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From: jgunthorpe@obsidianresearch.com (Jason Gunthorpe)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 1/3] ARM: Introduce atomic MMIO modify
Date: Fri, 6 Sep 2013 10:48:44 -0600	[thread overview]
Message-ID: <20130906164844.GA2308@obsidianresearch.com> (raw)
In-Reply-To: <20130905090841.GA9696@mudshark.cambridge.arm.com>

On Thu, Sep 05, 2013 at 10:08:42AM +0100, Will Deacon wrote:

> > I would like to make the things move on about this subject. Should it
> > be possible to merge this version of the patch set? Currently the
> > only users of this new API are drivers for ARM SoCs.
> 
> In the short term then, I'd keep this restricted to ARM. Without relaxed
> accessors available across all architectures, I don't think we can make this
> usefully generic (a readX/writeX version would be horribly slow on ARM).

Realistically though, the current use cases for this function have it
called only a few times during startup, so it 'horribly slow' isn't
really important at all.

So why not start with this in generic headers:

extern void atomic_io_modify(void __iomem *reg, u32 mask, u32 set);
#define atomic_io_modify_relaxed atomic_io_modify

And the relaxed optimization can come along in due course?

Jason

  parent reply	other threads:[~2013-09-06 16:48 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-23 10:24 [PATCH v3 0/3] Introduce atomic MMIO register modify Ezequiel Garcia
2013-08-23 10:24 ` [PATCH v3 1/3] ARM: Introduce atomic MMIO modify Ezequiel Garcia
2013-08-23 10:38   ` Baruch Siach
2013-08-23 11:07     ` Ezequiel Garcia
2013-08-23 11:32       ` Ezequiel Garcia
2013-08-23 11:48         ` Catalin Marinas
2013-08-30  9:08           ` Will Deacon
2013-08-30  9:15             ` Catalin Marinas
2013-08-30  9:20               ` Will Deacon
2013-08-30 10:03                 ` Catalin Marinas
2013-08-30 20:08                   ` Jason Gunthorpe
2013-08-30 22:18                     ` Russell King - ARM Linux
2013-09-05  8:59                   ` Gregory CLEMENT
2013-09-05  9:08                     ` Will Deacon
2013-09-05  9:20                       ` Gregory CLEMENT
2013-09-06 16:48                       ` Jason Gunthorpe [this message]
2013-08-23 11:28   ` Ezequiel Garcia
2013-08-23 10:24 ` [PATCH v3 2/3] clocksource: orion: Use atomic access for shared registers Ezequiel Garcia
2013-08-23 10:38   ` Baruch Siach
2013-08-23 10:49     ` Ezequiel Garcia
2013-08-23 10:24 ` [PATCH v3 3/3] watchdog: " Ezequiel Garcia

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