linux-kernel - Re: [PATCH 2/2] of/irq: do irq resolution in platform_get

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Message-ID: <20140424184207.GC27443@ulmo>
Date:	Thu, 24 Apr 2014 20:42:08 +0200
From:	Thierry Reding <thierry.reding@...il.com>
To:	Rob Herring <robherring2@...il.com>
Cc:	Russell King <linux@....linux.org.uk>,
	Tony Lindgren <tony@...mide.com>,
	Grant Likely <grant.likely@...aro.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Jean-Jacques Hiblot <jjhiblot@...phandler.com>,
	Rob Herring <robh@...nel.org>
Subject: Re: [PATCH 2/2] of/irq: do irq resolution in platform_get_irq

On Wed, Apr 23, 2014 at 05:57:41PM -0500, Rob Herring wrote:
> From: Rob Herring <robh@...nel.org>
> 
> Currently we get the following kind of errors if we try to use interrupt
> phandles to irqchips that have not yet initialized:
> 
> irq: no irq domain found for /ocp/pinmux@...02030 !
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at drivers/of/platform.c:171 of_device_alloc+0x144/0x184()
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-00038-g42a9708 #1012
> (show_stack+0x14/0x1c)
> (dump_stack+0x6c/0xa0)
> (warn_slowpath_common+0x64/0x84)
> (warn_slowpath_null+0x1c/0x24)
> (of_device_alloc+0x144/0x184)
> (of_platform_device_create_pdata+0x44/0x9c)
> (of_platform_bus_create+0xd0/0x170)
> (of_platform_bus_create+0x12c/0x170)
> (of_platform_populate+0x60/0x98)
> 
> This is because we're wrongly trying to populate resources that are not
> yet available. It's perfectly valid to create irqchips dynamically, so
> let's fix up the issue by resolving the interrupt resources when
> platform_get_irq is called.
> 
> And then we also need to accept the fact that some irqdomains do not
> exist that early on, and only get initialized later on. So we can
> make the current WARN_ON into just into a pr_debug().
> 
> We still attempt to populate irq resources when we create the devices.
> This allows current drivers which don't use platform_get_irq to continue
> to function. Once all drivers are fixed, this code can be removed.
> 
> Suggested-by: Russell King <linux@....linux.org.uk>
> Signed-off-by: Rob Herring <robh@...nel.org>
> Signed-off-by: Tony Lindgren <tony@...mide.com>
> ---
>  drivers/base/platform.c |  7 ++++++-
>  drivers/of/irq.c        | 26 ++++++++++++++++++++++++++
>  drivers/of/platform.c   |  4 +++-
>  include/linux/of_irq.h  |  7 ++++++-
>  4 files changed, 41 insertions(+), 3 deletions(-)

Hehe... that's largely what we already had back in January[0]. Glad to
see that people could finally agree on what to do about this.

Thierry

[0]: https://lkml.org/lkml/2014/1/8/240

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