diff options
Diffstat (limited to 'roms/u-boot/arch/arm/lib/crt0_64.S')
| -rw-r--r-- | roms/u-boot/arch/arm/lib/crt0_64.S | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/roms/u-boot/arch/arm/lib/crt0_64.S b/roms/u-boot/arch/arm/lib/crt0_64.S new file mode 100644 index 000000000..680e674fa --- /dev/null +++ b/roms/u-boot/arch/arm/lib/crt0_64.S @@ -0,0 +1,169 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * crt0 - C-runtime startup Code for AArch64 U-Boot + * + * (C) Copyright 2013 + * David Feng <fenghua@phytium.com.cn> + * + * (C) Copyright 2012 + * Albert ARIBAUD <albert.u.boot@aribaud.net> + */ + +#include <config.h> +#include <asm-offsets.h> +#include <asm/macro.h> +#include <linux/linkage.h> + +/* + * This file handles the target-independent stages of the U-Boot + * start-up where a C runtime environment is needed. Its entry point + * is _main and is branched into from the target's start.S file. + * + * _main execution sequence is: + * + * 1. Set up initial environment for calling board_init_f(). + * This environment only provides a stack and a place to store + * 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. 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 + * be available yet, , board_init_f() must use the current GD to + * store any data which must be passed on to later stages. These + * data include the relocation destination, the future stack, and + * the future GD location. + * + * 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. + * + * 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 (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(). + * + * TODO: For SPL, implement stack relocation on AArch64. + * + * 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. + * + * 7. Branch to board_init_r(). + * + * For more information see 'Board Initialisation Flow in README. + */ + +ENTRY(_main) + +/* + * Set up initial C runtime environment and call board_init_f(0). + */ +#if defined(CONFIG_TPL_BUILD) && defined(CONFIG_TPL_NEEDS_SEPARATE_STACK) + ldr x0, =(CONFIG_TPL_STACK) +#elif defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK) + ldr x0, =(CONFIG_SPL_STACK) +#elif defined(CONFIG_INIT_SP_RELATIVE) +#if CONFIG_POSITION_INDEPENDENT + adrp x0, __bss_start /* x0 <- Runtime &__bss_start */ + add x0, x0, #:lo12:__bss_start +#else + adr x0, __bss_start +#endif + add x0, x0, #CONFIG_SYS_INIT_SP_BSS_OFFSET +#else + ldr x0, =(CONFIG_SYS_INIT_SP_ADDR) +#endif + bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */ + mov x0, sp + bl board_init_f_alloc_reserve + mov sp, x0 + /* set up gd here, outside any C code */ + mov x18, x0 + bl board_init_f_init_reserve + + mov x0, #0 + bl board_init_f + +#if !defined(CONFIG_SPL_BUILD) +/* + * Set up intermediate environment (new sp and gd) and call + * relocate_code(addr_moni). Trick here is that we'll return + * 'here' but relocated. + */ + ldr x0, [x18, #GD_START_ADDR_SP] /* x0 <- gd->start_addr_sp */ + bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */ + ldr x18, [x18, #GD_NEW_GD] /* x18 <- gd->new_gd */ + + adr lr, relocation_return +#if CONFIG_POSITION_INDEPENDENT + /* Add in link-vs-runtime offset */ + adrp x0, _start /* x0 <- Runtime value of _start */ + add x0, x0, #:lo12:_start + ldr x9, _TEXT_BASE /* x9 <- Linked value of _start */ + sub x9, x9, x0 /* x9 <- Run-vs-link offset */ + add lr, lr, x9 +#if defined(CONFIG_SYS_RELOC_GD_ENV_ADDR) + ldr x0, [x18, #GD_ENV_ADDR] /* x0 <- gd->env_addr */ + add x0, x0, x9 + str x0, [x18, #GD_ENV_ADDR] +#endif +#endif + /* Add in link-vs-relocation offset */ + ldr x9, [x18, #GD_RELOC_OFF] /* x9 <- gd->reloc_off */ + add lr, lr, x9 /* new return address after relocation */ + ldr x0, [x18, #GD_RELOCADDR] /* x0 <- gd->relocaddr */ + b relocate_code + +relocation_return: + +/* + * Set up final (full) environment + */ + bl c_runtime_cpu_setup /* still call old routine */ +#endif /* !CONFIG_SPL_BUILD */ +#if !defined(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(FRAMEWORK) +#if defined(CONFIG_SPL_BUILD) + bl spl_relocate_stack_gd /* may return NULL */ + /* set up gd here, outside any C code, if new stack is returned */ + cmp x0, #0 + csel x18, x0, x18, ne + /* + * Perform 'sp = (x0 != NULL) ? x0 : sp' while working + * around the constraint that conditional moves can not + * have 'sp' as an operand + */ + mov x1, sp + cmp x0, #0 + csel x0, x0, x1, ne + mov sp, x0 +#endif + +/* + * Clear BSS section + */ + ldr x0, =__bss_start /* this is auto-relocated! */ + ldr x1, =__bss_end /* this is auto-relocated! */ +clear_loop: + str xzr, [x0], #8 + cmp x0, x1 + b.lo clear_loop + + /* call board_init_r(gd_t *id, ulong dest_addr) */ + mov x0, x18 /* gd_t */ + ldr x1, [x18, #GD_RELOCADDR] /* dest_addr */ + b board_init_r /* PC relative jump */ + + /* NOTREACHED - board_init_r() does not return */ +#endif + +ENDPROC(_main) |