common/init/board_init.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Code shared between SPL and U-Boot proper
   4  *
   5  * Copyright (c) 2015 Google, Inc
   6  * Written by Simon Glass <sjg@chromium.org>
   7  */
   8
   9 #include <common.h>
  10
  11 DECLARE_GLOBAL_DATA_PTR;
  12
  13 /* Unfortunately x86 or ARM can't compile this code as gd cannot be assigned */
  14 #if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
  15 __weak void arch_setup_gd(struct global_data *gd_ptr)
  16 {
  17         gd = gd_ptr;
  18 }
  19 #endif /* !CONFIG_X86 && !CONFIG_ARM */
  20
  21 /*
  22  * Allocate reserved space for use as 'globals' from 'top' address and
  23  * return 'bottom' address of allocated space
  24  *
  25  * Notes:
  26  *
  27  * Actual reservation cannot be done from within this function as
  28  * it requires altering the C stack pointer, so this will be done by
  29  * the caller upon return from this function.
  30  *
  31  * IMPORTANT:
  32  *
  33  * Alignment constraints may differ for each 'chunk' allocated. For now:
  34  *
  35  * - GD is aligned down on a 16-byte boundary
  36  *
  37  *  - the early malloc arena is not aligned, therefore it follows the stack
  38  *   alignment constraint of the architecture for which we are bulding.
  39  *
  40  *  - GD is allocated last, so that the return value of this functions is
  41  *   both the bottom of the reserved area and the address of GD, should
  42  *   the calling context need it.
  43  */
  44
  45 ulong board_init_f_alloc_reserve(ulong top)
  46 {
  47         /* Reserve early malloc arena */
  48 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
  49         top -= CONFIG_VAL(SYS_MALLOC_F_LEN);
  50 #endif
  51         /* LAST : reserve GD (rounded up to a multiple of 16 bytes) */
  52         top = rounddown(top-sizeof(struct global_data), 16);
  53
  54         return top;
  55 }
  56
  57 /*
  58  * Initialize reserved space (which has been safely allocated on the C
  59  * stack from the C runtime environment handling code).
  60  *
  61  * Notes:
  62  *
  63  * Actual reservation was done by the caller; the locations from base
  64  * to base+size-1 (where 'size' is the value returned by the allocation
  65  * function above) can be accessed freely without risk of corrupting the
  66  * C runtime environment.
  67  *
  68  * IMPORTANT:
  69  *
  70  * Upon return from the allocation function above, on some architectures
  71  * the caller will set gd to the lowest reserved location. Therefore, in
  72  * this initialization function, the global data MUST be placed at base.
  73  *
  74  * ALSO IMPORTANT:
  75  *
  76  * On some architectures, gd will already be good when entering this
  77  * function. On others, it will only be good once arch_setup_gd() returns.
  78  * Therefore, global data accesses must be done:
  79  *
  80  * - through gd_ptr if before the call to arch_setup_gd();
  81  *
  82  * - through gd once arch_setup_gd() has been called.
  83  *
  84  * Do not use 'gd->' until arch_setup_gd() has been called!
  85  *
  86  * IMPORTANT TOO:
  87  *
  88  * Initialization for each "chunk" (GD, early malloc arena...) ends with
  89  * an incrementation line of the form 'base += <some size>'. The last of
  90  * these incrementations seems useless, as base will not be used any
  91  * more after this incrementation; but if/when a new "chunk" is appended,
  92  * this increment will be essential as it will give base right value for
  93  * this new chunk (which will have to end with its own incrementation
  94  * statement). Besides, the compiler's optimizer will silently detect
  95  * and remove the last base incrementation, therefore leaving that last
  96  * (seemingly useless) incrementation causes no code increase.
  97  */
  98
  99 void board_init_f_init_reserve(ulong base)
 100 {
 101         struct global_data *gd_ptr;
 102
 103         /*
 104          * clear GD entirely and set it up.
 105          * Use gd_ptr, as gd may not be properly set yet.
 106          */
 107
 108         gd_ptr = (struct global_data *)base;
 109         /* zero the area */
 110         memset(gd_ptr, '\0', sizeof(*gd));
 111         /* set GD unless architecture did it already */
 112 #if !defined(CONFIG_ARM)
 113         arch_setup_gd(gd_ptr);
 114 #endif
 115         /* next alloc will be higher by one GD plus 16-byte alignment */
 116         base += roundup(sizeof(struct global_data), 16);
 117
 118         /*
 119          * record early malloc arena start.
 120          * Use gd as it is now properly set for all architectures.
 121          */
 122
 123 #if CONFIG_VAL(SYS_MALLOC_F_LEN)
 124         /* go down one 'early malloc arena' */
 125         gd->malloc_base = base;
 126         /* next alloc will be higher by one 'early malloc arena' size */
 127         base += CONFIG_VAL(SYS_MALLOC_F_LEN);
 128 #endif
 129 }
 130
 131 /*
 132  * Board-specific Platform code can reimplement show_boot_progress () if needed
 133  */
 134 __weak void show_boot_progress(int val) {}