From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
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: Thu, 17 Sep 2015 22:13:31 +0100 [thread overview]
Message-ID: <20150917211331.GU21084@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <55FA9CB1.8010402@linaro.org>
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.
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.
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.
--
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2015-09-17 21:13 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 [this message]
2015-09-18 7:53 ` Daniel Lezcano
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150917211331.GU21084@n2100.arm.linux.org.uk \
--to=linux@arm.linux.org.uk \
--cc=caesar.upstream@gmail.com \
--cc=catalin.marinas@arm.com \
--cc=daniel.lezcano@linaro.org \
--cc=heiko@sntech.de \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rockchip@lists.infradead.org \
--cc=tglx@linutronix.de \
--cc=will.deacon@arm.com \
--cc=wxt@rock-chips.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).