/**************************************************************************** * arch/arm/src/lm3s/lm3s_timerisr.c * * Copyright (C) 2009 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name NuttX nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include "clock_internal.h" #include "up_internal.h" #include "up_arch.h" #include "chip.h" #include "lm3s_internal.h" /**************************************************************************** * Definitions ****************************************************************************/ /* The desired timer interrupt frequency is provided by the definition * CLK_TCK (see include/time.h). CLK_TCK defines the desired number of * system clock ticks per second. That value is a user configurable setting * that defaults to 100 (100 ticks per second = 10 MS interval). * * The timer counts at the rate SYSCLK_FREQUENCY as defined in the board.h * header file. */ #define SYSTICK_RELOAD ((SYSCLK_FREQUENCY / CLK_TCK) - 1) /* The size of the reload field is 24 bits. Verify taht the reload value * will fit in the reload register. */ #if SYSTICK_RELOAD > 0x00ffffff # error SYSTICK_RELOAD exceeds the range of the RELOAD register #endif /**************************************************************************** * Private Types ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /**************************************************************************** * Global Functions ****************************************************************************/ /**************************************************************************** * Function: up_timerisr * * Description: * The timer ISR will perform a variety of services for various portions * of the systems. * ****************************************************************************/ int up_timerisr(int irq, uint32 *regs) { /* Process timer interrupt */ sched_process_timer(); return 0; } /**************************************************************************** * Function: up_timerinit * * Description: * This function is called during start-up to initialize * the timer interrupt. * ****************************************************************************/ void up_timerinit(void) { uint32 regval; /* Set the SysTick interrupt to the default priority */ regval = getreg32(NVIC_SYSH12_15_PRIORITY); regval &= ~NVIC_SYSH_PRIORITY_PR15_MASK; regval |= (NVIC_SYSH_PRIORITY_DEFAULT << NVIC_SYSH_PRIORITY_PR15_SHIFT); putreg32(regval, NVIC_SYSH12_15_PRIORITY); /* Configure SysTick to interrupt at the requested rate */ putreg32(SYSTICK_RELOAD, NVIC_SYSTICK_RELOAD); /* Attach the timer interrupt vector */ (void)irq_attach(LM3S_IRQ_SYSTICK, (xcpt_t)up_timerisr); /* Enable SysTick interrupts */ putreg32((NVIC_SYSTICK_CTRL_CLKSOURCE|NVIC_SYSTICK_CTRL_TICKINT|NVIC_SYSTICK_CTRL_ENABLE), NVIC_SYSTICK_CTRL); /* And enable the timer interrupt */ up_enable_irq(LM3S_IRQ_SYSTICK); }