Re: [PATCH] Documentation/IRQ-domain.txt: Document irq_domain_create_{linear, tree}

Randy Dunlap
2016-03-26T17:04:45Z

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@gmail.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