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authorMarc Zyngier <marc.zyngier@arm.com>2015-10-13 12:51:45 +0100
committerThomas Gleixner <tglx@linutronix.de>2015-10-13 19:01:25 +0200
commite7a46c818564329f977f8fa157b5e9e1d0d83012 (patch)
tree26f67d01cbe4b584166127b00e9f845a81ddf43f /include
parentbe5436c83ac8921f33fe07323fab03c6644ce52e (diff)
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 <marc.zyngier@arm.com> Tested-by: Hanjun Guo <hanjun.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: <linux-arm-kernel@lists.infradead.org> Cc: Tomasz Nowicki <tomasz.nowicki@linaro.org> Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> Cc: Graeme Gregory <graeme@xora.org.uk> Cc: Jake Oshins <jakeo@microsoft.com> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Link: http://lkml.kernel.org/r/1444737105-31573-18-git-send-email-marc.zyngier@arm.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include')
-rw-r--r--include/linux/irqdomain.h23
1 files changed, 10 insertions, 13 deletions
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