diff options
Diffstat (limited to 'arch/x86/lib/board.c')
| -rw-r--r-- | arch/x86/lib/board.c | 186 |
1 files changed, 89 insertions, 97 deletions
diff --git a/arch/x86/lib/board.c b/arch/x86/lib/board.c index 89721c7..5f0b62c 100644 --- a/arch/x86/lib/board.c +++ b/arch/x86/lib/board.c @@ -35,7 +35,7 @@ #include <watchdog.h> #include <stdio_dev.h> #include <asm/u-boot-x86.h> -#include <asm/processor.h> +#include <asm/relocate.h> #include <asm/init_helpers.h> #include <asm/init_wrappers.h> @@ -43,31 +43,58 @@ /* * Breath some life into the board... * - * Initialize an SMC for serial comms, and carry out some hardware - * tests. + * Getting the board up and running is a three-stage process: + * 1) Execute from Flash, SDRAM Uninitialised + * At this point, there is a limited amount of non-SDRAM memory + * (typically the CPU cache, but can also be SRAM or even a buffer of + * of some peripheral). This limited memory is used to hold: + * - The initial copy of the Global Data Structure + * - A temporary stack + * - A temporary x86 Global Descriptor Table + * - The pre-console buffer (if enabled) * - * The first part of initialization is running from Flash memory; - * its main purpose is to initialize the RAM so that we - * can relocate the monitor code to RAM. + * The following is performed during this phase of execution: + * - Core low-level CPU initialisation + * - Console initialisation + * - SDRAM initialisation + * + * 2) Execute from Flash, SDRAM Initialised + * At this point we copy Global Data from the initial non-SDRAM + * memory and set up the permanent stack in SDRAM. The CPU cache is no + * longer being used as temporary memory, so we can now fully enable + * it. + * + * The following is performed during this phase of execution: + * - Create final stack in SDRAM + * - Copy Global Data from temporary memory to SDRAM + * - Enabling of CPU cache(s), + * - Copying of U-Boot code and data from Flash to RAM + * - Clearing of the BSS + * - ELF relocation adjustments + * + * 3) Execute from SDRAM + * The following is performed during this phase of execution: + * - All remaining initialisation */ /* - * All attempts to come up with a "common" initialization sequence - * that works for all boards and architectures failed: some of the - * requirements are just _too_ different. To get rid of the resulting - * mess of board dependend #ifdef'ed code we now make the whole - * initialization sequence configurable to the user. - * - * The requirements for any new initalization function is simple: it - * receives a pointer to the "global data" structure as it's only - * argument, and returns an integer return code, where 0 means - * "continue" and != 0 means "fatal error, hang the system". + * The requirements for any new initalization function is simple: it is + * a function with no parameters which returns an integer return code, + * where 0 means "continue" and != 0 means "fatal error, hang the system" */ typedef int (init_fnc_t) (void); -static int calculate_relocation_address(void); -static int copy_gd_to_ram(void); - +/* + * init_sequence_f is the list of init functions which are run when U-Boot + * is executing from Flash with a limited 'C' environment. The following + * limitations must be considered when implementing an '_f' function: + * - 'static' variables are read-only + * - Global Data (gd->xxx) is read/write + * - Stack space is limited + * + * The '_f' sequence must, as a minimum, initialise SDRAM. It _should_ + * also initialise the console (to provide early debug output) + */ init_fnc_t *init_sequence_f[] = { cpu_init_f, board_early_init_f, @@ -81,7 +108,39 @@ init_fnc_t *init_sequence_f[] = { NULL, }; +/* + * init_sequence_f_r is the list of init functions which are run when + * U-Boot is executing from Flash with a semi-limited 'C' environment. + * The following limitations must be considered when implementing an + * '_f_r' function: + * - 'static' variables are read-only + * - Global Data (gd->xxx) is read/write + * + * The '_f_r' sequence must, as a minimum, copy U-Boot to RAM (if + * supported). It _should_, if possible, copy global data to RAM and + * initialise the CPU caches (to speed up the relocation process) + */ +init_fnc_t *init_sequence_f_r[] = { + copy_gd_to_ram_f_r, + init_cache_f_r, + copy_uboot_to_ram, + clear_bss, + do_elf_reloc_fixups, + + NULL, +}; + +/* + * init_sequence_r is the list of init functions which are run when U-Boot + * is executing from RAM with a full 'C' environment. There are no longer + * any limitations which must be considered when implementing an '_r' + * function, (i.e.'static' variables are read/write) + * + * If not already done, the '_r' sequence must copy global data to RAM and + * (should) initialise the CPU caches. + */ init_fnc_t *init_sequence_r[] = { + set_reloc_flag_r, init_bd_struct_r, mem_malloc_init_r, cpu_init_r, @@ -157,43 +216,6 @@ static void do_init_loop(init_fnc_t **init_fnc_ptr) } } -static int calculate_relocation_address(void) -{ - ulong text_start = (ulong)&__text_start; - ulong bss_end = (ulong)&__bss_end; - ulong dest_addr; - - /* - * NOTE: All destination address are rounded down to 16-byte - * boundary to satisfy various worst-case alignment - * requirements - */ - - /* Global Data is at top of available memory */ - dest_addr = gd->ram_size; - dest_addr -= GENERATED_GBL_DATA_SIZE; - dest_addr &= ~15; - gd->new_gd_addr = dest_addr; - - /* GDT is below Global Data */ - dest_addr -= X86_GDT_SIZE; - dest_addr &= ~15; - gd->gdt_addr = dest_addr; - - /* Stack is below GDT */ - gd->start_addr_sp = dest_addr; - - /* U-Boot is below the stack */ - dest_addr -= CONFIG_SYS_STACK_SIZE; - dest_addr -= (bss_end - text_start); - dest_addr &= ~15; - gd->relocaddr = dest_addr; - gd->reloc_off = (dest_addr - text_start); - - return 0; -} - -/* Perform all steps necessary to get RAM initialised ready for relocation */ void board_init_f(ulong boot_flags) { gd->flags = boot_flags; @@ -201,10 +223,9 @@ void board_init_f(ulong boot_flags) do_init_loop(init_sequence_f); /* - * 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 + * SDRAM and console are now initialised. The final stack can now + * be setup in SDRAM. Code execution will continue 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); @@ -216,51 +237,22 @@ void board_init_f(ulong boot_flags) void board_init_f_r(void) { - if (copy_gd_to_ram() != 0) - hang(); - - if (init_cache() != 0) - hang(); - - relocate_code(0, gd, 0); - - /* NOTREACHED - relocate_code() does not return */ - while (1) - ; -} - -static int copy_gd_to_ram(void) -{ - gd_t *ram_gd; + do_init_loop(init_sequence_f_r); /* - * Global data is still in temporary memory (the CPU cache). - * calculate_relocation_address() has set gd->new_gd_addr to - * where the global data lives in RAM but getting it there - * safely is a bit tricky due to the 'F-Segment Hack' that - * we need to use for x86 + * U-Boot has been copied into SDRAM, the BSS has been cleared etc. + * Transfer execution from Flash to RAM by calculating the address + * of the in-RAM copy of board_init_r() and calling it */ - ram_gd = (gd_t *)gd->new_gd_addr; - memcpy((void *)ram_gd, gd, sizeof(gd_t)); + (board_init_r + gd->reloc_off)(gd, gd->relocaddr); - /* - * Reload the Global Descriptor Table so FS points to the - * in-RAM copy of Global Data (calculate_relocation_address() - * has already calculated the in-RAM location of the GDT) - */ - ram_gd->gd_addr = (ulong)ram_gd; - init_gd(ram_gd, (u64 *)gd->gdt_addr); - - return 0; + /* NOTREACHED - board_init_r() does not return */ + while (1) + ; } void board_init_r(gd_t *id, ulong dest_addr) { - gd->flags |= GD_FLG_RELOC; - - /* compiler optimization barrier needed for GCC >= 3.4 */ - __asm__ __volatile__("" : : : "memory"); - do_init_loop(init_sequence_r); /* main_loop() can return to retry autoboot, if so just run it again. */ |