openthread: platform: radio_spinel: Spinel variables on global memory

This commits aims to move spinel related variables from heap to global
arrays.
In this way, HEAP_MEM_POOL_ADD_SIZE_ does not need to be defined, or
updated if any change in data structure might occur.

Signed-off-by: Cristian Bulacu <[email protected]>

Author: Cristib05

modules/openthread/platform/radio_spinel.cpp

@@ -1,6 +1,6 @@
 /*
  *  Copyright (c) 2021, The OpenThread Authors.
- *  Copyright (c) 2022-2024, NXP.
+ *  Copyright (c) 2022-2025, NXP.
  *
  *  All rights reserved.
  *
@@ -46,6 +46,8 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME, CONFIG_OPENTHREAD_PLATFORM_LOG_LEVEL);
 #include <zephyr/kernel.h>
 #include <zephyr/net/net_pkt.h>
 #include <openthread-system.h>
+#include <stdalign.h>
+#include <common/new.hpp>
 
 enum pending_events {
 	PENDING_EVENT_FRAME_TO_SEND, /* There is a tx frame to send  */
@@ -60,6 +62,11 @@ static ot::Url::Url *psRadioUrl;
 static ot::Hdlc::HdlcInterface *pSpinelInterface;
 static ot::Spinel::SpinelDriver *psSpinelDriver;
 
+alignas(ot::Spinel::RadioSpinel) static uint8_t gRadioBuf[sizeof(ot::Spinel::RadioSpinel)];
+alignas(ot::Url::Url) static uint8_t gUrlBuf[sizeof(ot::Url::Url)];
+alignas(ot::Hdlc::HdlcInterface) static uint8_t gIfaceBuf[sizeof(ot::Hdlc::HdlcInterface)];
+alignas(ot::Spinel::SpinelDriver) static uint8_t gDriverBuf[sizeof(ot::Spinel::SpinelDriver)];
+
 static const otRadioCaps sRequiredRadioCaps =
 #if OPENTHREAD_CONFIG_THREAD_VERSION >= OT_THREAD_VERSION_1_2
 	OT_RADIO_CAPS_TRANSMIT_SEC | OT_RADIO_CAPS_TRANSMIT_TIMING |
@@ -527,11 +534,11 @@ extern "C" void platformRadioInit(void)
 
 	iidList[0] = 0;
 
-	psRadioSpinel = new ot::Spinel::RadioSpinel();
-	psSpinelDriver = new ot::Spinel::SpinelDriver();
+	psRadioSpinel = new(gRadioBuf) ot::Spinel::RadioSpinel();
+	psSpinelDriver = new(gDriverBuf) ot::Spinel::SpinelDriver();
 
-	psRadioUrl = new ot::Url::Url();
-	pSpinelInterface = new ot::Hdlc::HdlcInterface(*psRadioUrl);
+	psRadioUrl = new(gUrlBuf) ot::Url::Url();
+	pSpinelInterface = new(gIfaceBuf) ot::Hdlc::HdlcInterface(*psRadioUrl);
 
 	OT_UNUSED_VARIABLE(psSpinelDriver->Init(*pSpinelInterface, true /* aSoftwareReset */,
 						iidList, OT_ARRAY_LENGTH(iidList)));