From: Arnd Bergmann <arnd@arndb.de>
To: George Kashperko <george@znau.edu.ua>
Subject: Re: [RFC][PATCH 01/10] bcma: Use array to store cores.
Date: Mon, 6 Jun 2011 15:03:14 +0200
Cc: =?utf-8?q?Rafa=C5=82_Mi=C5=82ecki?= <zajec5@gmail.com>,
	Hauke Mehrtens <hauke@hauke-m.de>, Greg KH <greg@kroah.com>,
	linux-wireless@vger.kernel.org, linux-mips@linux-mips.org,
	mb@bu3sch.de, arend@broadcom.com, b43-dev@lists.infradead.org,
	bernhardloos@googlemail.com
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On Monday 06 June 2011, George Kashperko wrote:
> > For an interrupt controller, it should be ok to have it initialized
> > late, as long as it's only responsible for the devices on the same
> > bus and not for instance for IPI interrupts. Just make sure that you
> > do the bus scan and the initialization of the IRQ driver before you
> > initialize any drivers that rely in on the interrupts to be working.
>
> Without proper timer init (which requires both the chipcommon and mips
> cores knowledge) kernel will get hung somewhere inside calibrate_delay.
> It could get addressed if get bus scan called in arch_init_irq or
> plat_time_init - both are executed before calibrate_delay and with slab
> available.

Ok, so you need the interrupt controller to be working for the timer tick,
right? I think another option (if that's not what you mean already) would
be to have a simpler way to find a device on the bus that can be called
before doing a full scan.

Early drivers would then have to know what is there and call a function
like "bcma_find_device(BCMA_DEV_ID_IRQ)", while drivers that are not
required to be up just register a regular device driver with a probe
function that gets called after the bus scan creates device structures.

	Arnd