common/init/board_init.c

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