text: /*
   * Code shared between SPL and U-Boot proper
   *
   * Copyright (c) 2015 Google, Inc
   * Written by Simon Glass <sjg@chromium.org>
   *
   * SPDX-License-Identifier:	GPL-2.0+
   */
  
  #include <common.h>
  
  DECLARE_GLOBAL_DATA_PTR;
  
  /*
   * It isn't trivial to figure out whether memcpy() exists. The arch-specific
   * memcpy() is not normally available in SPL due to code size.
   */
  #if !defined(CONFIG_SPL_BUILD) || \
  		(defined(CONFIG_SPL_LIBGENERIC_SUPPORT) && \
  		!defined(CONFIG_USE_ARCH_MEMSET))
  #define _USE_MEMCPY
  #endif
  
  /* Unfortunately x86 or ARM can't compile this code as gd cannot be assigned */
  #if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
  __weak void arch_setup_gd(struct global_data *gd_ptr)
  {
  	gd = gd_ptr;
  }
  #endif /* !CONFIG_X86 && !CONFIG_ARM */
  
  /*
   * Allocate reserved space for use as 'globals' from 'top' address and
   * return 'bottom' address of allocated space
   *
   * Notes:
   *
   * Actual reservation cannot be done from within this function as
   * it requires altering the C stack pointer, so this will be done by
   * the caller upon return from this function.
   *
   * IMPORTANT:
   *
   * Alignment constraints may differ for each 'chunk' allocated. For now:
   *
   * - GD is aligned down on a 16-byte boundary
   *
   *  - the early malloc arena is not aligned, therefore it follows the stack
   *   alignment constraint of the architecture for which we are bulding.
   *
   *  - GD is allocated last, so that the return value of this functions is
   *   both the bottom of the reserved area and the address of GD, should
   *   the calling context need it.
   */
  
  ulong board_init_f_alloc_reserve(ulong top)
  {
  	/* Reserve early malloc arena */
  #if defined(CONFIG_SYS_MALLOC_F)
  	top -= CONFIG_SYS_MALLOC_F_LEN;
  #endif
  	/* LAST : reserve GD (rounded up to a multiple of 16 bytes) */
  	top = rounddown(top-sizeof(struct global_data), 16);
  
  	return top;
  }
  
  /*
   * Initialize reserved space (which has been safely allocated on the C
   * stack from the C runtime environment handling code).
   *
   * Notes:
   *
   * Actual reservation was done by the caller; the locations from base
   * to base+size-1 (where 'size' is the value returned by the allocation
   * function above) can be accessed freely without risk of corrupting the
   * C runtime environment.
   *
   * IMPORTANT:
   *
   * Upon return from the allocation function above, on some architectures
   * the caller will set gd to the lowest reserved location. Therefore, in
   * this initialization function, the global data MUST be placed at base.
   *
   * ALSO IMPORTANT:
   *
   * On some architectures, gd will already be good when entering this
   * function. On others, it will only be good once arch_setup_gd() returns.
   * Therefore, global data accesses must be done:
   *
   * - through gd_ptr if before the call to arch_setup_gd();
   *
   * - through gd once arch_setup_gd() has been called.
   *
   * Do not use 'gd->' until arch_setup_gd() has been called!
   *
   * IMPORTANT TOO:
   *
   * Initialization for each "chunk" (GD, early malloc arena...) ends with
   * an incrementation line of the form 'base += <some size>'. The last of
   * these incrementations seems useless, as base will not be used any
   * more after this incrementation; but if/when a new "chunk" is appended,
   * this increment will be essential as it will give base right value for
   * this new chunk (which will have to end with its own incrementation
   * statement). Besides, the compiler's optimizer will silently detect
   * and remove the last base incrementation, therefore leaving that last
   * (seemingly useless) incrementation causes no code increase.
   */
  
  void board_init_f_init_reserve(ulong base)
  {
  	struct global_data *gd_ptr;
  #ifndef _USE_MEMCPY
  	int *ptr;
  #endif
  
  	/*
  	 * clear GD entirely and set it up.
  	 * Use gd_ptr, as gd may not be properly set yet.
  	 */
  
  	gd_ptr = (struct global_data *)base;
  	/* zero the area */
  #ifdef _USE_MEMCPY
  	memset(gd_ptr, '\0', sizeof(*gd));
  #else
  	for (ptr = (int *)gd_ptr; ptr < (int *)(gd_ptr + 1); )
  		*ptr++ = 0;
  #endif
  	/* set GD unless architecture did it already */
  #if !defined(CONFIG_ARM)
  	arch_setup_gd(gd_ptr);
  #endif
  	/* next alloc will be higher by one GD plus 16-byte alignment */
  	base += roundup(sizeof(struct global_data), 16);
  
  	/*
  	 * record early malloc arena start.
  	 * Use gd as it is now properly set for all architectures.
  	 */
  
  #if defined(CONFIG_SYS_MALLOC_F)
  	/* go down one 'early malloc arena' */
  	gd->malloc_base = base;
  	/* next alloc will be higher by one 'early malloc arena' size */
  	base += CONFIG_SYS_MALLOC_F_LEN;
  #endif
  }
  