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Subject: Re: [PATCH 2/4] Add irq_create_direct_mapping()
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Michael Ellerman <michael@ellerman.id.au>
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	<1e7f2ee0ff2e863d04e1f98f381f217359110163.1180961962.git.michael@ellerman.id.au>
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Date: Tue, 05 Jun 2007 08:44:04 +1000
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On Mon, 2007-06-04 at 23:00 +1000, Michael Ellerman wrote:
> This patch adds irq_create_direct_mapping(). This routine is
> an alternative to irq_create_mapping(), for irq controllers that
> can use linux virq numbers directly as hardware numbers.
> 
> Signed-off-by: Michael Ellerman <michael@ellerman.id.au>

Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

> ---
>  arch/powerpc/kernel/irq.c |   24 ++++++++++++++++++++++++
>  include/asm-powerpc/irq.h |    9 +++++++++
>  2 files changed, 33 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 9bafc88..fdb3b00 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -611,6 +611,30 @@ static int irq_setup_virq(struct irq_host *host, unsigned int virq,
>  	return 0;
>  }
>  
> +unsigned int irq_create_direct_mapping(struct irq_host *host)
> +{
> +	unsigned int virq;
> +
> +	if (host == NULL)
> +		host = irq_default_host;
> +
> +	BUG_ON(host == NULL);
> +	WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);
> +
> +	virq = irq_alloc_virt(host, 1, 0);
> +	if (virq == NO_IRQ) {
> +		pr_debug("irq: create_direct virq allocation failed\n");
> +		return NO_IRQ;
> +	}
> +
> +	pr_debug("irq: create_direct obtained virq %d\n", virq);
> +
> +	if (irq_setup_virq(host, virq, virq))
> +		return NO_IRQ;
> +
> +	return virq;
> +}
> +
>  unsigned int irq_create_mapping(struct irq_host *host,
>  				irq_hw_number_t hwirq)
>  {
> diff --git a/include/asm-powerpc/irq.h b/include/asm-powerpc/irq.h
> index 4734cc1..8384e3f 100644
> --- a/include/asm-powerpc/irq.h
> +++ b/include/asm-powerpc/irq.h
> @@ -226,6 +226,15 @@ extern void irq_dispose_mapping(unsigned int virq);
>  extern unsigned int irq_find_mapping(struct irq_host *host,
>  				     irq_hw_number_t hwirq);
>  
> +/**
> + * irq_create_direct_mapping - Allocate a virq for direct mapping
> + * @host: host to allocate the virq for or NULL for default host
> + *
> + * This routine is used for irq controllers which can choose the hardware
> + * interrupt numbers they generate. In such a case it's simplest to use
> + * the linux virq as the hardware interrupt number.
> + */
> +extern unsigned int irq_create_direct_mapping(struct irq_host *host);
>  
>  /**
>   * irq_radix_revmap - Find a linux virq from a hw irq number.