// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// File name    : spi_slave.h
// Description  : SPI1 Slave DMA LLI Ping-Pong transport layer for GMSP
//                national crypto co-processor firmware.
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#ifndef GMSP_SPI_SLAVE_H_
#define GMSP_SPI_SLAVE_H_

#include "type.h"
#include "../src/drv/inc/spi_drv.h"

/* Buffer size per Ping-Pong node (bytes) */
#define GMSP_BUF_SIZE     256

/* DMA channel used for SPI1 slave RX */
#define GMSP_SPI_RX_DMA_CH  DMACCH1

/* SPI1 data register address (base + 0x12 offset) */
#define GMSP_SPI1_DR_ADDR   (SPI1_BASE_ADDR + 0x12)

/*******************************************************************************
* Function Name  : gmsp_transport_init
* Description    : Initialize SPI1 as slave (CPOL=0, CPHA=0, 8-bit, MSB first)
*                  and start DMA LLI Ping-Pong dual-buffer receive.
* Input          : None
* Output         : None
* Return         : None
******************************************************************************/
void gmsp_transport_init(void);

/*******************************************************************************
* Function Name  : gmsp_recv_ready
* Description    : Check if a new DMA receive block has completed (non-blocking).
* Input          : None
* Output         : None
* Return         : 1 if data ready, 0 otherwise
******************************************************************************/
UINT8 gmsp_recv_ready(void);

/*******************************************************************************
* Function Name  : gmsp_get_rx_buf
* Description    : Get pointer to the most recently completed receive buffer
*                  and its length.
* Input          : out_len - pointer to receive the data length (may be NULL)
* Output         : *out_len = GMSP_BUF_SIZE
* Return         : Pointer to the completed buffer (buf_A or buf_B)
******************************************************************************/
UINT8 *gmsp_get_rx_buf(UINT16 *out_len);

/*******************************************************************************
* Function Name  : gmsp_send_response
* Description    : Send response data back to host via SPI1.
*                  Short responses (<=8 bytes) use SPI register write loop.
*                  Long responses use blocking DMA transfer.
* Input          : resp - pointer to response data
*                  len  - response length in bytes
* Output         : None
* Return         : None
******************************************************************************/
void gmsp_send_response(const UINT8 *resp, UINT16 len);

/*******************************************************************************
* Function Name  : gmsp_transport_rearm
* Description    : Reset DMA receive for next frame after processing.
*                  Stops TX DMA, restarts LLI Ping-Pong receive, clears flag.
* Input          : None
* Output         : None
* Return         : None
******************************************************************************/
void gmsp_transport_rearm(void);

#endif /* GMSP_SPI_SLAVE_H_ */