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u-boot_boot_sequence [2019/12/27 17:43]
rpjday [1.]
u-boot_boot_sequence [2019/12/28 08:33] (current)
rpjday [1.]
Line 19: Line 19:
 ===== arch/​arm/​lib/​crt0_64.S [ENTRY(_main)] ===== ===== arch/​arm/​lib/​crt0_64.S [ENTRY(_main)] =====
  
-==== 1. ====+==== Prologue ​====
  
 <​code>​ <​code>​
Line 25: Line 25:
  * start-up where a C runtime environment is needed. Its entry point  * 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.  * is _main and is branched into from the target'​s start.S file.
- * +</​code>​ 
- * _main execution sequence is: + 
- *+==== 1. ==== 
 + 
 +<​code>​
  * 1. Set up initial environment for calling board_init_f().  * 1. Set up initial environment for calling board_init_f().
  ​* ​   This environment only provides a stack and a place to store  ​* ​   This environment only provides a stack and a place to store
Line 71: Line 73:
  ​* ​   data include the relocation destination,​ the future stack, and  ​* ​   data include the relocation destination,​ the future stack, and
  ​* ​   the future GD location.  ​* ​   the future GD location.
 +</​code>​
 +
 +<​code>​
 +        mov     x0, #0
 +        bl      board_init_f
 </​code>​ </​code>​
  
Line 79: Line 86:
  ​* ​   ones allocated by board_init_f() in system RAM, but BSS and  ​* ​   ones allocated by board_init_f() in system RAM, but BSS and
  ​* ​   initialized non-const data are still not available.  ​* ​   initialized non-const data are still not available.
 +</​code>​
 +
 +<​code>​
 +#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 */
 +        adr     x0, _start ​             /* x0 <- Runtime value of _start */
 +        ldr     x9, _TEXT_BASE ​         /* x9 <- Linked value of _start */
 +        sub     x9, x9, x0              /* x9 <- Run-vs-link offset */
 +        add     lr, lr, x9
 +#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 */
 </​code>​ </​code>​
  
Line 87: Line 119:
  ​* ​   relocates U-Boot from its current location into the relocation  ​* ​   relocates U-Boot from its current location into the relocation
  ​* ​   destination computed by board_init_f().  ​* ​   destination computed by board_init_f().
 +</​code>​
 +
 +<​code>​
 +        b       ​relocate_code
 +
 +relocation_return:​
 </​code>​ </​code>​
  
Line 112: Line 150:
  ​* ​   at this point regarding memory, so call c_runtime_cpu_setup.  ​* ​   at this point regarding memory, so call c_runtime_cpu_setup.
 </​code>​ </​code>​
- 
-==== 7. ==== 
  
 <​code>​ <​code>​
- 7. Branch to board_init_r(). +/* 
-</code> + Set up final (fullenvironment 
- + *
-===== common/board_f.c ===== +        ​bl ​     c_runtime_cpu_setup ​            /* still call old routine *
- +#​endif ​/* !CONFIG_SPL_BUILD *
-===== common/board_r.c (only most common) ===== +#if !defined(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(FRAMEWORK) 
- +#if defined(CONFIG_SPL_BUILD) 
-==== initr_dm() [C] ==== +        ​bl      spl_relocate_stack_gd ​          /* may return NULL */ 
-==== board_init() [A,B] ==== +        ​/* set up gd here, outside any C code, if new stack is returned */ 
- +        ​cmp ​    x0, #
-==== board_early_init_r() (not for Zynq) ==== +        ​csel ​   x18, x0, x18, ne 
- +        ​/* 
-==== arch_early_init_r() [A] ==== +         * Perform 'sp = (x0 !NULL) ? x0 : sp' while working 
- +         * around the constraint that conditional moves can not 
-  * arch/arm/​mach-zynq/​cpu.c +         * have '​sp'​ as an operand 
-  ​arch/arm/​mach-zynq/​spl.c +         */ 
- +        ​mov     x1, sp 
-<​code>​ +        ​cmp     x0, #0 
-#if defined(CONFIG_ARCH_EARLY_INIT_R) +        ​csel    x0x0, x1, ne 
-int arch_early_init_r(void) +        mov     sp, x0
-+
-#if (defined(CONFIG_FPGA) && ​!defined(CONFIG_SPL_BUILD)) || +
-    ​(defined(CONFIG_SPL_FPGA_SUPPORT&& ​defined(CONFIG_SPL_BUILD)+
-        ​int cpu_id = cpu_desc_id();​ +
- +
-        if (cpu_id < 0) +
-                ​return ​0; +
- +
-        ​fpga.size ​zynq_fpga_descs[cpu_id].fpga_size;​ +
-        ​fpga.name = zynq_fpga_descs[cpu_id].devicename;​ +
-        ​fpga_init();​ +
-        ​fpga_add(fpga_xilinx&fpga);+
 #endif #endif
-        return 0; 
-} 
-#endif 
-</​code>​ 
- 
-==== initr_mmc() [C] ==== 
- 
-<​code>​ 
-#ifdef CONFIG_MMC 
-static int initr_mmc(void) 
-{ 
-        puts("​MMC: ​  "​);​ 
-        mmc_initialize(gd->​bd);​ 
-        return 0; 
-} 
-#endif 
-</​code>​ 
- 
-==== initr_env() [C] ==== 
- 
-<​code>​ 
-static int initr_env(void) 
-{ 
-        /* initialize environment */ 
-        if (should_load_env()) 
-                env_relocate();​ 
-        else 
-                set_default_env(NULL,​ 0); 
-#ifdef CONFIG_OF_CONTROL 
-        env_set_hex("​fdtcontroladdr",​ 
-                    (unsigned long)map_to_sysmem(gd->​fdt_blob));​ 
-#endif 
- 
-        /* Initialize from environment */ 
-        load_addr = env_get_ulong("​loadaddr",​ 16, load_addr); 
- 
-        return 0; 
-} 
-</​code>​ 
- 
-==== show_board_info() [C] ==== 
- 
-From ''​common/​board_info.c'':​ 
- 
-<​code>​ 
-int __weak checkboard(void) 
-{ 
-        return 0; 
-} 
  
 /* /*
- ​* ​If the root node of the DTB has a "​model"​ property, show it. + ​* ​Clear BSS section
- * Then call checkboard().+
  */  */
-int __weak show_board_info(void) +        ldr     x0, =__bss_start ​               /* this is auto-relocated! */ 
-+        ​ldr     x1, =__bss_end ​                 /this is auto-relocated! */ 
-#ifdef CONFIG_OF_CONTROL +clear_loop: 
-        ​DECLARE_GLOBAL_DATA_PTR;​ +        ​str     xzr[x0]#8 
-        const char *model; +        ​cmp     x0x1 
- +        ​b.lo ​   clear_loop
-        ​model = fdt_getprop(gd->​fdt_blob0"​model",​ NULL); +
- +
-        ​if (model) +
-                printf("​Model:​ %s\n"model); +
-#endif+
  
-        ​return checkboard(); +        ​/* call board_init_r(gd_t *id, ulong dest_addr*/ 
-}+        ​mov ​    x0, x18                         /* gd_t */ 
 +        ldr     x1, [x18, #​GD_RELOCADDR] ​       /* dest_addr */
 </​code>​ </​code>​
  
- +==== 7====
-For ''​zynqmp.c'':​+
  
 <​code>​ <​code>​
-int checkboard(void) + * 7. Branch to board_init_r().
-+
-        puts("​Board:​ Xilinx ZynqMP\n"​);​ +
-        return 0; +
-}+
 </​code>​ </​code>​
- 
-==== arch_misc_init() ==== 
- 
-Some arches and boards, not Zynq. 
  
 <​code>​ <​code>​
-#ifdef CONFIG_ARCH_MISC_INIT +        b       ​board_init_r ​                   /* PC relative jump */
-        arch_misc_init,​ +
-#endif +
-</code>+
  
-==== misc_init_r() ==== +        /* NOTREACHED - board_init_r() does not return */
- +
-<​code>​ +
-#ifdef CONFIG_MISC_INIT_R +
-        misc_init_r,​ +
-#endif+
 </​code>​ </​code>​
  
-==== initr_enable_interrupts() ​====+===== common/​board_f.c =====
  
 <​code>​ <​code>​
-#ifdef CONFIG_ARM +void board_init_f(ulong boot_flags)
-static int initr_enable_interrupts(void)+
 { {
-        ​enable_interrupts()+        ​gd->​flags = boot_flags
-        ​return ​0; +        ​gd->​have_console = 0; 
-} + 
-#endif+        if (initcall_run_list(init_sequence_f)) 
 +                hang(); 
 +                ...
 </​code>​ </​code>​
  
-From ''​arch/arm/​lib/​interrupts.c'':​+===== common/board_r.c =====
  
 <​code>​ <​code>​
-int interrupt_init (void)+void board_init_r(gd_t *new_gd, ulong dest_addr)
 { {
         /*         /*
-         ​* ​setup up stacks if necessary+         ​* ​Set up the new global data pointer. So far only x86 does this 
 +         * here. 
 +         * TODO(sjg@chromium.org):​ Consider doing this for all archs, or 
 +         * dropping the new_gd parameter.
          */          */
-        IRQ_STACK_START_IN = gd->​irq_sp + 8;+#if CONFIG_IS_ENABLED(X86_64) 
 +        arch_setup_gd(new_gd); 
 +#endif
  
-        return 0; +#ifdef CONFIG_NEEDS_MANUAL_RELOC 
-+        int i;
- +
-void enable_interrupts (void) +
-{ +
-        ​return; +
-+
-int disable_interrupts (void) +
-+
-        return 0; +
-+
-</​code>​ +
- +
-==== initr_ethaddr() [C] ==== +
- +
-<​code>​ +
-#ifdef CONFIG_CMD_NET +
-        initr_ethaddr,​+
 #endif #endif
-</​code>​ 
  
-<​code>​ +#if !defined(CONFIG_X86&& !defined(CONFIG_ARM) && !defined(CONFIG_ARM64
-#ifdef CONFIG_CMD_NET +        ​gd = new_gd;
-static int initr_ethaddr(void) +
-+
-        bd_t *bd = gd->​bd;​ +
- +
-        /* kept around for legacy kernels only ... ignore the next section */ +
-        eth_env_get_enetaddr("​ethaddr",​ bd->​bi_enetaddr)+
-#ifdef CONFIG_HAS_ETH1 +
-        ​eth_env_get_enetaddr("​eth1addr",​ bd->​bi_enet1addr);+
 #endif #endif
-#ifdef CONFIG_HAS_ETH2 +        gd->flags &= ~GD_FLG_LOG_READY;
-        eth_env_get_enetaddr("​eth2addr",​ bd->bi_enet2addr); +
-#endif +
-#ifdef CONFIG_HAS_ETH3 +
-        eth_env_get_enetaddr("​eth3addr",​ bd->​bi_enet3addr);​ +
-#endif +
-#ifdef CONFIG_HAS_ETH4 +
-        eth_env_get_enetaddr("​eth4addr",​ bd->​bi_enet4addr);​ +
-#endif +
-#ifdef CONFIG_HAS_ETH5 +
-        eth_env_get_enetaddr("​eth5addr",​ bd->​bi_enet5addr);​ +
-#endif +
-        return 0; +
-+
-#endif /* CONFIG_CMD_NET */ +
-</​code>​+
  
-==== board_late_init() [B] ==== +#ifdef CONFIG_NEEDS_MANUAL_RELOC 
- +        for (i 0; i < ARRAY_SIZE(init_sequence_r); i++) 
-(Defined in board/​xilinx/​zynq/​board.c.) +                init_sequence_r[i+gd->reloc_off;
- +
-<code> +
-#ifdef CONFIG_BOARD_LATE_INIT +
-        board_late_init,​+
 #endif #endif
-</​code>​ 
  
-==== initr_net() ====+        if (initcall_run_list(init_sequence_r)) 
 +                hang();
  
-<​code>​ +        /* NOTREACHED - run_main_loop() does not return */ 
-#ifdef CONFIG_CMD_NET +        ​hang();
-static int initr_net(void) +
-{ +
-        ​puts("​Net: ​  "​); +
-        eth_initialize();​ +
-#if defined(CONFIG_RESET_PHY_R) +
-        debug("​Reset Ethernet PHY\n"​);​ +
-        reset_phy();​ +
-#endif +
-        return 0; +
-+
-#endif+
 </​code>​ </​code>​
- 
u-boot_boot_sequence.1577468619.txt.gz · Last modified: 2019/12/27 17:43 by rpjday