Use the M0 to collect SGPIO samples

firmware/common/LPC43xx_M4_memory.ld

@@ -34,4 +34,6 @@ MEMORY
 }
 
 usb_bulk_buffer = ORIGIN(ram_usb);
+usb_bulk_buffer_offset = ORIGIN(ram_shared);
+usb_bulk_buffer_tx = ORIGIN(ram_shared)+4;
 PROVIDE(__ram_m0_start__ = ORIGIN(ram_m0));

firmware/common/streaming.c

@@ -26,8 +26,6 @@
 #include <libopencm3/lpc43xx/sgpio.h>
 
 void baseband_streaming_enable(sgpio_config_t* const sgpio_config) {
-	nvic_set_priority(NVIC_SGPIO_IRQ, 0);
-	nvic_enable_irq(NVIC_SGPIO_IRQ);
 	SGPIO_SET_EN_1 = (1 << SGPIO_SLICE_A);
 
 	sgpio_cpld_stream_enable(sgpio_config);
@@ -35,6 +33,4 @@ void baseband_streaming_enable(sgpio_config_t* const sgpio_config) {
 
 void baseband_streaming_disable(sgpio_config_t* const sgpio_config) {
 	sgpio_cpld_stream_disable(sgpio_config);
-
-	nvic_disable_irq(NVIC_SGPIO_IRQ);
 }

firmware/hackrf_usb/CMakeLists.txt

@@ -35,7 +35,6 @@ set(SRC_M4
 	hackrf_usb.c
 	"${PATH_HACKRF_FIRMWARE_COMMON}/tuning.c"
 	"${PATH_HACKRF_FIRMWARE_COMMON}/streaming.c"
-	sgpio_isr.c
 	usb_bulk_buffer.c
 	"${PATH_HACKRF_FIRMWARE_COMMON}/usb.c"
 	"${PATH_HACKRF_FIRMWARE_COMMON}/usb_request.c"
@@ -63,7 +62,7 @@ set(SRC_M4
 	"${PATH_HACKRF_FIRMWARE_COMMON}/operacake.c"
 )
 
-set(SRC_M0 sgpio_m0.c)
+set(SRC_M0 sgpio_m0.s)
 
 if(BOARD STREQUAL "HACKRF_ONE")
 	SET(SRC_M4

firmware/hackrf_usb/hackrf_usb.c

@@ -249,6 +249,7 @@ int main(void) {
 	operacake_init(operacake_allow_gpio);
 
 	unsigned int phase = 0;
+	usb_bulk_buffer_offset = 0;
 
 	while(true) {
 		// Check whether we need to initiate a CPLD update

firmware/hackrf_usb/sgpio_isr.c

@@ -1,85 +0,0 @@
-/*
- * Copyright 2012 Jared Boone
- * Copyright 2013 Benjamin Vernoux
- *
- * This file is part of HackRF.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; see the file COPYING.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street,
- * Boston, MA 02110-1301, USA.
- */
-
-#include "sgpio_isr.h"
-
-#include <libopencm3/lpc43xx/sgpio.h>
-
-#include "usb_bulk_buffer.h"
-
-void sgpio_isr_rx() {
-	SGPIO_CLR_STATUS_1 = (1 << SGPIO_SLICE_A);
-
-	uint32_t* const p = (uint32_t*)&usb_bulk_buffer[usb_bulk_buffer_offset];
-	__asm__(
-		"ldr r0, [%[SGPIO_REG_SS], #44]\n\t"
-		"str r0, [%[p], #0]\n\t"
-		"ldr r0, [%[SGPIO_REG_SS], #20]\n\t"
-		"str r0, [%[p], #4]\n\t"
-		"ldr r0, [%[SGPIO_REG_SS], #40]\n\t"
-		"str r0, [%[p], #8]\n\t"
-		"ldr r0, [%[SGPIO_REG_SS], #8]\n\t"
-		"str r0, [%[p], #12]\n\t"
-		"ldr r0, [%[SGPIO_REG_SS], #36]\n\t"
-		"str r0, [%[p], #16]\n\t"
-		"ldr r0, [%[SGPIO_REG_SS], #16]\n\t"
-		"str r0, [%[p], #20]\n\t"
-		"ldr r0, [%[SGPIO_REG_SS], #32]\n\t"
-		"str r0, [%[p], #24]\n\t"
-		"ldr r0, [%[SGPIO_REG_SS], #0]\n\t"
-		"str r0, [%[p], #28]\n\t"
-		:
-		: [SGPIO_REG_SS] "l" (SGPIO_PORT_BASE + 0x100),
-		  [p] "l" (p)
-		: "r0"
-	);
-	usb_bulk_buffer_offset = (usb_bulk_buffer_offset + 32) & usb_bulk_buffer_mask;
-}
-
-void sgpio_isr_tx() {
-	SGPIO_CLR_STATUS_1 = (1 << SGPIO_SLICE_A);
-
-	uint32_t* const p = (uint32_t*)&usb_bulk_buffer[usb_bulk_buffer_offset];
-	__asm__(
-		"ldr r0, [%[p], #0]\n\t"
-		"str r0, [%[SGPIO_REG_SS], #44]\n\t"
-		"ldr r0, [%[p], #4]\n\t"
-		"str r0, [%[SGPIO_REG_SS], #20]\n\t"
-		"ldr r0, [%[p], #8]\n\t"
-		"str r0, [%[SGPIO_REG_SS], #40]\n\t"
-		"ldr r0, [%[p], #12]\n\t"
-		"str r0, [%[SGPIO_REG_SS], #8]\n\t"
-		"ldr r0, [%[p], #16]\n\t"
-		"str r0, [%[SGPIO_REG_SS], #36]\n\t"
-		"ldr r0, [%[p], #20]\n\t"
-		"str r0, [%[SGPIO_REG_SS], #16]\n\t"
-		"ldr r0, [%[p], #24]\n\t"
-		"str r0, [%[SGPIO_REG_SS], #32]\n\t"
-		"ldr r0, [%[p], #28]\n\t"
-		"str r0, [%[SGPIO_REG_SS], #0]\n\t"
-		:
-		: [SGPIO_REG_SS] "l" (SGPIO_PORT_BASE + 0x100),
-		  [p] "l" (p)
-		: "r0"
-	);
-	usb_bulk_buffer_offset = (usb_bulk_buffer_offset + 32) & usb_bulk_buffer_mask;
-}

firmware/hackrf_usb/sgpio_isr.h

@@ -1,29 +0,0 @@
-/*
- * Copyright 2012 Jared Boone
- * Copyright 2013 Benjamin Vernoux
- *
- * This file is part of HackRF.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; see the file COPYING.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street,
- * Boston, MA 02110-1301, USA.
- */
-
-#ifndef __SGPIO_ISR_H__
-#define __SGPIO_ISR_H__
-
-void sgpio_isr_rx();
-void sgpio_isr_tx();
-
-#endif/*__SGPIO_ISR_H__*/

firmware/hackrf_usb/sgpio_m0.c

@@ -1,29 +0,0 @@
-/*
- * Copyright 2020 Mike Walters <mike@flomp.net>
- *
- * This file is part of HackRF.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; see the file COPYING.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street,
- * Boston, MA 02110-1301, USA.
- */
-
-#include "gpio_lpc.h"
-
-int main() {
-	while(1) {
-		*(uint8_t*)0x400f4048 ^= 1;
-		for (volatile int i = 0; i < 10000000; i++) {}
-	}
-}

firmware/hackrf_usb/sgpio_m0.s

@@ -0,0 +1,108 @@
+/*
+ * This file is part of GreatFET
+ *
+ * Specialized SGPIO interrupt handler for Rhododendron.
+ */
+
+
+// Constants that point to registers we'll need to modify in the SGPIO block.
+.equ SGPIO_REGISTER_BLOCK_BASE,            0x40101000
+.equ SGPIO_SHADOW_REGISTERS_BASE,          0x40101100
+.equ SGPIO_EXCHANGE_INTERRUPT_CLEAR_REG,   0x40101F30
+.equ SGPIO_EXCHANGE_INTERRUPT_STATUS_REG,  0x40101F2C
+.equ SGPIO_GPIO_INPUT,                     0x40101210
+
+
+// Buffer that we're funneling data to/from.
+.equ TARGET_DATA_BUFFER,                   0x20008000
+.equ TARGET_BUFFER_POSITION,               0x20007000
+.equ TARGET_BUFFER_TX,                     0x20007004
+.equ TARGET_BUFFER_MASK,                   0x7fff
+
+.global main
+.thumb_func
+main:
+
+	// Spin until we're ready to handle an SGPIO packet:
+	// Grab the exchange interrupt staus...
+	ldr r0, =SGPIO_EXCHANGE_INTERRUPT_STATUS_REG
+	ldr r0, [r0]
+
+	// ... check to see if it has any interrupt bits set...
+	lsr r0, #1
+
+	// ... and if not, jump back to the beginning.
+	bcc main
+
+	// Clear the interrupt pending bits for the SGPIO slices we're working with.
+	ldr r0, =SGPIO_EXCHANGE_INTERRUPT_CLEAR_REG
+	ldr r1, =0xffff
+	str r1, [r0]
+
+	// Grab the base address of the SGPIO shadow registers...
+	ldr r7, =SGPIO_SHADOW_REGISTERS_BASE
+
+	// ... and grab the address of the buffer segment we want to write to / read from.
+	ldr r0, =TARGET_DATA_BUFFER       // r0 = &buffer
+	ldr r3, =TARGET_BUFFER_POSITION   // r3 = &position_in_buffer
+	ldr r2, [r3]                      // r2 = position_in_buffer
+	add r6, r0, r2                    // r6 = buffer_target = &buffer + position_in_buffer
+
+	mov r8, r3                        // Store &position_in_buffer.
+
+	// Our slice chain is set up as follows (ascending data age; arrows are reversed for flow):
+	//     L  -> F  -> K  -> C -> J  -> E  -> I  -> A
+	// Which has equivalent shadow register offsets:
+	//     44 -> 20 -> 40 -> 8 -> 36 -> 16 -> 32 -> 0
+
+	// Load direction (TX or RX)
+	ldr r0, =TARGET_BUFFER_TX
+	ldr r0, [r0]
+
+	// TX?
+	lsr r0, #1
+	bcc direction_rx
+
+direction_tx:
+
+	ldm r6!, {r0-r5}
+	str r0,  [r7, #44]
+	str r1,  [r7, #20]
+	str r2,  [r7, #40]
+	str r3,  [r7, #8 ]
+	str r4,  [r7, #36]
+	str r5,  [r7, #16]
+
+	ldm r6!, {r0-r1}
+	str r0,  [r7, #32]
+	str r1,  [r7, #0]
+
+	b done
+
+direction_rx:
+
+	// 8 cycles
+	ldr r0,  [r7, #44] // 2
+	ldr r1,  [r7, #20] // 2
+	ldr r2,  [r7, #40] // 2
+	ldr r3,  [r7, #8 ] // 2
+	ldr r4,  [r7, #36] // 2
+	ldr r5,  [r7, #16] // 2
+	stm r6!, {r0-r5}   // 7
+
+	// 6 cycles
+	ldr r0,  [r7, #32] // 2
+	ldr r1,  [r7, #0]  // 2
+	stm r6!, {r0-r1}
+
+done:
+
+	// Finally, update the buffer location...
+	ldr r0, =TARGET_BUFFER_MASK
+	and r0, r6, r0         // r0 = (position_in_buffer + size_copied) % buffer_size
+
+	// ... restore &position_in_buffer, and store the new position there...
+	mov r1, r8
+	str r0, [r1]           // position_in_buffer = (position_in_buffer + size_copied) % buffer_size
+
+	b main

firmware/hackrf_usb/usb_api_transceiver.c

@@ -24,8 +24,7 @@
 
 #include "hackrf-ui.h"
 #include <libopencm3/cm3/vector.h>
-#include <libopencm3/lpc43xx/m4/nvic.h>
+#include "usb_bulk_buffer.h"
-#include "sgpio_isr.h"
 
 #include "usb_api_cpld.h" // Remove when CPLD update is handled elsewhere
 
@@ -257,18 +256,18 @@ void set_transceiver_mode(const transceiver_mode_t new_transceiver_mode) {
 		led_on(LED2);
 		usb_endpoint_init(&usb_endpoint_bulk_in);
 		rf_path_set_direction(&rf_path, RF_PATH_DIRECTION_RX);
-		vector_table.irq[NVIC_SGPIO_IRQ] = sgpio_isr_rx;
+		usb_bulk_buffer_tx = false;
 	} else if (_transceiver_mode == TRANSCEIVER_MODE_TX) {
 		led_off(LED2);
 		led_on(LED3);
 		usb_endpoint_init(&usb_endpoint_bulk_out);
 		rf_path_set_direction(&rf_path, RF_PATH_DIRECTION_TX);
-		vector_table.irq[NVIC_SGPIO_IRQ] = sgpio_isr_tx;
+		usb_bulk_buffer_tx = true;
 	} else {
 		led_off(LED2);
 		led_off(LED3);
 		rf_path_set_direction(&rf_path, RF_PATH_DIRECTION_OFF);
-		vector_table.irq[NVIC_SGPIO_IRQ] = sgpio_isr_rx;
+		usb_bulk_buffer_tx = false;
 	}
 
 

firmware/hackrf_usb/usb_bulk_buffer.c

@@ -22,5 +22,4 @@
 
 #include "usb_bulk_buffer.h"
 
-const uint32_t usb_bulk_buffer_mask = 32768 - 1;
 volatile uint32_t usb_bulk_buffer_offset = 0;

firmware/hackrf_usb/usb_bulk_buffer.h

@@ -23,6 +23,7 @@
 #ifndef __USB_BULK_BUFFER_H__
 #define __USB_BULK_BUFFER_H__
 
+#include <stdbool.h>
 #include <stdint.h>
 
 /* Address of usb_bulk_buffer is set in ldscripts. If you change the name of this
@@ -31,8 +32,8 @@
  */
 extern uint8_t usb_bulk_buffer[32768];
 
-extern const uint32_t usb_bulk_buffer_mask;
-
 extern volatile uint32_t usb_bulk_buffer_offset;
 
+extern bool usb_bulk_buffer_tx;
+
 #endif/*__USB_BULK_BUFFER_H__*/