arm_debug.h

/*
 * Simple ARM debug interface for Arduino, using the SWD (Serial Wire Debug) port.
 * 
 * Copyright (c) 2013 Micah Elizabeth Scott
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#pragma once
#include <stdint.h>
#include <stdbool.h>


class ARMDebug
{
public:
	enum LogLevel {
		LOG_NONE = 0,
		LOG_ERROR,
		LOG_NORMAL,
		LOG_TRACE
	};

	/**
	 * Reinitialize the debug interface, and identify the connected chip.
	 * This resets the target chip, putting it in SWD mode and logging its
	 * identity.
	 *
	 * Returns true on success, logs and returns false on error.
	 */
	bool begin(unsigned clockPin, unsigned dataPin, LogLevel logLevel = LOG_NORMAL);

	/// Memory store
	bool memStore(uint32_t addr, uint32_t data);
	bool memStore(uint32_t addr, uint32_t *data, unsigned count);

	/// Memory load
	bool memLoad(uint32_t addr, uint32_t &data);
	bool memLoad(uint32_t addr, uint32_t *data, unsigned count);

	/// The same logging method used internally to ARMDebug
	void log(int level, const char *fmt, ...);

private:
	uint8_t clockPin, dataPin;
	LogLevel logLevel;

	// Cached versions of ARM debug registers
	struct {
		uint32_t select;
	} cache;

	// Low-level wire interface (LSB-first)
	void wireWrite(uint32_t data, unsigned nBits);
	uint32_t wireRead(unsigned nBits);
	void wireWriteTurnaround();
	void wireReadTurnaround();

	// Packet assembly tools
	uint8_t packHeader(unsigned addr, bool APnDP, bool RnW);
	bool evenParity(uint32_t word);

	// Debug port layer
	bool dpWrite(unsigned addr, bool APnDP, uint32_t data);
	bool dpRead(unsigned addr, bool APnDP, uint32_t &data);
	bool dpSelect(unsigned accessPort, unsigned addr);

	// Access port layer
	bool apWrite(unsigned accessPort, unsigned addr, uint32_t data);
	bool apRead(unsigned accessPort, unsigned addr, uint32_t &data);
};