-----Original Message-----
From: Marc Zyngier <[email protected]>
Sent: 16 May 2020 17:59
To: Anup Patel <[email protected]>
Cc: Palmer Dabbelt <[email protected]>; Paul Walmsley
<[email protected]>; Thomas Gleixner <[email protected]>;
Jason
Cooper <[email protected]>; Atish Patra <[email protected]>;
Alistair
Francis <[email protected]>; Anup Patel <[email protected]>;
linux-
[email protected]; [email protected]
Subject: Re: [PATCH 3/4] irqchip/sifive-plic: Separate irq_chip for
muiltiple PLIC
instances
On 2020-05-16 07:39, Anup Patel wrote:
> To distinguish interrupts from multiple PLIC instances, we use a
> per-PLIC irq_chip instance with a different name.
>
> Signed-off-by: Anup Patel <[email protected]>
> ---
> drivers/irqchip/irq-sifive-plic.c | 28 +++++++++++++++-------------
> 1 file changed, 15 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/irqchip/irq-sifive-plic.c
> b/drivers/irqchip/irq-sifive-plic.c
> index 2d3db927a551..e42fc082ad18 100644
> --- a/drivers/irqchip/irq-sifive-plic.c
> +++ b/drivers/irqchip/irq-sifive-plic.c
> @@ -60,6 +60,7 @@
> #define PLIC_ENABLE_THRESHOLD 0
>
> struct plic_priv {
> + struct irq_chip chip;
> struct cpumask lmask;
> struct irq_domain *irqdomain;
> void __iomem *regs;
> @@ -76,6 +77,7 @@ struct plic_handler {
> void __iomem *enable_base;
> struct plic_priv *priv;
> };
> +static unsigned int plic_count;
> static bool plic_cpuhp_setup_done;
> static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
>
> @@ -164,20 +166,12 @@ static void plic_irq_eoi(struct irq_data *d)
> writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM); }
>
> -static struct irq_chip plic_chip = {
> - .name = "SiFive PLIC",
> - .irq_mask = plic_irq_mask,
> - .irq_unmask = plic_irq_unmask,
> - .irq_eoi = plic_irq_eoi,
> -#ifdef CONFIG_SMP
> - .irq_set_affinity = plic_set_affinity,
> -#endif
> -};
> -
> static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
> irq_hw_number_t hwirq)
> {
> - irq_domain_set_info(d, irq, hwirq, &plic_chip, d->host_data,
> + struct plic_priv *priv = d->host_data;
> +
> + irq_domain_set_info(d, irq, hwirq, &priv->chip, d->host_data,
> handle_fasteoi_irq, NULL, NULL);
> irq_set_noprobe(irq);
> return 0;
> @@ -294,6 +288,14 @@ static int __init plic_init(struct device_node
> *node,
> if (!priv)
> return -ENOMEM;
>
> + priv->chip.name = kasprintf(GFP_KERNEL, "PLIC%d", plic_count++);
> + priv->chip.irq_mask = plic_irq_mask,
> + priv->chip.irq_unmask = plic_irq_unmask,
> + priv->chip.irq_eoi = plic_irq_eoi,
> +#ifdef CONFIG_SMP
> + priv->chip.irq_set_affinity = plic_set_affinity, #endif
> +
> priv->regs = of_iomap(node, 0);
> if (WARN_ON(!priv->regs)) {
> error = -EIO;
> @@ -383,9 +385,9 @@ static int __init plic_init(struct device_node
> *node,
> }
>
> pr_info("interrupt-controller at 0x%llx "
> - "(interrupts=%d, contexts=%d, handlers=%d)\n",
> + "(interrupts=%d, contexts=%d, handlers=%d) (%s)\n",
> (unsigned long long)iores.start, nr_irqs,
> - nr_contexts, nr_handlers);
> + nr_contexts, nr_handlers, priv->chip.name);
> set_handle_irq(plic_handle_irq);
> return 0;
I really dislike this patch for multiple reasons:
- Allocating a new struc irq_chip just for a string seems over the
top,
specially as all the *useful* stuff stays the same.
- Even if I hate it, /proc is API. I'm sure something, somewhere is
parsing this. Changing the string is likely to confuse it.
