/* ----------------------------------------------------------------------------
 *         SAM Software Package License
 * ----------------------------------------------------------------------------
 * Copyright (c) 2012, Atmel Corporation
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following condition is 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.
 * ----------------------------------------------------------------------------
 */

#include "sam3n.h"

/* @cond 0 */
/**INDENT-OFF**/
#ifdef __cplusplus
extern "C" {
#endif
/**INDENT-ON**/
/* @endcond */

/* Clock settings (48MHz) */
#define SYS_BOARD_OSCOUNT   (CKGR_MOR_MOSCXTST(0x8UL))
#define SYS_BOARD_PLLAR		(CKGR_PLLAR_ONE \
							| CKGR_PLLAR_MULA(0x7UL) \
							| CKGR_PLLAR_PLLACOUNT(0x3fUL) \
							| CKGR_PLLAR_DIVA(0x1UL))
#define SYS_BOARD_MCKR      (PMC_MCKR_PRES_CLK_2 | PMC_MCKR_CSS_PLLA_CLK)

#define SYS_CKGR_MOR_KEY_VALUE	CKGR_MOR_KEY(0x37UL) /* Key to unlock MOR register */

/* FIXME: should be generated by sock */
uint32_t SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;

/**
 * \brief Setup the microcontroller system.
 * Initialize the System and update the SystemFrequency variable.
 */
void SystemInit(void)
{
	/* Set FWS according to SYS_BOARD_MCKR configuration */
	EFC->EEFC_FMR = EEFC_FMR_FWS(3);

	/* Initialize main oscillator */
	if (!(PMC->CKGR_MOR & CKGR_MOR_MOSCSEL)) {
		PMC->CKGR_MOR = SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT |
			                     CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN;
		while (!(PMC->PMC_SR & PMC_SR_MOSCXTS)) {
		}
	}

	/* Switch to 3-20MHz Xtal oscillator */
	PMC->CKGR_MOR = SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT |
	CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN | CKGR_MOR_MOSCSEL;

	while (!(PMC->PMC_SR & PMC_SR_MOSCSELS)) {
	}
	PMC->PMC_MCKR = (PMC->PMC_MCKR & ~(uint32_t)PMC_MCKR_CSS_Msk) |
		                    PMC_MCKR_CSS_MAIN_CLK;
	while (!(PMC->PMC_SR & PMC_SR_MCKRDY)) {
	}

	/* Initialize PLL */
	PMC->CKGR_PLLAR = SYS_BOARD_PLLAR;
	while (!(PMC->PMC_SR & PMC_SR_LOCKA)) {
	}

	/* Switch to main clock */
	PMC->PMC_MCKR = (SYS_BOARD_MCKR & ~PMC_MCKR_CSS_Msk) | PMC_MCKR_CSS_MAIN_CLK;
	while (!(PMC->PMC_SR & PMC_SR_MCKRDY)) {
	}

	/* Switch to PLLA */
	PMC->PMC_MCKR = SYS_BOARD_MCKR;
	while (!(PMC->PMC_SR & PMC_SR_MCKRDY)) {
	}

	SystemCoreClock = CHIP_FREQ_CPU_MAX;
}

void SystemCoreClockUpdate(void)
{
	/* Determine clock frequency according to clock register values */
	switch (PMC->PMC_MCKR & PMC_MCKR_CSS_Msk) {
	case PMC_MCKR_CSS_SLOW_CLK:	/* Slow clock */
		if (SUPC->SUPC_SR & SUPC_SR_OSCSEL) {
			SystemCoreClock = CHIP_FREQ_XTAL_32K;
		} else {
			SystemCoreClock = CHIP_FREQ_SLCK_RC;
		}
		break;
	case PMC_MCKR_CSS_MAIN_CLK:	/* Main clock */
		if (PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) {
			SystemCoreClock = CHIP_FREQ_XTAL_12M;
		} else {
			SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;

			switch (PMC->CKGR_MOR & CKGR_MOR_MOSCRCF_Msk) {
			case CKGR_MOR_MOSCRCF_4_MHz:
				break;
			case CKGR_MOR_MOSCRCF_8_MHz:
				SystemCoreClock *= 2U;
				break;
			case CKGR_MOR_MOSCRCF_12_MHz:
				SystemCoreClock *= 3U;
				break;
			default:
				break;
			}
		}
		break;
	case PMC_MCKR_CSS_PLLA_CLK:	/* PLLA clock */
		if (PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) {
			SystemCoreClock = CHIP_FREQ_XTAL_12M;
		} else {
			SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;

			switch (PMC->CKGR_MOR & CKGR_MOR_MOSCRCF_Msk) {
			case CKGR_MOR_MOSCRCF_4_MHz:
				break;
			case CKGR_MOR_MOSCRCF_8_MHz:
				SystemCoreClock *= 2U;
				break;
			case CKGR_MOR_MOSCRCF_12_MHz:
				SystemCoreClock *= 3U;
				break;
			default:
				break;
			}
		}
		SystemCoreClock *= ((((PMC->CKGR_PLLAR) & CKGR_PLLAR_MULA_Msk) >>
			                         CKGR_PLLAR_MULA_Pos) + 1U);
		SystemCoreClock /= ((((PMC->CKGR_PLLAR) & CKGR_PLLAR_DIVA_Msk) >>
			                         CKGR_PLLAR_DIVA_Pos));
		break;
	default:
		break;
	}

	if ((PMC->PMC_MCKR & PMC_MCKR_PRES_Msk) == PMC_MCKR_PRES_CLK_3) {
		SystemCoreClock /= 3U;
	} else {
		SystemCoreClock >>= ((PMC->PMC_MCKR & PMC_MCKR_PRES_Msk) >> PMC_MCKR_PRES_Pos);
	}
}

/**
 * Initialize flash.
 */
void system_init_flash(uint32_t dw_clk)
{
	/* Set FWS for embedded Flash access according to operating frequency */
	if (dw_clk < CHIP_FREQ_FWS_0) {
		EFC->EEFC_FMR = EEFC_FMR_FWS(0);
	} else if (dw_clk < CHIP_FREQ_FWS_1) {
		EFC->EEFC_FMR = EEFC_FMR_FWS(1);
	} else if (dw_clk < CHIP_FREQ_FWS_2) {
		EFC->EEFC_FMR = EEFC_FMR_FWS(2);
	} else {
		EFC->EEFC_FMR = EEFC_FMR_FWS(3);
	}
}

/* @cond 0 */
/**INDENT-OFF**/
#ifdef __cplusplus
}
#endif
/**INDENT-ON**/
/* @endcond */