portapack-mayhem/firmware/common/gpdma.cpp

/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 *
 * This file is part of PortaPack.
 *
 * 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, 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "gpdma.hpp"

#include <array>

namespace lpc43xx {
namespace gpdma {

namespace {

struct ChannelHandlers {
	TCHandler tc;
	ErrHandler err;

	constexpr ChannelHandlers(
	) : tc(nullptr),
		err(nullptr)
	{
	}
};

}

static std::array<ChannelHandlers, channels.size()> handlers_table { {} };

namespace channel {

void Channel::set_handlers(const TCHandler tc_handler, const ErrHandler err_handler) const {
	handlers_table[number].tc = tc_handler;
	handlers_table[number].err = err_handler;
}

void Channel::configure(
	const LLI& first_lli,
	const uint32_t config
) const {
	disable_force();
	clear_interrupts();

	LPC_GPDMA_Channel_Type* const channel = &LPC_GPDMA->CH[number];
	channel->SRCADDR = first_lli.srcaddr;
	channel->DESTADDR = first_lli.destaddr;
	channel->LLI = first_lli.lli;
	channel->CONTROL = first_lli.control;
	channel->CONFIG = config;
}

} /* namespace channel */

extern "C" {

LOCATE_IN_RAM
CH_IRQ_HANDLER(DMA_IRQHandler) {
	CH_IRQ_PROLOGUE();

	chSysLockFromIsr();

	const auto tc_stat = LPC_GPDMA->INTTCSTAT;
	/* TODO: Service the higher channel numbers first, they're higher priority
	 * right?!?
	 */
	for(size_t i=0; i<handlers_table.size(); i++) {
		if( (tc_stat >> i) & 1 ) {
			if( handlers_table[i].tc ) {
				handlers_table[i].tc();
			}
		}
	}
	LPC_GPDMA->INTTCCLR = tc_stat;

	/* Test for *any* error first, before looping, since errors should be
	 * exceptional and we should spend as little time on them in the common
	 * case.
	 */
	const auto err_stat = LPC_GPDMA->INTERRSTAT;
	if( err_stat ) {
		for(size_t i=0; i<handlers_table.size(); i++) {
			if( (err_stat >> i) & 1 ) {
				if( handlers_table[i].err ) {
					handlers_table[i].err();
				}
			}
		}
		LPC_GPDMA->INTERRCLR = err_stat;
	}

	chSysUnlockFromIsr();

	CH_IRQ_EPILOGUE();
}
}

} /* namespace gpdma */
} /* namespace lpc43xx */