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From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 02/10] irqchip: add irqchip driver for nuc900
Date: Fri, 15 Jul 2016 09:00:22 +0200	[thread overview]
Message-ID: <16178876.fFBuoBSjbd@wuerfel> (raw)
In-Reply-To: <5788718E.7080708@iommu.org>

On Friday, July 15, 2016 1:15:58 PM CEST Wan Zongshun wrote:
> 
> Actually, I have two choice to implement this function:
> 
> option1:
> 
> void __exception_irq_entry aic_handle_irq(struct pt_regs *regs)
> {
>         u32 hwirq;
> 
>         (void)readl(aic_base + REG_AIC_IPER);
>         hwirq = readl(aic_base + REG_AIC_ISNR);
> 
>         handle_IRQ((irq_find_mapping(aic_domain, hwirq)), regs);
> }

(side note: I think you want handle_domain_irq())

> option2:
> 
> void __exception_irq_entry aic_handle_irq(struct pt_regs *regs)
> {
>         u32 hwirq;
> 
>         hwirq = readl(aic_base + REG_AIC_IPER);
>         hwirq <<= 2;
> 
>         handle_IRQ((irq_find_mapping(aic_domain, hwirq)), regs);
> }
> 
> Though the option2 do shift for hwirq, but it seems better than do io 
> operation by readl,so I prefer to option2, agree?

That will only return an irq number that is a multiple of four, which
seems wrong since the numbers are not that. Did you mean to write

	hwirq = ilog2(hwirq);   ?

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.

	Arnd

  reply	other threads:[~2016-07-15  7:00 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 [this message]
2016-07-15  9:44             ` Wan ZongShun
2016-07-15 10:02               ` Arnd Bergmann
2016-07-21 18:45                 ` Jason Cooper
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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