AM4378: Scanf statement doesn't work

Monish27

Part Number: AM4378

Hi,

I want to get string input from the user in u-boot. When I tried by including scanf function, I am getting errors like an implicit declaration of the function and unable to get the string. Help me to give steps to get a string.

over 4 years ago

0 Hong Guan64 over 4 years ago

TI__Guru 73720 points

Hi Monish,

One example for reading user input string from serial terminal @u-boot is listed below for your reference.

/cmd/nvedit.c
static int do_env_edit(cmd_tbl_t *cmdtp, int flag, int argc,
		       char * const argv[])
{
...
	if (cli_readline_into_buffer("edit: ", buffer, 0) < 0)
		return 1;
...
}

Best,

-Hong

0 Monish27 over 4 years ago in reply to Hong Guan64

Intellectual 636 points

Hi Guan,

I am not using the command line argument to get the input from user. I want to get string/word input from the user through debug UART. I am able to get a character from the user using getc() function, but I want to get more than two character from the user. So I thought of using scanf() function to get a string. But I am unable to use the function in U-Boot, it shows an error when I try to build the code in U-Boot. So kindly do the needful.

Regards,

Monish P

0 Hong Guan64 over 4 years ago in reply to Monish27

TI__Guru 73720 points

I uploaded a reference call flow in attachment.
You would refer to functions listed in the attached call flow, and use/modify one of them for your specific user case.
Alternatively you could search community for the same as it is a generic question.

Fullscreen am3_cli_readline.txt Download

B::area_log1












===================================================
26. Feb 2021
15:16:46
===================================================
B::Register
N _  R0         60  R8          1  ^S+ ^Stack_+
Z _  R1   44E09014  R9   BDF46EB8
C _  R2   44E35000  R10        0A
V _  R3          0  R11         1
Q _  R4          1  R12  BFFD3BE0
     R5          0  R13  BDF38760
0 _  R6   BFFCC010  R14  BFF90F6D
1 _  R7   BFFBB242  PC   BFF90EEC
2 _  SPSR        0  CPSR     01B3
3 _
4 _  USR:           FIQ:
     R8          1  R8          0
     R9   BDF46EB8  R9          0
I I  R10        0A  R10  20000000
F _  R11         1  R11         0
     R12  BFFD3BE0  R12         0
T T  R13         0  R13         0
J _  R14         0  R14         0
svc                 SPSR        0
nsec
     SVC:           IRQ:
A A  R13  BDF38760  R13  00A00500
E _  R14  BFF90F6D  R14  04100003
     SPSR        0  SPSR        0
0 _
1 _  UND:           ABT:
2 _  R13  EC0280C0  R13         0
3 _  R14  04CA8081  R14         0
     SPSR        0  SPSR        0

     MON:
     R13
     R14
     SPSR
B::Var.Frame_/Locals_/Caller
-000|serial_in_shift(inline)
-000|ns16550_readb.isra.1(
    |  ?)
    |  addr = 0x44E09014
    |  addr = 0x44E09014
    |
-001|ns16550_serial_pending(
    |  ?,
    |  ?)
    |
    |                return (serial_in(&com_port->lsr) & UART_LSR_DR) ? 1 : 0;
-002|fgetc.part.0(
    |    file = 0x0)
    |
    |
-003|cread_line(inline)
-003|cli_readline_into_buffer(
    |    prompt = 0xBFFBB242,
    |    buffer = 0xBFFD4284,
    |    timeout = 0x0)
    |  p = 0xBFFD4284
    |  timeout = 0x0
    |  buf = 0xBFFD4284
    |  prompt = 0xBFFBB242
    |  num = 0x2
    |  eol_num = 0x2
    |  insert = 0x1
    |  esc_len = 0x0
    |  esc_save = (0x2, 0x0, 0x0, 0x0, 0x0A, 0x0, 0x0, 0x0)
    |  first = 0x1
    |
    |                        }
    |                        first = 0;
    |                }
    |
    |                ichar = getcmd_getch();
-004|get_user_input(inline)
-004|file_get(
    |    i = 0xBDF3884C)
    |  ch = 0x0
    |  i = 0xBDF3884C
    |  n = 0x60
    |  i = 0xBDF3884C
    |
    |...
    |#else
    |        *prompt_str = (promptmode==1)? PS1 : PS2;
    |#endif
    |        debug_printf("result %s\n",*prompt_str);
    |}
    |#endif
    |
    |#ifdef __U_BOOT__
    |static int uboot_cli_readline(struct in_str *i)
    |{
    |        char *prompt;
    |        char __maybe_unused *ps_prompt = NULL;
    |
    |        if (i->promptmode == 1)
    |...
    |        if (i->promptmode == 1)
    |                ps_prompt = env_get("PS1");
    |        else
    |                ps_prompt = env_get("PS2");
    |        if (ps_prompt)
    |                prompt = ps_prompt;
    |#endif
    |
    |        return cli_readline(prompt);
    |        n = uboot_cli_readline(i);
-005|parse_stream(inline)
-005|parse_stream_outer(
    |  eoinp = 0xBDF3884C,
    |  inflag = 0x2)
    |  ctx = (child = 0xBDF548F8, list_head = 0xBDF548E0, pipe = 0xBDF548E0, w = RES_NONE = 0x0, old_flag = 0x0, stack = 0x0, type = 0x2)
    |  temp = (data = 0x0, length = 0x0, maxlen = 0x0, quote = 0x0, nonnull = 0x0)
    |
    |                rcode = parse_stream(&temp, &ctx, inp,
-006|parse_file_outer()
    |  rcode = 0x60
    |  input = (p = 0xBFFD3BE1, __promptme = 0x1, promptmode = 0x1, get = 0xBFF74D95, peek = 0xBFF74FE5)
    |
    |#endif
    |        rcode = parse_stream_outer(&input, FLAG_PARSE_SEMICOLON);
-007|cli_loop()
    |
    |}
    |#endif /* CONFIG_IS_ENABLED(OF_CONTROL) */
    |
    |void cli_loop(void)
    |{
    |#ifdef CONFIG_HUSH_PARSER
    |        parse_file_outer();
-008|bootstage_mark_name(inline)
-008|main_loop()
    |  s = 0xBDF508F0
    |
    |        cli_loop();
-009|run_main_loop()
    |#ireturn = 0x60
    |
    |        for (;;)
    |                main_loop();
    |        return 0;
    |}
    |
    |/*
-010|initcall_run_list(
    |    init_sequence = 0xBFFCBF54)
    |  init_fnc_ptr = 0xBFFCBFEC
    |  ret = 0x60
    |
    |                if (ret) {
-011|board_init_r(
    |  ?,
    |  ?)
    |
    |#endif
    |
    |        if (initcall_run_list(init_sequence_r))
    |                hang();
    |
    |        /* NOTREACHED - run_main_loop() does not return */
    |        hang();
-012|board_init_r(
    |  rsnew_gd = 0x60,
    |  rcdest_addr = 0x44E09014)
    |
    |}
    |
 ---|end of frame

Processors

Processors forum

AM4378: Scanf statement doesn't work