simtrace2/firmware/libboard/common/source/board_lowlevel.c

/* ----------------------------------------------------------------------------
 *         ATMEL Microcontroller Software Support
 * ----------------------------------------------------------------------------
 * Copyright (c) 2009, Atmel Corporation
 * Copyright (c) 2018, sysmocom -s.f.m.c. GmbH, Author: Kevin Redon <kredon@sysmocom.de>
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the disclaimer below.
 *
 * Atmel's name may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
 * ----------------------------------------------------------------------------
 */

/**
 * \file
 *
 * Provides the low-level initialization function that called on chip startup.
 */

/*----------------------------------------------------------------------------
 *        Headers
 *----------------------------------------------------------------------------*/

#include "board.h"

/*----------------------------------------------------------------------------
 *        Local definitions
 *----------------------------------------------------------------------------*/

#define BOARD_OSCOUNT   (CKGR_MOR_MOSCXTST(0x8))
#define BOARD_MCKR      (PMC_MCKR_PRES_CLK | PMC_MCKR_CSS_PLLA_CLK)

/** configure PLL to generate main clock based on main oscillator frequency */
#if (BOARD_MAINOSC == 12000000) && (BOARD_MCK == 48000000)
#define BOARD_PLLAR     (CKGR_PLLAR_STUCKTO1 \
					   | CKGR_PLLAR_MULA(8-1) \
					   | CKGR_PLLAR_PLLACOUNT(0x1) \
					   | CKGR_PLLAR_DIVA(2))
#elif (BOARD_MAINOSC == 12000000) && (BOARD_MCK == 58000000)
#define BOARD_PLLAR     (CKGR_PLLAR_STUCKTO1 \
					   | CKGR_PLLAR_MULA(29-1) \
					   | CKGR_PLLAR_PLLACOUNT(0x1) \
					   | CKGR_PLLAR_DIVA(6))
#elif (BOARD_MAINOSC == 12000000) && (BOARD_MCK == 60000000)
#define BOARD_PLLAR     (CKGR_PLLAR_STUCKTO1 \
					   | CKGR_PLLAR_MULA(10-1) \
					   | CKGR_PLLAR_PLLACOUNT(0x1) \
					   | CKGR_PLLAR_DIVA(2))
#elif (BOARD_MAINOSC == 18432000) && (BOARD_MCK == 47923200)
#define BOARD_PLLAR     (CKGR_PLLAR_STUCKTO1 \
					   | CKGR_PLLAR_MULA(13-1) \
					   | CKGR_PLLAR_PLLACOUNT(0x1) \
					   | CKGR_PLLAR_DIVA(5))
#elif (BOARD_MAINOSC == 18432000) && (BOARD_MCK == 58982400)
#define BOARD_PLLAR     (CKGR_PLLAR_STUCKTO1 \
					   | CKGR_PLLAR_MULA(16-1) \
					   | CKGR_PLLAR_PLLACOUNT(0x1) \
					   | CKGR_PLLAR_DIVA(5))
#elif (BOARD_MAINOSC == 18432000) && (BOARD_MCK == 64512000)
#define BOARD_PLLAR     (CKGR_PLLAR_STUCKTO1 \
					   | CKGR_PLLAR_MULA(7-1) \
					   | CKGR_PLLAR_PLLACOUNT(0x1) \
					   | CKGR_PLLAR_DIVA(2))
#else
	#error "Please define PLLA config for your BOARD_MCK/MAINOSC frequency"
#endif

#if (BOARD_MAINOSC == 12000000)
#define PLLB_CFG (CKGR_PLLBR_DIVB(2)|CKGR_PLLBR_MULB(8-1)|CKGR_PLLBR_PLLBCOUNT_Msk)
#elif (BOARD_MAINOSC == 18432000)
#define PLLB_CFG (CKGR_PLLBR_DIVB(5)|CKGR_PLLBR_MULB(13-1)|CKGR_PLLBR_PLLBCOUNT_Msk)
#else
#error "Please configure PLLB for your MAINOSC freq"
#endif

/* Define clock timeout */
#define CLOCK_TIMEOUT    0xFFFFFFFF

/**
 * \brief Configure 48MHz Clock for USB
 */
static void _ConfigureUsbClock(void)
{
	/* Enable PLLB for USB */
	PMC->CKGR_PLLBR = PLLB_CFG;
	while ((PMC->PMC_SR & PMC_SR_LOCKB) == 0) ;

	/* USB Clock uses PLLB */
	PMC->PMC_USB = PMC_USB_USBDIV(0)	/* /1 (no divider)  */
			    | PMC_USB_USBS;	/* PLLB */
}

/*----------------------------------------------------------------------------
 *        Exported functions
 *----------------------------------------------------------------------------*/

/**
 * \brief Performs the low-level initialization of the chip.
 * This includes EFC and master clock configuration.
 * It also enable a low level on the pin NRST triggers a user reset.
 */
extern WEAK void LowLevelInit( void )
{
	uint32_t timeout = 0;

	/* Configure the Supply Monitor to reset the CPU in case VDDIO is
	 * lower than 3.0V.  As we run the board on 3.3V, any lower voltage
	 * might be some kind of leakage that creeps in some way, but is not
	 * the "official" power supply */
	SUPC->SUPC_SMMR = SUPC_SMMR_SMTH_3_0V | SUPC_SMMR_SMSMPL_CSM |
	    	      SUPC_SMMR_SMRSTEN_ENABLE;

	/* disable ERASE pin to prevent accidental flash erase */
	MATRIX->CCFG_SYSIO |= CCFG_SYSIO_SYSIO12;

	/* enable both LED and green LED */
	PIOA->PIO_PER |= PIO_LED_RED | PIO_LED_GREEN;
	PIOA->PIO_OER |= PIO_LED_RED | PIO_LED_GREEN;
	PIOA->PIO_CODR |= PIO_LED_RED | PIO_LED_GREEN;

	/* Set 3 FWS for Embedded Flash Access */
	EFC->EEFC_FMR = EEFC_FMR_FWS(3);

	/* Select external slow clock */
/*    if ((SUPC->SUPC_SR & SUPC_SR_OSCSEL) != SUPC_SR_OSCSEL_CRYST)
	{
		SUPC->SUPC_CR = (uint32_t)(SUPC_CR_XTALSEL_CRYSTAL_SEL | SUPC_CR_KEY(0xA5));
		timeout = 0;
		while (!(SUPC->SUPC_SR & SUPC_SR_OSCSEL_CRYST) );
	}
*/

#ifndef BOARD_MAINOSC_BYPASS
	/* Initialize main oscillator */
	if ( !(PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) )
	{
		PMC->CKGR_MOR = CKGR_MOR_KEY(0x37) | BOARD_OSCOUNT | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN;
		timeout = 0;
		while (!(PMC->PMC_SR & PMC_SR_MOSCXTS) && (timeout++ < CLOCK_TIMEOUT));
	}

	/* Switch to 3-20MHz Xtal oscillator */
	PIOB->PIO_PDR = (1 << 8) | (1 << 9);
	PIOB->PIO_PUDR = (1 << 8) | (1 << 9);
	PIOB->PIO_PPDDR = (1 << 8) | (1 << 9);
	PMC->CKGR_MOR = CKGR_MOR_KEY(0x37) | BOARD_OSCOUNT | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN | CKGR_MOR_MOSCSEL;
	/* wait for Main XTAL oscillator stabilization */
	timeout = 0;
	while (!(PMC->PMC_SR & PMC_SR_MOSCSELS) && (timeout++ < CLOCK_TIMEOUT));
#else
	/* Board has external clock, not a crystal oscillator */
	PIOB->PIO_PDR = (1 << 9);
	PIOB->PIO_PUDR = (1 << 9);
	PIOB->PIO_PPDDR = (1 << 9);
	PMC->CKGR_MOR = CKGR_MOR_KEY(0x37) | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTBY | CKGR_MOR_MOSCSEL;
#endif

	/* disable the red LED after main clock initialization */
	PIOA->PIO_SODR = PIO_LED_RED;

	/* "switch" to main clock as master clock source (should already be the case */
	PMC->PMC_MCKR = (PMC->PMC_MCKR & ~(uint32_t)PMC_MCKR_CSS_Msk) | PMC_MCKR_CSS_MAIN_CLK;
	/* wait for master clock to be ready */
	for ( timeout = 0; !(PMC->PMC_SR & PMC_SR_MCKRDY) && (timeout++ < CLOCK_TIMEOUT) ; );

	/* Initialize PLLA */
	PMC->CKGR_PLLAR = BOARD_PLLAR;
	/* Wait for PLLA to lock */
	timeout = 0;
	while (!(PMC->PMC_SR & PMC_SR_LOCKA) && (timeout++ < CLOCK_TIMEOUT));

	/* Switch to main clock (again ?!?) */
	PMC->PMC_MCKR = (BOARD_MCKR & ~PMC_MCKR_CSS_Msk) | PMC_MCKR_CSS_MAIN_CLK;
	/* wait for master clock to be ready */
	for ( timeout = 0; !(PMC->PMC_SR & PMC_SR_MCKRDY) && (timeout++ < CLOCK_TIMEOUT) ; );

	/* switch to PLLA as master clock source */
	PMC->PMC_MCKR = BOARD_MCKR ;
	/* wait for master clock to be ready */
	for ( timeout = 0; !(PMC->PMC_SR & PMC_SR_MCKRDY) && (timeout++ < CLOCK_TIMEOUT) ; );

	/* Configure SysTick for 1ms */
	SysTick_Config(BOARD_MCK/1000);

	_ConfigureUsbClock();
}

/* SysTick based delay function */

volatile uint32_t jiffies;

/* Interrupt handler for SysTick interrupt */
void SysTick_Handler(void)
{
	jiffies++;
}

void mdelay(unsigned int msecs)
{
	uint32_t jiffies_start = jiffies;
	do {
	} while ((jiffies - jiffies_start) < msecs);
}

void abort() {
	NVIC_SystemReset();
	while(1) {};
}