From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Wed, 04 Mar 2015 10:38:06 +0100
Subject: [PATCH v4 2/8] arm64: dts: exynos: Add dts files for 64-bit
 Exynos5433 SoC
In-Reply-To: <54F6AD6B.70007@samsung.com>
References: <1424755011-15999-1-git-send-email-cw00.choi@samsung.com>
 <13467157.nyRCsNWIp6@wuerfel> <54F6AD6B.70007@samsung.com>
Message-ID: <2449954.zWisnqDpUA@wuerfel>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Wednesday 04 March 2015 15:59:55 Chanwoo Choi wrote:
> On 03/02/2015 06:22 AM, Arnd Bergmann wrote:
> > On Saturday 28 February 2015 09:47:01 Chanwoo Choi wrote:
> >> "earlycon=exynos4210,0x14C20000" is correct bootparam. You can check
> >> it on Documentation/kernel-parameters.txt as following.
> >>
> >>      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.
> >>
> >>
> > 
> > But it's crazy to do this when you have a DT. Please fix the existing
> > devicetree files that use this to just list 'earlycon'.
> > 
> > The syntax above only makes sense for classic board files that we
> > do not support for exynos any more.
> 
> Following earlycon patch for exynos soc was merged in Linux 4.0-rc1.
> - commit-id: b94ba0328d3b36ff95f5074c0e9b44f90dc56bb5 (serial: samsung: Add support for early console)
> Almost Exynos SoC use the same UART IP of Exynos4210.
> 
> If you mean that "earlycon=exynos4210" naming will be changed to "earlycon=exynos",
> we have to modify the drivers/tty/serial/samsung.c.

No, what I mean is that you should use just "earlycon" instead of "earlycon=..."
when you have a DTB. You have the OF_EARLYCON_DECLARE() in the driver as
well, so that should just work.

EARLYCON_DECLARE() is really just a hack that allows users to override the
early console from the command line without modifying the stdout-path
property. Don't put that into a dts file.

	Arnd