#include <stdint.h>

#define SPI_DEV             "/dev/spidev0"
#define SPI_SPEED           10000000

#define SPI_TUN_NAME        "tun0"

#define SPI_GPIO_DEV        "/dev/gpiochip3"
#define SPI_GPIO_CTS        28
#define SPI_GPIO_RTS        25

#define SPI_MTU             1500
#define SPI_SIZE_HDR        3
#define SPI_SIZE_BUF        (SPI_MTU + SPI_SIZE_HDR)
#define SPI_SIZE_RECEIVE    16  /* guestimate on number of bytes for transaction initiated by falling RTS */

#define SPI_SIZE_BUFQ       64
#define SPI_SIZE_MSGQ_IN    32
#define SPI_SIZE_MSGQ_OUT   32

#define SPI_MTYPE_TUN       1

#define SPI_OK              0
#define SPI_ERR             -1
#define SPI_ERR_OPEN        -10
#define SPI_ERR_MSG         -11

unsigned char *spi_alloc(void);
void spi_free(unsigned char *buffer);
int spi_xchg(unsigned char mtype, unsigned char *buffer, uint16_t len);
int spi_init(void);