/*
 * This module implements speed enhancement logic for our serial
 * SIM interface back end.
 */

#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>

extern u_char atr_buf[];
extern unsigned baud_spenh, spenh_host_max;

void
spenh_logic()
{
	unsigned spenh_sim_max, use_spenh;
	u_char pts_req[4], pts_resp[4];
	int rc;

	if (!(atr_buf[1] & 0x10)) {
no_spenh:	printf("X SIM does not support speed enhancement\n");
		return;
	}
	switch (atr_buf[2]) {
	case 0x94:
		spenh_sim_max = 1;
		break;
	case 0x95:
		spenh_sim_max = 2;
		break;
	case 0x96:
		spenh_sim_max = 4;
		break;
	case 0x97:
		spenh_sim_max = 8;
		break;
	default:
		goto no_spenh;
	}
	use_spenh = spenh_sim_max;
	if (use_spenh > spenh_host_max)
		use_spenh = spenh_host_max;
	pts_req[0] = 0xFF;
	pts_req[1] = 0x10;
	switch (use_spenh) {
	case 1:
		pts_req[2] = 0x94;
		break;
	case 2:
		pts_req[2] = 0x95;
		break;
	case 4:
		pts_req[2] = 0x96;
		break;
	case 8:
		pts_req[2] = 0x97;
		break;
	}
	pts_req[3] = pts_req[0] ^ pts_req[1] ^ pts_req[2];
	rc = send_bytes_to_sim(pts_req, 4);
	if (rc < 0)
		exit(1);
	rc = collect_bytes_from_sim(pts_resp, 4);
	if (rc < 0)
		exit(1);
	if (bcmp(pts_req, pts_resp, 4)) {
		fprintf(stderr, "error: PTS response does not match request\n");
		exit(1);
	}
	set_serial_params(baud_spenh * use_spenh);
	printf("X Using F=512 D=%u speed enhancement\n", use_spenh * 8);
}