User Tools

Site Tools


u-boot_boot_sequence

This is an old revision of the document!


Overview

The U-boot boot process, using Xilinx ZCU102 (Rev 1.0) as an example.

arch/arm/cpu/armv8/start.S

/*************************************************************************
 *
 * Startup Code (reset vector)
 *
 *************************************************************************/
...
master_cpu:
        bl    _main

arch/arm/lib/crt0_64.S [ENTRY(_main)]

common/board_f.c

common/board_r.c (only most common)

initr_dm() [C]

board_init() [A,B]

board_early_init_r() (not for Zynq)

arch_early_init_r() [A]

  • arch/arm/mach-zynq/cpu.c
  • arch/arm/mach-zynq/spl.c
#if defined(CONFIG_ARCH_EARLY_INIT_R)
int arch_early_init_r(void)
{
#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
        return 0;
}
#endif

initr_mmc() [C]

#ifdef CONFIG_MMC
static int initr_mmc(void)
{
        puts("MMC:   ");
        mmc_initialize(gd->bd);
        return 0;
}
#endif

initr_env() [C]

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;
}

show_board_info() [C]

From common/board_info.c:

int __weak checkboard(void)
{
        return 0;
}

/*
 * If the root node of the DTB has a "model" property, show it.
 * Then call checkboard().
 */
int __weak show_board_info(void)
{
#ifdef CONFIG_OF_CONTROL
        DECLARE_GLOBAL_DATA_PTR;
        const char *model;

        model = fdt_getprop(gd->fdt_blob, 0, "model", NULL);

        if (model)
                printf("Model: %s\n", model);
#endif

        return checkboard();
}

For zynqmp.c:

int checkboard(void)
{
        puts("Board: Xilinx ZynqMP\n");
        return 0;
}

arch_misc_init()

Some arches and boards, not Zynq.

#ifdef CONFIG_ARCH_MISC_INIT
        arch_misc_init,
#endif

misc_init_r()

#ifdef CONFIG_MISC_INIT_R
        misc_init_r,
#endif

initr_enable_interrupts()

#ifdef CONFIG_ARM
static int initr_enable_interrupts(void)
{
        enable_interrupts();
        return 0;
}
#endif

From arch/arm/lib/interrupts.c:

int interrupt_init (void)
{
        /*
         * setup up stacks if necessary
         */
        IRQ_STACK_START_IN = gd->irq_sp + 8;

        return 0;
}

void enable_interrupts (void)
{
        return;
}
int disable_interrupts (void)
{
        return 0;
}

initr_ethaddr() [C]

#ifdef CONFIG_CMD_NET
        initr_ethaddr,
#endif
#ifdef CONFIG_CMD_NET
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
#ifdef CONFIG_HAS_ETH2
        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 */

board_late_init() [B]

(Defined in board/xilinx/zynq/board.c.)

#ifdef CONFIG_BOARD_LATE_INIT
        board_late_init,
#endif

initr_net()

#ifdef CONFIG_CMD_NET
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
u-boot_boot_sequence.1577468390.txt.gz · Last modified: 2019/12/27 17:39 by rpjday