Re: [PATCH 3/3] irqchip/loongson-pch-pic: Reserve legacy LPC irqs

[Marc Zyngier <maz@kernel.org>]

On 2020-09-09 05:09, Huacai Chen wrote:
> Reserve legacy LPC irqs (0~15) to avoid spurious interrupts.

How can they be spurious? Why are they enabled the first place?

This looks like you are papering over a much bigger issue.

         M.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Huacai Chen <chenhc@lemote.com>
> ---
>  drivers/irqchip/irq-loongson-pch-pic.c | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-loongson-pch-pic.c
> b/drivers/irqchip/irq-loongson-pch-pic.c
> index 9bf6b9a..9f6719c 100644
> --- a/drivers/irqchip/irq-loongson-pch-pic.c
> +++ b/drivers/irqchip/irq-loongson-pch-pic.c
> @@ -35,6 +35,7 @@
> 
>  struct pch_pic {
>  	void __iomem		*base;
> +	struct irq_domain	*lpc_domain;
>  	struct irq_domain	*pic_domain;
>  	u32			ht_vec_base;
>  	raw_spinlock_t		pic_lock;
> @@ -184,9 +185,9 @@ static void pch_pic_reset(struct pch_pic *priv)
>  static int pch_pic_of_init(struct device_node *node,
>  				struct device_node *parent)
>  {
> +	int i, base, err;
>  	struct pch_pic *priv;
>  	struct irq_domain *parent_domain;
> -	int err;
> 
>  	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
>  	if (!priv)
> @@ -213,6 +214,22 @@ static int pch_pic_of_init(struct device_node 
> *node,
>  		goto iounmap_base;
>  	}
> 
> +	base = irq_alloc_descs(-1, 0, NR_IRQS_LEGACY, 0);
> +	if (base < 0) {
> +		pr_err("Failed to allocate LPC IRQ numbers\n");
> +		goto iounmap_base;
> +	}
> +
> +	priv->lpc_domain = irq_domain_add_legacy(node, NR_IRQS_LEGACY, 0, 0,
> +						 &irq_domain_simple_ops, NULL);
> +	if (!priv->lpc_domain) {
> +		pr_err("Failed to add irqdomain for LPC controller");
> +		goto iounmap_base;
> +	}
> +
> +	for (i = 0; i < NR_IRQS_LEGACY; i++)
> +		irq_set_chip_and_handler(i, &dummy_irq_chip, handle_simple_irq);
> +
>  	priv->pic_domain = irq_domain_create_hierarchy(parent_domain, 0,
>  						       PIC_COUNT,
>  						       of_node_to_fwnode(node),

-- 
Jazz is not dead. It just smells funny...