/* STM32H750XBHx - RT-Thread linker script (GCC/ld)
 *
 * XIP QSPI FLASH: 0x9000_0000 (8MB)  -> .isr_vector/.text/.rodata/const tables
 * DTCM RAM     : 0x2000_0000 (128KB)-> .data/.bss (fast CPU access, NOT for DMA)
 * AXI SRAM     : 0x2400_0000 (512KB)-> system heap recommended
 * D2 SRAM      : 0x3000_0000 (288KB)-> USB DMA buffers (nocache/buffer) recommended
 * D3 SRAM      : 0x3800_0000 (64KB)
 * ITCM RAM     : 0x0000_0000 (64KB)
 */

ENTRY(Reset_Handler)

/* Memory regions */
MEMORY
{
  ITCMRAM (xrw)  : ORIGIN = 0x00000000, LENGTH = 64K
  DTCMRAM (xrw)  : ORIGIN = 0x20000000, LENGTH = 128K
  RAM    (xrw)   : ORIGIN = 0x24000000, LENGTH = 512K
  RAM_D2 (xrw)   : ORIGIN = 0x30000000, LENGTH = 288K
  RAM_D3 (xrw)   : ORIGIN = 0x38000000, LENGTH = 64K
  FLASH  (rx)    : ORIGIN = 0x90000000, LENGTH = 8192K
}

/* MSP stack top (startup uses this) */
_estack = ORIGIN(DTCMRAM) + LENGTH(DTCMRAM);

/* Only for link-check / startup template compatibility
 * NOTE: RT-Thread thread stacks are NOT defined by this.
 */
_Min_Stack_Size = 0x800;
_Min_Heap_Size  = 0x400;

/* RT-Thread heap range in AXI SRAM (use these in board.c/board.h) */
PROVIDE(__heap_start__ = ORIGIN(RAM));
PROVIDE(__heap_end__   = ORIGIN(RAM) + LENGTH(RAM));

SECTIONS
{
  /* Vector table */
  .isr_vector :
  {
    . = ALIGN(4);
    KEEP(*(.isr_vector))
    . = ALIGN(4);
  } > FLASH

  /* Code + rodata + RT-Thread tables */
  .text :
  {
    . = ALIGN(4);
    _stext = .;

    *(.text)
    *(.text*)
    *(.glue_7)
    *(.glue_7t)
    *(.eh_frame)

    *(.rodata)
    *(.rodata*)

    /* finsh shell symbol table */
    . = ALIGN(4);
    __fsymtab_start = .;
    KEEP(*(FSymTab))
    __fsymtab_end = .;

    . = ALIGN(4);
    __vsymtab_start = .;
    KEEP(*(VSymTab))
    __vsymtab_end = .;

    /* rt_init section */
    . = ALIGN(4);
    __rt_init_start = .;
    KEEP(*(SORT(.rti_fn*)))
    __rt_init_end = .;

    /* optional old-style ctors/dtors (some libs still emit these) */
    . = ALIGN(4);
    PROVIDE(__ctors_start__ = .);
    KEEP(*(SORT(.ctors.*)))
    KEEP(*(.ctors))
    PROVIDE(__ctors_end__ = .);

    . = ALIGN(4);
    PROVIDE(__dtors_start__ = .);
    KEEP(*(SORT(.dtors.*)))
    KEEP(*(.dtors))
    PROVIDE(__dtors_end__ = .);

    . = ALIGN(4);
    _etext = .;
  } > FLASH

  /* ARM exception tables */
  .ARM.extab :
  {
    . = ALIGN(4);
    *(.ARM.extab* .gnu.linkonce.armextab.*)
    . = ALIGN(4);
  } > FLASH

  .ARM.exidx :
  {
    . = ALIGN(4);
    __exidx_start = .;
    *(.ARM.exidx* .gnu.linkonce.armexidx.*)
    __exidx_end = .;
    . = ALIGN(4);
  } > FLASH

  /* C++ init arrays */
  .preinit_array :
  {
    . = ALIGN(4);
    PROVIDE_HIDDEN(__preinit_array_start = .);
    KEEP(*(.preinit_array*))
    PROVIDE_HIDDEN(__preinit_array_end = .);
    . = ALIGN(4);
  } > FLASH

  .init_array :
  {
    . = ALIGN(4);
    PROVIDE_HIDDEN(__init_array_start = .);
    KEEP(*(SORT(.init_array.*)))
    KEEP(*(.init_array*))
    PROVIDE_HIDDEN(__init_array_end = .);
    . = ALIGN(4);
  } > FLASH

  .fini_array :
  {
    . = ALIGN(4);
    PROVIDE_HIDDEN(__fini_array_start = .);
    KEEP(*(SORT(.fini_array.*)))
    KEEP(*(.fini_array*))
    PROVIDE_HIDDEN(__fini_array_end = .);
    . = ALIGN(4);
  } > FLASH

  /* Initialized data -> DTCM, load from FLASH */
  .data :
  {
    . = ALIGN(4);
    _sdata = .;

    *(.data)
    *(.data*)
    *(.RamFunc)
    *(.RamFunc*)

    . = ALIGN(4);
    _edata = .;
  } > DTCMRAM AT> FLASH

  /* Used by startup to copy .data from FLASH to DTCM */
  _sidata = LOADADDR(.data);

  /* BSS -> DTCM */
  .bss (NOLOAD) :
  {
    . = ALIGN(4);
    _sbss = .;
    __bss_start__ = _sbss;

    *(.bss)
    *(.bss*)
    *(COMMON)

    . = ALIGN(4);
    _ebss = .;
    __bss_end__ = _ebss;
    PROVIDE(__bss_end = .);
  } > DTCMRAM

  /* ---------------- USB DMA buffers in D2 SRAM ----------------
   * Put all USB DMA related buffers here:
   *   __attribute__((section(".usb_nocache"))) / ".noncacheable"
   * Align to 32 bytes for safety (future D-Cache + cache-line ops)
   */
  .usb_nocache (NOLOAD) :
  {
    . = ALIGN(32);
    __usb_nocache_start__ = .;

    *(.usb_nocache)
    *(.usb_nocache*)
    *(.noncacheable)
    *(.noncacheable*)

    . = ALIGN(32);
    __usb_nocache_end__ = .;
  } > RAM_D2

  /* End symbols (end of DTCM used sections) */
  PROVIDE(end = .);
  PROVIDE(_end = .);

  /* Link check: ensure DTCM has room for at least Min Stack */
  ._user_stack (NOLOAD) :
  {
    . = ALIGN(8);
    . = . + _Min_Stack_Size;
    . = ALIGN(8);
  } > DTCMRAM
}

/* Optional: sanity checks */
ASSERT(_ebss <= (ORIGIN(DTCMRAM) + LENGTH(DTCMRAM)), "DTCMRAM overflow: .data/.bss too large");
ASSERT(__usb_nocache_end__ <= (ORIGIN(RAM_D2) + LENGTH(RAM_D2)), "D2 overflow: USB nocache section too large");