From e7a46c818564329f977f8fa157b5e9e1d0d83012 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 13 Oct 2015 12:51:45 +0100 Subject: irqdomain: Documentation updates Update the IRQ domain documentation to reflect the changes made while divorcing the domain infrastructure from Device Tree. Signed-off-by: Marc Zyngier Tested-by: Hanjun Guo Tested-by: Lorenzo Pieralisi Cc: Cc: Tomasz Nowicki Cc: Suravee Suthikulpanit Cc: Graeme Gregory Cc: Jake Oshins Cc: Jiang Liu Cc: Jason Cooper Cc: Rafael J. Wysocki Link: http://lkml.kernel.org/r/1444737105-31573-18-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner --- include/linux/irqdomain.h | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) (limited to 'include/linux/irqdomain.h') diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h index 2b3340ae915d..d5e5c5bef28c 100644 --- a/include/linux/irqdomain.h +++ b/include/linux/irqdomain.h @@ -5,9 +5,10 @@ * helpful for interrupt controllers to implement mapping between hardware * irq numbers and the Linux irq number space. * - * irq_domains also have a hook for translating device tree interrupt - * representation into a hardware irq number that can be mapped back to a - * Linux irq number without any extra platform support code. + * irq_domains also have hooks for translating device tree or other + * firmware interrupt representations into a hardware irq number that + * can be mapped back to a Linux irq number without any extra platform + * support code. * * Interrupt controller "domain" data structure. This could be defined as a * irq domain controller. That is, it handles the mapping between hardware @@ -17,16 +18,12 @@ * model). It's the domain callbacks that are responsible for setting the * irq_chip on a given irq_desc after it's been mapped. * - * The host code and data structures are agnostic to whether or not - * we use an open firmware device-tree. We do have references to struct - * device_node in two places: in irq_find_host() to find the host matching - * a given interrupt controller node, and of course as an argument to its - * counterpart domain->ops->match() callback. However, those are treated as - * generic pointers by the core and the fact that it's actually a device-node - * pointer is purely a convention between callers and implementation. This - * code could thus be used on other architectures by replacing those two - * by some sort of arch-specific void * "token" used to identify interrupt - * controllers. + * The host code and data structures use a fwnode_handle pointer to + * identify the domain. In some cases, and in order to preserve source + * code compatibility, this fwnode pointer is "upgraded" to a DT + * device_node. For those firmware infrastructures that do not provide + * a unique identifier for an interrupt controller, the irq_domain + * code offers a fwnode allocator. */ #ifndef _LINUX_IRQDOMAIN_H -- cgit