Quad I2S input for Teensy 4.0

input_i2s_quad.cpp

 #include <Arduino.h>
 #include "input_i2s_quad.h"
 #include "output_i2s_quad.h"
+#include "output_i2s.h"
 
-DMAMEM static uint32_t i2s_rx_buffer[AUDIO_BLOCK_SAMPLES*2];
+DMAMEM __attribute__((aligned(32))) static uint32_t i2s_rx_buffer[AUDIO_BLOCK_SAMPLES*2];
 audio_block_t * AudioInputI2SQuad::block_ch1 = NULL;
 audio_block_t * AudioInputI2SQuad::block_ch2 = NULL;
 audio_block_t * AudioInputI2SQuad::block_ch3 = NULL;
 bool AudioInputI2SQuad::update_responsibility = false;
 DMAChannel AudioInputI2SQuad::dma(false);
 
-#if defined(__MK20DX256__) || defined(__MK64FX512__) || defined(__MK66FX1M0__)
+#if defined(__MK20DX256__) || defined(__MK64FX512__) || defined(__MK66FX1M0__) || defined(__IMXRT1062__)
 
 void AudioInputI2SQuad::begin(void)
 {
 	dma.begin(true); // Allocate the DMA channel first
 
+#if defined(KINETISK)
 	// TODO: should we set & clear the I2S_RCSR_SR bit here?
 	AudioOutputI2SQuad::config_i2s();
 
 	I2S0_RCSR |= I2S_RCSR_RE | I2S_RCSR_BCE | I2S_RCSR_FRDE | I2S_RCSR_FR;
 	I2S0_TCSR |= I2S_TCSR_TE | I2S_TCSR_BCE; // TX clock enable, because sync'd to TX
 	dma.attachInterrupt(isr);
+
+#elif defined(__IMXRT1062__)
+	const int pinoffset = 0; // TODO: make this configurable...
+	AudioOutputI2S::config_i2s();
+	I2S1_RCR3 = I2S_RCR3_RCE_2CH << pinoffset;
+	switch (pinoffset) {
+	  case 0:
+		CORE_PIN8_CONFIG = 3;
+		CORE_PIN6_CONFIG = 3;
+		IOMUXC_SAI1_RX_DATA0_SELECT_INPUT = 2; // GPIO_B1_00_ALT3, pg 873
+		IOMUXC_SAI1_RX_DATA1_SELECT_INPUT = 1; // GPIO_B0_10_ALT3, pg 873
+		break;
+	  case 1:
+		CORE_PIN6_CONFIG = 3;
+		CORE_PIN9_CONFIG = 3;
+		IOMUXC_SAI1_RX_DATA1_SELECT_INPUT = 1; // GPIO_B0_10_ALT3, pg 873
+		IOMUXC_SAI1_RX_DATA2_SELECT_INPUT = 1; // GPIO_B0_11_ALT3, pg 874
+		break;
+	  case 2:
+		CORE_PIN9_CONFIG = 3;
+		CORE_PIN32_CONFIG = 3;
+		IOMUXC_SAI1_RX_DATA2_SELECT_INPUT = 1; // GPIO_B0_11_ALT3, pg 874
+		IOMUXC_SAI1_RX_DATA3_SELECT_INPUT = 1; // GPIO_B0_12_ALT3, pg 875
+		break;
+	}
+	dma.TCD->SADDR = (void *)((uint32_t)&I2S1_RDR0 + 2 + pinoffset * 4);
+	dma.TCD->SOFF = 4;
+	dma.TCD->ATTR = DMA_TCD_ATTR_SSIZE(1) | DMA_TCD_ATTR_DSIZE(1);
+	dma.TCD->NBYTES_MLOFFYES = DMA_TCD_NBYTES_SMLOE |
+		DMA_TCD_NBYTES_MLOFFYES_MLOFF(-8) |
+		DMA_TCD_NBYTES_MLOFFYES_NBYTES(4);
+	dma.TCD->SLAST = -8;
+	dma.TCD->DADDR = i2s_rx_buffer;
+	dma.TCD->DOFF = 2;
+	dma.TCD->CITER_ELINKNO = AUDIO_BLOCK_SAMPLES * 2;
+	dma.TCD->DLASTSGA = -sizeof(i2s_rx_buffer);
+	dma.TCD->BITER_ELINKNO = AUDIO_BLOCK_SAMPLES * 2;
+	dma.TCD->CSR = DMA_TCD_CSR_INTHALF | DMA_TCD_CSR_INTMAJOR;
+	dma.triggerAtHardwareEvent(DMAMUX_SOURCE_SAI1_RX);
+
+	I2S1_RCSR = 0;
+	I2S1_RCR3 = I2S_RCR3_RCE_2CH << pinoffset;
+
+	I2S1_RCSR = I2S_RCSR_RE | I2S_RCSR_BCE | I2S_RCSR_FRDE | I2S_RCSR_FR;
+	update_responsibility = update_setup();
+	dma.enable();
+	dma.attachInterrupt(isr);
+#endif
 }
 
 void AudioInputI2SQuad::isr(void)
 	if (block_ch1) {
 		offset = block_offset;
 		if (offset <= AUDIO_BLOCK_SAMPLES/2) {
+			arm_dcache_delete(src, sizeof(i2s_rx_buffer) / 2);
 			block_offset = offset + AUDIO_BLOCK_SAMPLES/2;
 			dest1 = &(block_ch1->data[offset]);
 			dest2 = &(block_ch2->data[offset]);