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esp8266/libraries/SPI/SPI.cpp
Max Prokhorov 599492ec43 libraries/SPI: abs -> std::abs and cast fixes (#7362) 
* libraries/SPI: remove pointless abs(...) call

SPI library code erroneously assumed that:
- abs() is a C function, so include stdlib.h is required.
  what happens instead is Arduino.h shadows `abs()` with it's own macro
- uint32_t() - int32_t() promotes to int32_t, thus needing abs()

Fix both issues, leaving existing calculations as-is.

* additional changes for freq and constants

- restore abs call, cast freq to correctly display the intent
- update magic numbers comments
- move some spiclk_t magic numbers to func consts
2020-06-13 11:17:06 -07:00

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/*
SPI.cpp - SPI library for esp8266
Copyright (c) 2015 Hristo Gochkov. All rights reserved.
This file is part of the esp8266 core for Arduino environment.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "SPI.h"
#include "HardwareSerial.h"
#define SPI_PINS_HSPI 0 // Normal HSPI mode (MISO = GPIO12, MOSI = GPIO13, SCLK = GPIO14);
#define SPI_PINS_HSPI_OVERLAP 1 // HSPI Overllaped in spi0 pins (MISO = SD0, MOSI = SDD1, SCLK = CLK);
#define SPI_OVERLAP_SS 0
typedef union {
uint32_t regValue;
struct {
unsigned regL :6;
unsigned regH :6;
unsigned regN :6;
unsigned regPre :13;
unsigned regEQU :1;
};
} spiClk_t;
SPIClass::SPIClass() {
useHwCs = false;
pinSet = SPI_PINS_HSPI;
}
bool SPIClass::pins(int8_t sck, int8_t miso, int8_t mosi, int8_t ss)
{
if (sck == 6 &&
miso == 7 &&
mosi == 8 &&
ss == 0) {
pinSet = SPI_PINS_HSPI_OVERLAP;
} else if (sck == 14 &&
miso == 12 &&
mosi == 13) {
pinSet = SPI_PINS_HSPI;
} else {
return false;
}
return true;
}
void SPIClass::begin() {
switch (pinSet) {
case SPI_PINS_HSPI_OVERLAP:
IOSWAP |= (1 << IOSWAP2CS);
//SPI0E3 |= 0x1; This is in the MP3_DECODER example, but makes the WD kick in here.
SPI1E3 |= 0x3;
setHwCs(true);
break;
case SPI_PINS_HSPI:
default:
pinMode(SCK, SPECIAL); ///< GPIO14
pinMode(MISO, SPECIAL); ///< GPIO12
pinMode(MOSI, SPECIAL); ///< GPIO13
break;
}
SPI1C = 0;
setFrequency(1000000); ///< 1MHz
SPI1U = SPIUMOSI | SPIUDUPLEX | SPIUSSE;
SPI1U1 = (7 << SPILMOSI) | (7 << SPILMISO);
SPI1C1 = 0;
}
void SPIClass::end() {
switch (pinSet) {
case SPI_PINS_HSPI:
pinMode(SCK, INPUT);
pinMode(MISO, INPUT);
pinMode(MOSI, INPUT);
if (useHwCs) {
pinMode(SS, INPUT);
}
break;
case SPI_PINS_HSPI_OVERLAP:
IOSWAP &= ~(1 << IOSWAP2CS);
if (useHwCs) {
SPI1P |= SPIPCS1DIS | SPIPCS0DIS | SPIPCS2DIS;
pinMode(SPI_OVERLAP_SS, INPUT);
}
break;
}
}
void SPIClass::setHwCs(bool use) {
switch (pinSet) {
case SPI_PINS_HSPI:
if (use) {
pinMode(SS, SPECIAL); ///< GPIO15
SPI1U |= (SPIUCSSETUP | SPIUCSHOLD);
} else {
if (useHwCs) {
pinMode(SS, INPUT);
SPI1U &= ~(SPIUCSSETUP | SPIUCSHOLD);
}
}
break;
case SPI_PINS_HSPI_OVERLAP:
if (use) {
pinMode(SPI_OVERLAP_SS, FUNCTION_1); // GPI0 to SPICS2 mode
SPI1P &= ~SPIPCS2DIS;
SPI1P |= SPIPCS1DIS | SPIPCS0DIS;
SPI1U |= (SPIUCSSETUP | SPIUCSHOLD);
}
else {
if (useHwCs) {
pinMode(SPI_OVERLAP_SS, INPUT);
SPI1P |= SPIPCS1DIS | SPIPCS0DIS | SPIPCS2DIS;
SPI1U &= ~(SPIUCSSETUP | SPIUCSHOLD);
}
}
break;
}
useHwCs = use;
}
void SPIClass::beginTransaction(SPISettings settings) {
while(SPI1CMD & SPIBUSY) {}
setFrequency(settings._clock);
setBitOrder(settings._bitOrder);
setDataMode(settings._dataMode);
}
void SPIClass::endTransaction() {
}
void SPIClass::setDataMode(uint8_t dataMode) {
/**
SPI_MODE0 0x00 - CPOL: 0 CPHA: 0
SPI_MODE1 0x01 - CPOL: 0 CPHA: 1
SPI_MODE2 0x10 - CPOL: 1 CPHA: 0
SPI_MODE3 0x11 - CPOL: 1 CPHA: 1
*/
bool CPOL = (dataMode & 0x10); ///< CPOL (Clock Polarity)
bool CPHA = (dataMode & 0x01); ///< CPHA (Clock Phase)
// https://github.com/esp8266/Arduino/issues/2416
// https://github.com/esp8266/Arduino/pull/2418
if(CPOL) // Ensure same behavior as
CPHA ^= 1; // SAM, AVR and Intel Boards
if(CPHA) {
SPI1U |= (SPIUSME);
} else {
SPI1U &= ~(SPIUSME);
}
if(CPOL) {
SPI1P |= 1<<29;
} else {
SPI1P &= ~(1<<29);
//todo test whether it is correct to set CPOL like this.
}
}
void SPIClass::setBitOrder(uint8_t bitOrder) {
if(bitOrder == MSBFIRST) {
SPI1C &= ~(SPICWBO | SPICRBO);
} else {
SPI1C |= (SPICWBO | SPICRBO);
}
}
/**
* calculate the Frequency based on the register value
* @param reg
* @return
*/
static uint32_t ClkRegToFreq(spiClk_t * reg) {
return (ESP8266_CLOCK / ((reg->regPre + 1) * (reg->regN + 1)));
}
void SPIClass::setFrequency(uint32_t freq) {
static uint32_t lastSetFrequency = 0;
static uint32_t lastSetRegister = 0;
if(freq >= ESP8266_CLOCK) {
// magic number to set spi sysclock bit (see below.)
setClockDivider(0x80000000);
return;
}
if(lastSetFrequency == freq && lastSetRegister == SPI1CLK) {
// do nothing (speed optimization)
return;
}
const spiClk_t minFreqReg = { 0x7FFFF020 };
uint32_t minFreq = ClkRegToFreq((spiClk_t*) &minFreqReg);
if(freq < minFreq) {
// use minimum possible clock regardless
setClockDivider(minFreqReg.regValue);
lastSetRegister = SPI1CLK;
lastSetFrequency = freq;
return;
}
uint8_t calN = 1;
spiClk_t bestReg = { 0 };
int32_t bestFreq = 0;
// aka 0x3F, aka 63, max for regN:6
const uint8_t regNMax = (1 << 6) - 1;
// aka 0x1fff, aka 8191, max for regPre:13
const int32_t regPreMax = (1 << 13) - 1;
// find the best match for the next 63 iterations
while(calN <= regNMax) {
spiClk_t reg = { 0 };
int32_t calFreq;
int32_t calPre;
int8_t calPreVari = -2;
reg.regN = calN;
while(calPreVari++ <= 1) { // test different variants for Pre (we calculate in int so we miss the decimals, testing is the easyest and fastest way)
calPre = (((ESP8266_CLOCK / (reg.regN + 1)) / freq) - 1) + calPreVari;
if(calPre > regPreMax) {
reg.regPre = regPreMax;
} else if(calPre <= 0) {
reg.regPre = 0;
} else {
reg.regPre = calPre;
}
reg.regL = ((reg.regN + 1) / 2);
// reg.regH = (reg.regN - reg.regL);
// test calculation
calFreq = ClkRegToFreq(&reg);
//os_printf("-----[0x%08X][%d]\t EQU: %d\t Pre: %d\t N: %d\t H: %d\t L: %d = %d\n", reg.regValue, freq, reg.regEQU, reg.regPre, reg.regN, reg.regH, reg.regL, calFreq);
if(calFreq == static_cast<int32_t>(freq)) {
// accurate match use it!
memcpy(&bestReg, &reg, sizeof(bestReg));
break;
} else if(calFreq < static_cast<int32_t>(freq)) {
// never go over the requested frequency
auto cal = std::abs(static_cast<int32_t>(freq) - calFreq);
auto best = std::abs(static_cast<int32_t>(freq) - bestFreq);
if(cal < best) {
bestFreq = calFreq;
memcpy(&bestReg, &reg, sizeof(bestReg));
}
}
}
if(calFreq == static_cast<int32_t>(freq)) {
// accurate match use it!
break;
}
calN++;
}
// os_printf("[0x%08X][%d]\t EQU: %d\t Pre: %d\t N: %d\t H: %d\t L: %d\t - Real Frequency: %d\n", bestReg.regValue, freq, bestReg.regEQU, bestReg.regPre, bestReg.regN, bestReg.regH, bestReg.regL, ClkRegToFreq(&bestReg));
setClockDivider(bestReg.regValue);
lastSetRegister = SPI1CLK;
lastSetFrequency = freq;
}
void SPIClass::setClockDivider(uint32_t clockDiv) {
if(clockDiv == 0x80000000) {
GPMUX |= (1 << 9); // Set bit 9 if sysclock required
} else {
GPMUX &= ~(1 << 9);
}
SPI1CLK = clockDiv;
}
inline void SPIClass::setDataBits(uint16_t bits) {
const uint32_t mask = ~((SPIMMOSI << SPILMOSI) | (SPIMMISO << SPILMISO));
bits--;
SPI1U1 = ((SPI1U1 & mask) | ((bits << SPILMOSI) | (bits << SPILMISO)));
}
uint8_t SPIClass::transfer(uint8_t data) {
while(SPI1CMD & SPIBUSY) {}
// reset to 8Bit mode
setDataBits(8);
SPI1W0 = data;
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
return (uint8_t) (SPI1W0 & 0xff);
}
uint16_t SPIClass::transfer16(uint16_t data) {
union {
uint16_t val;
struct {
uint8_t lsb;
uint8_t msb;
};
} in, out;
in.val = data;
if((SPI1C & (SPICWBO | SPICRBO))) {
//LSBFIRST
out.lsb = transfer(in.lsb);
out.msb = transfer(in.msb);
} else {
//MSBFIRST
out.msb = transfer(in.msb);
out.lsb = transfer(in.lsb);
}
return out.val;
}
void SPIClass::transfer(void *buf, uint16_t count) {
uint8_t *cbuf = reinterpret_cast<uint8_t*>(buf);
// cbuf may not be 32bits-aligned
for (; (((unsigned long)cbuf) & 3) && count; cbuf++, count--)
*cbuf = transfer(*cbuf);
// cbuf is now aligned
// count may not be a multiple of 4
uint16_t count4 = count & ~3;
transferBytes(cbuf, cbuf, count4);
// finish the last <4 bytes
cbuf += count4;
count -= count4;
for (; count; cbuf++, count--)
*cbuf = transfer(*cbuf);
}
void SPIClass::write(uint8_t data) {
while(SPI1CMD & SPIBUSY) {}
// reset to 8Bit mode
setDataBits(8);
SPI1W0 = data;
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
}
void SPIClass::write16(uint16_t data) {
write16(data, !(SPI1C & (SPICWBO | SPICRBO)));
}
void SPIClass::write16(uint16_t data, bool msb) {
while(SPI1CMD & SPIBUSY) {}
// Set to 16Bits transfer
setDataBits(16);
if(msb) {
// MSBFIRST Byte first
SPI1W0 = (data >> 8) | (data << 8);
} else {
// LSBFIRST Byte first
SPI1W0 = data;
}
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
}
void SPIClass::write32(uint32_t data) {
write32(data, !(SPI1C & (SPICWBO | SPICRBO)));
}
void SPIClass::write32(uint32_t data, bool msb) {
while(SPI1CMD & SPIBUSY) {}
// Set to 32Bits transfer
setDataBits(32);
if(msb) {
union {
uint32_t l;
uint8_t b[4];
} data_;
data_.l = data;
// MSBFIRST Byte first
data = (data_.b[3] | (data_.b[2] << 8) | (data_.b[1] << 16) | (data_.b[0] << 24));
}
SPI1W0 = data;
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
}
/**
* Note:
* data need to be aligned to 32Bit
* or you get an Fatal exception (9)
* @param data uint8_t *
* @param size uint32_t
*/
void SPIClass::writeBytes(const uint8_t * data, uint32_t size) {
while(size) {
if(size > 64) {
writeBytes_(data, 64);
size -= 64;
data += 64;
} else {
writeBytes_(data, size);
size = 0;
}
}
}
void SPIClass::writeBytes_(const uint8_t * data, uint8_t size) {
while(SPI1CMD & SPIBUSY) {}
// Set Bits to transfer
setDataBits(size * 8);
uint32_t * fifoPtr = (uint32_t*)&SPI1W0;
const uint32_t * dataPtr = (uint32_t*) data;
uint32_t dataSize = ((size + 3) / 4);
while(dataSize--) {
*fifoPtr = *dataPtr;
dataPtr++;
fifoPtr++;
}
__sync_synchronize();
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
}
/**
* @param data uint8_t *
* @param size uint8_t max for size is 64Byte
* @param repeat uint32_t
*/
void SPIClass::writePattern(const uint8_t * data, uint8_t size, uint32_t repeat) {
if(size > 64) return; //max Hardware FIFO
while(SPI1CMD & SPIBUSY) {}
uint32_t buffer[16];
uint8_t *bufferPtr=(uint8_t *)&buffer;
const uint8_t *dataPtr = data;
volatile uint32_t * fifoPtr = &SPI1W0;
uint8_t r;
uint32_t repeatRem;
uint8_t i;
if((repeat * size) <= 64){
repeatRem = repeat * size;
r = repeat;
while(r--){
dataPtr = data;
for(i=0; i<size; i++){
*bufferPtr = *dataPtr;
bufferPtr++;
dataPtr++;
}
}
r = repeatRem;
if(r & 3) r = r / 4 + 1;
else r = r / 4;
for(i=0; i<r; i++){
*fifoPtr = buffer[i];
fifoPtr++;
}
SPI1U = SPIUMOSI | SPIUSSE;
} else {
//Orig
r = 64 / size;
repeatRem = repeat % r * size;
repeat = repeat / r;
while(r--){
dataPtr = data;
for(i=0; i<size; i++){
*bufferPtr = *dataPtr;
bufferPtr++;
dataPtr++;
}
}
//Fill fifo with data
for(i=0; i<16; i++){
*fifoPtr = buffer[i];
fifoPtr++;
}
r = 64 / size;
SPI1U = SPIUMOSI | SPIUSSE;
setDataBits(r * size * 8);
while(repeat--){
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
}
}
//End orig
setDataBits(repeatRem * 8);
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
SPI1U = SPIUMOSI | SPIUDUPLEX | SPIUSSE;
}
/**
* @param out uint8_t *
* @param in uint8_t *
* @param size uint32_t
*/
void SPIClass::transferBytes(const uint8_t * out, uint8_t * in, uint32_t size) {
while(size) {
if(size > 64) {
transferBytes_(out, in, 64);
size -= 64;
if(out) out += 64;
if(in) in += 64;
} else {
transferBytes_(out, in, size);
size = 0;
}
}
}
/**
* Note:
* in and out need to be aligned to 32Bit
* or you get an Fatal exception (9)
* @param out uint8_t *
* @param in uint8_t *
* @param size uint8_t (max 64)
*/
void SPIClass::transferBytesAligned_(const uint8_t * out, uint8_t * in, uint8_t size) {
if (!size)
return;
while(SPI1CMD & SPIBUSY) {}
// Set in/out Bits to transfer
setDataBits(size * 8);
volatile uint32_t *fifoPtr = &SPI1W0;
if (out) {
uint8_t outSize = ((size + 3) / 4);
uint32_t *dataPtr = (uint32_t*) out;
while (outSize--) {
*(fifoPtr++) = *(dataPtr++);
}
} else {
uint8_t outSize = ((size + 3) / 4);
// no out data only read fill with dummy data!
while (outSize--) {
*(fifoPtr++) = 0xFFFFFFFF;
}
}
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
if (in) {
uint32_t *dataPtr = (uint32_t*) in;
fifoPtr = &SPI1W0;
int inSize = size;
// Unlike outSize above, inSize tracks *bytes* since we must transfer only the requested bytes to the app to avoid overwriting other vars.
while (inSize >= 4) {
*(dataPtr++) = *(fifoPtr++);
inSize -= 4;
in += 4;
}
volatile uint8_t *fifoPtrB = (volatile uint8_t *)fifoPtr;
while (inSize--) {
*(in++) = *(fifoPtrB++);
}
}
}
void SPIClass::transferBytes_(const uint8_t * out, uint8_t * in, uint8_t size) {
if (!((uint32_t)out & 3) && !((uint32_t)in & 3)) {
// Input and output are both 32b aligned or NULL
transferBytesAligned_(out, in, size);
} else {
// HW FIFO has 64b limit and ::transferBytes breaks up large xfers into 64byte chunks before calling this function
// We know at this point at least one direction is misaligned, so use temporary buffer to align everything
// No need for separate out and in aligned copies, we can overwrite our out copy with the input data safely
uint8_t aligned[64]; // Stack vars will be 32b aligned
if (out) {
memcpy(aligned, out, size);
}
transferBytesAligned_(out ? aligned : nullptr, in ? aligned : nullptr, size);
if (in) {
memcpy(in, aligned, size);
}
}
}
#if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_SPI)
SPIClass SPI;
#endif
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