커널 매개변수 "console"과 "earlycon"이 이전 하드웨어를 참조합니까?

처음에는 매개변수를 조사하여 이것을 찾았 earlycon지만 찾은 옵션은 console거의 동일해 보였습니다. 둘 다 아래에 나와 있으며 다음에서 발췌했습니다.이것원천:

우리가 가지고 있는 문서에서 console:

console=    [KNL] Output console device and options.

    tty<n>  Use the virtual console device <n>.

    ttyS<n>[,options]
    ttyUSB0[,options]
        Use the specified serial port.  The options are of
        the form "bbbbpnf", where "bbbb" is the baud rate,
        "p" is parity ("n", "o", or "e"), "n" is number of
        bits, and "f" is flow control ("r" for RTS or
        omit it).  Default is "9600n8".

        See Documentation/serial-console.txt for more
        information.  See
        Documentation/networking/netconsole.txt for an
        alternative.

    uart[8250],io,<addr>[,options]
    uart[8250],mmio,<addr>[,options]
    uart[8250],mmio16,<addr>[,options]
    uart[8250],mmio32,<addr>[,options]
    uart[8250],0x<addr>[,options]
        Start an early, polled-mode console on the 8250/16550
        UART at the specified I/O port or MMIO address,
        switching to the matching ttyS device later.
        MMIO inter-register address stride is either 8-bit
        (mmio), 16-bit (mmio16), or 32-bit (mmio32).
        If none of [io|mmio|mmio16|mmio32], <addr> is assumed
        to be equivalent to 'mmio'. 'options' are specified in
        the same format described for ttyS above; if unspecified,
        the h/w is not re-initialized.

    hvc<n>  Use the hypervisor console device <n>. This is for
        both Xen and PowerPC hypervisors.

            If the device connected to the port is not a TTY but a braille
            device, prepend "brl," before the device type, for instance
        console=brl,ttyS0
    For now, only VisioBraille is supported.

우리가 가지고 있는 문서에서 earlycon:

earlycon=   [KNL] Output early console device and options.

        When used with no options, the early console is
        determined by the stdout-path property in device
        tree's chosen node.

    cdns,<addr>
        Start an early, polled-mode console on a cadence serial
        port at the specified address. The cadence serial port
        must already be setup and configured. Options are not
        yet supported.

    uart[8250],io,<addr>[,options]
    uart[8250],mmio,<addr>[,options]
    uart[8250],mmio32,<addr>[,options]
    uart[8250],mmio32be,<addr>[,options]
    uart[8250],0x<addr>[,options]
        Start an early, polled-mode console on the 8250/16550
        UART at the specified I/O port or MMIO address.
        MMIO inter-register address stride is either 8-bit
        (mmio) or 32-bit (mmio32 or mmio32be).
        If none of [io|mmio|mmio32|mmio32be], <addr> is assumed
        to be equivalent to 'mmio'. 'options' are specified
        in the same format described for "console=ttyS<n>"; if
        unspecified, the h/w is not initialized.

    pl011,<addr>
    pl011,mmio32,<addr>
        Start an early, polled-mode console on a pl011 serial
        port at the specified address. The pl011 serial port
        must already be setup and configured. Options are not
        yet supported.  If 'mmio32' is specified, then only
        the driver will use only 32-bit accessors to read/write
        the device registers.

    meson,<addr>
        Start an early, polled-mode console on a meson serial
        port at the specified address. The serial port must
        already be setup and configured. Options are not yet
        supported.

    msm_serial,<addr>
        Start an early, polled-mode console on an msm serial
        port at the specified address. The serial port
        must already be setup and configured. Options are not
        yet supported.

    msm_serial_dm,<addr>
        Start an early, polled-mode console on an msm serial
        dm port at the specified address. The serial port
        must already be setup and configured. Options are not
        yet supported.

    smh Use ARM semihosting calls for early console.

    s3c2410,<addr>
    s3c2412,<addr>
    s3c2440,<addr>
    s3c6400,<addr>
    s5pv210,<addr>
    exynos4210,<addr>
        Use early console provided by serial driver available
        on Samsung SoCs, requires selecting proper type and
        a correct base address of the selected UART port. The
        serial port must already be setup and configured.
        Options are not yet supported.

    lpuart,<addr>
    lpuart32,<addr>
        Use early console provided by Freescale LP UART driver
        found on Freescale Vybrid and QorIQ LS1021A processors.
        A valid base address must be provided, and the serial
        port must already be setup and configured.

    armada3700_uart,<addr>
        Start an early, polled-mode console on the
        Armada 3700 serial port at the specified
        address. The serial port must already be setup
        and configured. Options are not yet supported.

사용 예는 다음과 같습니다.

earlycon=uart8250,0x21c0500

내 질문은 다음과 같습니다

• 참조가 왜 있는거죠?8250/16550물리적 하드웨어? 이 오래된 구현이 현대 디자인의 인터페이스 사양에 통합되었습니까? 즉, 이러한 통신 장치가 SoC 외부에 있을 때 호환 가능한 UART 드라이버를 계속 사용하고 있습니까?

• MMIO가 있는 경우메모리 매핑된 IO, 이 맥락에서 "정상" IO는 무엇을 의미합니까?

• 매개변수는 무엇입니까 <addr>? 이것이 이 코어를 실행 중인 특정 SoC에 대한 UART 구성 레지스터의 시작입니까? 대부분의 UART 구성 레지스터는 일반 UART 드라이버가 하드웨어를 올바르게 구성할 수 있도록 특정 레지스터 레이아웃을 준수합니까?