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From:   Doug Anderson <dianders@chromium.org>
Date:   Fri, 24 Apr 2020 11:17:59 -0700
Message-ID: <CAD=FV=X8NY+3pECsF27SC80FQmzewJ1gSs48wzB=PTYRZ4pCaA@mail.gmail.com>
Subject: Re: [PATCH] serial: amba-pl011: Support earlycon_kgdboc
To:     Sumit Garg <sumit.garg@linaro.org>
Cc:     linux-serial@vger.kernel.org,
        Russell King - ARM Linux <linux@armlinux.org.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Jason Wessel <jason.wessel@windriver.com>,
        kgdb-bugreport@lists.sourceforge.net,
        LKML <linux-kernel@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi,

On Fri, Apr 24, 2020 at 1:15 AM Sumit Garg <sumit.garg@linaro.org> wrote:
>
> Implement the read() function in the early console driver. With
> recently added earlycon_kgdboc feature, this allows you to use kgdb
> to debug fairly early into the system boot.
>
> We only bother implementing this if polling is enabled since kgdb can't
> be enabled without that.
>
> Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> ---
>
> Depends on kgdb patch series: https://lkml.org/lkml/2020/4/21/1179
>
>  drivers/tty/serial/amba-pl011.c | 32 ++++++++++++++++++++++++++++++++
>  1 file changed, 32 insertions(+)

This is the first time I've ever looked at the code for this
particular serial driver, but with that caveat your patch looks right
to me.  Specifically:

* Code, naming, and style of your new read routine match the existing
write routine used for earlycon.

* The read routine looks to read the same registers / works the same
as the main "polling" read routine, pl011_get_poll_char().

Thus:

Reviewed-by: Douglas Anderson <dianders@chromium.org>