/*
 * This file is part of the ws2815 project.
 * Copyright 2020 Edward V. Emelianov <edward.emelianoff@gmail.com>.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "hardware.h"
//#include "ws2815.h"

// DMA for data transfer
DMA_Channel_TypeDef * const WS2815DMAch = DMA1_Channel5;
DMA_TypeDef * const WS2815DMA = DMA1;

static inline void gpio_setup(){
    // Enable clocks to the GPIO subsystems (PB for ADC), turn on AFIO clocking to disable SWD/JTAG
    RCC->APB2ENR |= RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_AFIOEN;
    // turn off SWJ/JTAG
//    AFIO->MAPR = AFIO_MAPR_SWJ_CFG_DISABLE;
    AFIO->MAPR = AFIO_MAPR_SWJ_CFG_JTAGDISABLE; // for PA15
    // Set led as opendrain output
    GPIOC->CRH |= CRH(13, CNF_ODOUTPUT|MODE_SLOW);
    // USB pullup (PA15) - pushpull output; timer output: pushpull (PA8)
    GPIOA->CRH = CRH(15, CNF_PPOUTPUT|MODE_SLOW) | CRH(8, CNF_AFPP | MODE_FAST);
}

/*
WS2815 timigs:
T0H - 220..380ns,  T0L - 580..1600ns
T1H - 580..1600ns, T1L - 220..420ns
1 tick @72MHz = 13.(8)ns -> PSC=7 - 111.(1)ns @tick
TIM1->CCR1: T0H, T1L - 3 (333ns), T0L, T1H - 6 (667ns)
TIM1->ARR = (3+6-1) = 8
****
Tres > 280mks
CCR1 = 0, PSC = 3599
 */
// PWM @PA8 (T1Ch1 -> DMA1Ch2)
static inline void tim1_setup(){
    RCC->APB2ENR |= RCC_APB2ENR_TIM1EN; // enable TIM1 clocking
    TIM1->ARR = 8; // 9 ticks till UEV
    TIM1->PSC = 7; // 9MHz
    // PWM mode 1 (active->inactive)
    TIM1->CCMR1 = TIM_CCMR1_OC1M_2 | TIM_CCMR1_OC1M_1;
    // main output
    TIM1->BDTR = TIM_BDTR_MOE;
    // main PWM output
    TIM1->CCER = TIM_CCER_CC1E;
    TIM1->DIER = TIM_DIER_UDE; // enable DMA requests
    //NVIC_EnableIRQ(TIM1_CC_IRQn);
    RCC->AHBENR |= RCC_AHBENR_DMA1EN; // DMA1 clocking
    // memsize 8bit, periphsize 16bit, memincr, circular, mem2periph, half & full transfer interrupt
    WS2815DMAch->CCR = DMA_CCR_PSIZE_0 | DMA_CCR_MINC | DMA_CCR_CIRC | DMA_CCR_DIR | DMA_CCR_HTIE | DMA_CCR_TCIE;
    WS2815DMAch->CPAR = (uint32_t)&TIM1->CCR1;
    NVIC_EnableIRQ(DMA1_Channel5_IRQn);
}

void hw_setup(){
    gpio_setup();
    tim1_setup();
}

void iwdg_setup(){
    uint32_t tmout = 16000000;
    RCC->CSR |= RCC_CSR_LSION;
    while((RCC->CSR & RCC_CSR_LSIRDY) != RCC_CSR_LSIRDY){if(--tmout == 0) break;} /* (2) */
    IWDG->KR = IWDG_START;
    IWDG->KR = IWDG_WRITE_ACCESS;
    IWDG->PR = IWDG_PR_PR_1;
    IWDG->RLR = 1250;
    tmout = 16000000;
    while(IWDG->SR){if(--tmout == 0) break;}
    IWDG->KR = IWDG_REFRESH;
}