/* 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/>.
 *
 */
/** library to control multiple software USARTs (code)
 *  @file usart_soft.c
 *  @author King Kévin <kingkevin@cuvoodoo.info>
 *  @date 2016
 *  @note peripherals used: GPIO @ref usart_soft_gpio, timer @ref usart_soft_timer
 */

/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdlib.h> // general utilities

/* STM32 (including CM3) libraries */
#include <libopencm3/stm32/rcc.h> // real-time control clock library
#include <libopencm3/stm32/gpio.h> // general purpose input output library
#include <libopencm3/stm32/timer.h> // timer library
#include <libopencm3/cm3/nvic.h> // interrupt handler

#include "usart_soft.h" // software USART library API
#include "global.h" // common methods

/** @defgroup usart_soft_gpio GPIO used for the software USART ports
 *  @note up to 4 pins supported, comment if unused
 *  @{
 */
#define USART_SOFT_RX_PORT0 A
#define USART_SOFT_RX_PIN0 0
#define USART_SOFT_RX_PORT1 A
#define USART_SOFT_RX_PIN1 0
#define USART_SOFT_RX_PORT2 A
#define USART_SOFT_RX_PIN2 0
#define USART_SOFT_RX_PORT3 A
#define USART_SOFT_RX_PIN3 0
#define USART_SOFT_TX_PORT0 A
#define USART_SOFT_TX_PIN0 0
#define USART_SOFT_TX_PORT1 A
#define USART_SOFT_TX_PIN1 0
#define USART_SOFT_TX_PORT2 A
#define USART_SOFT_TX_PIN2 0
#define USART_SOFT_TX_PORT3 A
#define USART_SOFT_TX_PIN3 0
/** @} */

/** @defgroup usart_soft_config USART configurations (2400-115200 bps)
 *  @note this implementation is designed for 8 bits, no parity, any stop configuration since this is the most common case
 *  @{
 */
#define USART_SOFT_RX_BAUDRATE0 0
#define USART_SOFT_RX_BAUDRATE1 0
#define USART_SOFT_RX_BAUDRATE2 0
#define USART_SOFT_RX_BAUDRATE3 0
#define USART_SOFT_TX_BAUDRATE0 0
#define USART_SOFT_TX_BAUDRATE1 0
#define USART_SOFT_TX_BAUDRATE2 0
#define USART_SOFT_TX_BAUDRATE3 0
/** @} */

/** @defgroup usart_soft_timer timer used to same USART signals
 *  @{
 */
#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0)) || (defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1)) || (defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2)) || (defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN0))
	#define USART_SOFT_RX_TIMER 3 /**< timer peripheral for receive signals */
#endif
#if (defined(USART_SOFT_TX_PORT0) && defined(USART_SOFT_TX_PIN0)) || (defined(USART_SOFT_TX_PORT1) && defined(USART_SOFT_TX_PIN1)) || (defined(USART_SOFT_TX_PORT2) && defined(USART_SOFT_TX_PIN2)) || (defined(USART_SOFT_TX_PORT3) && defined(USART_SOFT_TX_PIN0))
	#define USART_SOFT_TX_TIMER 4 /**< timer peripheral for transmit signals */
#endif
/** @} */

/** @defgroup usart_soft_state
 *  @{
 */
#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0))
volatile bool rx0_state = 0; /**< state of the GPIO */
volatile uint8_t rx0_bit = 0; /**< next bit to receive */
#endif
/** @} */

bool usart_soft_setup(void)
{
	// verify configuration
	#if (defined(USART_SOFT_RX_BAUDRATE0) && ((USART_SOFT_RX_BAUDRATE0<2400) || (USART_SOFT_RX_BAUDRATE0>115200)))
		return false;
	#endif
	#if (defined(USART_SOFT_RX_BAUDRATE1) && ((USART_SOFT_RX_BAUDRATE1<2400) || (USART_SOFT_RX_BAUDRATE1>115200)))
		return false;
	#endif
	#if (defined(USART_SOFT_RX_BAUDRATE2) && ((USART_SOFT_RX_BAUDRATE2<2400) || (USART_SOFT_RX_BAUDRATE2>115200)))
		return false;
	#endif
	#if (defined(USART_SOFT_RX_BAUDRATE3) && ((USART_SOFT_RX_BAUDRATE3<2400) || (USART_SOFT_RX_BAUDRATE3>115200)))
		return false;
	#endif
	#if (defined(USART_SOFT_TX_BAUDRATE0) && ((USART_SOFT_TX_BAUDRATE0<2400) || (USART_SOFT_TX_BAUDRATE0>115200)))
		return false;
	#endif
	#if (defined(USART_SOFT_TX_BAUDRATE1) && ((USART_SOFT_TX_BAUDRATE1<2400) || (USART_SOFT_TX_BAUDRATE1>115200)))
		return false;
	#endif
	#if (defined(USART_SOFT_TX_BAUDRATE2) && ((USART_SOFT_TX_BAUDRATE2<2400) || (USART_SOFT_TX_BAUDRATE2>115200)))
		return false;
	#endif
	#if (defined(USART_SOFT_TX_BAUDRATE3) && ((USART_SOFT_TX_BAUDRATE3<2400) || (USART_SOFT_TX_BAUDRATE3>115200)))
		return false;
	#endif

	// setup GPIOs
	#if defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0)
		rcc_periph_clock_enable(RCC_GPIO(USART_SOFT_RX_PORT0)); // enable clock for GPIO peripheral
		gpio_set_mode(GPIO(USART_SOFT_RX_PORT0), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO(USART_SOFT_RX_PIN0)); // setup GPIO pin USART receive
		gpio_set(GPIO(USART_SOFT_RX_PORT0), GPIO(USART_SOFT_RX_PIN0)); // pull up to avoid noise when not connected
		rx0_state = gpio_get(GPIO(USART_SOFT_RX_PORT0), GPIO(USART_SOFT_RX_PIN0)); // save state of GPIO
		rx0_bit = 0; // reset bits received
	#endif
	#if defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1)
		rcc_periph_clock_enable(RCC_GPIO(USART_SOFT_RX_PORT1)); // enable clock for GPIO peripheral
		gpio_set_mode(GPIO(USART_SOFT_RX_PORT1), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO(USART_SOFT_RX_PIN1)); // setup GPIO pin USART receive
		gpio_set(GPIO(USART_SOFT_RX_PORT1), GPIO(USART_SOFT_RX_PIN1)); // pull up to avoid noise when not connected
	#endif
	#if defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2)
		rcc_periph_clock_enable(RCC_GPIO(USART_SOFT_RX_PORT2)); // enable clock for GPIO peripheral
		gpio_set_mode(GPIO(USART_SOFT_RX_PORT2), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO(USART_SOFT_RX_PIN2)); // setup GPIO pin USART receive
		gpio_set(GPIO(USART_SOFT_RX_PORT2), GPIO(USART_SOFT_RX_PIN2)); // pull up to avoid noise when not connected
	#endif
	#if defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN3)
		rcc_periph_clock_enable(RCC_GPIO(USART_SOFT_RX_PORT3)); // enable clock for GPIO peripheral
		gpio_set_mode(GPIO(USART_SOFT_RX_PORT3), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO(USART_SOFT_RX_PIN3)); // setup GPIO pin USART receive
		gpio_set(GPIO(USART_SOFT_RX_PORT3), GPIO(USART_SOFT_RX_PIN3)); // pull up to avoid noise when not connected
	#endif
	#if defined(USART_SOFT_TX_PORT0) && defined(USART_SOFT_TX_PIN0)
		rcc_periph_clock_enable(RCC_GPIO(USART_SOFT_TX_PORT0)); // enable clock for GPIO peripheral
		gpio_set_mode(GPIO(USART_SOFT_TX_PORT0), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(USART_SOFT_TX_PIN0));
	#endif
	#if defined(USART_SOFT_TX_PORT1) && defined(USART_SOFT_TX_PIN1)
		rcc_periph_clock_enable(RCC_GPIO(USART_SOFT_TX_PORT1)); // enable clock for GPIO peripheral
		gpio_set_mode(GPIO(USART_SOFT_TX_PORT1), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(USART_SOFT_TX_PIN1));
	#endif
	#if defined(USART_SOFT_TX_PORT2) && defined(USART_SOFT_TX_PIN2)
		rcc_periph_clock_enable(RCC_GPIO(USART_SOFT_TX_PORT2)); // enable clock for GPIO peripheral
		gpio_set_mode(GPIO(USART_SOFT_TX_PORT2), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(USART_SOFT_TX_PIN2));
	#endif
	#if defined(USART_SOFT_TX_PORT3) && defined(USART_SOFT_TX_PIN3)
		rcc_periph_clock_enable(RCC_GPIO(USART_SOFT_TX_PORT3)); // enable clock for GPIO peripheral
		gpio_set_mode(GPIO(USART_SOFT_TX_PORT3), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(USART_SOFT_TX_PIN3));
	#endif

	// setup timer
	#if defined(USART_SOFT_RX_TIMER)
		rcc_periph_clock_enable(RCC_TIM(USART_SOFT_RX_TIMER)); // enable clock for timer peripheral
		timer_reset(TIM(USART_SOFT_RX_TIMER)); // reset timer state
		timer_set_mode(TIM(USART_SOFT_RX_TIMER), TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock, edge alignment (simple count), and count up
		timer_set_prescaler(TIM(USART_SOFT_RX_TIMER), 0); // prescaler to be able to sample 2400-115200 bps (72MHz/2^16=1099<2400bps)
		nvic_enable_irq(NVIC_TIM_IRQ(USART_SOFT_RX_TIMER)); // allow interrupt for timer
	#endif
	#if defined(USART_SOFT_TX_TIMER)
		rcc_periph_clock_enable(RCC_TIM(USART_SOFT_TX_TIMER)); // enable clock for timer peripheral
		timer_reset(TIM(USART_SOFT_TX_TIMER)); // reset timer state
		timer_set_mode(TIM(USART_SOFT_TX_TIMER), TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock, edge alignment (simple count), and count up
		timer_set_prescaler(TIM(USART_SOFT_TX_TIMER), 0); // prescaler to be able to sample 2400-115200 bps (72MHz/2^16=1099<2400bps)
		nvic_enable_irq(NVIC_TIM_IRQ(USART_SOFT_TX_TIMER)); // allow interrupt for timer
	#endif

	return true; // setup completed
}

#if defined(USART_SOFT_RX_TIMER)
void TIM_ISR(USART_SOFT_RX_TIMER)(void)
{
}
#endif

#if defined(USART_SOFT_TX_TIMER)
void TIM_ISR(USART_SOFT_TX_TIMER)(void)
{
}
#endif

/** central function handling receive signal activity */
static void rx_activity(void)
{

}

#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0) && USART_SOFT_RX_PIN0==0) || (defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1) && USART_SOFT_RX_PIN1==0) || (defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2) && USART_SOFT_RX_PIN2==0) || (defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN3) && USART_SOFT_RX_PIN3==0)
void exti0_isr(void)
{
	rx_activity();
}
#endif
#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0) && USART_SOFT_RX_PIN0==1) || (defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1) && USART_SOFT_RX_PIN1==1) || (defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2) && USART_SOFT_RX_PIN2==1) || (defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN3) && USART_SOFT_RX_PIN3==1)
void exti1_isr(void)
{
	rx_activity();
}
#endif
#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0) && USART_SOFT_RX_PIN0==2) || (defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1) && USART_SOFT_RX_PIN1==2) || (defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2) && USART_SOFT_RX_PIN2==2) || (defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN3) && USART_SOFT_RX_PIN3==2)
void exti2_isr(void)
{
	rx_activity();
}
#endif
#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0) && USART_SOFT_RX_PIN0==3) || (defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1) && USART_SOFT_RX_PIN1==3) || (defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2) && USART_SOFT_RX_PIN2==3) || (defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN3) && USART_SOFT_RX_PIN3==3)
void exti3_isr(void)
{
	rx_activity();
}
#endif
#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0) && USART_SOFT_RX_PIN0==4) || (defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1) && USART_SOFT_RX_PIN1==4) || (defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2) && USART_SOFT_RX_PIN2==4) || (defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN3) && USART_SOFT_RX_PIN3==4)
void exti4_isr(void)
{
	rx_activity();
}
#endif
#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0) && (USART_SOFT_RX_PIN0==5 || USART_SOFT_RX_PIN0==6 || USART_SOFT_RX_PIN0==7 || USART_SOFT_RX_PIN0==8 || USART_SOFT_RX_PIN0==9)) || (defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1) && (USART_SOFT_RX_PIN1==5 || USART_SOFT_RX_PIN1==6 || USART_SOFT_RX_PIN1==7 || USART_SOFT_RX_PIN1==8 || USART_SOFT_RX_PIN1==9)) || (defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2) && (USART_SOFT_RX_PIN2==5 || USART_SOFT_RX_PIN2==6 || USART_SOFT_RX_PIN2==7 || USART_SOFT_RX_PIN2==8 || USART_SOFT_RX_PIN2==9)) || (defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN3) && (USART_SOFT_RX_PIN3==5 || USART_SOFT_RX_PIN3==6 || USART_SOFT_RX_PIN3==7 || USART_SOFT_RX_PIN3==8 || USART_SOFT_RX_PIN3==9))
void exti9_5_isr(void)
{
	rx_activity();
}
#endif
#if (defined(USART_SOFT_RX_PORT0) && defined(USART_SOFT_RX_PIN0) && (USART_SOFT_RX_PIN0==10 || USART_SOFT_RX_PIN0==11 || USART_SOFT_RX_PIN0==12 || USART_SOFT_RX_PIN0==13 || USART_SOFT_RX_PIN0==14 || USART_SOFT_RX_PIN0==15)) || (defined(USART_SOFT_RX_PORT1) && defined(USART_SOFT_RX_PIN1) && (USART_SOFT_RX_PIN1==10 || USART_SOFT_RX_PIN1==11 || USART_SOFT_RX_PIN1==12 || USART_SOFT_RX_PIN1==13 || USART_SOFT_RX_PIN1==14 || USART_SOFT_RX_PIN1==15)) || (defined(USART_SOFT_RX_PORT2) && defined(USART_SOFT_RX_PIN2) && (USART_SOFT_RX_PIN2==10 || USART_SOFT_RX_PIN2==11 || USART_SOFT_RX_PIN2==12 || USART_SOFT_RX_PIN2==13 || USART_SOFT_RX_PIN2==14 || USART_SOFT_RX_PIN2==15)) || (defined(USART_SOFT_RX_PORT3) && defined(USART_SOFT_RX_PIN3) && (USART_SOFT_RX_PIN3==10 || USART_SOFT_RX_PIN3==11 || USART_SOFT_RX_PIN3==12 || USART_SOFT_RX_PIN3==13 || USART_SOFT_RX_PIN3==14 || USART_SOFT_RX_PIN3==15))
void exti15_10_isr(void)
{
	rx_activity();
}
#endif