From fcd98e59c2a12ec4a7f28f14deb2862b618da280 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 26 Jan 2016 13:52:25 +0000 Subject: [PATCH] UPSTREAM: 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. Change-Id: Ia71c7475354eb38ab9b15423560aa3d28ae16381 Signed-off-by: Marc Zyngier Cc: Greg Kroah-Hartman Cc: Rob Herring Cc: Frank Rowand Cc: Grant Likely Cc: Thomas Petazzoni Cc: Jiang Liu Link: http://lkml.kernel.org/r/1453816347-32720-2-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner Signed-off-by: Caesar Wang (cherry picked from commit 530cbe100ef7587aa5b5ac3a4b670cda4d50e598) --- include/linux/irqdomain.h | 1 + kernel/irq/irqdomain.c | 11 ++++++++--- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h index 4950a71ef77d..8b60c95f4417 100644 --- a/include/linux/irqdomain.h +++ b/include/linux/irqdomain.h @@ -70,6 +70,7 @@ struct irq_fwspec { */ enum irq_domain_bus_token { DOMAIN_BUS_ANY = 0, + DOMAIN_BUS_WIRED, DOMAIN_BUS_PCI_MSI, DOMAIN_BUS_PLATFORM_MSI, DOMAIN_BUS_NEXUS, diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 7f34d98ebfc4..6ca9bda5777c 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -573,10 +573,15 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) unsigned int type = IRQ_TYPE_NONE; int virq; - if (fwspec->fwnode) - domain = irq_find_matching_fwnode(fwspec->fwnode, DOMAIN_BUS_ANY); - else + if (fwspec->fwnode) { + domain = irq_find_matching_fwnode(fwspec->fwnode, + DOMAIN_BUS_WIRED); + if (!domain) + domain = irq_find_matching_fwnode(fwspec->fwnode, + DOMAIN_BUS_ANY); + } else { domain = irq_default_domain; + } if (!domain) { pr_warn("no irq domain found for %s !\n", -- 2.34.1