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From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/4] dmaengine: dw_dmac: move to generic DMA binding
Date: Sat, 16 Feb 2013 13:43:43 +0000	[thread overview]
Message-ID: <201302161343.43434.arnd@arndb.de> (raw)
In-Reply-To: <20130216105159.GN17833@n2100.arm.linux.org.uk>

On Saturday 16 February 2013, Russell King - ARM Linux wrote:
> On Sat, Feb 16, 2013 at 10:07:39AM +0000, Arnd Bergmann wrote:
> > On Saturday 16 February 2013, Viresh Kumar wrote:
> > > On 15 February 2013 23:51, Arnd Bergmann <arnd@arndb.de> wrote:
> > > > +static bool dw_dma_generic_filter(struct dma_chan *chan, void *param)
> > > >  {
> > > 
> > > > +       dws->cfg_hi     = 0xffffffff;
> > > > +       dws->cfg_lo     = 0xffffffff;
> > > 
> > > s/0xffffffff/-1 ?
> > 
> > It's an 'unsigned int'. While -1 would work here, I always find it a little
> > odd to rely on that feature of the C language.
> 
> However, relying on an 'int' being 32-bits is also rather odd, and
> probably much more dubious too.  If you want to set all bits in an
> int, the portable way to do that is ~0.

Right, I can do that, too. All I really need here though is to make sure
I use the same value in this place and when comparing it in dwc_initialize,
and it needs to be something that cannot be a valid register setting.

Thanks,

	Arnd

WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
	Vinod Koul <vinod.koul@linux.intel.com>,
	Vinod Koul <vinod.koul@intel.com>,
	devicetree-discuss@lists.ozlabs.org,
	linux-kernel@vger.kernel.org, Dan Williams <djbw@fb.com>,
	Olof Johansson <olof@lixom.net>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/4] dmaengine: dw_dmac: move to generic DMA binding
Date: Sat, 16 Feb 2013 13:43:43 +0000	[thread overview]
Message-ID: <201302161343.43434.arnd@arndb.de> (raw)
In-Reply-To: <20130216105159.GN17833@n2100.arm.linux.org.uk>

On Saturday 16 February 2013, Russell King - ARM Linux wrote:
> On Sat, Feb 16, 2013 at 10:07:39AM +0000, Arnd Bergmann wrote:
> > On Saturday 16 February 2013, Viresh Kumar wrote:
> > > On 15 February 2013 23:51, Arnd Bergmann <arnd@arndb.de> wrote:
> > > > +static bool dw_dma_generic_filter(struct dma_chan *chan, void *param)
> > > >  {
> > > 
> > > > +       dws->cfg_hi     = 0xffffffff;
> > > > +       dws->cfg_lo     = 0xffffffff;
> > > 
> > > s/0xffffffff/-1 ?
> > 
> > It's an 'unsigned int'. While -1 would work here, I always find it a little
> > odd to rely on that feature of the C language.
> 
> However, relying on an 'int' being 32-bits is also rather odd, and
> probably much more dubious too.  If you want to set all bits in an
> int, the portable way to do that is ~0.

Right, I can do that, too. All I really need here though is to make sure
I use the same value in this place and when comparing it in dwc_initialize,
and it needs to be something that cannot be a valid register setting.

Thanks,

	Arnd

  reply	other threads:[~2013-02-16 13:43 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-15 18:21 [PATCH 0/4] dw_dmac: introduce generic DMA binding for DT Arnd Bergmann
2013-02-15 18:21 ` Arnd Bergmann
2013-02-15 18:21 ` [PATCH 1/4] Revert "ARM: SPEAr13xx: Pass DW DMAC platform data from DT" Arnd Bergmann
2013-02-15 18:21   ` Arnd Bergmann
2013-02-15 18:21 ` [PATCH 2/4] dmaengine: dw_dmac: move to generic DMA binding Arnd Bergmann
2013-02-15 18:21   ` Arnd Bergmann
2013-02-15 18:21   ` Arnd Bergmann
2013-02-16  3:26   ` Viresh Kumar
2013-02-16  3:26     ` Viresh Kumar
2013-02-16 10:07     ` Arnd Bergmann
2013-02-16 10:07       ` Arnd Bergmann
2013-02-16 10:07       ` Arnd Bergmann
2013-02-16 10:51       ` Russell King - ARM Linux
2013-02-16 10:51         ` Russell King - ARM Linux
2013-02-16 10:51         ` Russell King - ARM Linux
2013-02-16 13:43         ` Arnd Bergmann [this message]
2013-02-16 13:43           ` Arnd Bergmann
2013-02-16 11:13   ` Andy Shevchenko
2013-02-16 11:13     ` Andy Shevchenko
2013-02-16 11:13     ` Andy Shevchenko
2013-02-16 14:00     ` Arnd Bergmann
2013-02-16 14:00       ` Arnd Bergmann
2013-02-16 14:00       ` Arnd Bergmann
2013-02-16 14:53       ` Andy Shevchenko
2013-02-16 14:53         ` Andy Shevchenko
2013-02-16 22:21         ` [PATCHv3 " Arnd Bergmann
2013-02-16 22:21           ` Arnd Bergmann
2013-02-16 22:21           ` Arnd Bergmann
2013-02-16 22:54           ` Andy Shevchenko
2013-02-16 22:54             ` Andy Shevchenko
2013-02-16 23:24             ` [PATCHv4 " Arnd Bergmann
2013-02-16 23:24               ` Arnd Bergmann
2013-02-16 23:24               ` Arnd Bergmann
2013-02-16 23:28             ` [PATCHv3 " Arnd Bergmann
2013-02-16 23:28               ` Arnd Bergmann
2013-02-16 22:23         ` [BONUS PATCH] dmaengine: dw_dmac: simplify master selection Arnd Bergmann
2013-02-16 22:23           ` Arnd Bergmann
2013-02-15 18:21 ` [PATCH 3/4] spi: pl022: use generic DMA slave configuration if possible Arnd Bergmann
2013-02-15 18:21   ` Arnd Bergmann
2013-02-15 18:21 ` [PATCH 4/4] serial: pl011: " Arnd Bergmann
2013-02-15 18:21   ` Arnd Bergmann
2013-02-16  3:26 ` [PATCH 0/4] dw_dmac: introduce generic DMA binding for DT Viresh Kumar
2013-02-16  3:26   ` Viresh Kumar
2013-02-16  3:26   ` Viresh Kumar
2013-02-20  8:03 ` Vinod Koul
2013-02-20  8:03   ` Vinod Koul
2013-02-20  9:50   ` Arnd Bergmann
2013-02-20  9:50     ` Arnd Bergmann
2013-02-20  9:50     ` Arnd Bergmann
2013-02-20  9:58     ` Vinod Koul
2013-02-20  9:58       ` Vinod Koul
2013-02-20 11:10       ` Arnd Bergmann
2013-02-20 11:10         ` Arnd Bergmann

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