From f48dd6fc6cc9fdf15408e98132dc5575a31026cf Mon Sep 17 00:00:00 2001 From: Graeme Russ Date: Sun, 1 Jan 2012 15:06:39 +1100 Subject: [PATCH] x86: Simplify Flash-to-RAM code execution transition Move the relocation offset calculation out of assembler and into C. This also paves the way for the upcoming init sequence simplification by adding the board_init_f_r flash to RAM transitional function -- Changes for v2: - Added commit message - Minor adjustment to new stack address comment --- arch/x86/cpu/start.S | 22 ++++++---------------- arch/x86/include/asm/u-boot-x86.h | 2 ++ arch/x86/lib/board.c | 25 ++++++++++++++++++++++--- 3 files changed, 30 insertions(+), 19 deletions(-) diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S index 6027f54186..69a9b2cddc 100644 --- a/arch/x86/cpu/start.S +++ b/arch/x86/cpu/start.S @@ -96,32 +96,22 @@ car_init_ret: movw $0x85, %ax jmp die -.globl relocate_code -.type relocate_code, @function -relocate_code: +.globl board_init_f_r_trampoline +.type board_init_f_r_trampoline, @function +board_init_f_r_trampoline: /* * SDRAM has been initialised, U-Boot code has been copied into * RAM, BSS has been cleared and relocation adjustments have been * made. It is now time to jump into the in-RAM copy of U-Boot * - * %eax = Address of top of stack - * %edx = Address of Global Data - * %ecx = Base address of in-RAM copy of U-Boot + * %eax = Address of top of new stack */ /* Setup stack in RAM */ movl %eax, %esp - /* Setup call address of in-RAM copy of board_init_r() */ - movl $board_init_r, %ebp - addl (GENERATED_GD_RELOC_OFF)(%edx), %ebp - - /* Setup parameters to board_init_r() */ - movl %edx, %eax - movl %ecx, %edx - - /* Jump to in-RAM copy of board_init_r() */ - call *%ebp + /* Re-enter U-Boot by calling board_init_f_r */ + call board_init_f_r die: hlt diff --git a/arch/x86/include/asm/u-boot-x86.h b/arch/x86/include/asm/u-boot-x86.h index 755f88af04..c3d2277834 100644 --- a/arch/x86/include/asm/u-boot-x86.h +++ b/arch/x86/include/asm/u-boot-x86.h @@ -61,5 +61,7 @@ u32 isa_map_rom(u32 bus_addr, int size); int video_bios_init(void); int video_init(void); +void board_init_f_r_trampoline(ulong) __attribute__ ((noreturn)); +void board_init_f_r(void) __attribute__ ((noreturn)); #endif /* _U_BOOT_I386_H_ */ diff --git a/arch/x86/lib/board.c b/arch/x86/lib/board.c index f9eb15bed3..382ada784b 100644 --- a/arch/x86/lib/board.c +++ b/arch/x86/lib/board.c @@ -253,10 +253,29 @@ void board_init_f(ulong boot_flags) gd->flags |= GD_FLG_RELOC; - /* Enter the relocated U-Boot! */ - relocate_code(gd->start_addr_sp, gd, gd->relocaddr); + /* + * SDRAM is now initialised, U-Boot has been copied into SDRAM, + * the BSS has been cleared etc. The final stack can now be setup + * in SDRAM. Code execution will continue (momentarily) in Flash, + * but with the stack in SDRAM and Global Data in temporary memory + * (CPU cache) + */ + board_init_f_r_trampoline(gd->start_addr_sp); + + /* NOTREACHED - board_init_f_r_trampoline() does not return */ + while (1) + ; +} + +void board_init_f_r(void) +{ + /* + * Transfer execution from Flash to RAM by calculating the address + * of the in-RAM copy of board_init_r() and calling it + */ + (board_init_r + gd->reloc_off)(gd, gd->relocaddr); - /* NOTREACHED - relocate_code() does not return */ + /* NOTREACHED - board_init_r() does not return */ while (1) ; } -- 2.39.2