From edc7a2bb80656f64fa44baf63dfb57e106070a13 Mon Sep 17 00:00:00 2001
From: Peter van der Perk <57130844+PetervdPerk-NXP@users.noreply.github.com>
Date: Fri, 10 Oct 2025 19:46:26 +0200
Subject: [PATCH] fmu-v6xrt: Add DTCM to heap (#25733)

Move ramvectors from DTCM to ITCM, this seems to better in general.
Also ITCM is marked as RO so is safer anyhow, now that DTCM is fully
unused we add DTCM region of 256kB to memory allocator. Increases usable
memory from 1536kB to 1792kB and decrease system load a bit since DTCM
is faster
---
 boards/px4/fmu-v6xrt/nuttx-config/nsh/defconfig     | 6 ++++--
 boards/px4/fmu-v6xrt/nuttx-config/scripts/script.ld | 9 ++-------
 2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/boards/px4/fmu-v6xrt/nuttx-config/nsh/defconfig b/boards/px4/fmu-v6xrt/nuttx-config/nsh/defconfig
index 0ab458bed6..855c435833 100644
--- a/boards/px4/fmu-v6xrt/nuttx-config/nsh/defconfig
+++ b/boards/px4/fmu-v6xrt/nuttx-config/nsh/defconfig
@@ -78,7 +78,8 @@ CONFIG_HAVE_CXXINITIALIZE=y
 CONFIG_I2C=y
 CONFIG_I2C_RESET=y
 CONFIG_IDLETHREAD_STACKSIZE=2048
-CONFIG_IMXRT_DTCM=0
+CONFIG_IMXRT_DTCM=256
+CONFIG_IMXRT_DTCM_HEAP=y
 CONFIG_IMXRT_EDMA=y
 CONFIG_IMXRT_EDMA_EDBG=y
 CONFIG_IMXRT_EDMA_ELINK=y
@@ -104,7 +105,7 @@ CONFIG_IMXRT_GPIO6_0_15_IRQ=y
 CONFIG_IMXRT_GPIO6_16_31_IRQ=y
 CONFIG_IMXRT_GPIO_IRQ=y
 CONFIG_IMXRT_INIT_FLEXRAM=y
-CONFIG_IMXRT_ITCM=0
+CONFIG_IMXRT_ITCM=256
 CONFIG_IMXRT_LPI2C1=y
 CONFIG_IMXRT_LPI2C2=y
 CONFIG_IMXRT_LPI2C3=y
@@ -190,6 +191,7 @@ CONFIG_MEMSET_64BIT=y
 CONFIG_MEMSET_OPTSPEED=y
 CONFIG_MMCSD=y
 CONFIG_MMCSD_SDIO=y
+CONFIG_MM_REGIONS=2
 CONFIG_MTD=y
 CONFIG_MTD_BYTE_WRITE=y
 CONFIG_MTD_PARTITION=y
diff --git a/boards/px4/fmu-v6xrt/nuttx-config/scripts/script.ld b/boards/px4/fmu-v6xrt/nuttx-config/scripts/script.ld
index 70d861f30a..f9eb6915d0 100644
--- a/boards/px4/fmu-v6xrt/nuttx-config/scripts/script.ld
+++ b/boards/px4/fmu-v6xrt/nuttx-config/scripts/script.ld
@@ -35,7 +35,7 @@
 MEMORY
 {
   flash (rx)  : ORIGIN = 0x30020000, LENGTH = 4M-128K /* We have 64M but we do not want to wait to program it all */
-  sram  (rwx) : ORIGIN = 0x20240000, LENGTH = 2M-256k-512k
+  sram  (rwx) : ORIGIN = 0x20240000, LENGTH = 2M-256k
   itcm  (rwx) : ORIGIN = 0x00000000, LENGTH = 256K   /* TODO FlexRAM partition */
   dtcm  (rwx) : ORIGIN = 0x20000000, LENGTH = 256K
 }
@@ -83,6 +83,7 @@ SECTIONS
         _sitcmfuncs = ABSOLUTE(.);
         FILL(0xFF)
         . = 0x40 ;
+        *(.ram_vectors)
         INCLUDE "itcm_static_functions.ld"
         INCLUDE "itcm_functions_includes.ld"
         . = ALIGN(8);
@@ -91,12 +92,6 @@ SECTIONS
 
     _fitcmfuncs = LOADADDR(.itcmfunc);
 
-    /* The RAM vector table (if present) should lie at the beginning of SRAM */
-
-    .ram_vectors (COPY) : {
-        *(.ram_vectors)
-    } > dtcm
-
     .text : ALIGN(4)
     {
         _stext = ABSOLUTE(.);