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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>
hifive-unleashed-5.1
Marc Zyngier 2015-10-13 12:51:45 +01:00 committed by Thomas Gleixner
parent be5436c83a
commit e7a46c8185
2 changed files with 14 additions and 17 deletions
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8
Documentation/IRQ-domain.txt
View File

@ -32,9 +32,9 @@ top of the irq_alloc_desc*() API. An irq_domain to manage mapping is
preferred over interrupt controller drivers open coding their own
reverse mapping scheme.
irq_domain also implements translation from Device Tree interrupt
specifiers to hwirq numbers, and can be easily extended to support
other IRQ topology data sources.
irq_domain also implements translation from an abstract irq_fwspec
structure to hwirq numbers (Device Tree and ACPI GSI so far), and can
be easily extended to support other IRQ topology data sources.
=== irq_domain usage ===
An interrupt controller driver creates and registers an irq_domain by
@ -184,7 +184,7 @@ There are four major interfaces to use hierarchy irq_domain:
related resources associated with these interrupts.
3) irq_domain_activate_irq(): activate interrupt controller hardware to
deliver the interrupt.
3) irq_domain_deactivate_irq(): deactivate interrupt controller hardware
4) irq_domain_deactivate_irq(): deactivate interrupt controller hardware
to stop delivering the interrupt.
Following changes are needed to support hierarchy irq_domain.

23
include/linux/irqdomain.h
View File

@ -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