Re: [PATCH v1] irqchip: loongson-liointc: add hierarchy irq support

From: Marc Zyngier
Date: Wed Dec 07 2022 - 03:09:46 EST


On Wed, 07 Dec 2022 01:45:55 +0000,
Yinbo Zhu <zhuyinbo@xxxxxxxxxxx> wrote:
>
> When the irq of hierarchical interrupt chip was routed to liointc
> that asked liointc driver to support hierarchy irq and this patch
> was to add such support.
>
> In addition, this patch only consider dts, and acpi hierarchy irq
> support will be added later as required.
>
> Signed-off-by: Yinbo Zhu <zhuyinbo@xxxxxxxxxxx>
> ---
> drivers/irqchip/irq-loongson-liointc.c | 31 ++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/drivers/irqchip/irq-loongson-liointc.c b/drivers/irqchip/irq-loongson-liointc.c
> index 0da8716f8f24..58e43a2cd02e 100644
> --- a/drivers/irqchip/irq-loongson-liointc.c
> +++ b/drivers/irqchip/irq-loongson-liointc.c
> @@ -177,6 +177,32 @@ static const struct irq_domain_ops acpi_irq_gc_ops = {
> .xlate = liointc_domain_xlate,
> };
>
> +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
> +static int liointc_domain_alloc(struct irq_domain *domain, unsigned int virq,
> + unsigned int nr_irqs, void *arg)
> +{
> + int i, ret;
> + irq_hw_number_t hwirq;
> + unsigned int type = IRQ_TYPE_NONE;
> + struct irq_fwspec *fwspec = arg;
> +
> + ret = irq_domain_translate_twocell(domain, fwspec, &hwirq, &type);
> + if (ret)
> + return ret;
> +
> + for (i = 0; i < nr_irqs; i++)
> + irq_map_generic_chip(domain, virq + i, hwirq + i);
> +
> + return 0;
> +}
> +
> +static const struct irq_domain_ops of_irq_gc_ops = {
> + .translate = irq_domain_translate_twocell,
> + .alloc = liointc_domain_alloc,
> + .free = irq_domain_free_irqs_top,
> +};
> +#endif
> +
> static int liointc_init(phys_addr_t addr, unsigned long size, int revision,
> struct fwnode_handle *domain_handle, struct device_node *node)
> {
> @@ -218,8 +244,13 @@ static int liointc_init(phys_addr_t addr, unsigned long size, int revision,
> domain = irq_domain_create_linear(domain_handle, LIOINTC_CHIP_IRQ,
> &acpi_irq_gc_ops, priv);
> else
> +#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
> + domain = irq_domain_create_linear(domain_handle, LIOINTC_CHIP_IRQ,
> + &of_irq_gc_ops, priv);
> +#else
> domain = irq_domain_create_linear(domain_handle, LIOINTC_CHIP_IRQ,
> &irq_generic_chip_ops, priv);
> +#endif

Two things:

- Why do we need three calls to create the same domains depending on
what firmware is used and kernel configuration?

- who is going to decide whether to select the
CONFIG_IRQ_DOMAIN_HIERARCHY option?

I'd really like to see a statement from the Loongson folks about what
this whole DT stuff is all about. AFAICT, the core ACPICA stuff isn't
even fully merged (i.e. we still rely on arch-specific hacks).

Can you *please* finish what you've started before adding another
layer of quality stuff on top?

M.

--
Without deviation from the norm, progress is not possible.