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From: jason@lakedaemon.net (Jason Cooper)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 02/10] irqchip: add irqchip driver for nuc900
Date: Thu, 21 Jul 2016 18:45:34 +0000	[thread overview]
Message-ID: <20160721184534.GI5814@io.lakedaemon.net> (raw)
In-Reply-To: <1885052.EkH2ZADWZS@wuerfel>

Wan ZongShun,

On Fri, Jul 15, 2016 at 12:02:55PM +0200, Arnd Bergmann wrote:
> On Friday, July 15, 2016 5:44:50 PM CEST Wan ZongShun wrote:
> > 2016-07-15 15:00 GMT+08:00 Arnd Bergmann <arnd@arndb.de>:
> > > On Friday, July 15, 2016 1:15:58 PM CEST Wan Zongshun wrote:
...
> > > That assumes that REG_AIC_IPER contains a 32-bit value with one single
> > > bit set to indicate which IRQ was triggered.
> > >
> > > If the difference is only in performance, you could try measuring which
> > > of the two ends up being faster.
> > 
> > It seems hard to measure. I think Do IO operation should be slower
> > than shift 2. 
> 
> It depends on how fast that particular I/O path is. A lot of readl()
> operations are awfully slow, but the hardware design for the interrupt
> controller may in fact have optimized this to be reasonably fast.
> 
> Another option would be to avoid the shift and just use the raw value
> of the REG_AIC_IPER register as the hwirq, with a custom map()
> callback that turns shifts the number read from the DT two bits
> so it matches the register value.

Good idea.  Are the two lsb bits constant or do they need to be masked?

thx,

Jason.

  reply	other threads:[~2016-07-21 18:45 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-10  7:27 [PATCH v2 00/10] ARM: NUC900: Add NUC970 SoC support Wan Zongshun
2016-07-10  7:27 ` [PATCH v2 01/10] ARM: NUC900: Add nuc970 machine support Wan Zongshun
2016-07-10 22:11   ` Arnd Bergmann
2016-07-11 16:04   ` Arnd Bergmann
2016-07-12  4:30     ` Wan Zongshun
2016-07-12  7:14       ` Wan Zongshun
2016-07-12  8:23         ` Arnd Bergmann
2016-07-10  7:27 ` [PATCH v2 02/10] irqchip: add irqchip driver for nuc900 Wan Zongshun
2016-07-10 21:51   ` Paul Gortmaker
2016-07-11  2:19     ` Wan Zongshun
2016-07-11 15:46   ` Arnd Bergmann
2016-07-12  7:04     ` Wan Zongshun
2016-07-12  8:26       ` Arnd Bergmann
2016-07-14  8:52         ` Wan Zongshun
2016-07-14 11:09           ` Arnd Bergmann
2016-07-13 20:09   ` Jason Cooper
2016-07-14  3:36     ` Wan Zongshun
2016-07-14 13:54       ` Jason Cooper
2016-07-15  5:15         ` Wan Zongshun
2016-07-15  7:00           ` Arnd Bergmann
2016-07-15  9:44             ` Wan ZongShun
2016-07-15 10:02               ` Arnd Bergmann
2016-07-21 18:45                 ` Jason Cooper [this message]
2016-07-15 15:45               ` Jason Cooper
2016-07-10  7:27 ` [PATCH v2 03/10] Clocksource: add nuc970 clocksource driver Wan Zongshun
2016-07-11 15:36   ` Arnd Bergmann
2016-07-12  7:32     ` Wan Zongshun
2016-07-12  8:28       ` Arnd Bergmann
2016-07-21 12:52         ` Daniel Lezcano
2016-07-21 12:54           ` Arnd Bergmann
2016-07-10  7:27 ` [PATCH v2 04/10] clk: add Clock driver for nuc970 Wan Zongshun
2016-07-11 22:14   ` Michael Turquette
2016-07-10  7:27 ` [PATCH v2 05/10] power/reset: Add reset driver support for nuc900 Wan Zongshun
2016-07-10 21:56   ` Paul Gortmaker
2016-07-11  2:30     ` Wan Zongshun
2016-07-11  2:58       ` Paul Gortmaker
2016-07-10  7:27 ` [PATCH v2 06/10] soc: Add SoC specific " Wan Zongshun
2016-07-11  8:03   ` Arnd Bergmann
2016-07-11  9:07     ` Wan Zongshun
2016-07-11 10:24       ` Arnd Bergmann
2016-07-11 10:28         ` Wan ZongShun
2016-07-11 10:36           ` Arnd Bergmann
2016-07-12  9:06     ` Wan Zongshun
2016-07-12  9:50       ` Arnd Bergmann
2016-07-10  7:27 ` [PATCH v2 07/10] ARM: dts: Add clock header file into dt-bindings Wan Zongshun

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