spihw.c

/*
 * Copyright (C) 2015,2016 Urja Rannikko <urjaman@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include "main.h"
#include "uart.h"
#include "fast-usbserial.h"
#include "spihw.h"

#if (defined __AVR_ATmega16U4__) || (defined __AVR_ATmega32U4__)
void spi_hw_chk(void) {
	/* Set PB4/D8=~HOLD and PB5/D9=~WP to 1.. */
	PORTB |= _BV(4) | _BV(5);
	DDRB |= _BV(4) | _BV(5);
	/* TODO: Do the actual check... */
	/* PD5 to 0 drives the green LED. */
	PORTD &= ~_BV(5);
	DDRD |= _BV(5);
}
#else
void spi_hw_chk(void) { }
#endif

void flash_set_safe(void) {
	spi_uninit();
	DDR_SPI &= ~_BV(MOSI);
	DDR_SPI &= ~_BV(SCK);
	DDR_SPI &= ~_BV(SS);
#ifdef SPI_CS
	DDR_SPI &= ~_BV(SPI_CS);
#endif
}

void flash_select_protocol(uint8_t allowed_protocols) {
	(void)allowed_protocols;
	SPI_PORT |= _BV(SS);
	SPI_PORT &= ~_BV(MOSI);
	SPI_PORT &= ~_BV(SCK);
	DDR_SPI = (1<<MOSI)|(1<<SCK)|(1<<SS);
#ifdef SPI_CS
	/* Some other pin is used as the actual CS output in push-pull fashion (OC just works :P) */
	SPI_PORT |= _BV(SPI_CS);
	DDR_SPI |= _BV(SPI_CS);
#endif
	spi_hw_chk();
	spi_init();
}

static void spi_spiop_start(uint32_t sbytes) {
	spi_select();
	if (sbytes) do {
		uint8_t rxc;
		do {
			rxc = uart_isdata();
		} while (!rxc);
		if (rxc > sbytes) rxc = sbytes;
		uint8_t dc = rxc;
		do {
			spi_txrx(Endpoint_Read_Byte());
		} while(--rxc);
		uart_recv_ctrl_cnt(dc);
		sbytes -= dc;
	} while (sbytes);
}

static void spi_spiop_end(uint32_t rbytes) {
	if (rbytes) do {
		SPDR = 0xFF;
		uint8_t txc = uart_send_getfree();
		if (txc > rbytes) txc = rbytes;
		uint8_t dc = txc;
		txc--;
		if (txc) do {
			loop_until_bit_is_set(SPSR,SPIF);
			Endpoint_Write_Byte(SPDR);
			SPDR = 0xFF;
		} while (--txc);
		rbytes -= dc;
		loop_until_bit_is_set(SPSR,SPIF);
		Endpoint_Write_Byte(SPDR);
		uart_send_ctrl_cnt(dc);
	} while (rbytes);
	spi_deselect();
}

void flash_spiop(uint32_t sbytes, uint32_t rbytes) {
	spi_spiop_start(sbytes);
	SEND(S_ACK);
	spi_spiop_end(rbytes);
}