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with working DMA transfers

This commit is contained in:
Jorj Bauer 2022-01-20 18:19:11 -05:00
parent eb60d86ab5
commit 17752f0c12
3 changed files with 100 additions and 116 deletions
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199
teensy/RA8875_t4.cpp
View File

@ -2,6 +2,8 @@
#include "RA8875_registers.h"
// Discussion about DMA channels: http://forum.pjrc.com/threads/25778-Could-there-be-something-like-an-ISR-template-function/page3
// Thread discussing the way to get started: https://forum.pjrc.com/threads/63353-Teensy-4-1-How-to-start-using-DMA
// Thread of someone writing an LCD interface: https://forum.pjrc.com/threads/67247-Teensy-4-0-DMA-SPI
// And these libraries use it:
// https://github.com/PaulStoffregen/Audio
// https://github.com/PaulStoffregen/OctoWS2811
@ -26,6 +28,10 @@
* - The RA8875 driver supports multiple different pixel-size
* displays (and vendors' interfaces). Aiie only supports 800x480
* using the Adafruit RA8875 display module.
* - Each dmasettings looks like it can address 32767 bytes of data,
* so while the 320*240 16-bit structure needs 3 structs (well,
* 2.34 structs) the 800*480 8-bit structure needs 12 structs.
*
*
* The initialization sets us to 8bpp color mode, so that 800*480 fits
* within 512k of RAM (800*480 bytes = 375k; if this were 16bpp, then
@ -64,7 +70,13 @@
* I don't know if the way I'm maybeUpdateTCR-ing with
* LPSPI_TCR_PCS(3) is correct or not -- I haven't fully comprehended
* what the code in 9341/7735 are doing there, because it's combined
* with the D/C pin functionality.
* with the D/C pin functionality. But LPSPI_TCR_PCS refers to
* the SPI peripheral chip select: 00 = LPSPI_PCS[0]; 01 = 1; etc.
* From what I see in the original maybeUpdateTCR method, it's using
* LPSPI_TCR_PCS(3) as a CARRIER of the expected state of the _dc
* pin. It is masked back out before setting TCR. So I think the
* right thing to do here is completely remove all of the LPSPI_TCR_PCS
* bits. ... but it still isn't getting to an interrupt state.
*
* Some pages I've been reading:
* https://forum.pjrc.com/threads/57280-RA8875-from-Buydisplay/page9?highlight=lpspi_tcr_pcs (pg9)
@ -73,36 +85,32 @@
* https://github-wiki-see.page/m/TeensyUser/doc/wiki/Memory-Mapping
*/
#define COUNT_PIXELS_WRITE (RA8875_WIDTH * RA8875_HEIGHT)
// at 8bpp, each pixel is 1 byte
#define PIXELSIZE 1
#define TCR_MASK (LPSPI_TCR_PCS(3) | LPSPI_TCR_FRAMESZ(31) | LPSPI_TCR_CONT | LPSPI_TCR_RXMSK )
#define COUNT_PIXELS_WRITE (RA8875_WIDTH * RA8875_HEIGHT)
#define TCR_MASK ( LPSPI_TCR_FRAMESZ(31) | LPSPI_TCR_CONT | LPSPI_TCR_RXMSK )
#define _565toR(c) ( ((c) & 0xF800) >> 8 )
#define _565toG(c) ( ((c) & 0x07E0) >> 3 )
#define _565toB(c) ( ((c) & 0x001F) << 3 )
// 3 of these, one for each of the 3 busses, so that 3 separate
// displays could be driven. FIXME: I don't really need all 3 in this
// application, so this can be pared down.
static RA8875_t4 *_dmaActiveDisplay[3];
RA8875_t4::RA8875_t4(const uint8_t cs_pin, const uint8_t rst_pin, const uint8_t mosi_pin, const uint8_t sck_pin, const uint8_t miso_pin)
{
pinMode(13, OUTPUT);
digitalWrite(13, HIGH);
_mosi = mosi_pin;
_miso = miso_pin;
_cs = cs_pin;
_rst = rst_pin;
_sck = sck_pin;
_interruptStates = 0b00000000;
_pspi = NULL;
_pfbtft = NULL;
_dma_state = 0;
_frame_complete_callback = NULL;
_frame_callback_on_HalfDone = false;
_dma_frame_count = 0;
_dma_sub_frame_count = 0;
_dmaActiveDisplay[0] = _dmaActiveDisplay[1] = _dmaActiveDisplay[2] = NULL;
}
@ -112,7 +120,6 @@ RA8875_t4::~RA8875_t4()
void RA8875_t4::begin(uint32_t spi_clock, uint32_t spi_clock_read)
{
_interruptStates = 0b00000000;
_spi_clock = spi_clock;
_spi_clock_read = spi_clock_read;
_clock = 4000000UL; // start at low speed
@ -143,15 +150,12 @@ void RA8875_t4::begin(uint32_t spi_clock, uint32_t spi_clock_read)
_pspi->begin();
_csport = portOutputRegister(_cs);
_cspinmask = digitalPinToBitMask(_cs);
pinMode(_cs, OUTPUT);
// DIRECT_WRITE_HIGH(_csport, _cspinmask);
digitalWriteFast(_cs, HIGH);
_spi_tcr_current = _pimxrt_spi->TCR; // get the current TCR value
maybeUpdateTCR(LPSPI_TCR_PCS(3)|LPSPI_TCR_FRAMESZ(7));
maybeUpdateTCR(LPSPI_TCR_FRAMESZ(7));
_initializeTFT();
}
@ -161,11 +165,11 @@ void RA8875_t4::_initializeTFT()
// toggle RST low to reset
if (_rst < 255) {
pinMode(_rst, OUTPUT);
digitalWrite(_rst, HIGH);
digitalWriteFast(_rst, HIGH);
delay(10);
digitalWrite(_rst, LOW);
digitalWriteFast(_rst, LOW);
delay(220);
digitalWrite(_rst, HIGH);
digitalWriteFast(_rst, HIGH);
delay(300);
} else {
// Try a soft reset
@ -287,40 +291,29 @@ void RA8875_t4::initDMASettings()
if (_dma_state & RA8875_DMA_INIT)
return;
Serial.println("Initializing DMA");
uint8_t dmaTXevent = _spi_hardware->tx_dma_channel;
if (_dma_state & RA8875_DMA_EVER_INIT) {
_dmasettings[0].sourceBuffer(_pfbtft, COUNT_PIXELS_WRITE * PIXELSIZE);
// FIXME: I don't know if arm_dcache_flush is sufficient to break the cache? cf https://github-wiki-see.page/m/TeensyUser/doc/wiki/Memory-Mapping
// The ILI9341 code uses 3 buffers and "copies the data" - but _pfbtft is malloc'd a 2* the size of the pixels (+32, presumably for alignment?) - and it's 16-bit, so 2* pixels is just the data itself.
// So how is it that dmasettings[0] -> _pfbtft, and
// dmasettings[1] -> _pfbtft[middle] and
// dmasettings[2] -> _pfbtft[end] yet [1] and [2] also refer to the full buffer size? That would mean
// _pfbtft is malloc'd to double the size it needs and there's some floating copying going on?
// I see no memcpy() calls... and in "first time we init" it looks diferent too, so I'm very confused
_dmasettings[1].sourceBuffer(&_pfbtft[COUNT_PIXELS_WRITE], COUNT_PIXELS_WRITE*PIXELSIZE);
_dmasettings[2].sourceBuffer(&_pfbtft[COUNT_PIXELS_WRITE*2], COUNT_PIXELS_WRITE*PIXELSIZE);
if (_frame_callback_on_HalfDone) _dmasettings[1].interruptAtHalf();
else _dmasettings[1].TCD->CSR &= ~DMA_TCD_CSR_INTHALF; // DMA_TCDn_CSR
} else {
_dmasettings[0].sourceBuffer(_pfbtft, COUNT_PIXELS_WRITE * PIXELSIZE);
_dmasettings[0].destination(_pimxrt_spi->TDR); // DMA sends data to LPSPI's transmit data register
_dmasettings[0].TCD->ATTR_DST = 1;
_dmasettings[0].replaceSettingsOnCompletion(_dmasettings[1]);
_dmasettings[1].sourceBuffer(_pfbtft, COUNT_PIXELS_WRITE*PIXELSIZE);
_dmasettings[1].destination(_pimxrt_spi->TDR);
_dmasettings[1].TCD->ATTR_DST = 1;
if (_frame_callback_on_HalfDone) _dmasettings[1].interruptAtHalf();
else _dmasettings[1].TCD->CSR &= ~DMA_TCD_CSR_INTHALF;
_dmasettings[1].replaceSettingsOnCompletion(_dmasettings[2]);
_dmasettings[2].sourceBuffer(_pfbtft, COUNT_PIXELS_WRITE*PIXELSIZE);
_dmasettings[2].destination(_pimxrt_spi->TDR);
_dmasettings[2].TCD->ATTR_DST = 1;
_dmasettings[2].replaceSettingsOnCompletion(_dmasettings[0]);
_dmasettings[2].interruptAtCompletion();
// Each DMA structure can only track 32767 words written (where a
// word here is 8 bits). So we need 12 of these to cover the whole
// set of 800*480 display data.
uint16_t pixelsWrittenPerDMAreq = COUNT_PIXELS_WRITE / 12;
if (_dma_state & RA8875_DMA_EVER_INIT) {
for (int i=0; i<12; i++) {
_dmasettings[i].sourceBuffer(&_pfbtft[pixelsWrittenPerDMAreq*i], pixelsWrittenPerDMAreq);
}
} else {
for (int i=0; i<12; i++) {
_dmasettings[i].sourceBuffer(&_pfbtft[pixelsWrittenPerDMAreq*i], pixelsWrittenPerDMAreq);
_dmasettings[i].destination(_pimxrt_spi->TDR); // DMA sends data to LPSPI's transmit data register
_dmasettings[i].TCD->ATTR_DST = 0; // 8-bit destination size (%000)
_dmasettings[i].replaceSettingsOnCompletion(_dmasettings[(i+1)%12]);
}
// "half done" for 12 is at the end of index 5, so we don't have to set up interruptAtHalf()
// but we do have to change the way we deal with sub-frame counting. If we need it. I don't
// think we do, so I'm leaving this here as a comment for now...
// _dmasettings[5].interruptAtCompletion();
_dmasettings[11].interruptAtCompletion();
_dmatx = _dmasettings[0];
_dmatx.begin(true);
@ -328,40 +321,43 @@ void RA8875_t4::initDMASettings()
if (_spi_num == 0) _dmatx.attachInterrupt(dmaInterrupt);
else if (_spi_num == 1) _dmatx.attachInterrupt(dmaInterrupt1);
else _dmatx.attachInterrupt(dmaInterrupt2);
Serial.print("DMA is set up on SPI ");
Serial.println(_spi_num);
_dma_state = RA8875_DMA_INIT | RA8875_DMA_EVER_INIT;
}
}
bool RA8875_t4::updateScreenAsync(bool update_cont)
// This should be removable after async updates are running
void RA8875_t4::updateScreenSync()
{
/* DEBUGGING: doing a sync update */
// Set the X/Y cursor
_writeRegister(RA8875_CURV0, 0);
_writeRegister(RA8875_CURV0+1, 0);
_writeRegister(RA8875_CURH0, 0);
_writeRegister(RA8875_CURH0+1, 0);
// start a memory write
writeCommand(RA8875_MRWC);
// Send all the screen pixel data
_startSend();
_pspi->transfer(RA8875_DATAWRITE);
uint8_t *pfbtft_end = &_pfbtft[COUNT_PIXELS_WRITE];
uint8_t *pftbft = _pfbtft;
while (pftbft < pfbtft_end) {
// Each pixel is 8 bpp...
_pspi->transfer(*pftbft++);
}
// done!
_endSend();
}
return true;
// DEBUG END
bool RA8875_t4::updateScreenAsync(bool update_cont)
{
if (!_pfbtft) return false;
initDMASettings();
if (_dma_state & RA8875_DMA_ACTIVE)
if (_dma_state & RA8875_DMA_ACTIVE) {
return false;
}
Serial.println("-");
// Half of main ram has a 32k cache. This tells it to flush the cache if necessary.
if ((uint32_t)_pfbtft >= 0x20200000u) arm_dcache_flush(_pfbtft, RA8875_WIDTH*RA8875_HEIGHT);
@ -384,7 +380,7 @@ bool RA8875_t4::updateScreenAsync(bool update_cont)
// Set transmit command register: disable RX ("mask out RX"), enable
// TX from FIFO (b/c it's not masked out), and 8-bit data transfers
// (7+1).
maybeUpdateTCR(LPSPI_TCR_PCS(3)|LPSPI_TCR_FRAMESZ(7) | LPSPI_TCR_RXMSK /*| LPSPI_TCR_CONT*/);
maybeUpdateTCR(LPSPI_TCR_FRAMESZ(7) | LPSPI_TCR_RXMSK /*| LPSPI_TCR_CONT*/);
// Set up the DMA Enable Register to enable transmit DMA (and not receive DMA)
_pimxrt_spi->DER = LPSPI_DER_TDDE;
// Clear the status register %0011 1111 0000 0000 == set DMF, REF,
@ -392,21 +388,23 @@ bool RA8875_t4::updateScreenAsync(bool update_cont)
// data match; REF: rec error flag; TEF: xmit error flag; TCF:
// xmit complete flag; FCF: frame complete flag; WCF: word
// complete flag; RDF: rec data flag; TDF: xmit data flag
_pimxrt_spi->SR = 0x3f00; // clear out all of the other status...
_pimxrt_spi->SR = 0x3f00; // Why setting these bits? Should this be '&=' ?
_dmatx.triggerAtHardwareEvent( _spi_hardware->tx_dma_channel );
_dmatx = _dmasettings[0];
_dmatx.begin(false);
_dmatx.enable();
_dma_frame_count = 0;
_dmaActiveDisplay[_spi_num] = this;
_dmatx.begin(false);
_dmatx.enable();
if (update_cont) {
_dma_state |= RA8875_DMA_CONT;
} else {
_dmasettings[2].disableOnCompletion();
_dmasettings[11].disableOnCompletion();
_dma_state &= ~RA8875_DMA_CONT;
}
_dma_state |= RA8875_DMA_ACTIVE;
return true;
}
@ -464,7 +462,7 @@ void RA8875_t4::drawPixel(int16_t x, int16_t y, uint16_t color)
uint32_t RA8875_t4::frameCount()
{
return 0;
return _dma_frame_count;
}
void RA8875_t4::writeCommand(const uint8_t d)
@ -564,7 +562,6 @@ void RA8875_t4::dmaInterrupt1(void) {
// I'm using single (not continuous) async writes, so this *should* go off; and then call the interrupt; and then clear the state, so I get a second dash printed to the serial console, showing that it's doing another update. But instead I get one dash and then the sound buffer OVERRRUN messages b/c the main thread isn't running. It's got to be the DMA code that's hanging it somewhere.
digitalWrite(13, LOW);
if (_dmaActiveDisplay[1]) {
_dmaActiveDisplay[1]->process_dma_interrupt();
}
@ -578,46 +575,40 @@ void RA8875_t4::dmaInterrupt2(void) {
void RA8875_t4::process_dma_interrupt(void) {
_dmatx.clearInterrupt();
if (_frame_callback_on_HalfDone && (_dmatx.TCD->SADDR > _dmasettings[1].TCD->SADDR)) {
_dma_sub_frame_count = 1; // set as partial frame.
_dma_frame_count++;
if ((_dma_state & RA8875_DMA_CONT) == 0) {
// Single refresh, or the user canceled, so release the CS pin
while (_pimxrt_spi->FSR & 0x1f) ; // wait until transfer is done
while (_pimxrt_spi->SR & LPSPI_SR_MBF) ; // ... and the module is not busy
_dmatx.clearComplete();
_pimxrt_spi->FCR = LPSPI_FCR_TXWATER(15);
_pimxrt_spi->DER = 0; // turn off tx and rx DMA
_pimxrt_spi->CR = LPSPI_CR_MEN | LPSPI_CR_RRF | LPSPI_CR_RTF; //RRF: reset receive FIFO; RTF: reset transmit FIFO; MEN: enable module
_pimxrt_spi->SR = 0x3f00; // Why setting these bits? Should this be '&=' ?
// DMF: data match flag set
// REF: receive error flag set
// TEF: transmit error flag set
// TCF: transfer complete flag set
// FCF: frame complete flag set
// WCF: word complete flag set
maybeUpdateTCR(LPSPI_TCR_FRAMESZ(7));
// *** the other modules send a NOP here, don't know why
_endSend();
_dma_state &= ~RA8875_DMA_ACTIVE;
_dmaActiveDisplay[_spi_num] = 0;
} else {
if (_frame_complete_callback)
(*_frame_complete_callback)();
} else {
_dma_frame_count++;
_dma_sub_frame_count = 0; // this is a full frame
if ((_dma_state & RA8875_DMA_CONT) == 0) {
// Single refresh, or the user canceled, so release the CS pin
while (_pimxrt_spi->FSR & 0x1f) ; // wait until transfer is done
while (_pimxrt_spi->SR & LPSPI_SR_MBF) ; // ... and the module is not busy
_dmatx.clearComplete();
_pimxrt_spi->FCR = LPSPI_FCR_TXWATER(15);
_pimxrt_spi->DER = 0; // turn off tx and rx DMA
_pimxrt_spi->CR = LPSPI_CR_MEN | LPSPI_CR_RRF | LPSPI_CR_RTF; //RRF: reset receive FIFO; RTF: reset transmit FIFO; MEN: enable module
_pimxrt_spi->SR = 0x3f00; // DMF|REF|TEF|TCF|FCF|WCF:
// DMF: data match flag set
// REF: receive error flag set
// TEF: transmit error flag set
// TCF: transfer complete flag set
// FCF: frame complete flag set
// WCF: word complete flag set
maybeUpdateTCR(LPSPI_TCR_PCS(3)|LPSPI_TCR_FRAMESZ(7)); // *** This is an 'assert_dc' moment
// *** the other modules send a NOP here, don't know why
_endSend();
_dma_state &= ~RA8875_DMA_ACTIVE;
_dmaActiveDisplay[_spi_num] = 0;
} else {
if (_frame_complete_callback)
(*_frame_complete_callback)();
else {
// Try to flush memory
if ((uint32_t)_pfbtft >= 0x20200000u)
arm_dcache_flush(_pfbtft, RA8875_WIDTH*RA8875_HEIGHT);
}
else {
// Try to flush memory
if ((uint32_t)_pfbtft >= 0x20200000u)
arm_dcache_flush(_pfbtft, RA8875_WIDTH*RA8875_HEIGHT);
}
// make sure the code is synchronized - memory access must be
// complete before we continue
asm("dsb");
}
// make sure the code is synchronized - memory access must be
// complete before we continue
asm("dsb");
}
// Other possible methods, that I don't think we'll need:

9
teensy/RA8875_t4.h
View File

@ -33,6 +33,7 @@ class RA8875_t4 {
void setFrameBuffer(uint8_t *frame_buffer);
bool asyncUpdateActive();
void updateScreenSync();
bool updateScreenAsync(bool update_cont = false);
void drawPixel(int16_t x, int16_t y, uint16_t color);
@ -69,7 +70,6 @@ private:
protected:
uint8_t _cs, _miso, _mosi, _sck, _rst;
volatile uint8_t _interruptStates;
SPIClass *_pspi;
IMXRT_LPSPI_t *_pimxrt_spi;
@ -78,24 +78,19 @@ private:
uint32_t _spi_clock; // desired clock
uint32_t _spi_clock_read;
uint32_t _clock; // current clock, used in starting transactions (b/c we have to slow down sometimes)
volatile uint32_t *_csport;
uint32_t _cspinmask;
// DMA stuff
DMASetting _dmasettings[3];
DMASetting _dmasettings[12];
DMAChannel _dmatx;
volatile uint32_t _dma_pixel_index = 0;
uint16_t _dma_buffer_size;
uint16_t _dma_cnt_sub_frames_per_frame;
uint32_t _spi_fcr_save;
uint8_t *_pfbtft;
volatile uint8_t _dma_state;
uint32_t _spi_tcr_current;
volatile uint32_t _dma_frame_count;
volatile uint16_t _dma_sub_frame_count;
void (*_frame_complete_callback)();
bool _frame_callback_on_HalfDone;
protected:
void DIRECT_WRITE_LOW(volatile uint32_t * base, uint32_t mask) __attribute__((always_inline)) {

8
teensy/teensy-display.cpp
View File

@ -21,7 +21,7 @@ extern const unsigned char interface_glyphs[256];
#define RA8875_HEIGHT 480
#endif
DMAMEM uint8_t dmaBuffer[RA8875_HEIGHT][RA8875_WIDTH];
DMAMEM uint8_t dmaBuffer[RA8875_HEIGHT][RA8875_WIDTH] /*__attribute__((aligned(32))*/;
#include <SPI.h>
#define _clock 20000000u // FIXME bring this up - it's under the default now
@ -112,12 +112,10 @@ void TeensyDisplay::drawImageOfSizeAt(const uint8_t *img,
void TeensyDisplay::blit()
{
// Start updates, if they're not running already
// if (!tft.asyncUpdateActive())
// tft.updateScreenAsync(true);
if (!tft.asyncUpdateActive())
tft.updateScreenAsync(true);
// DEBUGGING: not refreshing every time so I can see the machine boot
static uint32_t ctr = 0;
if (((ctr++) & 0x0F) == 0)
tft.updateScreenAsync(false);
// draw overlay, if any, occasionally
{