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Message-ID: <56F6C127.3020405@infradead.org>
Date: Sat, 26 Mar 2016 10:04:39 -0700
From: Randy Dunlap <rdunlap@...radead.org>
To: Jianyu Zhan <nasa4836@...il.com>, jiang.liu@...ux.intel.com,
marc.zyngier@....com, corbet@....net, grant.likely@...retlab.ca
Cc: linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Documentation/IRQ-domain.txt: Document
irq_domain_create_{linear, tree}
On 03/26/16 06:07, Jianyu Zhan wrote:
> They have the same functionalities as irq_domain_add_{linear, tree},
> except fro accepting different first argument.
>
> Signed-off-by: Jianyu Zhan <nasa4836@...il.com>
> ---
> Documentation/IRQ-domain.txt | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/Documentation/IRQ-domain.txt b/Documentation/IRQ-domain.txt
> index 8d990bd..89dda22 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 abstration 'struct fwnode_handle'.
abstraction
> +
> 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 abstration 'struct fwnode_handle'.
ditto
> +
> Very few drivers should need this mapping.
>
> ==== No Map ===-
>
--
~Randy
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