/**
 * @file bsp_usart.h
 * @brief USART1 support: printf retarget (polling TX), DMA TX, RX DMA
 *        circular ring + IDLE interrupt. TX=PB6, RX=PB7, 460800 8N1.
 */
#ifndef __BSP_USART_H__
#define __BSP_USART_H__

#ifdef __cplusplus
extern "C" {
#endif

#include "n32wb03x.h"

#define BSP_USARTx              USART1
#define BSP_USART_CLK           RCC_APB2_PERIPH_USART1
#define BSP_USART_GPIO          GPIOB
#define BSP_USART_GPIO_CLK      RCC_APB2_PERIPH_GPIOB
#define BSP_USART_TX_PIN        GPIO_PIN_6
#define BSP_USART_RX_PIN        GPIO_PIN_7
#define BSP_USART_TX_GPIO_AF    GPIO_AF4_USART1
#define BSP_USART_RX_GPIO_AF    GPIO_AF4_USART1
#define BSP_USART_BAUDRATE      460800

/* USART1 TX DMA channel (remap required on this chip) */
#define BSP_USART_TX_DMA_CH     DMA_CH1
#define BSP_USART_TX_DMA_TC     DMA_FLAG_TC1
#define BSP_USART_TX_DMA_REMAP  DMA_REMAP_USART1_TX
/* USART1 RX DMA channel: circular mode into a 2KB ring, drained by
 * bsp_usart_read_byte(). DMA keeps sampling while interrupts are off
 * (flash erase windows during UART OTA streaming). */
#define BSP_USART_RX_DMA_CH     DMA_CH2
#define BSP_USART_RX_DMA_REMAP  DMA_REMAP_USART1_RX
#define BSP_USART_DAT_ADDR      (USART1_BASE + 0x04)

/* Pass to bsp_usart_read_byte() to block without timeout */
#define BSP_USART_WAIT_FOREVER  0xFFFFFFFFu

void bsp_usart_init(void);

/* Re-apply the baud rate at runtime (keeps RX interrupt/DMA setup).
 * Used by the "uartrst" CLI command after a baud parameter change. */
void bsp_usart_set_baud(uint32_t baud);

/* TX: send a buffer through DMA (polled completion) */
void bsp_usart_write_dma(const uint8_t* data, uint16_t len);

/* RX: fetch one received byte. Source order: the inject queue (BLE
 * downlink feeding the CLI) first, then the DMA RX ring. Returns 1 on
 * success, 0 on timeout. */
int bsp_usart_read_byte(uint8_t* ch, uint32_t timeout_ms);

/* RX: inject bytes from task context (BLE downlink feeds the CLI through
 * this). Bytes are dropped when the inject queue is full. */
void bsp_usart_rx_inject(const uint8_t* data, uint16_t len);

/* TX mutex so that DMA bursts and polling printf lines do not interleave.
 * No-ops while the scheduler is not running. */
void bsp_usart_tx_lock(void);
void bsp_usart_tx_unlock(void);

/* Called from USART1_IRQHandler (see n32wb03x_it.c) */
void bsp_usart_rx_isr_handler(void);

#ifdef __cplusplus
}
#endif

#endif /* __BSP_USART_H__ */