Move M0 offset and tx variables into a state struct.

These variables are already placed together; this commit just groups
them into a struct and declares this in a new header.

This commit should not result in any change to the firmware binary.
Only the names of symbols are changed.

firmware/common/LPC43xx_M4_memory.ld

@@ -34,6 +34,5 @@ MEMORY
 }
 
 usb_bulk_buffer = ORIGIN(ram_usb);
-usb_bulk_buffer_offset = ORIGIN(ram_shared);
-usb_bulk_buffer_tx = ORIGIN(ram_shared)+4;
+m0_state = ORIGIN(ram_shared);
 PROVIDE(__ram_m0_start__ = ORIGIN(ram_m0));

firmware/hackrf_usb/m0_state.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2022 Great Scott Gadgets
+ *
+ * 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 __M0_STATE_H__
+#define __M0_STATE_H__
+
+struct m0_state {
+	uint32_t offset;
+	uint32_t tx;
+};
+
+/* Address of m0_state is set in ldscripts. If you change the name of this
+ * variable, it won't be where it needs to be in the processor's address space,
+ * unless you also adjust the ldscripts.
+ */
+extern volatile struct m0_state m0_state;
+
+#endif/*__M0_STATE_H__*/

firmware/hackrf_usb/usb_api_sweep.c

@@ -25,6 +25,7 @@
 #include <hackrf_core.h>
 #include "usb_api_transceiver.h"
 #include "usb_bulk_buffer.h"
+#include "m0_state.h"
 #include "tuning.h"
 #include "usb_endpoint.h"
 #include "streaming.h"
@@ -99,7 +100,7 @@ void sweep_mode(void) {
 
 	while (TRANSCEIVER_MODE_RX_SWEEP == transceiver_mode()) {
 		// Set up IN transfer of buffer 0.
-		if ( usb_bulk_buffer_offset >= 16384 && phase == 1) {
+		if ( m0_state.offset >= 16384 && phase == 1) {
 			transfer = true;
 			buffer = &usb_bulk_buffer[0x0000];
 			phase = 0;
@@ -107,7 +108,7 @@ void sweep_mode(void) {
 		}
 
 		// Set up IN transfer of buffer 1.
-		if ( usb_bulk_buffer_offset < 16384 && phase == 0) {
+		if ( m0_state.offset < 16384 && phase == 0) {
 			transfer = true;
 			buffer = &usb_bulk_buffer[0x4000];
 			phase = 1;

firmware/hackrf_usb/usb_api_transceiver.c

@@ -27,6 +27,7 @@
 
 #include <libopencm3/cm3/vector.h>
 #include "usb_bulk_buffer.h"
+#include "m0_state.h"
 
 #include "usb_api_cpld.h" // Remove when CPLD update is handled elsewhere
 
@@ -262,20 +263,20 @@ void set_transceiver_mode(const transceiver_mode_t new_transceiver_mode) {
 		led_off(LED3);
 		led_on(LED2);
 		rf_path_set_direction(&rf_path, RF_PATH_DIRECTION_RX);
-		usb_bulk_buffer_tx = false;
+		m0_state.tx = false;
 		break;
 	case TRANSCEIVER_MODE_TX:
 		led_off(LED2);
 		led_on(LED3);
 		rf_path_set_direction(&rf_path, RF_PATH_DIRECTION_TX);
-		usb_bulk_buffer_tx = true;
+		m0_state.tx = true;
 		break;
 	case TRANSCEIVER_MODE_OFF:
 	default:
 		led_off(LED2);
 		led_off(LED3);
 		rf_path_set_direction(&rf_path, RF_PATH_DIRECTION_OFF);
-		usb_bulk_buffer_tx = false;
+		m0_state.tx = false;
 	}
 
 
@@ -284,7 +285,7 @@ void set_transceiver_mode(const transceiver_mode_t new_transceiver_mode) {
 
         hw_sync_enable(_hw_sync_mode);
 
-		usb_bulk_buffer_offset = 0;
+		m0_state.offset = 0;
 	}
 }
 
@@ -330,7 +331,7 @@ void rx_mode(void) {
 
 	while (TRANSCEIVER_MODE_RX == _transceiver_mode) {
 		// Set up IN transfer of buffer 0.
-		if (16384 <= usb_bulk_buffer_offset && 1 == phase) {
+		if (16384 <= m0_state.offset && 1 == phase) {
 			usb_transfer_schedule_block(
 				&usb_endpoint_bulk_in,
 				&usb_bulk_buffer[0x0000],
@@ -340,7 +341,7 @@ void rx_mode(void) {
 			phase = 0;
 		}
 		// Set up IN transfer of buffer 1.
-		if (16384 > usb_bulk_buffer_offset && 0 == phase) {
+		if (16384 > m0_state.offset && 0 == phase) {
 			usb_transfer_schedule_block(
 				&usb_endpoint_bulk_in,
 				&usb_bulk_buffer[0x4000],
@@ -368,7 +369,7 @@ void tx_mode(void) {
 
 	while (TRANSCEIVER_MODE_TX == _transceiver_mode) {
 		// Set up OUT transfer of buffer 0.
-		if (16384 <= usb_bulk_buffer_offset && 1 == phase) {
+		if (16384 <= m0_state.offset && 1 == phase) {
 			usb_transfer_schedule_block(
 				&usb_endpoint_bulk_out,
 				&usb_bulk_buffer[0x0000],
@@ -378,7 +379,7 @@ void tx_mode(void) {
 			phase = 0;
 		}
 		// Set up OUT transfer of buffer 1.
-		if (16384 > usb_bulk_buffer_offset && 0 == phase) {
+		if (16384 > m0_state.offset && 0 == phase) {
 			usb_transfer_schedule_block(
 				&usb_endpoint_bulk_out,
 				&usb_bulk_buffer[0x4000],

firmware/hackrf_usb/usb_bulk_buffer.h

@@ -32,8 +32,4 @@
  */
 extern uint8_t usb_bulk_buffer[32768];
 
-extern volatile uint32_t usb_bulk_buffer_offset;
-
-extern bool usb_bulk_buffer_tx;
-
 #endif/*__USB_BULK_BUFFER_H__*/