lkml.org 
[lkml]   [2022]   [Jan]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 2/6] irqchip/riscv-intc: Set intc domain as the default host
On Wed, 26 Jan 2022 03:16:55 +0000,
Anup Patel <anup@brainfault.org> wrote:
>
> On Tue, Jan 25, 2022 at 11:47 PM Marc Zyngier <maz@kernel.org> wrote:
> >
> > On Tue, 25 Jan 2022 05:42:13 +0000,
> > Anup Patel <apatel@ventanamicro.com> wrote:
> > >
> > > We have quite a few RISC-V drivers (such as RISC-V SBI IPI driver,
> > > RISC-V timer driver, RISC-V PMU driver, etc) which do not have a
> > > dedicated DT/ACPI fwnode. This patch makes intc domain as the default
> > > host so that these drivers can directly create local interrupt mapping
> > > using standardized local interrupt numbers
> > >
> > > Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> > > ---
> > > drivers/clocksource/timer-riscv.c | 17 +----------------
> > > drivers/irqchip/irq-riscv-intc.c | 9 +++++++++
> > > 2 files changed, 10 insertions(+), 16 deletions(-)
> > >
> > > diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c
> > > index 1767f8bf2013..dd6916ae6365 100644
> > > --- a/drivers/clocksource/timer-riscv.c
> > > +++ b/drivers/clocksource/timer-riscv.c
> > > @@ -102,8 +102,6 @@ static irqreturn_t riscv_timer_interrupt(int irq, void *dev_id)
> > > static int __init riscv_timer_init_dt(struct device_node *n)
> > > {
> > > int cpuid, hartid, error;
> > > - struct device_node *child;
> > > - struct irq_domain *domain;
> > >
> > > hartid = riscv_of_processor_hartid(n);
> > > if (hartid < 0) {
> > > @@ -121,20 +119,7 @@ static int __init riscv_timer_init_dt(struct device_node *n)
> > > if (cpuid != smp_processor_id())
> > > return 0;
> > >
> > > - domain = NULL;
> > > - child = of_get_compatible_child(n, "riscv,cpu-intc");
> > > - if (!child) {
> > > - pr_err("Failed to find INTC node [%pOF]\n", n);
> > > - return -ENODEV;
> > > - }
> > > - domain = irq_find_host(child);
> > > - of_node_put(child);
> > > - if (!domain) {
> > > - pr_err("Failed to find IRQ domain for node [%pOF]\n", n);
> > > - return -ENODEV;
> > > - }
> > > -
> > > - riscv_clock_event_irq = irq_create_mapping(domain, RV_IRQ_TIMER);
> > > + riscv_clock_event_irq = irq_create_mapping(NULL, RV_IRQ_TIMER);
> > > if (!riscv_clock_event_irq) {
> > > pr_err("Failed to map timer interrupt for node [%pOF]\n", n);
> > > return -ENODEV;
> > > diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
> > > index b65bd8878d4f..9f0a7a8a5c4d 100644
> > > --- a/drivers/irqchip/irq-riscv-intc.c
> > > +++ b/drivers/irqchip/irq-riscv-intc.c
> > > @@ -125,6 +125,15 @@ static int __init riscv_intc_init(struct device_node *node,
> > > return rc;
> > > }
> > >
> > > + /*
> > > + * Make INTC as the default domain which will allow drivers
> > > + * not having dedicated DT/ACPI fwnode (such as RISC-V SBI IPI
> > > + * driver, RISC-V timer driver, RISC-V PMU driver, etc) can
> > > + * directly create local interrupt mapping using standardized
> > > + * local interrupt numbers.
> > > + */
> > > + irq_set_default_host(intc_domain);
> >
> > No, please. This really is a bad idea. This sort of catch-all have
> > constantly proven to be a nuisance, because they discard all the
> > topology information. Eventually, you realise that you need to know
> > where this is coming from, but it really is too late.
> >
> > I'd rather you *synthesise* a fwnode (like ACPI does) rather then do
> > this.
>
> In absence of INTC as the default domain, currently we have various
> drivers looking up INTC irq_domain from DT (or ACPI). This is quite a
> bit of duplicate code across various drivers.
>
> How about having a irq_domain lookup routine (riscv_intc_find_irq_domain())
> exported by the RISC-V INTC driver or arch/riscv ?
> OR
> Do you have an alternative suggestion ?

But *why* don't you provide an interrupt controller node for DT? I
really don't think that's outlandish to require.

For ACPI, we already have an interface that allows a fwnode to be
registered (acpi_set_irq_model) and interrupts mapped
(acpi_register_gsi).

You should already have all the required tools you need.

M.

--
Without deviation from the norm, progress is not possible.
\
 
 \ /
  Last update: 2022-01-26 10:02    [W:0.089 / U:0.528 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site