u-boot_boot_sequence

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u-boot_boot_sequence [2019/12/27 17:44] – [2.] rpjdayu-boot_boot_sequence [2019/12/28 08:33] (current) – [1.] rpjday
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 ===== 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 84: 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 92: 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 117: 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 (full) environment 
- + */ 
-===== 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, #0 
-==== 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    x0, x0, 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     x0, x1 
 +        b.lo    clear_loop
  
-        model = fdt_getprop(gd->fdt_blob, 0, "model", NULL); +        /* call board_init_r(gd_t *id, ulong dest_addr) */ 
- +        mov     x0, x18                         /* gd_t */ 
-        if (model) +        ldr     x1, [x18, #GD_RELOCADDR]        /* dest_addr */
-                printf("Model: %s\n", model); +
-#endif +
- +
-        return checkboard(); +
-}+
 </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.1577468644.txt.gz
  • Last modified: 2019/12/27 17:44
  • by rpjday