set timer to generate interrupt every rtems_configuration_get_microseconds_per_tick()
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* MR0/(LPC22xx_Fpclk/(PR0+1)) = 10/1000 = 0.01s
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*/
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#define Clock_driver_support_initialize_hardware() \
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do { \
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T0TCR &= 0; /* disable and clear timer 0, set to */ \
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T0PC = 0; /* TC is incrementet on every pclk.*/ \
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T0MR0 = ((LPC22xx_Fpclk/1000* rtems_configuration_get_microseconds_per_tick()) / 1000); /* initialize the timer period and prescaler */ \
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/*T0PR = (((LPC22xx_Fpclk / 1000) * rtems_configuration_get_microseconds_per_tick()) / 1000-1); \ */ \
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T0MCR |= 0x03; /* generate interrupt when T0MR0 match T0TC and Reset Timer Count*/ \
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T0EMR = 0; /*No external match*/ \
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T0TCR = 1; /*enable timer0*/ \
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T0IR|=0x01;/*enable interrupt, skyeye will check this*/\
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} while (0)
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/**
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* Do whatever you need to shut the clock down and remove the
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* interrupt handler. Since this normally only gets called on
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* RTEMS shutdown, you may not need to do anything other than
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* remove the ISR.
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*/
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#define Clock_driver_support_shutdown_hardware() \
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do { \
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/* Disable timer */ \
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T0TCR&=~0x02; \
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BSP_remove_rtems_irq_handler(&clock_isr_data); \
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} while (0)
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uint32_t bsp_clock_nanoseconds_since_last_tick(void)
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{
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uint32_t clicks;
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clicks = T0TC; /*T0TC is the 32bit time counter 0*/
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return (uint32_t) (rtems_configuration_get_microseconds_per_tick() - clicks) * 1000;
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}
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#define Clock_driver_nanoseconds_since_last_tick bsp_clock_nanoseconds_since_last_tick
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/**
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* Enables clock interrupt.
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*
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* If the interrupt is always on, this can be a NOP.
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*/
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static void clock_isr_on(const rtems_irq_connect_data *unused)
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{
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T0IR&=0x01;
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//return;
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}
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/**
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* Disables clock interrupts
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*
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* If the interrupt is always on, this can be a NOP.
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*/
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static void clock_isr_off(const rtems_irq_connect_data *unused)
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{
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T0IR=0x00;
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//return;
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}
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/**
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* Tests to see if clock interrupt is enabled, and returns 1 if so.
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* If interrupt is not enabled, returns 0.
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*
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* If the interrupt is always on, this always returns 1.
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*/
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static int clock_isr_is_on(const rtems_irq_connect_data *irq)
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{
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return T0IR & 0x01; /*MR0 mask*/
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}
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/* Make sure to include this, and only at the end of the file */
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#include "../../../../libbsp/shared/clockdrv_shell.h"
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