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

[Huacai Chen <chenhc@lemote.com>]

Hi, Jiaxun,

On Thu, Sep 10, 2020 at 8:52 AM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>
>
>
> 在 2020/9/9 12:09, Huacai Chen 写道:
> > Reserve legacy LPC irqs (0~15) to avoid spurious interrupts.
>
> It doesn't make sense at all.
>
> How can you allocate IRQ without irqchip backing it?
>
> - Jiaxun
As you know, this patch resolves the kdump problem, and 0~15 is really
needed to reserve for LPC, right?

Huacai
>
> >
> > 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),