From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tom Rini <trini@konsulko.com>
Date: Tue, 17 Jul 2018 09:25:27 -0400
Subject: [U-Boot] [PATCH] serial: ns16550: Add register shift variable
In-Reply-To: <96ec8334-d8d5-7ba3-3b16-4ff1e2c1b6e7@suse.de>
References: <1531492980-16543-1-git-send-email-fb@ltec.ch>
 <20180714104721.A8B69240175@gemini.denx.de>
 <20180714154933.GF2888@bill-the-cat>
 <96ec8334-d8d5-7ba3-3b16-4ff1e2c1b6e7@suse.de>
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On Mon, Jul 16, 2018 at 02:53:26PM +0200, Alexander Graf wrote:
> On 07/14/2018 05:49 PM, Tom Rini wrote:
> >On Sat, Jul 14, 2018 at 12:47:21PM +0200, Wolfgang Denk wrote:
> >>Dear Felix,
> >>
> >>In message <1531492980-16543-1-git-send-email-fb@ltec.ch> you wrote:
> >>>The motivation for writing this patch originates in the
> >>>effort of synchronizing U-Boot DT to Linux DT for am33xx SOCs.
> >>>The current am33xx.dtsi file from U-Boot defines the <reg-shift>
> >>>property for all UART nodes. The actual (4.18+) am33xx.dtsi
> >>>file from Linux does not define <reg-shift> anymore. To prevent
> >>>(probably difficult) changes in many .dts and .dtsi files once
> >>>the synchronization is done, one can use this new variable. For
> >>>the pdu001 board, for example, SYS_NS16550_REG_SHIFT is set
> >>>to 2; no need to clutter U-Boot and board specific dts files
> >>>with <reg-shift> properties.
> >>Does this mean that U-Boot will not be able to use the same DTB as
> >>Linux?
> >To be clear, it's the other way around.  We can't use the Linux dtb/dts
> >files as they've dropped (and in other cases, aren't adding) these
> >properties as it's handled differently.
> 
> What does "differently" mean? Linux tries quite hard to be platform
> agnostic, so a per-build-target #define surely isn't what they're doing.

Yes, what exactly is the Linux kernel doing here?

-- 
Tom
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