From: David Daney <ddaney@caviumnetworks.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: David Daney <ddaney.cavm@gmail.com>, <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 09:45:28 -0700 [thread overview]
Message-ID: <51C1E028.2040700@caviumnetworks.com> (raw)
In-Reply-To: <2302882.NVjP8DdXWY@wuerfel>
On 06/19/2013 03:01 AM, Arnd Bergmann wrote:
> 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.
I will rework the patch to avoid this problem.
> It's also wrong to use the
> __raw_* variant, which is not guaranteed to be atomic and is not
> endian-safe.
We do runtime probing and only use this function on platforms where it
is appropriate, so atomicity is not an issue. As for endianess, I used
the __raw_ variant precisely because it is correct for both big and
little endian kernels.
David Daney
next prev parent reply other threads:[~2013-06-19 16:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-18 19:12 [PATCH 0/5] MIPS/tty/8250: Use standard 8250 drivers for OCTEON David Daney
2013-06-18 19:12 ` [PATCH 1/5] Revert "MIPS: Octeon: Fix build error if CONFIG_SERIAL_8250=n" David Daney
2013-06-18 19:12 ` [PATCH 2/5] MIPS: OCTEON: Set proper UART clock in internal device trees David Daney
2013-06-18 19:12 ` [PATCH 3/5] tty/8250_dw: Add support for OCTEON UARTS David Daney
2013-06-18 19:26 ` Greg Kroah-Hartman
2013-06-19 10:01 ` Arnd Bergmann
2013-06-19 10:52 ` Ralf Baechle
2013-06-19 16:45 ` David Daney [this message]
2013-06-19 18:52 ` Arnd Bergmann
2013-06-19 19:12 ` David Daney
2013-06-19 14:10 ` Heikki Krogerus
2013-06-19 16:47 ` David Daney
2013-06-18 19:12 ` [PATCH 4/5] MIPS: OCTEON: Remove custom serial setup code David Daney
2013-06-18 19:12 ` [PATCH 5/5] MIPS: Update cavium_octeon_defconfig David Daney
2013-06-18 19:26 ` [PATCH 0/5] MIPS/tty/8250: Use standard 8250 drivers for OCTEON Greg Kroah-Hartman
2013-06-18 19:36 ` Ralf Baechle
2013-06-18 19:59 ` David Daney
2013-06-18 21:28 ` Jamie Iles
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