Re: [PATCH] irqchip/riscv-intc: Mark INTC nodes for secondary CPUs as initialized.

From: Marc Zyngier <maz@kernel.org>
To: Anup Patel <apatel@ventanamicro.com>
Cc: Dmitry Dunaev <dunaev@tecon.ru>,
	dunaich@mail.ru, Thomas Gleixner <tglx@linutronix.de>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [PATCH] irqchip/riscv-intc: Mark INTC nodes for secondary CPUs as initialized.
Date: Wed, 04 Oct 2023 11:18:09 +0100	[thread overview]
Message-ID: <86il7mofmm.wl-maz@kernel.org> (raw)
In-Reply-To: <CAK9=C2UiBNQtv0Q2yJMKqc5pMX_jam+ZmfRz3Rme0ZYuqN68HA@mail.gmail.com>

On Tue, 26 Sep 2023 11:36:31 +0100,
Anup Patel <apatel@ventanamicro.com> wrote:
> 
> On Tue, Sep 26, 2023 at 3:59 PM Dmitry Dunaev <dunaev@tecon.ru> wrote:
> >
> > The current Linux driver irq-riscv-intc initialize IRQ domain only once,
> > when init function called on primary hart. In other cases no IRQ domain is
> > created and no operation on interrupt-controller node is performed.
> > This is cause of that no common Linux driver can use per-cpu interrupts
> > mapped to several CPUs because fwnode of secondary cores INTC is not
> > marked as initialized. This device is always will be marked as deferred.
> > For example the system with devicetree
> >
> >     cpu0: cpu@0 {
> >         cpu0_intc: interrupt-controller {
> >             interrupt-controller;
> >             compatible = riscv,cpu-intc;
> >         };
> >     };
> >
> >     cpu1: cpu@1 {
> >         cpu1_intc: interrupt-controller {
> >             interrupt-controller;
> >             compatible = riscv,cpu-intc;
> >         };
> >     };
> >
> >     buserr {
> >         compatible = riscv,buserr;
> >         interrupts-extended = <&cpu0_intc 16 &cpu1_intc 16>;
> >     };
> >
> > will always report 'buserr' node as deferred without calling any
> > bus probe function.
> >
> > This patch will mark all secondary nodes passed to irq-riscv-intc
> > driver init function as initialized to be able to act as correct
> > IRQ phandle node.
> >
> > Signed-off-by: Dmitry Dunaev <dunaev@tecon.ru>
> > ---
> >  drivers/irqchip/irq-riscv-intc.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
> > index 4adeee1bc391..c01a4e8d4983 100644
> > --- a/drivers/irqchip/irq-riscv-intc.c
> > +++ b/drivers/irqchip/irq-riscv-intc.c
> > @@ -155,8 +155,10 @@ static int __init riscv_intc_init(struct device_node *node,
> >          * for each INTC DT node. We only need to do INTC initialization
> >          * for the INTC DT node belonging to boot CPU (or boot HART).
> >          */
> > -       if (riscv_hartid_to_cpuid(hartid) != smp_processor_id())
> > +       if (riscv_hartid_to_cpuid(hartid) != smp_processor_id()) {
> > +               fwnode_dev_initialized(of_node_to_fwnode(node), true);
> 
> There is already a patch on LKML to address this.
> https://www.spinics.net/lists/kernel/msg4929886.html

If this is a fix, why is it buried in a huge series and not brought
forward as an independent fix that needs to be picked early?

	M.

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

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