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U-boot下netconsole实现

参考1.函数main_loop和u-boot命令执行

上面的do-while会循环命令解析器的"命令输入解析–执行"运行模式。
其中的函数run_list执行如下的函数调用流程：run_list–>run_list_real–>run_pipe_real->cmd_process

源码跟读

# u-boot/common/main.cvoid main_loop(void)cli_init();...s = bootdelay_process();	...autoboot_command(s);cli_loop();	# u-boot/common/board_r.c	
;...
static init_fnc_t init_sequence_r[] = {...stdio_init_tables,INIT_LIST_HEAD(&(devs.list));initr_serial,serial_initialize();	serial_init();		...stdio_add_devices,drv_system_init ();...strcpy (dev.name, "serial");dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;dev.putc  = stdio_serial_putc;		#ifdef CONFIG_NETCONSOLEdrv_nc_init ();...strcpy(dev.name, "nc");dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT;dev.start = nc_stdio_start;dev.putc  = nc_stdio_putc;...run_main_loop,for (;;)main_loop();		// 进入交互终端void main_loop(void)			cli_init();			#ifdef CONFIG_HUSH_PARSER		// 使用HUSH解释器u_boot_hush_start();if (top_vars == NULL) {top_vars = malloc(sizeof(struct variables));top_vars->name  = "HUSH_VERSION";			// 使用命令showvar可查看 top_vars->value = "0.01";		...s = bootdelay_process();s = env_get("bootdelay");		// 获取bootdelay信息bootdelay = s ? (int)simple_strtol(s, NULL, 10) : CONFIG_BOOTDELAY;#ifdef CONFIG_OF_CONTROLbootdelay = fdtdec_get_config_int(gd->fdt_blob, "bootdelay", bootdelay);			// 支持fdt中修改的bootdelay；...s = env_get("bootcmd");			// 获取默认引导命令；process_fdt_options(gd->fdt_blob);	// 获取：kernel-offset、rootdisk-offset信息；stored_bootdelay = bootdelay;	// 记录引导倒计时：bootdelayreturn s;						// 返回引导命令：bootcmd...autoboot_command(s);				// 执行引导命令：bootcmdif (stored_bootdelay != -1 && s && !abortboot(stored_bootdelay)) {		// 有设置bootdelay，引导命令非空，无人为打断run_command_list(s, -1, 0);			// 执行autoboot_command_fail_handle();cli_loop();							// 自动引导未正常进行后，进入命令行交互#ifndef CONFIG_CONSOLE_DISABLE_CLI
void cli_loop(void)#ifdef CONFIG_HUSH_PARSER				// rk3568_defconfig, 开启parse_file_outer();struct in_str input;setup_file_in_str(&input);i->peek = file_peek;i->get  = file_get;				// 与b_getch 关联：#define b_getch(input) ((input)->get(input))...rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON);			// flags标记：分号...do {...rcode = parse_stream(&temp, &ctx, inp, flag & FLAG_CONT_ON_NEWLINE ? -1 : '\n');/* This point is never reached */	// 不应运行到此for (;;);