linux/kernel/irq
Marc Zyngier 530cbe100e irqdomain: Allow domain lookup with DOMAIN_BUS_WIRED token
Let's take the (outlandish) example of an interrupt controller
capable of handling both wired interrupts and PCI MSIs.

With the current code, the PCI MSI domain is going to be tagged
with DOMAIN_BUS_PCI_MSI, and the wired domain with DOMAIN_BUS_ANY.

Things get hairy when we start looking up the domain for a wired
interrupt (typically when creating it based on some firmware
information - DT or ACPI).

In irq_create_fwspec_mapping(), we perform the lookup using
DOMAIN_BUS_ANY, which is actually used as a wildcard. This gives
us one chance out of two to end up with the wrong domain, and
we try to configure a wired interrupt with the MSI domain.
Everything grinds to a halt pretty quickly.

What we really need to do is to start looking for a domain that
would uniquely identify a wired interrupt domain, and only use
DOMAIN_BUS_ANY as a fallback.

In order to solve this, let's introduce a new DOMAIN_BUS_WIRED
token, which is going to be used exactly as described above.
Of course, this depends on the irqchip to setup the domain
bus_token, and nobody had to implement this so far.

Only so far.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Link: http://lkml.kernel.org/r/1453816347-32720-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-26 16:00:14 +01:00
..
autoprobe.c genirq: Handle pending irqs in irq_startup() 2012-02-15 11:56:59 +01:00
chip.c genirq/msi: Export functions to allow MSI domains in modules 2015-12-20 12:26:52 +01:00
cpuhotplug.c genirq: Make the cpuhotplug migration code less noisy 2015-10-22 14:34:57 +02:00
debug.h irq: hide debug macros so they don't collide with others. 2012-04-23 12:30:03 -04:00
devres.c genirq: devres: Fix testing return value of request_any_context_irq() 2015-05-13 10:47:37 +02:00
dummychip.c Merge branch 'linus' into irq/core 2015-06-05 22:25:01 +02:00
generic-chip.c genirq: Add chip_[suspend|resume] PM support to irq_chip 2015-07-27 08:09:38 +02:00
handle.c genirq: Validate action before dereferencing it in handle_irq_event_percpu() 2016-01-14 20:09:49 +01:00
internals.h genirq/PM: Restore system wake up from chained interrupts 2015-11-10 09:11:31 -05:00
irqdesc.c genirq: Free irq_desc with rcu 2015-12-14 10:03:46 +01:00
irqdomain.c irqdomain: Allow domain lookup with DOMAIN_BUS_WIRED token 2016-01-26 16:00:14 +01:00
Kconfig genirq: Introduce generic irq migration for cpu hotunplug 2015-10-01 14:51:15 +02:00
Makefile genirq: Introduce generic irq migration for cpu hotunplug 2015-10-01 14:51:15 +02:00
manage.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-01-11 18:28:06 -08:00
migration.c genirq: Remove bogus restriction in irq_move_mask_irq() 2015-06-20 19:05:14 +02:00
msi.c genirq/msi: Add msi_domain_populate_irqs 2015-12-16 15:29:44 +00:00
pm.c Merge branches 'irq-urgent-for-linus' and 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-11-15 09:30:48 -08:00
proc.c genirq/PM: Restore system wake up from chained interrupts 2015-11-10 09:11:31 -05:00
resend.c genirq: Remove irq argument from irq flow handlers 2015-09-16 15:47:51 +02:00
settings.h genirq: Add flag to force mask in disable_irq[_nosync]() 2015-10-11 11:33:42 +02:00
spurious.c genirq: Remove the irq argument from note_interrupt() 2015-07-11 23:14:25 +02:00