/*  
 *      This is free software: you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License version 2, as 
 *      published by the Free Software Foundation.
 *
 *      this software is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU General Public License for more details.
 *
 *      You should have received a copy of the GNU General Public License
 *      along with this software.  If not, see <http://www.gnu.org/licenses/>.
 *
 *      Author: Daniele Lacamera
 *      
 *
 */  
#include <stdint.h>
#include "system.h"
#include <unicore-mx/stm32/gpio.h>
#include <unicore-mx/stm32/rcc.h>
#include <unicore-mx/cm3/nvic.h>

extern uint32_t cpu_freq;

static void flash_set_waitstates(int waitstates)
{
    FLASH_ACR |=  waitstates | FLASH_ACR_ENABLE_DATA_CACHE | FLASH_ACR_ENABLE_INST_CACHE;
}

void clock_pll_off(void)
{
    uint32_t reg32;
    /* Enable internal high-speed oscillator. */
    RCC_CR |= RCC_CR_HSION;
    DMB();
    while ((RCC_CR & RCC_CR_HSIRDY) == 0) {};

    /* Select HSI as SYSCLK source. */
    reg32 = RCC_CFGR;
    reg32 &= ~((1 << 1) | (1 << 0));
    RCC_CFGR = (reg32 | RCC_CFGR_SW_HSI);
    DMB();

    /* Turn off PLL */
    RCC_CR &= ~RCC_CR_PLLON;
    DMB();
}


void clock_pll_on(int powersave)
{
    uint32_t reg32;
    uint32_t plln, pllm, pllq, pllp, pllr, hpre, ppre1, ppre2, flash_waitstates;
    
    /* Enable Power controller */
    APB1_CLOCK_ER |= PWR_APB1_CLOCK_ER_VAL;

    /* Select clock parameters */
    cpu_freq = 100000000;
    pllm = 12;
    plln = 192;
    pllp = 2;
    pllq = 4;
    pllr = 0;
    hpre = RCC_PRESCALER_DIV_NONE;
    ppre1 = RCC_PRESCALER_DIV_2; 
    ppre2 = RCC_PRESCALER_DIV_NONE;
    flash_waitstates = 2;

    flash_set_waitstates(flash_waitstates);

    /* Enable internal high-speed oscillator. */
    RCC_CR |= RCC_CR_HSION;
    DMB();
    while ((RCC_CR & RCC_CR_HSIRDY) == 0) {};

    /* Select HSI as SYSCLK source. */
    reg32 = RCC_CFGR;
    reg32 &= ~((1 << 1) | (1 << 0));
    RCC_CFGR = (reg32 | RCC_CFGR_SW_HSI);
    DMB();

    /* Enable external high-speed oscillator 12MHz. */
    RCC_CR |= RCC_CR_HSEON;
    DMB();
    while ((RCC_CR & RCC_CR_HSERDY) == 0) {};

    /*
     * Set prescalers for AHB, ADC, ABP1, ABP2.
     */
    reg32 = RCC_CFGR;
    reg32 &= ~(0xF0);
    RCC_CFGR = (reg32 | (hpre << 4));
    DMB();
    reg32 = RCC_CFGR;
    reg32 &= ~(0x1C00);
    RCC_CFGR = (reg32 | (ppre1 << 10));
    DMB();
    reg32 = RCC_CFGR;
    reg32 &= ~(0x07 << 13);
    RCC_CFGR = (reg32 | (ppre2 << 13));
    DMB();

    /* Set PLL config */
    reg32 = RCC_PLLCFGR;
    reg32 &= ~(PLL_FULL_MASK);
    RCC_PLLCFGR = reg32 | RCC_PLLCFGR_PLLSRC | pllm | 
        (plln << 6) | (((pllp >> 1) - 1) << 16) | 
        (pllq << 24); 
    DMB();

    /* Enable power-save mode if selected */
    POW_CR |= (POW_CR_VOS);

    /* Enable PLL oscillator and wait for it to stabilize. */
    RCC_CR |= RCC_CR_PLLON;
    DMB();
    while ((RCC_CR & RCC_CR_PLLRDY) == 0) {};

    /* Select PLL as SYSCLK source. */
    reg32 = RCC_CFGR;
    reg32 &= ~((1 << 1) | (1 << 0));
    RCC_CFGR = (reg32 | RCC_CFGR_SW_PLL);
    DMB();

    /* Wait for PLL clock to be selected. */
    while ((RCC_CFGR & ((1 << 1) | (1 << 0))) != RCC_CFGR_SW_PLL) {};

    /* Disable internal high-speed oscillator. */
    RCC_CR &= ~RCC_CR_HSION;
}

void *__attribute__((weak)) memcpy(void *d, void *s, uint32_t len)
{
    uint32_t *src, *dst;
    uint8_t *sb, *db;
    src = s;
    dst = d;
    while(len > 3) {
        *(dst++) = *(src++);
        len -= 4;
    }
    sb = (uint8_t *)src;
    db = (uint8_t *)dst;
    while(len > 0) {
        *(db++) = *(sb++);
        len--;
    }
    return d; 
}