u-boot serial_check_stdout函数

#if CONFIG_IS_ENABLED(SERIAL_PRESENT)

static int serial_check_stdout(const void *blob, struct udevice **devp)

{

    int node = -1;

    const char *str, *p, *name;

    int namelen;

    /* Check for a chosen console */

    str = fdtdec_get_chosen_prop(blob, "stdout-path");

    if (str) {

        p = strchr(str, ':');

        namelen = p ? p - str : strlen(str);

        node = fdt_path_offset_namelen(blob, str, namelen);

        if (node < 0) {

            /*

             * Deal with things like

             *  stdout-path = "serial0:115200n8";

             *

             * We need to look up the alias and then follow it to

             * the correct node.

             */

            name = fdt_get_alias_namelen(blob, str, namelen);

            if (name)

                node = fdt_path_offset(blob, name);

        }

    }

    if (node < 0)

        node = fdt_path_offset(blob, "console");

    if (!uclass_get_device_by_of_offset(UCLASS_SERIAL, node, devp))

        return 0;

    /*

     * If the console is not marked to be bound before relocation, bind it

     * anyway.

     */

    if (node > 0 && !lists_bind_fdt(gd->dm_root, offset_to_ofnode(node),

                    devp, false)) {

        if (!device_probe(*devp))

            return 0;

    }

    return -ENODEV;

}