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Merge pull request #91 from Makuna/Esp8266DmaLargerCountSupport
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Esp8266 Dma Method now supports dynamic DMA duffer descriptors
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@Makuna
Makuna committed Apr 2, 2016
2 parents 302c974 + 9244cbb commit 89dcbb7
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Showing 2 changed files with 110 additions and 72 deletions.
2 changes: 1 addition & 1 deletion library.properties
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
name=NeoPixelBus by Makuna
version=2.0.6
version=2.0.7
author=Michael C. Miller ([email protected])
maintainer=Michael C. Miller ([email protected])
sentence=A library that makes controlling NeoPixels (WS2811, WS2812 & SK6812) easy.
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180 changes: 109 additions & 71 deletions src/internal/NeoEsp8266DmaMethod.h
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Original file line number Diff line number Diff line change
Expand Up @@ -3,9 +3,9 @@ NeoPixel library helper functions for Esp8266.
Written by Michael C. Miller.
Thanks to g3gg0.de for porting the initial DMA support.
Thanks to github/cnlohr for the original work on DMA support, which is
located at https://github.com/cnlohr/esp8266ws2812i2s.
Thanks to g3gg0.de for porting the initial DMA support which lead to this.
Thanks to github/cnlohr for the original work on DMA support, which opend
all our minds to a better way (located at https://github.com/cnlohr/esp8266ws2812i2s).
I invest time and resources providing this open source code,
please support me by dontating (see https://github.com/Makuna/NeoPixelBus)
Expand Down Expand Up @@ -84,32 +84,43 @@ enum NeoDmaState
NeoDmaState_Pending,
NeoDmaState_Sending,
};
const uint16_t c_maxDmaBlockSize = 4095;
const uint16_t c_dmaBytesPerPixelBytes = 4;
const uint8_t c_I2sPin = 3; // due to I2S hardware, the pin used is restricted to this

template<typename T_SPEED> class NeoEsp8266DmaMethodBase
{
public:
NeoEsp8266DmaMethodBase(uint8_t pin, uint16_t pixelCount, size_t elementSize)
{
_sizePixels = pixelCount * elementSize;
_bitBufferSize = CalculateI2sBufferSize(pixelCount, elementSize);
uint16_t dmaPixelSize = c_dmaBytesPerPixelBytes * elementSize;

_pixels = (uint8_t*)malloc(_sizePixels);
memset(_pixels, 0x00, _sizePixels);
_pixelsSize = pixelCount * elementSize;
_i2sBufferSize = pixelCount * dmaPixelSize;

_i2sBlock = (uint8_t*)malloc(_bitBufferSize);
memset(_i2sBlock, 0x00, _bitBufferSize);
_pixels = (uint8_t*)malloc(_pixelsSize);
memset(_pixels, 0x00, _pixelsSize);

_i2sBuffer = (uint8_t*)malloc(_i2sBufferSize);
memset(_i2sBuffer, 0x00, _i2sBufferSize);

memset(_i2sZeroes, 0x00, sizeof(_i2sZeroes));

s_this = this;
_is2BufMaxBlockSize = (c_maxDmaBlockSize / dmaPixelSize) * dmaPixelSize;

_i2sBufDescCount = (_i2sBufferSize / _is2BufMaxBlockSize) + 1 + 2; // need two more for state/latch blocks
_i2sBufDesc = (slc_queue_item*)malloc(_i2sBufDescCount * sizeof(slc_queue_item));

s_this = this; // store this for the ISR
}

~NeoEsp8266DmaMethodBase()
{
StopDma();

free(_pixels);
free(_i2sBlock);
free(_i2sBuffer);
free(_i2sBufDesc);
}

bool IsReadyToUpdate() const
Expand All @@ -119,31 +130,58 @@ template<typename T_SPEED> class NeoEsp8266DmaMethodBase

void Initialize()
{
_dmaState = NeoDmaState_Idle;

// prepare linked DMA descriptors, having EOF set only for the data
// primary data item
_i2sBufDescData.owner = 1;
_i2sBufDescData.eof = 1;
_i2sBufDescData.sub_sof = 0;
_i2sBufDescData.datalen = sizeof(_i2sZeroes); // will get modified in ISR
_i2sBufDescData.blocksize = sizeof(_i2sZeroes); // will get modified in ISR
_i2sBufDescData.buf_ptr = (uint32_t)_i2sZeroes; // will get modified in ISR
_i2sBufDescData.unused = 0;
_i2sBufDescData.next_link_ptr = (uint32_t)&_i2sBufDescLatch;

// this zero-buffer block helps implements the latch/reset signal
// and gives the ISR time to modify buf_ptr in _i2sBufDescData
_i2sBufDescLatch.owner = 1;
_i2sBufDescLatch.eof = 0; // no need to trigger interrupt
_i2sBufDescLatch.sub_sof = 0;
_i2sBufDescLatch.datalen = sizeof(_i2sZeroes);
_i2sBufDescLatch.blocksize = sizeof(_i2sZeroes);
_i2sBufDescLatch.buf_ptr = (uint32_t)_i2sZeroes;
_i2sBufDescLatch.unused = 0;
_i2sBufDescLatch.next_link_ptr = (uint32_t)&_i2sBufDescData;

_dmaState = NeoDmaState_Sending; // start off sending empty buffer

uint8_t* is2Buffer = _i2sBuffer;
uint32_t is2BufferSize = _i2sBufferSize;
uint16_t indexDesc;

// prepare main data block decriptors that point into our one static dma buffer
for (indexDesc = 0; indexDesc < (_i2sBufDescCount - 2); indexDesc++)
{
uint32_t blockSize = (is2BufferSize > _is2BufMaxBlockSize) ? _is2BufMaxBlockSize : is2BufferSize;

_i2sBufDesc[indexDesc].owner = 1;
_i2sBufDesc[indexDesc].eof = 0; // no need to trigger interrupt generally
_i2sBufDesc[indexDesc].sub_sof = 0;
_i2sBufDesc[indexDesc].datalen = blockSize;
_i2sBufDesc[indexDesc].blocksize = blockSize;
_i2sBufDesc[indexDesc].buf_ptr = (uint32_t)is2Buffer;
_i2sBufDesc[indexDesc].unused = 0;
_i2sBufDesc[indexDesc].next_link_ptr = (uint32_t)&(_i2sBufDesc[indexDesc + 1]);

Serial.print("block #");
Serial.print(indexDesc);
Serial.print(" 0x");
Serial.print(_i2sBufDesc[indexDesc].buf_ptr, HEX);
Serial.print(" (");
Serial.print(_i2sBufDesc[indexDesc].blocksize);
Serial.println(")");

is2Buffer += blockSize;
is2BufferSize -= blockSize;
}

// prepare the two state/latch descriptors
for (; indexDesc < _i2sBufDescCount; indexDesc++)
{
_i2sBufDesc[indexDesc].owner = 1;
_i2sBufDesc[indexDesc].eof = 0; // no need to trigger interrupt generally
_i2sBufDesc[indexDesc].sub_sof = 0;
_i2sBufDesc[indexDesc].datalen = sizeof(_i2sZeroes);
_i2sBufDesc[indexDesc].blocksize = sizeof(_i2sZeroes);
_i2sBufDesc[indexDesc].buf_ptr = (uint32_t)_i2sZeroes;
_i2sBufDesc[indexDesc].unused = 0;
_i2sBufDesc[indexDesc].next_link_ptr = (uint32_t)&(_i2sBufDesc[indexDesc + 1]);
}

// the first state block will trigger the interrupt
_i2sBufDesc[indexDesc - 2].eof = 1;
// the last state block will loop to the first state block by defualt
_i2sBufDesc[indexDesc - 1].next_link_ptr = (uint32_t)&(_i2sBufDesc[indexDesc - 2]);

// setup the rest of i2s DMA
//
ETS_SLC_INTR_DISABLE();
SLCC0 |= SLCRXLR | SLCTXLR;
SLCC0 &= ~(SLCRXLR | SLCTXLR);
Expand All @@ -160,9 +198,9 @@ template<typename T_SPEED> class NeoEsp8266DmaMethodBase
// expect. The TXLINK part still needs a valid DMA descriptor, even if it's unused: the DMA engine will throw
// an error at us otherwise. Just feed it any random descriptor.
SLCTXL &= ~(SLCTXLAM << SLCTXLA); // clear TX descriptor address
SLCTXL |= (uint32)&_i2sBufDescLatch << SLCTXLA; // set TX descriptor address. any random desc is OK, we don't use TX but it needs to be valid
SLCTXL |= (uint32)&(_i2sBufDesc[_i2sBufDescCount-1]) << SLCTXLA; // set TX descriptor address. any random desc is OK, we don't use TX but it needs to be valid
SLCRXL &= ~(SLCRXLAM << SLCRXLA); // clear RX descriptor address
SLCRXL |= (uint32)&_i2sBufDescData << SLCRXLA; // set RX descriptor address
SLCRXL |= (uint32)_i2sBufDesc << SLCRXLA; // set RX descriptor address

ETS_SLC_INTR_ATTACH(i2s_slc_isr, NULL);
SLCIE = SLCIRXEOF; // Enable only for RX EOF interrupt
Expand All @@ -173,7 +211,7 @@ template<typename T_SPEED> class NeoEsp8266DmaMethodBase
SLCTXL |= SLCTXLS;
SLCRXL |= SLCRXLS;

pinMode(3, FUNCTION_1); // I2S0_DATA
pinMode(c_I2sPin, FUNCTION_1); // I2S0_DATA

I2S_CLK_ENABLE();
I2SIC = 0x3F;
Expand Down Expand Up @@ -219,29 +257,32 @@ template<typename T_SPEED> class NeoEsp8266DmaMethodBase

size_t getPixelsSize() const
{
return _sizePixels;
return _pixelsSize;
}

private:
static NeoEsp8266DmaMethodBase* s_this; // for the ISR

size_t _sizePixels; // Size of '_pixels' buffer below
size_t _pixelsSize; // Size of '_pixels' buffer
uint8_t* _pixels; // Holds LED color values

struct slc_queue_item _i2sBufDescData;
struct slc_queue_item _i2sBufDescLatch;
uint32_t _i2sBufferSize; // total size of _i2sBuffer
uint8_t* _i2sBuffer; // holds the DMA buffer that is referenced by _i2sBufDesc

uint32_t _bitBufferSize;
uint8_t* _i2sBlock;
// normally 24 bytes creates the minimum 50us latch per spec but
// normally 24 bytes creates the minimum 50us latch per spec, but
// with the new logic, this latch is used to space between three states
uint8_t _i2sZeroes[8];

slc_queue_item* _i2sBufDesc; // dma block descriptors
uint16_t _i2sBufDescCount; // count of block descriptors in _i2sBufDesc
uint16_t _is2BufMaxBlockSize; // max size based on size of a pixel of a single block

volatile NeoDmaState _dmaState;

// This routine is called as soon as the DMA routine has something to tell us. All we
// handle here is the RX_EOF_INT status, which indicate the DMA has sent a buffer whose
// descriptor has the 'EOF' field set to 1.
// in the case of this code, the second to last state descriptor
volatile static void ICACHE_RAM_ATTR i2s_slc_isr(void)
{
uint32_t slc_intr_status = SLCIS;
Expand All @@ -252,45 +293,42 @@ template<typename T_SPEED> class NeoEsp8266DmaMethodBase
{
ETS_SLC_INTR_DISABLE();

slc_queue_item* finished_item = (slc_queue_item*)SLCRXEDA;

if (finished_item == &(s_this->_i2sBufDescData))
switch (s_this->_dmaState)
{
switch (s_this->_dmaState)
case NeoDmaState_Idle:
break;

case NeoDmaState_Pending:
{
case NeoDmaState_Idle:
break;
slc_queue_item* finished_item = (slc_queue_item*)SLCRXEDA;

case NeoDmaState_Pending:
// data block has pending data waiting to send, prepare it
finished_item->datalen = s_this->_bitBufferSize;
finished_item->blocksize = s_this->_bitBufferSize;
finished_item->buf_ptr = (uint32_t)(s_this->_i2sBlock);
// point last state block to top
(finished_item + 1)->next_link_ptr = (uint32_t)(s_this->_i2sBufDesc);

s_this->_dmaState = NeoDmaState_Sending;
break;
}
break;

case NeoDmaState_Sending:
{
slc_queue_item* finished_item = (slc_queue_item*)SLCRXEDA;

case NeoDmaState_Sending:
// the data block had actual data, clear it
finished_item->datalen = sizeof(s_this->_i2sZeroes);
finished_item->blocksize = sizeof(s_this->_i2sZeroes);
finished_item->buf_ptr = (uint32_t)(s_this->_i2sZeroes);
// the data block had actual data sent
// point last state block to first state block thus
// just looping and not sending the data blocks
(finished_item + 1)->next_link_ptr = (uint32_t)(finished_item);

s_this->_dmaState = NeoDmaState_Idle;
break;
}
break;
}


ETS_SLC_INTR_ENABLE();
}
}

static uint32_t CalculateI2sBufferSize(uint16_t pixelCount, size_t elementSize)
{
// 4 I2S bytes per pixels byte
return ((uint32_t)pixelCount * elementSize * 4);
}

void FillBuffers()
{
const uint16_t bitpatterns[16] =
Expand All @@ -301,8 +339,8 @@ template<typename T_SPEED> class NeoEsp8266DmaMethodBase
0b1110111010001000, 0b1110111010001110, 0b1110111011101000, 0b1110111011101110,
};

uint16_t* pDma = (uint16_t*)_i2sBlock;
uint8_t* pPixelsEnd = _pixels + _sizePixels;
uint16_t* pDma = (uint16_t*)_i2sBuffer;
uint8_t* pPixelsEnd = _pixels + _pixelsSize;
for (uint8_t* pPixel = _pixels; pPixel < pPixelsEnd; pPixel++)
{
*(pDma++) = bitpatterns[((*pPixel) & 0x0f)];
Expand All @@ -318,7 +356,7 @@ template<typename T_SPEED> class NeoEsp8266DmaMethodBase
SLCTXL &= ~(SLCTXLAM << SLCTXLA); // clear TX descriptor address
SLCRXL &= ~(SLCRXLAM << SLCRXLA); // clear RX descriptor address

pinMode(3, INPUT);
pinMode(c_I2sPin, INPUT);
}
};

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