Merge branch 'master' of git://www.denx.de/git/u-boot-dm

[oweals/u-boot.git] / arch / arm / lib / crt0.S

diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index afd4f102dc87d4c0bcc5d9f2198f121d66f9f62f..8415f77e1b1e02b5159b3059dd19c572ccb16098 100644 (file)
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -25,7 +25,8 @@
  *    the GD ('global data') structure, both located in some readily
  *    available RAM (SRAM, locked cache...). In this context, VARIABLE
  *    global data, initialized or not (BSS), are UNAVAILABLE; only
- *    CONSTANT initialized data are available.
+ *    CONSTANT initialized data are available. GD should be zeroed
+ *    before board_init_f() is called.
  *
  * 2. Call board_init_f(). This function prepares the hardware for
  *    execution from system RAM (DRAM, DDR...) As system RAM may not
@@ -34,24 +35,29 @@
  *    data include the relocation destination, the future stack, and
  *    the future GD location.
  *
- * (the following applies only to non-SPL builds)
- *
  * 3. Set up intermediate environment where the stack and GD are the
  *    ones allocated by board_init_f() in system RAM, but BSS and
  *    initialized non-const data are still not available.
  *
- * 4. Call relocate_code(). This function relocates U-Boot from its
- *    current location into the relocation destination computed by
- *    board_init_f().
+ * 4a.For U-Boot proper (not SPL), call relocate_code(). This function
+ *    relocates U-Boot from its current location into the relocation
+ *    destination computed by board_init_f().
+ *
+ * 4b.For SPL, board_init_f() just returns (to crt0). There is no
+ *    code relocation in SPL.
  *
  * 5. Set up final environment for calling board_init_r(). This
  *    environment has BSS (initialized to 0), initialized non-const
  *    data (initialized to their intended value), and stack in system
- *    RAM. GD has retained values set by board_init_f(). Some CPUs
- *    have some work left to do at this point regarding memory, so
- *    call c_runtime_cpu_setup.
+ *    RAM (for SPL moving the stack and GD into RAM is optional - see
+ *    CONFIG_SPL_STACK_R). GD has retained values set by board_init_f().
+ *
+ * 6. For U-Boot proper (not SPL), some CPUs have some work left to do
+ *    at this point regarding memory, so call c_runtime_cpu_setup.
  *
- * 6. Branch to board_init_r().
+ * 7. Branch to board_init_r().
+ *
+ * For more information see 'Board Initialisation Flow in README.
  */
 
 /*
@@ -76,31 +82,14 @@ ENTRY(_main)
 #else
        bic     sp, sp, #7      /* 8-byte alignment for ABI compliance */
 #endif
-       mov     r2, sp
-       sub     sp, sp, #GD_SIZE        /* allocate one GD above SP */
-#if defined(CONFIG_CPU_V7M)    /* v7M forbids using SP as BIC destination */
-       mov     r3, sp
-       bic     r3, r3, #7
-       mov     sp, r3
-#else
-       bic     sp, sp, #7      /* 8-byte alignment for ABI compliance */
-#endif
-       mov     r9, sp          /* GD is above SP */
-       mov     r1, sp
+       mov     r0, sp
+       bl      board_init_f_alloc_reserve
+       mov     sp, r0
+       /* set up gd here, outside any C code */
+       mov     r9, r0
+       bl      board_init_f_init_reserve
+
        mov     r0, #0
-clr_gd:
-       cmp     r1, r2                  /* while not at end of GD */
-#if defined(CONFIG_CPU_V7M)
-       itt     lo
-#endif
-       strlo   r0, [r1]                /* clear 32-bit GD word */
-       addlo   r1, r1, #4              /* move to next */
-       blo     clr_gd
-#if defined(CONFIG_SYS_MALLOC_F_LEN)
-       sub     sp, sp, #CONFIG_SYS_MALLOC_F_LEN
-       str     sp, [r9, #GD_MALLOC_BASE]
-#endif
-       /* mov r0, #0 not needed due to above code */
        bl      board_init_f
 
 #if ! defined(CONFIG_SPL_BUILD)
@@ -147,6 +136,7 @@ here:
        bl      spl_relocate_stack_gd
        cmp     r0, #0
        movne   sp, r0
+       movne   r9, r0
 # endif
        ldr     r0, =__bss_start        /* this is auto-relocated! */
 
@@ -177,8 +167,12 @@ clbss_l:cmp        r0, r1                  /* while not at end of BSS */
        mov     r0, r9                  /* gd_t */
        ldr     r1, [r9, #GD_RELOCADDR] /* dest_addr */
        /* call board_init_r */
+#if defined(CONFIG_SYS_THUMB_BUILD)
+       ldr     lr, =board_init_r       /* this is auto-relocated! */
+       bx      lr
+#else
        ldr     pc, =board_init_r       /* this is auto-relocated! */
-
+#endif
        /* we should not return here. */
 #endif