10ae76531SDavid Feng/* 20ae76531SDavid Feng * crt0 - C-runtime startup Code for AArch64 U-Boot 30ae76531SDavid Feng * 40ae76531SDavid Feng * (C) Copyright 2013 50ae76531SDavid Feng * David Feng <fenghua@phytium.com.cn> 60ae76531SDavid Feng * 70ae76531SDavid Feng * (C) Copyright 2012 80ae76531SDavid Feng * Albert ARIBAUD <albert.u.boot@aribaud.net> 90ae76531SDavid Feng * 100ae76531SDavid Feng * SPDX-License-Identifier: GPL-2.0+ 110ae76531SDavid Feng */ 120ae76531SDavid Feng 130ae76531SDavid Feng#include <config.h> 140ae76531SDavid Feng#include <asm-offsets.h> 150ae76531SDavid Feng#include <asm/macro.h> 160ae76531SDavid Feng#include <linux/linkage.h> 170ae76531SDavid Feng 180ae76531SDavid Feng/* 190ae76531SDavid Feng * This file handles the target-independent stages of the U-Boot 200ae76531SDavid Feng * start-up where a C runtime environment is needed. Its entry point 210ae76531SDavid Feng * is _main and is branched into from the target's start.S file. 220ae76531SDavid Feng * 230ae76531SDavid Feng * _main execution sequence is: 240ae76531SDavid Feng * 250ae76531SDavid Feng * 1. Set up initial environment for calling board_init_f(). 260ae76531SDavid Feng * This environment only provides a stack and a place to store 270ae76531SDavid Feng * the GD ('global data') structure, both located in some readily 280ae76531SDavid Feng * available RAM (SRAM, locked cache...). In this context, VARIABLE 290ae76531SDavid Feng * global data, initialized or not (BSS), are UNAVAILABLE; only 300ae76531SDavid Feng * CONSTANT initialized data are available. 310ae76531SDavid Feng * 320ae76531SDavid Feng * 2. Call board_init_f(). This function prepares the hardware for 330ae76531SDavid Feng * execution from system RAM (DRAM, DDR...) As system RAM may not 340ae76531SDavid Feng * be available yet, , board_init_f() must use the current GD to 350ae76531SDavid Feng * store any data which must be passed on to later stages. These 360ae76531SDavid Feng * data include the relocation destination, the future stack, and 370ae76531SDavid Feng * the future GD location. 380ae76531SDavid Feng * 390ae76531SDavid Feng * (the following applies only to non-SPL builds) 400ae76531SDavid Feng * 410ae76531SDavid Feng * 3. Set up intermediate environment where the stack and GD are the 420ae76531SDavid Feng * ones allocated by board_init_f() in system RAM, but BSS and 430ae76531SDavid Feng * initialized non-const data are still not available. 440ae76531SDavid Feng * 450ae76531SDavid Feng * 4. Call relocate_code(). This function relocates U-Boot from its 460ae76531SDavid Feng * current location into the relocation destination computed by 470ae76531SDavid Feng * board_init_f(). 480ae76531SDavid Feng * 490ae76531SDavid Feng * 5. Set up final environment for calling board_init_r(). This 500ae76531SDavid Feng * environment has BSS (initialized to 0), initialized non-const 510ae76531SDavid Feng * data (initialized to their intended value), and stack in system 520ae76531SDavid Feng * RAM. GD has retained values set by board_init_f(). Some CPUs 530ae76531SDavid Feng * have some work left to do at this point regarding memory, so 540ae76531SDavid Feng * call c_runtime_cpu_setup. 550ae76531SDavid Feng * 560ae76531SDavid Feng * 6. Branch to board_init_r(). 570ae76531SDavid Feng */ 580ae76531SDavid Feng 590ae76531SDavid FengENTRY(_main) 600ae76531SDavid Feng 610ae76531SDavid Feng/* 620ae76531SDavid Feng * Set up initial C runtime environment and call board_init_f(0). 630ae76531SDavid Feng */ 64*b2d5ac59SScott Wood#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK) 65*b2d5ac59SScott Wood ldr x0, =(CONFIG_SPL_STACK) 66*b2d5ac59SScott Wood#else 670ae76531SDavid Feng ldr x0, =(CONFIG_SYS_INIT_SP_ADDR) 68*b2d5ac59SScott Wood#endif 69b263302aSDavid Feng sub x18, x0, #GD_SIZE /* allocate one GD above SP */ 70b263302aSDavid Feng bic x18, x18, #0x7 /* 8-byte alignment for GD */ 71b263302aSDavid Fengzero_gd: 72b263302aSDavid Feng sub x0, x0, #0x8 73b263302aSDavid Feng str xzr, [x0] 74b263302aSDavid Feng cmp x0, x18 75b263302aSDavid Feng b.gt zero_gd 76b263302aSDavid Feng#if defined(CONFIG_SYS_MALLOC_F_LEN) 77b263302aSDavid Feng sub x0, x18, #CONFIG_SYS_MALLOC_F_LEN 78b263302aSDavid Feng str x0, [x18, #GD_MALLOC_BASE] 79b263302aSDavid Feng#endif 800ae76531SDavid Feng bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */ 810ae76531SDavid Feng mov x0, #0 820ae76531SDavid Feng bl board_init_f 830ae76531SDavid Feng 84*b2d5ac59SScott Wood#if !defined(CONFIG_SPL_BUILD) 850ae76531SDavid Feng/* 860ae76531SDavid Feng * Set up intermediate environment (new sp and gd) and call 870ae76531SDavid Feng * relocate_code(addr_moni). Trick here is that we'll return 880ae76531SDavid Feng * 'here' but relocated. 890ae76531SDavid Feng */ 900ae76531SDavid Feng ldr x0, [x18, #GD_START_ADDR_SP] /* x0 <- gd->start_addr_sp */ 910ae76531SDavid Feng bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */ 920ae76531SDavid Feng ldr x18, [x18, #GD_BD] /* x18 <- gd->bd */ 930ae76531SDavid Feng sub x18, x18, #GD_SIZE /* new GD is below bd */ 940ae76531SDavid Feng 950ae76531SDavid Feng adr lr, relocation_return 960ae76531SDavid Feng ldr x9, [x18, #GD_RELOC_OFF] /* x9 <- gd->reloc_off */ 970ae76531SDavid Feng add lr, lr, x9 /* new return address after relocation */ 980ae76531SDavid Feng ldr x0, [x18, #GD_RELOCADDR] /* x0 <- gd->relocaddr */ 990ae76531SDavid Feng b relocate_code 1000ae76531SDavid Feng 1010ae76531SDavid Fengrelocation_return: 1020ae76531SDavid Feng 1030ae76531SDavid Feng/* 1040ae76531SDavid Feng * Set up final (full) environment 1050ae76531SDavid Feng */ 1060ae76531SDavid Feng bl c_runtime_cpu_setup /* still call old routine */ 1070ae76531SDavid Feng 1080ae76531SDavid Feng/* 1090ae76531SDavid Feng * Clear BSS section 1100ae76531SDavid Feng */ 1110ae76531SDavid Feng ldr x0, =__bss_start /* this is auto-relocated! */ 1120ae76531SDavid Feng ldr x1, =__bss_end /* this is auto-relocated! */ 1130ae76531SDavid Feng mov x2, #0 1140ae76531SDavid Fengclear_loop: 1150ae76531SDavid Feng str x2, [x0] 1160ae76531SDavid Feng add x0, x0, #8 1170ae76531SDavid Feng cmp x0, x1 1180ae76531SDavid Feng b.lo clear_loop 1190ae76531SDavid Feng 1200ae76531SDavid Feng /* call board_init_r(gd_t *id, ulong dest_addr) */ 1210ae76531SDavid Feng mov x0, x18 /* gd_t */ 1220ae76531SDavid Feng ldr x1, [x18, #GD_RELOCADDR] /* dest_addr */ 1230ae76531SDavid Feng b board_init_r /* PC relative jump */ 1240ae76531SDavid Feng 1250ae76531SDavid Feng /* NOTREACHED - board_init_r() does not return */ 1260ae76531SDavid Feng 127*b2d5ac59SScott Wood#endif /* !CONFIG_SPL_BUILD */ 128*b2d5ac59SScott Wood 1290ae76531SDavid FengENDPROC(_main) 130