From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Caesar Wang <caesar.upstream@gmail.com>,
Heiko Stuebner <heiko@sntech.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
Caesar Wang <wxt@rock-chips.com>
Subject: Re: [PATCH 1/3] clocksource: rockchip: Make the driver more readability and compatible
Date: Fri, 18 Sep 2015 09:53:20 +0200 [thread overview]
Message-ID: <55FBC2F0.7010708@linaro.org> (raw)
In-Reply-To: <20150917211331.GU21084@n2100.arm.linux.org.uk>
On 09/17/2015 11:13 PM, Russell King - ARM Linux wrote:
> On Thu, Sep 17, 2015 at 12:57:53PM +0200, Daniel Lezcano wrote:
>> Hi Thomas,
>>
>> there is one thing I don't understand.
>>
>> If the IRQ0 is invalid, irq_of_parse_and_map returning zero means an error
>> and from what you said it is ok.
>>
>> But I see the NO_IRQ on ARM is (-1) and the drivers are checking with NO_IRQ
>> the return code of irq_of_parse_and_map. So if there is an error, that won't
>> be detected.
Hi Russel,
> NO_IRQ being -1 is a legacy thing for ARM - all ARM drivers are supposed
> to be converted to use <= 0 or == 0 to detect invalid IRQs, and _eventually_
> once all users are gone, NO_IRQ deleted.
>
> Moreover, there are supposed to be no _new_ users of NO_IRQ ever added to
> the kernel.
>
> Modern drivers should _all_ be using !irq to detect invalid IRQs, and not
> using NO_IRQ.
Ah, ok. Thanks for the clarification.
> The steps here are:
>
> 1. Convert all ARM platforms to start numbering IRQs from 1 rather than 0.
> 2. Convert all drivers used on ARM to detect lack of IRQ by checking for
> <= 0.
> 3. Replace NO_IRQ assignments with zero-initialisations.
> 4. Remove NO_IRQ.
>
> The reason it hasn't happened is that it requires effort and testing,
> and rather than running around getting old platforms to boot (which
> includes remembering _how_ to get them to boot) with recent kernels,
> I prefer to spend my time doing more productive work with modern code.
I understand. I will take the opportunity track down those NO_IRQ in the
clocksource directory.
-- Daniel
--
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs
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next prev parent reply other threads:[~2015-09-18 7:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-17 7:51 [PATCH 0/3] Support the timer on RK3368 SoC Caesar Wang
2015-09-17 7:51 ` [PATCH 1/3] clocksource: rockchip: Make the driver more readability and compatible Caesar Wang
2015-09-17 9:11 ` Daniel Lezcano
2015-09-17 9:28 ` Caesar Wang
2015-09-17 9:43 ` Heiko Stübner
2015-09-17 10:06 ` Daniel Lezcano
2015-09-17 10:19 ` Thomas Gleixner
2015-09-17 10:57 ` Daniel Lezcano
2015-09-17 21:13 ` Russell King - ARM Linux
2015-09-18 7:53 ` Daniel Lezcano [this message]
2015-09-17 10:19 ` Caesar Wang
2015-09-18 7:55 ` Daniel Lezcano
2015-09-18 8:22 ` Caesar Wang
2015-09-18 9:08 ` Russell King - ARM Linux
2015-09-17 7:51 ` [PATCH 2/3] arm64: Enable the timer on Rockchip architecture Caesar Wang
2015-09-17 7:51 ` [PATCH 3/3] arm64: dts: rockchip: Add the needed timer for rk3368 SoC Caesar Wang
2015-09-17 19:01 ` Heiko Stübner
2015-09-18 1:16 ` Caesar Wang
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