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Ide 1.5.x AVR and sam (ARM) SPI atomicity fixes #2376

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1c8355e
AVR SPI atomicity fixes
xxxajk Oct 18, 2014
27107d1
sam (ARM) SPI atomicity fixes
xxxajk Oct 18, 2014
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259 changes: 161 additions & 98 deletions hardware/arduino/avr/libraries/SPI/SPI.cpp
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Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
/*
* Copyright (c) 2010 by Cristian Maglie <[email protected]>
* Copyright (c) 2014 by Paul Stoffregen <[email protected]> (Transaction API)
* Copyright (c) 2014 by Matthijs Kooijman <[email protected]> (SPISettings AVR)
* Copyright (c) 2014 by Andrew J. Kroll <[email protected]> (atomicity fixes)
* SPI Master library for arduino.
*
* This file is free software; you can redistribute it and/or modify
Expand All @@ -10,123 +12,184 @@
*/

#include "SPI.h"
#include "pins_arduino.h"

SPIClass SPI;

uint8_t SPIClass::interruptMode = 0;
SPIflags_t SPIClass::modeFlags = {false, false, 0};
uint8_t SPIClass::interruptMask = 0;
uint8_t SPIClass::interruptSave = 0;
#ifdef SPI_TRANSACTION_MISMATCH_LED
uint8_t SPIClass::inTransactionFlag = 0;
#endif

void SPIClass::begin()
{
// Set SS to high so a connected chip will be "deselected" by default
digitalWrite(SS, HIGH);
void SPIClass::begin() {
uint8_t sreg = SREG;
noInterrupts(); // Protect from a scheduler and prevent transactionBegin
if(!modeFlags.initialized) {
modeFlags.initialized = true;
// Set SS to high so a connected chip will be "deselected" by default
digitalWrite(SS, HIGH);

// When the SS pin is set as OUTPUT, it can be used as
// a general purpose output port (it doesn't influence
// SPI operations).
pinMode(SS, OUTPUT);
// When the SS pin is set as OUTPUT, it can be used as
// a general purpose output port (it doesn't influence
// SPI operations).
pinMode(SS, OUTPUT);

// Warning: if the SS pin ever becomes a LOW INPUT then SPI
// automatically switches to Slave, so the data direction of
// the SS pin MUST be kept as OUTPUT.
SPCR |= _BV(MSTR);
SPCR |= _BV(SPE);
// Warning: if the SS pin ever becomes a LOW INPUT then SPI
// automatically switches to Slave, so the data direction of
// the SS pin MUST be kept as OUTPUT.
SPCR |= _BV(MSTR);
SPCR |= _BV(SPE);

// Set direction register for SCK and MOSI pin.
// MISO pin automatically overrides to INPUT.
// By doing this AFTER enabling SPI, we avoid accidentally
// clocking in a single bit since the lines go directly
// from "input" to SPI control.
// http://code.google.com/p/arduino/issues/detail?id=888
pinMode(SCK, OUTPUT);
pinMode(MOSI, OUTPUT);
// Set direction register for SCK and MOSI pin.
// MISO pin automatically overrides to INPUT.
// By doing this AFTER enabling SPI, we avoid accidentally
// clocking in a single bit since the lines go directly
// from "input" to SPI control.
// http://code.google.com/p/arduino/issues/detail?id=888
pinMode(SCK, OUTPUT);
pinMode(MOSI, OUTPUT);
}
SREG = sreg;
}

void SPIClass::end() {
SPCR &= ~_BV(SPE);
uint8_t sreg = SREG;
noInterrupts(); // Protect from a scheduler and prevent transactionBegin
if(!modeFlags.interruptMode && modeFlags.initialized) {
SPCR &= ~_BV(SPE);
modeFlags.initialized = false;
#ifdef SPI_TRANSACTION_MISMATCH_LED
modeFlags.inTransactionFlag = false;
#endif
}
SREG = sreg;
}

// mapping of interrupt numbers to bits within SPI_AVR_EIMSK
#if defined(__AVR_ATmega32U4__)
#define SPI_INT0_MASK (1<<INT0)
#define SPI_INT1_MASK (1<<INT1)
#define SPI_INT2_MASK (1<<INT2)
#define SPI_INT3_MASK (1<<INT3)
#define SPI_INT4_MASK (1<<INT6)
#define SPI_INT0_MASK (1<<INT0)
#define SPI_INT1_MASK (1<<INT1)
#define SPI_INT2_MASK (1<<INT2)
#define SPI_INT3_MASK (1<<INT3)
#define SPI_INT4_MASK (1<<INT6)
#elif defined(__AVR_AT90USB646__) || defined(__AVR_AT90USB1286__)
#define SPI_INT0_MASK (1<<INT0)
#define SPI_INT1_MASK (1<<INT1)
#define SPI_INT2_MASK (1<<INT2)
#define SPI_INT3_MASK (1<<INT3)
#define SPI_INT4_MASK (1<<INT4)
#define SPI_INT5_MASK (1<<INT5)
#define SPI_INT6_MASK (1<<INT6)
#define SPI_INT7_MASK (1<<INT7)
#define SPI_INT0_MASK (1<<INT0)
#define SPI_INT1_MASK (1<<INT1)
#define SPI_INT2_MASK (1<<INT2)
#define SPI_INT3_MASK (1<<INT3)
#define SPI_INT4_MASK (1<<INT4)
#define SPI_INT5_MASK (1<<INT5)
#define SPI_INT6_MASK (1<<INT6)
#define SPI_INT7_MASK (1<<INT7)
#elif defined(EICRA) && defined(EICRB) && defined(EIMSK)
#define SPI_INT0_MASK (1<<INT4)
#define SPI_INT1_MASK (1<<INT5)
#define SPI_INT2_MASK (1<<INT0)
#define SPI_INT3_MASK (1<<INT1)
#define SPI_INT4_MASK (1<<INT2)
#define SPI_INT5_MASK (1<<INT3)
#define SPI_INT6_MASK (1<<INT6)
#define SPI_INT7_MASK (1<<INT7)
#define SPI_INT0_MASK (1<<INT4)
#define SPI_INT1_MASK (1<<INT5)
#define SPI_INT2_MASK (1<<INT0)
#define SPI_INT3_MASK (1<<INT1)
#define SPI_INT4_MASK (1<<INT2)
#define SPI_INT5_MASK (1<<INT3)
#define SPI_INT6_MASK (1<<INT6)
#define SPI_INT7_MASK (1<<INT7)
#else
#ifdef INT0
#define SPI_INT0_MASK (1<<INT0)
#endif
#ifdef INT1
#define SPI_INT1_MASK (1<<INT1)
#endif
#ifdef INT2
#define SPI_INT2_MASK (1<<INT2)
#endif
#ifdef INT0
#define SPI_INT0_MASK (1<<INT0)
#endif
#ifdef INT1
#define SPI_INT1_MASK (1<<INT1)
#endif
#ifdef INT2
#define SPI_INT2_MASK (1<<INT2)
#endif
#endif

void SPIClass::usingInterrupt(uint8_t interruptNumber)
{
uint8_t mask;

if (interruptMode > 1) return;

noInterrupts();
switch (interruptNumber) {
#ifdef SPI_INT0_MASK
case 0: mask = SPI_INT0_MASK; break;
#endif
#ifdef SPI_INT1_MASK
case 1: mask = SPI_INT1_MASK; break;
#endif
#ifdef SPI_INT2_MASK
case 2: mask = SPI_INT2_MASK; break;
#endif
#ifdef SPI_INT3_MASK
case 3: mask = SPI_INT3_MASK; break;
#endif
#ifdef SPI_INT4_MASK
case 4: mask = SPI_INT4_MASK; break;
#endif
#ifdef SPI_INT5_MASK
case 5: mask = SPI_INT5_MASK; break;
#endif
#ifdef SPI_INT6_MASK
case 6: mask = SPI_INT6_MASK; break;
#endif
#ifdef SPI_INT7_MASK
case 7: mask = SPI_INT7_MASK; break;
#endif
default:
interruptMode = 2;
interrupts();
return;
}
interruptMode = 1;
interruptMask |= mask;
interrupts();
void SPIClass::usingInterrupt(uint8_t interruptNumber) {
uint8_t mask = 0;
uint8_t sreg = SREG;
noInterrupts(); // Protect from a scheduler and prevent transactionBegin
switch(interruptNumber) {
#ifdef SPI_INT0_MASK
case 0: mask = SPI_INT0_MASK;
break;
#endif
#ifdef SPI_INT1_MASK
case 1: mask = SPI_INT1_MASK;
break;
#endif
#ifdef SPI_INT2_MASK
case 2: mask = SPI_INT2_MASK;
break;
#endif
#ifdef SPI_INT3_MASK
case 3: mask = SPI_INT3_MASK;
break;
#endif
#ifdef SPI_INT4_MASK
case 4: mask = SPI_INT4_MASK;
break;
#endif
#ifdef SPI_INT5_MASK
case 5: mask = SPI_INT5_MASK;
break;
#endif
#ifdef SPI_INT6_MASK
case 6: mask = SPI_INT6_MASK;
break;
#endif
#ifdef SPI_INT7_MASK
case 7: mask = SPI_INT7_MASK;
break;
#endif
default:
modeFlags.interruptMode = 2;
break;
}
interruptMask |= mask;
if(!modeFlags.interruptMode) modeFlags.interruptMode = 1;
SREG = sreg;
}

void SPIClass::notUsingInterrupt(uint8_t interruptNumber) {
uint8_t mask = 0;
uint8_t sreg = SREG;
noInterrupts(); // Protect from a scheduler and prevent transactionBegin
switch(interruptNumber) {
#ifdef SPI_INT0_MASK
case 0: mask = SPI_INT0_MASK;
break;
#endif
#ifdef SPI_INT1_MASK
case 1: mask = SPI_INT1_MASK;
break;
#endif
#ifdef SPI_INT2_MASK
case 2: mask = SPI_INT2_MASK;
break;
#endif
#ifdef SPI_INT3_MASK
case 3: mask = SPI_INT3_MASK;
break;
#endif
#ifdef SPI_INT4_MASK
case 4: mask = SPI_INT4_MASK;
break;
#endif
#ifdef SPI_INT5_MASK
case 5: mask = SPI_INT5_MASK;
break;
#endif
#ifdef SPI_INT6_MASK
case 6: mask = SPI_INT6_MASK;
break;
#endif
#ifdef SPI_INT7_MASK
case 7: mask = SPI_INT7_MASK;
break;
#endif
default:
if(interruptMask) {
modeFlags.interruptMode = 1;
} else {
modeFlags.interruptMode = 0;
}
break;
}
interruptMask &= ~mask;
SREG = sreg;
}
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