From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: Locking in the clk API
Date: Thu, 27 Jan 2011 21:15:56 +0000 [thread overview]
Message-ID: <20110127211556.GD1597@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <20110127210729.79eef2c1@lxorguk.ukuu.org.uk>
On Thu, Jan 27, 2011 at 09:07:29PM +0000, Alan Cox wrote:
> > > For internal tree purposes, does .set_termios need to be atomic? Can it
> > > grab mutexes instead of spinlock?
> >
> > I think I already answered that question above where I said "protect
> > against the interrupt handler accessing the port->* stuff".
>
> I'm not sure you answered it correctly however as the locking nowdays is
> a bit different.
Oh, and the other bit to this is protecting the hardware against two
concurrent accesses if that's what's required.
Eg, 8250 having characters written to the 'transmit' register while
DLAB is set, thereby corrupting the divisor being programmed into it.
There's other UARTs which shouldn't have FIFOs loaded while the UART
is disabled across an update.
Can you guarantee without locks that writes to the UART registers by
the interrupt handler won't happen while the .set_termios is
reprogramming the UART?
next prev parent reply other threads:[~2011-01-27 21:15 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-11 2:16 Locking in the clk API Jeremy Kerr
2011-01-11 3:15 ` Paul Mundt
2011-01-11 4:11 ` Jeremy Kerr
2011-01-11 4:54 ` Paul Mundt
2011-01-20 16:32 ` Ben Dooks
2011-01-20 18:57 ` Russell King - ARM Linux
2011-01-21 3:43 ` Saravana Kannan
2011-01-21 9:31 ` Russell King - ARM Linux
2011-01-11 9:03 ` Sascha Hauer
2011-01-11 9:28 ` Russell King - ARM Linux
2011-01-11 14:34 ` Pavel Machek
2011-01-20 16:29 ` Ben Dooks
2011-01-20 18:56 ` Russell King - ARM Linux
2011-01-20 21:30 ` Nicolas Pitre
2011-01-21 2:06 ` Dima Zavin
2011-01-21 4:12 ` Saravana Kannan
2011-01-21 9:32 ` Russell King - ARM Linux
2011-01-22 1:53 ` Saravana Kannan
2011-01-22 2:24 ` Colin Cross
2011-01-22 2:56 ` Saravana Kannan
2011-01-22 9:15 ` Russell King - ARM Linux
2011-01-24 19:31 ` Saravana Kannan
2011-01-21 21:03 ` Dima Zavin
2011-01-21 21:53 ` Nicolas Pitre
2011-01-21 22:02 ` Russell King - ARM Linux
2011-01-21 22:28 ` Colin Cross
2011-01-21 23:21 ` Benjamin Herrenschmidt
2011-01-21 23:50 ` Nicolas Pitre
2011-01-22 1:35 ` Saravana Kannan
2011-01-22 2:22 ` Colin Cross
2011-01-21 22:29 ` Nicolas Pitre
2011-01-21 23:28 ` Bryan Huntsman
2011-01-11 9:16 ` Russell King - ARM Linux
2011-01-11 9:44 ` Jeremy Kerr
2011-01-11 10:13 ` Paul Mundt
2011-01-11 10:30 ` Jeremy Kerr
2011-01-11 12:18 ` Paul Mundt
2011-01-11 13:52 ` Uwe Kleine-König
2011-01-11 14:35 ` Jeremy Kerr
2011-01-12 3:25 ` Saravana Kannan
2011-01-12 7:40 ` Uwe Kleine-König
2011-01-12 1:54 ` Saravana Kannan
2011-01-12 2:25 ` Paul Mundt
2011-01-20 16:57 ` Ben Dooks
2011-01-20 16:53 ` Ben Dooks
2011-01-20 16:40 ` Ben Dooks
2011-01-11 10:39 ` Uwe Kleine-König
2011-01-11 10:47 ` Russell King - ARM Linux
2011-01-11 10:56 ` Uwe Kleine-König
2011-01-11 11:15 ` Richard Zhao
2011-01-20 17:02 ` Ben Dooks
2011-01-20 19:08 ` Russell King - ARM Linux
2011-01-21 0:09 ` Jassi Brar
2011-01-21 4:47 ` Jassi Brar
2011-01-21 9:39 ` Russell King - ARM Linux
2011-01-21 10:11 ` Jassi Brar
2011-01-22 4:08 ` Richard Zhao
2011-01-22 5:30 ` Jassi Brar
2011-01-21 7:16 ` Saravana Kannan
2011-01-21 9:40 ` Russell King - ARM Linux
2011-01-22 1:47 ` Saravana Kannan
2011-01-27 4:34 ` Saravana Kannan
2011-01-27 8:54 ` Russell King - ARM Linux
2011-01-27 20:30 ` Saravana Kannan
2011-01-27 20:43 ` Russell King - ARM Linux
2011-01-27 21:07 ` Alan Cox
2011-01-27 21:11 ` Russell King - ARM Linux
2011-01-27 21:15 ` Russell King - ARM Linux [this message]
2011-01-28 3:29 ` Saravana Kannan
2011-01-28 3:27 ` Saravana Kannan
2011-01-11 12:11 ` Jassi Brar
2011-01-12 2:56 ` Saravana Kannan
2011-01-12 9:03 ` Russell King - ARM Linux
2011-01-15 14:02 ` Christer Weinigel
2011-01-15 14:53 ` Russell King - ARM Linux
2011-01-15 15:03 ` Uwe Kleine-König
2011-01-15 15:15 ` Russell King - ARM Linux
2011-01-15 16:03 ` Uwe Kleine-König
2011-01-15 16:21 ` Russell King - ARM Linux
2011-01-15 16:31 ` Uwe Kleine-König
2011-01-16 6:59 ` Grant Likely
2011-01-15 17:07 ` Christer Weinigel
2011-01-15 17:20 ` Russell King - ARM Linux
2011-01-15 17:44 ` Christer Weinigel
2011-01-15 20:30 ` Russell King - ARM Linux
2011-01-17 1:19 ` Jeremy Kerr
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