[PATCH v2 2/8] powerpc/xive: Introduce an IPI interrupt domain

[Greg Kurz]

On Wed, 3 Mar 2021 18:48:51 +0100
Cédric Le Goater <clg at kaod.org> wrote:

> The IPI interrupt is a special case of the XIVE IRQ domain. When
> mapping and unmapping the interrupts in the Linux interrupt number
> space, the HW interrupt number 0 (XIVE_IPI_HW_IRQ) is checked to
> distinguish the IPI interrupt from other interrupts of the system.
> 
> Simplify the XIVE interrupt domain by introducing a specific domain
> for the IPI.
> 
> Signed-off-by: Cédric Le Goater <clg at kaod.org>
> ---

Nice !

Reviewed-by: Greg Kurz <groug at kaod.org>

>  arch/powerpc/sysdev/xive/common.c | 51 +++++++++++++------------------
>  1 file changed, 22 insertions(+), 29 deletions(-)
> 
> diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c
> index b8e456da28aa..e7783760d278 100644
> --- a/arch/powerpc/sysdev/xive/common.c
> +++ b/arch/powerpc/sysdev/xive/common.c
> @@ -63,6 +63,8 @@ static const struct xive_ops *xive_ops;
>  static struct irq_domain *xive_irq_domain;
>  
>  #ifdef CONFIG_SMP
> +static struct irq_domain *xive_ipi_irq_domain;
> +
>  /* The IPIs all use the same logical irq number */
>  static u32 xive_ipi_irq;
>  #endif
> @@ -1067,20 +1069,32 @@ static struct irq_chip xive_ipi_chip = {
>  	.irq_unmask = xive_ipi_do_nothing,
>  };
>  
> +/*
> + * IPIs are marked per-cpu. We use separate HW interrupts under the
> + * hood but associated with the same "linux" interrupt
> + */
> +static int xive_ipi_irq_domain_map(struct irq_domain *h, unsigned int virq,
> +				   irq_hw_number_t hw)
> +{
> +	irq_set_chip_and_handler(virq, &xive_ipi_chip, handle_percpu_irq);
> +	return 0;
> +}
> +
> +static const struct irq_domain_ops xive_ipi_irq_domain_ops = {
> +	.map = xive_ipi_irq_domain_map,
> +};
> +
>  static void __init xive_request_ipi(void)
>  {
>  	unsigned int virq;
>  
> -	/*
> -	 * Initialization failed, move on, we might manage to
> -	 * reach the point where we display our errors before
> -	 * the system falls appart
> -	 */
> -	if (!xive_irq_domain)
> +	xive_ipi_irq_domain = irq_domain_add_linear(NULL, 1,
> +						    &xive_ipi_irq_domain_ops, NULL);
> +	if (WARN_ON(xive_ipi_irq_domain == NULL))
>  		return;
>  
>  	/* Initialize it */
> -	virq = irq_create_mapping(xive_irq_domain, XIVE_IPI_HW_IRQ);
> +	virq = irq_create_mapping(xive_ipi_irq_domain, XIVE_IPI_HW_IRQ);
>  	xive_ipi_irq = virq;
>  
>  	WARN_ON(request_irq(virq, xive_muxed_ipi_action,
> @@ -1178,19 +1192,6 @@ static int xive_irq_domain_map(struct irq_domain *h, unsigned int virq,
>  	 */
>  	irq_clear_status_flags(virq, IRQ_LEVEL);
>  
> -#ifdef CONFIG_SMP
> -	/* IPIs are special and come up with HW number 0 */
> -	if (hw == XIVE_IPI_HW_IRQ) {
> -		/*
> -		 * IPIs are marked per-cpu. We use separate HW interrupts under
> -		 * the hood but associated with the same "linux" interrupt
> -		 */
> -		irq_set_chip_and_handler(virq, &xive_ipi_chip,
> -					 handle_percpu_irq);
> -		return 0;
> -	}
> -#endif
> -
>  	rc = xive_irq_alloc_data(virq, hw);
>  	if (rc)
>  		return rc;
> @@ -1202,15 +1203,7 @@ static int xive_irq_domain_map(struct irq_domain *h, unsigned int virq,
>  
>  static void xive_irq_domain_unmap(struct irq_domain *d, unsigned int virq)
>  {
> -	struct irq_data *data = irq_get_irq_data(virq);
> -	unsigned int hw_irq;
> -
> -	/* XXX Assign BAD number */
> -	if (!data)
> -		return;
> -	hw_irq = (unsigned int)irqd_to_hwirq(data);
> -	if (hw_irq != XIVE_IPI_HW_IRQ)
> -		xive_irq_free_data(virq);
> +	xive_irq_free_data(virq);
>  }
>  
>  static int xive_irq_domain_xlate(struct irq_domain *h, struct device_node *ct,