linux-kernel - Re: [PATCH 1/2] tty: serial: 8250

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Message-ID: <1822504.xkcBG8sz41@wuerfel>
Date:	Thu, 18 Dec 2014 10:12:33 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Matthias Brugger <matthias.bgg@...il.com>
Cc:	Eddie Huang <eddie.huang@...iatek.com>,
	Mark Rutland <mark.rutland@....com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	srv_heupstream <srv_heupstream@...iatek.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will.deacon@....com>, Jiri Slaby <jslaby@...e.cz>,
	Alan Cox <alan@...ux.intel.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-serial@...r.kernel.org, Sascha Hauer <kernel@...gutronix.de>,
	Yingjoe Chen <yingjoe.chen@...iatek.com>,
	YH Chen (陳昱豪) <yh.chen@...iatek.com>
Subject: Re: [PATCH 1/2] tty: serial: 8250_mtk: Add earlycon

On Thursday 18 December 2014 09:48:31 Matthias Brugger wrote:
> > +static void __init mtk8250_serial_putc(struct uart_port *port, int c)
> > +{
> > +       while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) !=
> > +               BOTH_EMPTY)
> > +               ;
> 
> Please delete newline before the semicolon.
> 

No, that newline is best kept in there for clarity. An even better way
to write this would be using cpu_relax():

	while ((readl(port->membase + (UART_LSR << 2)) & BOTH_EMPTY) != BOTH_EMPTY)
		cpu_relax();

which the kernel convention for doing busy-loops.

	Arnd
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