Re: [PATCH 3/5] tty/8250_dw: Add support for OCTEON UARTS.

From: Arnd Bergmann <arnd@arndb.de>
To: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org,
	Jamie Iles <jamie@jamieiles.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.cz>,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
	David Daney <david.daney@cavium.com>
Subject: Re: [PATCH 3/5] tty/8250_dw: Add support for OCTEON UARTS.
Date: Wed, 19 Jun 2013 12:01:06 +0200	[thread overview]
Message-ID: <2302882.NVjP8DdXWY@wuerfel> (raw)
In-Reply-To: <1371582775-12141-4-git-send-email-ddaney.cavm@gmail.com>

On Tuesday 18 June 2013 12:12:53 David Daney wrote:
> +static unsigned int dw8250_serial_inq(struct uart_port *p, int offset)
> +{
> +       offset <<= p->regshift;
> +
> +       return (u8)__raw_readq(p->membase + offset);
> +}
> +
> +static void dw8250_serial_outq(struct uart_port *p, int offset, int value)
> +{
> +       struct dw8250_data *d = p->private_data;
> +
> +       if (offset == UART_LCR)
> +               d->last_lcr = value;
> +
> +       offset <<= p->regshift;
> +       __raw_writeq(value, p->membase + offset);
> +       dw8250_serial_inq(p, UART_LCR);
> +}

This breaks building on 32 bit architectures as I found on my daily ARM
builds: __raw_writeq cannot be defined on architectures that don't have
native 64 bit data access instructions. It's also wrong to use the
__raw_* variant, which is not guaranteed to be atomic and is not
endian-safe.

	Arnd