/**************************************************************************** * arch/arm/src/sam34/sam_timerisr.c * * Copyright (C) 2010, 2013-2014 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 "nvic.h" #include "clock/clock.h" #include "up_internal.h" #include "up_arch.h" #include "chip.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Select MCU-specific settings * * For the SAM3U, SAM3A, and SAM3X, Systick is driven by the main clock * (This could be the MCK/8 but that option has not yet been necessary). * For the SAM4L, SAM4S, and SAM4E, Systick is driven by the CPU clock which * is just the main clock divided down. */ #if defined(CONFIG_ARCH_CHIP_SAM3U) || defined(CONFIG_ARCH_CHIP_SAM3X) || \ defined(CONFIG_ARCH_CHIP_SAM3A) # define SAM_SYSTICK_CLOCK BOARD_MCK_FREQUENCY /* Frequency of the main clock */ #elif defined(CONFIG_ARCH_CHIP_SAM4L) || defined(CONFIG_ARCH_CHIP_SAM4CM) || \ defined(CONFIG_ARCH_CHIP_SAM4S) || defined(CONFIG_ARCH_CHIP_SAM4E) # define SAM_SYSTICK_CLOCK BOARD_CPU_FREQUENCY /* CPU frequency */ #else # error Unrecognized SAM architecture #endif /* 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 SAM3U feeds the Cortex System Timer (SysTick) with the MCK clock or * the MCK clock divided by 8, configurable with the CLKSOURCE bit in the * SysTick Control and Status register. */ #undef CONFIG_SAM34_SYSTICK_HCLKd8 /* Power up default is MCK, not MCK/8 */ #ifdef CONFIG_SAM34_SYSTICK_HCLKd8 # define SYSTICK_RELOAD ((SAM_SYSTICK_CLOCK / 8 / CLK_TCK) - 1) #else # define SYSTICK_RELOAD ((SAM_SYSTICK_CLOCK / CLK_TCK) - 1) #endif /* The size of the reload field is 24 bits. Verify that 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 ****************************************************************************/ /**************************************************************************** * Public 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_t *regs) { /* Process timer interrupt */ sched_process_timer(); return 0; } /**************************************************************************** * Function: up_timer_initialize * * Description: * This function is called during start-up to initialize the timer * interrupt. * ****************************************************************************/ void up_timer_initialize(void) { uint32_t 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); /* Make sure that the SYSTICK clock source is set correctly */ #if 0 /* Does not work. Comes up with HCLK source and I can't change it */ regval = getreg32(NVIC_SYSTICK_CTRL); #ifdef CONFIG_SAM34_SYSTICK_HCLKd8 regval &= ~NVIC_SYSTICK_CTRL_CLKSOURCE; #else regval |= NVIC_SYSTICK_CTRL_CLKSOURCE; #endif putreg32(regval, NVIC_SYSTICK_CTRL); #endif /* Configure SysTick to interrupt at the requested rate */ putreg32(SYSTICK_RELOAD, NVIC_SYSTICK_RELOAD); putreg32(0, NVIC_SYSTICK_CURRENT); /* Attach the timer interrupt vector */ (void)irq_attach(SAM_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(SAM_IRQ_SYSTICK); }