Re: [PATCH v2] irqchip: Add support for ARMv7-M's NVIC

From: Arnd Bergmann
Date: Thu Mar 28 2013 - 18:33:05 EST


On Monday 18 March 2013, Uwe Kleine-KÃnig wrote:

> +static int __init nvic_init_bases(struct device_node *node,
> + void __iomem *nvic_base)
> +{

There is probably no point to keep this function separate from
nvic_of_init any more, unless you plan to mke it globally
accessible and called from non-DT platforms. In that case
you would need an irq_base argument though.

> + irq_base = irq_alloc_descs_from(16, irqs, numa_node_id());
> + if (irq_base < 0) {
> + pr_warn("Cannot allocate irq_descs\n");
> + ret = irq_base;
> + goto err_irq_alloc_descs;
> + }
> + if (irq_base != 16) {
> + /*
> + * The entry code just passes the exception number (i.e. irq
> + * number + 16) to asm_do_IRQ, so the offset needs to be fixed
> + * here.
> + */
> + pr_warn("Failed to allocate irq_descs at offset 16\n");
> + goto err_wrong_irq_base;
> + }
> +
> + irq_domain = irq_domain_add_legacy(node, irqs, irq_base, 0,
> + &irq_domain_simple_ops, NULL);

Why do you use a legacy domain here, and hardcode the irq_base?
For a fully DT-enabled platform, the base should not matter and you
can use irq_domain_add_linear, while a legacy platform would likely
need a different base.

> +static int __init nvic_of_init(struct device_node *node,
> + struct device_node *parent)
> +{
> + void __iomem *nvic_base;
> +
> + if (!node)
> + return -ENODEV;

As Thomas commented, the check for !node is pointless here.

Arnd
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