From dbe7fcdaf94052faf65172bb91d4266d20b5458b Mon Sep 17 00:00:00 2001
From: Jianyu Zhan <nasa4836@gmail.com>
Date: Sun, 27 Mar 2016 11:51:20 +0800
Subject: [PATCH] Documentation/IRQ-domain.txt: Document
irq_domain_create_{linear, tree}
They have the same functionalities as irq_domain_add_{linear, tree},
except fro accepting different first argument.
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
---
Documentation/IRQ-domain.txt | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/Documentation/IRQ-domain.txt b/Documentation/IRQ-domain.txt
index 8d990bde8693f..82001a25a14bd 100644
--- a/Documentation/IRQ-domain.txt
+++ b/Documentation/IRQ-domain.txt
@@ -70,6 +70,7 @@ of the reverse map types are described below:
==== Linear ====
irq_domain_add_linear()
+irq_domain_create_linear()
The linear reverse map maintains a fixed size table indexed by the
hwirq number. When a hwirq is mapped, an irq_desc is allocated for
@@ -81,10 +82,16 @@ map are fixed time lookup for IRQ numbers, and irq_descs are only
allocated for in-use IRQs. The disadvantage is that the table must be
as large as the largest possible hwirq number.
+irq_domain_add_linear() and irq_domain_create_linear() are functionally
+equivalent, except for the first argument is different - the former
+accepts an Open Firmware specific 'struct device_node', while the latter
+accepts a more general abstraction 'struct fwnode_handle'.
+
The majority of drivers should use the linear map.
==== Tree ====
irq_domain_add_tree()
+irq_domain_create_tree()
The irq_domain maintains a radix tree map from hwirq numbers to Linux
IRQs. When an hwirq is mapped, an irq_desc is allocated and the
@@ -95,6 +102,11 @@ since it doesn't need to allocate a table as large as the largest
hwirq number. The disadvantage is that hwirq to IRQ number lookup is
dependent on how many entries are in the table.
+irq_domain_add_tree() and irq_domain_create_tree() are functionally
+equivalent, except for the first argument is different - the former
+accepts an Open Firmware specific 'struct device_node', while the latter
+accepts a more general abstraction 'struct fwnode_handle'.
+
Very few drivers should need this mapping.
==== No Map ===-
--
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