// Copyright (c) 2013-2015 by Felix Rusu, LowPowerLab.com
// SPI Flash memory library for arduino/moteino.
// This works with 256byte/page SPI flash memory
// For instance a 4MBit (512Kbyte) flash chip will have 2048 pages: 256*2048 = 524288 bytes (512Kbytes)
// Minimal modifications should allow chips that have different page size but modifications
// DEPENDS ON: Arduino SPI library
// > Updated Jan. 5, 2015, TomWS1, modified writeBytes to allow blocks > 256 bytes and handle page misalignment.
// > Updated Feb. 26, 2015 TomWS1, added support for SPI Transactions (Arduino 1.5.8 and above)
// > Selective merge by Felix after testing in IDE 1.0.6, 1.6.4
// > Updated May 19, 2016 D-H-R, added support for SST25/Microchip Flash which does not support Page programming with OPCode 0x02,
// >                             use define MY_SPIFLASH_SST25TYPE for SST25 Type Flash Memory
// > Updated Sep 07, 2018 tekka, sync with https://github.com/LowPowerLab/SPIFlash
// **********************************************************************************
// License
// **********************************************************************************
// 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 3 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.
//
// You should have received a copy of the GNU General
// Public License along with this program.
// If not, see <http://www.gnu.org/licenses/>.
//
// Licence can be viewed at
// http://www.gnu.org/licenses/gpl-3.0.txt
//
// Please maintain this license information along with authorship
// and copyright notices in any redistribution of this code

#include "SPIFlash.h"

uint8_t SPIFlash::UNIQUEID[8];

/// IMPORTANT: NAND FLASH memory requires erase before write, because
///            it can only transition from 1s to 0s and only the erase command can reset all 0s to 1s
/// See http://en.wikipedia.org/wiki/Flash_memory
/// The smallest range that can be erased is a sector (4K, 32K, 64K); there is also a chip erase command

/// Constructor. JedecID is optional but recommended, since this will ensure that the device is present and has a valid response
/// get this from the datasheet of your flash chip
/// Example for Atmel-Adesto 4Mbit AT25DF041A: 0x1F44 (page 27: http://www.adestotech.com/sites/default/files/datasheets/doc3668.pdf)
/// Example for Winbond 4Mbit W25X40CL: 0xEF30 (page 14: http://www.winbond.com/NR/rdonlyres/6E25084C-0BFE-4B25-903D-AE10221A0929/0/W25X40CL.pdf)
// Suppress uninitialized member variable in constructor because some memory can be saved with
// on-demand initialization of these members
// cppcheck-suppress uninitMemberVar
SPIFlash::SPIFlash(uint8_t slaveSelectPin, uint16_t jedecID)
{
	_slaveSelectPin = slaveSelectPin;
	_jedecID = jedecID;
}

/// Select the flash chip
void SPIFlash::select()
{
	//save current SPI settings
#ifndef SPI_HAS_TRANSACTION
	noInterrupts();
#endif
#if defined(SPCR) && defined(SPSR)
	_SPCR = SPCR;
	_SPSR = SPSR;
#endif

#ifdef SPI_HAS_TRANSACTION
	SPI.beginTransaction(_settings);
#else
	// set FLASH SPI settings
	SPI.setDataMode(SPI_MODE0);
	SPI.setBitOrder(MSBFIRST);
	SPI.setClockDivider(
	    SPI_CLOCK_DIV4); //decided to slow down from DIV2 after SPI stalling in some instances, especially visible on mega1284p when RFM69 and FLASH chip both present
#endif
	hwDigitalWrite(_slaveSelectPin, LOW);
}

/// UNselect the flash chip
void SPIFlash::unselect()
{
	hwDigitalWrite(_slaveSelectPin, HIGH);
	//restore SPI settings to what they were before talking to the FLASH chip
#ifdef SPI_HAS_TRANSACTION
	SPI.endTransaction();
#else
	interrupts();
#endif
#if defined(SPCR) && defined(SPSR)
	SPCR = _SPCR;
	SPSR = _SPSR;
#endif
}

/// setup SPI, read device ID etc...
bool SPIFlash::initialize()
{
#if defined(SPCR) && defined(SPSR)
	_SPCR = SPCR;
	_SPSR = SPSR;
#endif
	hwPinMode(_slaveSelectPin, OUTPUT);
	SPI.begin(); // see https://github.com/LowPowerLab/SPIFlash/issues/20
#ifdef SPI_HAS_TRANSACTION
	_settings = SPISettings(4000000, MSBFIRST, SPI_MODE0);
#endif

	unselect();
	wakeup();

	if (_jedecID == 0 || readDeviceId() == _jedecID) {
		command(SPIFLASH_STATUSWRITE, true); // Write Status Register
		SPI.transfer(0);                     // Global Unprotect
		unselect();
		return true;
	}
	return false;
}

/// Get the manufacturer and device ID bytes (as a short word)
uint16_t SPIFlash::readDeviceId()
{
#if defined(__AVR_ATmega32U4__) // Arduino Leonardo, MoteinoLeo
	command(SPIFLASH_IDREAD); // Read JEDEC ID
#else
	select();
	SPI.transfer(SPIFLASH_IDREAD);
#endif
	uint16_t jedecid = SPI.transfer(0) << 8;
	jedecid |= SPI.transfer(0);
	unselect();
	return jedecid;
}

/// Get the 64 bit unique identifier, stores it in UNIQUEID[8]. Only needs to be called once, ie after initialize
/// Returns the byte pointer to the UNIQUEID byte array
/// Read UNIQUEID like this:
/// flash.readUniqueId(); for (uint8_t i=0;i<8;i++) { Serial.print(flash.UNIQUEID[i], HEX); Serial.print(' '); }
/// or like this:
/// flash.readUniqueId(); uint8_t* MAC = flash.readUniqueId(); for (uint8_t i=0;i<8;i++) { Serial.print(MAC[i], HEX); Serial.print(' '); }
uint8_t* SPIFlash::readUniqueId()
{
	command(SPIFLASH_MACREAD);
	SPI.transfer(0);
	SPI.transfer(0);
	SPI.transfer(0);
	SPI.transfer(0);
	for (uint8_t i=0; i<8; i++) {
		UNIQUEID[i] = SPI.transfer(0);
	}
	unselect();
	return UNIQUEID;
}

/// read 1 byte from flash memory
uint8_t SPIFlash::readByte(uint32_t addr)
{
	command(SPIFLASH_ARRAYREADLOWFREQ);
	SPI.transfer(addr >> 16);
	SPI.transfer(addr >> 8);
	SPI.transfer(addr);
	uint8_t result = SPI.transfer(0);
	unselect();
	return result;
}

/// read unlimited # of bytes
void SPIFlash::readBytes(uint32_t addr, void* buf, uint16_t len)
{
	command(SPIFLASH_ARRAYREAD);
	SPI.transfer(addr >> 16);
	SPI.transfer(addr >> 8);
	SPI.transfer(addr);
	SPI.transfer(0); //"dont care"
	for (uint16_t i = 0; i < len; ++i) {
		((uint8_t*) buf)[i] = SPI.transfer(0);
	}
	unselect();
}

/// Send a command to the flash chip, pass TRUE for isWrite when its a write command
void SPIFlash::command(uint8_t cmd, bool isWrite)
{
#if defined(__AVR_ATmega32U4__) // Arduino Leonardo, MoteinoLeo
	DDRB |= B00000001;            // Make sure the SS pin (PB0 - used by RFM12B on MoteinoLeo R1) is set as output HIGH!
	PORTB |= B00000001;
#endif
	if (isWrite) {
		command(SPIFLASH_WRITEENABLE); // Write Enable
		unselect();
	}
	//wait for any write/erase to complete
	//  a time limit cannot really be added here without it being a very large safe limit
	//  that is because some chips can take several seconds to carry out a chip erase or other similar multi block or entire-chip operations
	//  a recommended alternative to such situations where chip can be or not be present is to add a 10k or similar weak pulldown on the
	//  open drain MISO input which can read noise/static and hence return a non 0 status byte, causing the while() to hang when a flash chip is not present
	while(busy());
	select();
	SPI.transfer(cmd);
}

/// check if the chip is busy erasing/writing
bool SPIFlash::busy()
{
	/*
	select();
	SPI.transfer(SPIFLASH_STATUSREAD);
	uint8_t status = SPI.transfer(0);
	unselect();
	return status & 1;
	*/
	return readStatus() & 1;
}

/// return the STATUS register
uint8_t SPIFlash::readStatus()
{
	select();
	SPI.transfer(SPIFLASH_STATUSREAD);
	uint8_t status = SPI.transfer(0);
	unselect();
	return status;
}


/// Write 1 byte to flash memory
/// WARNING: you can only write to previously erased memory locations (see datasheet)
///          use the block erase commands to first clear memory (write 0xFFs)
void SPIFlash::writeByte(uint32_t addr, uint8_t byt)
{
	command(SPIFLASH_BYTEPAGEPROGRAM, true);  // Byte/Page Program
	SPI.transfer(addr >> 16);
	SPI.transfer(addr >> 8);
	SPI.transfer(addr);
	SPI.transfer(byt);
	unselect();
}

/// write multiple bytes to flash memory (up to 64K)
/// WARNING: you can only write to previously erased memory locations (see datasheet)
///          use the block erase commands to first clear memory (write 0xFFs)
/// This version handles both page alignment and data blocks larger than 256 bytes.
/// See documentation of #MY_SPIFLASH_SST25TYPE define for more information
void SPIFlash::writeBytes(uint32_t addr, const void* buf, uint16_t len)
{
#ifdef MY_SPIFLASH_SST25TYPE
	//SST25 Type of Flash does not support Page Programming but AAI Word Programming
	uint16_t i=0;
	uint8_t oddAdr=0;

	command(SPIFLASH_AAIWORDPROGRAM, true);  // Byte/Page Program
	SPI.transfer(addr >> 16);
	SPI.transfer(addr >> 8);
	SPI.transfer(addr);

	if (addr%2) {
		//start address is not even, i.e. first byte of word must be 0xff
		SPI.transfer(0xff);
		SPI.transfer(((uint8_t*) buf)[0]);
		unselect();
		oddAdr=1; //following addresses must all be shifted one off
		len--;
		if (len > 0) {
			command(SPIFLASH_AAIWORDPROGRAM); //If for loop will run issue Wordprogram command
		}
	}

	for (i=0; i<(len/2); i++) {
		//AAI command must be set before every new word
		if (i>0) {
			command(SPIFLASH_AAIWORDPROGRAM); //Wordprogram command for first write has been issued before
		}
		SPI.transfer(((uint8_t*) buf)[i*2+oddAdr]);
		SPI.transfer(((uint8_t*) buf)[i*2+1+oddAdr]);
		unselect();
	}

	if (len-i*2 == 1) {
		//There is one byte (i.e. half word) left. This happens if len was odd or (len was even and addr odd)
		if (i>0) {
			command(SPIFLASH_AAIWORDPROGRAM); //if for loop had not run wordprogram command from before is still valid
		}
		SPI.transfer(((uint8_t*) buf)[i*2+oddAdr]);
		SPI.transfer(0xff);
		unselect();
	}

	command(SPIFLASH_WRITEDISABLE); //end AAI programming
	unselect();
#else
	uint16_t maxBytes = 256-(addr%256);  // force the first set of bytes to stay within the first page
	uint16_t offset = 0;
	while (len>0) {
		uint16_t n = (len<=maxBytes) ? len : maxBytes;
		command(SPIFLASH_BYTEPAGEPROGRAM, true);  // Byte/Page Program
		SPI.transfer(addr >> 16);
		SPI.transfer(addr >> 8);
		SPI.transfer(addr);

		for (uint16_t i = 0; i < n; i++) {
			SPI.transfer(((uint8_t*) buf)[offset + i]);
		}
		unselect();

		addr+=n;  // adjust the addresses and remaining bytes by what we've just transferred.
		offset +=n;
		len -= n;
		maxBytes = 256;   // now we can do up to 256 bytes per loop
	}
#endif
}

/// erase entire flash memory array
/// may take several seconds depending on size, but is non blocking
/// so you may wait for this to complete using busy() or continue doing
/// other things and later check if the chip is done with busy()
/// note that any command will first wait for chip to become available using busy()
/// so no need to do that twice
void SPIFlash::chipErase()
{
	command(SPIFLASH_CHIPERASE, true);
	unselect();
}

/// erase a 4Kbyte block
void SPIFlash::blockErase4K(uint32_t addr)
{
	command(SPIFLASH_BLOCKERASE_4K, true); // Block Erase
	SPI.transfer(addr >> 16);
	SPI.transfer(addr >> 8);
	SPI.transfer(addr);
	unselect();
}

/// erase a 32Kbyte block
void SPIFlash::blockErase32K(uint32_t addr)
{
	command(SPIFLASH_BLOCKERASE_32K, true); // Block Erase
	SPI.transfer(addr >> 16);
	SPI.transfer(addr >> 8);
	SPI.transfer(addr);
	unselect();
}
/// erase a 64Kbyte block
void SPIFlash::blockErase64K(uint32_t addr)
{
	command(SPIFLASH_BLOCKERASE_64K, true); // Block Erase
	SPI.transfer(addr >> 16);
	SPI.transfer(addr >> 8);
	SPI.transfer(addr);
	unselect();
}

void SPIFlash::sleep()
{
	command(SPIFLASH_SLEEP);
	unselect();
}

void SPIFlash::wakeup()
{
	command(SPIFLASH_WAKE);
	unselect();
}

/// cleanup
void SPIFlash::end()
{
	SPI.end();
}