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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Roland Hieber <r.hieber@pengutronix.de>
Cc: barebox@lists.infradead.org,
	Rouven Czerwinski <r.czerwinski@pengutronix.de>
Subject: Re: [PATCH v4 2/7] ARM: rpi: retrieve miniuart clock from firmware
Date: Tue, 18 Dec 2018 08:17:36 +0100	[thread overview]
Message-ID: <20181218071736.3fb5pq5zjrgq5rlu@pengutronix.de> (raw)
In-Reply-To: <20181218032610.zpsxavqsbzswg3ry@pengutronix.de>

On Tue, Dec 18, 2018 at 04:26:10AM +0100, Roland Hieber wrote:
> On Mon, Dec 17, 2018 at 09:10:40AM +0100, Rouven Czerwinski wrote:
> > The miniuart uses the core clock as the clock source. This clock is fixed by the
> > firmware to 250Mhz if enable_uart=1 is set in the config.txt file.
> > However a user could still choose to overclock the core frequency,
> > which would result in wrong baudrates computed by barebox.
> > Retrieve the core clock frequency from the firmware to allow all potential
> > firmware configurations to work with barebox.
> > 
> > Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
> > ---
> >  arch/arm/boards/raspberry-pi/rpi-common.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
> > index 490aeef..e29177d 100644
> > --- a/arch/arm/boards/raspberry-pi/rpi-common.c
> > +++ b/arch/arm/boards/raspberry-pi/rpi-common.c
> > @@ -309,6 +309,13 @@ static int rpi_console_clock_init(void)
> >  	clkdev_add_physbase(clk, 0x20201000, NULL);
> >  	clkdev_add_physbase(clk, 0x3f201000, NULL);
> >  
> > +	clk = rpi_register_firmware_clock(BCM2835_MBOX_CLOCK_ID_CORE,
> > +					  "uart1-8250");
> > +	if (IS_ERR(clk))
> > +		return PTR_ERR(clk);
> > +
> > +	clkdev_add_physbase(clk, 0x3f215040, NULL);
> 
> This magic value could probably have an explaining comment somewhere
> next to it.

Or better a #define BCM2835_xxx_BASE 0x3f215040.

Sascha

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  reply	other threads:[~2018-12-18  7:17 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-17  8:10 [PATCH v4 0/7] Raspberry Pi miniuart support Rouven Czerwinski
2018-12-17  8:10 ` [PATCH v4 1/7] ARM: rpi: move clks into board specific rpi-common Rouven Czerwinski
2018-12-17  8:10 ` [PATCH v4 2/7] ARM: rpi: retrieve miniuart clock from firmware Rouven Czerwinski
2018-12-18  3:26   ` Roland Hieber
2018-12-18  7:17     ` Sascha Hauer [this message]
2018-12-18  7:21   ` Sascha Hauer
2018-12-18  8:39     ` Rouven Czerwinski
2018-12-18  8:45       ` Sascha Hauer
2018-12-17  8:10 ` [PATCH v4 3/7] serial_ns16550: handle default reg-io-width Rouven Czerwinski
2018-12-17  8:10 ` [PATCH v4 4/7] serial_ns16550: add raspberry pi compatible and init Rouven Czerwinski
2018-12-18  3:29   ` Roland Hieber
2018-12-17  8:10 ` [PATCH v4 5/7] ARM: rpi: add NS16550 support Rouven Czerwinski
2018-12-17  8:10 ` [PATCH v4 6/7] ARM: rpi: choose miniuart as stdout Rouven Czerwinski
2018-12-17  8:10 ` [PATCH v4 7/7] doc: bcm283x: remove miniuart overlay instruction Rouven Czerwinski
2018-12-17 10:13 ` [PATCH v4 0/7] Raspberry Pi miniuart support Sascha Hauer

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