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// rp2040 serial
//
// Copyright (C) 2021 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU GPLv3 license.
#include <stdint.h> // uint32_t
#include "autoconf.h" // Include configuration header
#include "board/armcm_boot.h" // armcm_enable_irq
#include "board/irq.h" // irq_save
#include "board/serial_irq.h" // serial_rx_data
#include "hardware/structs/resets.h" // RESETS_RESET_UART0/1_BITS
#include "hardware/structs/uart.h" // uart0_hw, uart1_hw
#include "internal.h" // UART0_IRQn, UART1_IRQn
#include "sched.h" // DECL_INIT
// Dynamically select UART and IRQ based on configuration
#if CONFIG_RP2040_SERIAL_UART0_PINS_0_1
#define GPIO_Rx 1
#define GPIO_Tx 0
#define UARTx uart0_hw
#define UARTx_IRQn UART0_IRQ_IRQn
#elif CONFIG_RP2040_SERIAL_UART0_PINS_12_13
#define GPIO_Rx 13
#define GPIO_Tx 12
#define UARTx uart0_hw
#define UARTx_IRQn UART0_IRQ_IRQn
#elif CONFIG_RP2040_SERIAL_UART0_PINS_16_17
#define GPIO_Rx 17
#define GPIO_Tx 16
#define UARTx uart0_hw
#define UARTx_IRQn UART0_IRQ_IRQn
#elif CONFIG_RP2040_SERIAL_UART0_PINS_28_29
#define GPIO_Rx 29
#define GPIO_Tx 28
#define UARTx uart1_hw
#define UARTx_IRQn UART1_IRQ_IRQn
#define UARTx uart0_hw
#define UARTx_IRQn UART0_IRQ_IRQn
#elif CONFIG_RP2040_SERIAL_UART1_PINS_4_5
#define GPIO_Rx 5
#define GPIO_Tx 4
#define UARTx uart1_hw
#define UARTx_IRQn UART1_IRQ_IRQn
#elif CONFIG_RP2040_SERIAL_UART1_PINS_8_9
#define GPIO_Rx 9
#define GPIO_Tx 8
#define UARTx uart1_hw
#define UARTx_IRQn UART1_IRQ_IRQn
#elif CONFIG_RP2040_SERIAL_UART1_PINS_20_21
#define GPIO_Rx 20
#define GPIO_Tx 21
#define UARTx uart1_hw
#define UARTx_IRQn UART1_IRQ_IRQn
#elif CONFIG_RP2040_SERIAL_UART1_PINS_24_25
#define GPIO_Rx 24
#define GPIO_Tx 25
#define UARTx uart1_hw
#define UARTx_IRQn UART1_IRQ_IRQn
#endif
// Write tx bytes to the serial port
static void
kick_tx(void)
{
for (;;) {
if (UARTx->fr & UART_UARTFR_TXFF_BITS) {
// Output fifo full - enable tx irq
UARTx->imsc = (UART_UARTIMSC_RXIM_BITS | UART_UARTIMSC_RTIM_BITS
| UART_UARTIMSC_TXIM_BITS);
break;
}
uint8_t data;
int ret = serial_get_tx_byte(&data);
if (ret) {
// No more data to send - disable tx irq
UARTx->imsc = UART_UARTIMSC_RXIM_BITS | UART_UARTIMSC_RTIM_BITS;
break;
}
UARTx->dr = data;
}
}
void
UARTx_IRQHandler(void)
{
uint32_t mis = UARTx->mis;
if (mis & (UART_UARTMIS_RXMIS_BITS | UART_UARTMIS_RTMIS_BITS)) {
do {
serial_rx_byte(UARTx->dr);
} while (!(UARTx->fr & UART_UARTFR_RXFE_BITS));
} else if (mis & UART_UARTMIS_TXMIS_BITS) {
kick_tx();
}
}
void
serial_enable_tx_irq(void)
{
if (!(UARTx->fr & UART_UARTFR_TXFF_BITS)) {
irqstatus_t flag = irq_save();
kick_tx();
irq_restore(flag);
}
}
void
serial_init(void)
{
uint32_t pclk= 0x00;
if (UARTx == uart0_hw){
enable_pclock(RESETS_RESET_UART0_BITS);
pclk= get_pclock_frequency(RESETS_RESET_UART0_BITS);
} else {
enable_pclock(RESETS_RESET_UART1_BITS);
pclk = get_pclock_frequency(RESETS_RESET_UART1_BITS);
}
// Setup baud
uint32_t div = DIV_ROUND_CLOSEST(pclk * 4, CONFIG_SERIAL_BAUD);
UARTx->ibrd = div >> 6;
UARTx->fbrd = div & 0x3f;
// Enable fifo, set 8N1
UARTx->lcr_h = UART_UARTLCR_H_FEN_BITS | UART_UARTLCR_H_WLEN_BITS;
UARTx->ifls = 0;
UARTx->cr = (UART_UARTCR_RXE_BITS | UART_UARTCR_TXE_BITS
| UART_UARTCR_UARTEN_BITS);
// Setup pins
gpio_peripheral(GPIO_Rx, 2, 1);
gpio_peripheral(GPIO_Tx, 2, 0);
// Enable receive irq
armcm_enable_irq(UARTx_IRQHandler, UARTx_IRQn, 0);
UARTx->imsc = UART_UARTIMSC_RXIM_BITS | UART_UARTIMSC_RTIM_BITS;
}
DECL_INIT(serial_init);
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