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From: Ahmad Fatoum <a.fatoum@pengutronix.de>
To: Sascha Hauer <sha@pengutronix.de>, Roland Hieber <rhi@pengutronix.de>
Cc: barebox@lists.infradead.org, Ahmad Fatoum <ahmad@a3f.at>,
	Andrew John <andrew@mobius-embedded-systems.co.uk>,
	Robert Carnecky <robert@neopsis.com>,
	Rouven Czerwinski <rcz@pengutronix.de>
Subject: Re: [PATCH 11/11] doc: bcm283x: document use of mini-uart on Raspberry Pi Zero W / CM3
Date: Mon, 07 Dec 2020 11:00:49 +0100	[thread overview]
Message-ID: <7b844847d222acd42afd79b23c1c3135fdace598.camel@pengutronix.de> (raw)
In-Reply-To: <20201207071058.GB3977@pengutronix.de>

On Mon, 2020-12-07 at 08:10 +0100, Sascha Hauer wrote:
> On Sun, Nov 29, 2020 at 08:50:42PM +0100, Roland Hieber wrote:
> > On Sat, Nov 28, 2020 at 10:39:34PM +0100, Ahmad Fatoum wrote:
> > > As described in the UART configuration[1] article in the
> > > Raspberry Pi
> > > Foundation documentation, Raspberry Pi 3 & 4 as well as Zero W
> > > use the
> > > mini-uart as primary (easily user-accessible) UART. At least on
> > > the
> > > Raspberry Zero W and CM3, we need to pass uart_2ndstage=1, so the
> > > BootROM leaves the 8250 IP in a suitable state for use by
> > > barebox.
> > > Document this.
> > > 
> > > [1]: 
> > > https://www.raspberrypi.org/documentation/configuration/uart.md
> > > 
> > > Cc: Roland Hieber <rhi@pengutronix.de>
> > > Cc: Rouven Czerwinski <rcz@pengutronix.de>
> > > Cc: Robert Carnecky <robert@neopsis.com>
> > > Cc: Andrew John <andrew@mobius-embedded-systems.co.uk>
> > > Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
> > > ---
> > >  Documentation/boards/bcm2835.rst | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> > > 
> > > diff --git a/Documentation/boards/bcm2835.rst
> > > b/Documentation/boards/bcm2835.rst
> > > index c896871e0d82..dbdfc2633173 100644
> > > --- a/Documentation/boards/bcm2835.rst
> > > +++ b/Documentation/boards/bcm2835.rst
> > > @@ -23,6 +23,13 @@ Raspberry Pi
> > >           kernel=barebox.img
> > >           enable_uart=1
> > >  
> > > +     If you want to use the mini-uart instead of the PL011, you
> > > might need to additionally set::
> > > +
> > > +         uart_2ndstage=1
> > > +
> > > +     This is useful on newer boards like the Raspberry Pi Zero W
> > > and CM3, which route the
> > > +     more easily accessible primary UART to the mini-uart.
> > 
> > This seems to be non-optional on RPi Zero W, so I would word it
> > more
> > strongly.
> > 
> > With this series, at least barebox boots, which is better than in
> > master
> > :-) However, I cannot get the stock kernel (/boot/kernel.img) to
> > boot on
> > Zero W, and I cannot figure out why:
> 
> Should I wait for this being fixed before I merge this series?

I sent a fixup. I think it's ok to merge that way.

> 
> Sascha
> 


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  reply	other threads:[~2020-12-07 10:00 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-28 21:39 [PATCH 01/11] Revert "ARM: dts: bcm2835-rpi: re-enable booting from SD card" Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 02/11] ARM: dts: rpi: drop unnecessary /chosen/stdout-path overrides Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 03/11] ARM: rpi: make functions in rpi-common.c static Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 04/11] ARM: rpi: move rpi_model_init() to postcore Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 05/11] ARM: rpi: support raspberry pi 1 and zero mini-uart Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 06/11] ARM: rpi: add new init function for Raspberry Pi Zero Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 07/11] ARM: rpi: Add Raspberry Pi Zero W mini-uart support Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 08/11] ARM: rpi: drop no longer needed environment Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 09/11] ARM: rpi: fix model description string Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 10/11] ARM: rpi: add new rpi boot target Ahmad Fatoum
2020-11-28 21:39 ` [PATCH 11/11] doc: bcm283x: document use of mini-uart on Raspberry Pi Zero W / CM3 Ahmad Fatoum
2020-11-29 19:50   ` Roland Hieber
2020-11-29 20:20     ` Ahmad Fatoum
2020-12-07  7:10     ` Sascha Hauer
2020-12-07 10:00       ` Ahmad Fatoum [this message]
2020-12-07 10:29         ` Sascha Hauer
2020-12-07 10:00   ` [PATCH] fixup! " Ahmad Fatoum

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