Re: [PATCH 3/3] Serial: Separate out earlycon support

From: Greg KH <gregkh@linuxfoundation.org>
To: Akash Asthana <akashast@codeaurora.org>
Cc: bjorn.andersson@linaro.org, devicetree@vger.kernel.org,
	linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org,
	mka@chromium.org, dianders@chromium.org,
	linux-kernel@vger.kernel.org, saravanak@google.com
Subject: Re: [PATCH 3/3] Serial: Separate out earlycon support
Date: Mon, 7 Dec 2020 14:55:40 +0100	[thread overview]
Message-ID: <X840XDgspqwuPt1C@kroah.com> (raw)
In-Reply-To: <ab693e13-0478-5301-5ccb-9d8b1191afa1@codeaurora.org>

On Mon, Dec 07, 2020 at 05:52:32PM +0530, Akash Asthana wrote:
> Hi Greg,
> 
> On 12/7/2020 2:41 PM, Greg KH wrote:
> > On Mon, Dec 07, 2020 at 02:17:27PM +0530, Akash Asthana wrote:
> > > Separate out earlycon support from serial driver and remove it's
> > > dependency on QUP wrapper driver.
> > > 
> > > This enable us to manage earlycon independently and we can re-use the
> > > same earlycon driver for android project which currently uses
> > > downstream version of QUP drivers.
> > What do you mean by "downstream" here?
> > 
> > > Signed-off-by: Akash Asthana <akashast@codeaurora.org>
> > > ---
> > >   drivers/tty/serial/Kconfig              |   9 +
> > >   drivers/tty/serial/Makefile             |   1 +
> > >   drivers/tty/serial/qcom_geni_earlycon.c | 649 ++++++++++++++++++++++++++++++++
> > >   drivers/tty/serial/qcom_geni_serial.c   |  97 -----
> > So you are replacing 97 lines of code with 649 lines?  How is this
> > benefiting anyone?
> > 
> > confused,
> 
> We have 2 versions of QUP driver, upstream version(Present in linus tree,
> mostly used for chromium project) and downstream version(belong to vendor
> part of code in GKI design, used for all the other project).

Why do you have 2 different versions?  Why not merge them both into the
kernel tree?  That seems like madness to try to support 2.  And why
would we care about any out-of-tree code?  This is increasing our
complexity for code that isn't even being merged here, not anything you
would do if you were the maintainer of it, right?

> There is need to enable geni earlycon in Google provided boot image for GKI
> to facilitate the debug until real console(belong to vendor code) is up.

Then submit the code for that here please.

> Currently it won't be possible because geni earlycon cannot be enabled
> independently, it depends on upstream QUP wrapper driver
> (soc/qcom/qcom-geni-se.c) and upstream serial
> driver(serial/qcom_geni_serial.c).
> 
> With this patch I am trying to break any dependency btw earlycon hook and
> QUP kernel drivers, so it can be managed independently.

Please submit the code that depends on this change, and we will be glad
to review it.

thanks,

greg k-h