diff options
| -rw-r--r-- | common/board_f.c | 13 | ||||
| -rw-r--r-- | include/common.h | 43 |
2 files changed, 54 insertions, 2 deletions
diff --git a/common/board_f.c b/common/board_f.c index 74f77f1ea1..37b7bf5e36 100644 --- a/common/board_f.c +++ b/common/board_f.c @@ -1027,16 +1027,25 @@ void board_init_f_r(void) } #endif /* CONFIG_X86 */ +/* Unfortunately x86 can't compile this code as gd cannot be assigned */ #ifndef CONFIG_X86 +__weak void arch_setup_gd(struct global_data *gd_ptr) +{ + gd = gd_ptr; +} + ulong board_init_f_mem(ulong top) { + struct global_data *gd_ptr; + /* Leave space for the stack we are running with now */ top -= 0x40; top -= sizeof(struct global_data); top = ALIGN(top, 16); - gd = (struct global_data *)top; - memset((void *)gd, '\0', sizeof(*gd)); + gd_ptr = (struct global_data *)top; + memset(gd_ptr, '\0', sizeof(*gd)); + arch_setup_gd(gd_ptr); #ifdef CONFIG_SYS_MALLOC_F_LEN top -= CONFIG_SYS_MALLOC_F_LEN; diff --git a/include/common.h b/include/common.h index 5c076d6ce1..c48e5bc11b 100644 --- a/include/common.h +++ b/include/common.h @@ -217,6 +217,49 @@ extern char console_buffer[]; /* arch/$(ARCH)/lib/board.c */ void board_init_f(ulong); void board_init_r(gd_t *, ulong) __attribute__ ((noreturn)); + +/** + * board_init_f_mem() - Allocate global data and set stack position + * + * This function is called by each architecture very early in the start-up + * code to set up the environment for board_init_f(). It allocates space for + * global_data (see include/asm-generic/global_data.h) and places the stack + * below this. + * + * This function requires a stack[1] Normally this is at @top. The function + * starts allocating space from 64 bytes below @top. First it creates space + * for global_data. Then it calls arch_setup_gd() which sets gd to point to + * the global_data space and can reserve additional bytes of space if + * required). Finally it allocates early malloc() memory + * (CONFIG_SYS_MALLOC_F_LEN). The new top of the stack is just below this, + * and it returned by this function. + * + * [1] Strictly speaking it would be possible to implement this function + * in C on many archs such that it does not require a stack. However this + * does not seem hugely important as only 64 byte are wasted. The 64 bytes + * are used to handle the calling standard which generally requires pushing + * addresses or registers onto the stack. We should be able to get away with + * less if this becomes important. + * + * @top: Top of available memory, also normally the top of the stack + * @return: New stack location + */ +ulong board_init_f_mem(ulong top); + +/** + * arch_setup_gd() - Set up the global_data pointer + * + * This pointer is special in some architectures and cannot easily be assigned + * to. For example on x86 it is implemented by adding a specific record to its + * Global Descriptor Table! So we we provide a function to carry out this task. + * For most architectures this can simply be: + * + * gd = gd_ptr; + * + * @gd_ptr: Pointer to global data + */ +void arch_setup_gd(gd_t *gd_ptr); + int checkboard(void); int show_board_info(void); int checkflash(void); |