[PATCH 5/8] lib: sbi_irqchip: Support irqchip device targetting subset of harts

[Anup Patel]

On Tue, Feb 10, 2026 at 1:55 AM Raymond Mao <raymondmaoca at gmail.com> wrote:
>
> Hi Anup,
>
> On 2026-02-07 5:25 a.m., anup.patel at oss.qualcomm.com (Anup Patel) wrote:
> > It is possible to have platform where an irqchip device targets
> > a subset of harts and there are multiple irqchip devices to cover
> > all harts.
> >
> > To support this scenario:
> > 1) Add target_harts hartmask to struct sbi_irqchip_device which
> >     represents the set of harts targetted by the irqchip device
> > 2) Call warm_init() and irq_handle() callbacks of an irqchip device
> >     on a hart only if irqchip device targets that particular hart
> >
> > Signed-off-by: Anup Patel <anup.patel at oss.qualcomm.com>
> > ---
> >   include/sbi/sbi_irqchip.h |  8 +++++--
> >   lib/sbi/sbi_irqchip.c     | 48 ++++++++++++++++++++++++++++-----------
> >   lib/utils/irqchip/aplic.c | 12 +++++++++-
> >   lib/utils/irqchip/imsic.c |  7 ++++--
> >   lib/utils/irqchip/plic.c  |  5 ++--
> >   5 files changed, 59 insertions(+), 21 deletions(-)
> >
> > diff --git a/include/sbi/sbi_irqchip.h b/include/sbi/sbi_irqchip.h
> > index cda1e50f..c3ded271 100644
> > --- a/include/sbi/sbi_irqchip.h
> > +++ b/include/sbi/sbi_irqchip.h
> > @@ -10,6 +10,7 @@
> >   #ifndef __SBI_IRQCHIP_H__
> >   #define __SBI_IRQCHIP_H__
> >
> > +#include <sbi/sbi_hartmask.h>
> >   #include <sbi/sbi_list.h>
> >   #include <sbi/sbi_types.h>
> >
> > @@ -20,11 +21,14 @@ struct sbi_irqchip_device {
> >       /** Node in the list of irqchip devices */
> >       struct sbi_dlist node;
> >
> > +     /** Set of harts targetted by this irqchip */
> > +     struct sbi_hartmask target_harts;
> > +
> >       /** Initialize per-hart state for the current hart */
> >       int (*warm_init)(struct sbi_irqchip_device *chip);
> >
> >       /** Process hardware interrupts from this irqchip */
> > -     int (*process_hwirqs)(void);
> > +     int (*process_hwirqs)(struct sbi_irqchip_device *chip);
> >   };
> >
> >   /**
> > @@ -38,7 +42,7 @@ struct sbi_irqchip_device {
> >   int sbi_irqchip_process(void);
> >
> >   /** Register an irqchip device to receive callbacks */
> > -void sbi_irqchip_add_device(struct sbi_irqchip_device *chip);
> > +int sbi_irqchip_add_device(struct sbi_irqchip_device *chip);
> >
> >   /** Initialize interrupt controllers */
> >   int sbi_irqchip_init(struct sbi_scratch *scratch, bool cold_boot);
> > diff --git a/lib/sbi/sbi_irqchip.c b/lib/sbi/sbi_irqchip.c
> > index 3b970527..77ec05af 100644
> > --- a/lib/sbi/sbi_irqchip.c
> > +++ b/lib/sbi/sbi_irqchip.c
> > @@ -13,24 +13,44 @@
> >
> >   static SBI_LIST_HEAD(irqchip_list);
> >
> > -static int default_irqfn(void)
> > +int sbi_irqchip_process(void)
> >   {
> > -     return SBI_ENODEV;
> > -}
> > +     struct sbi_irqchip_device *chip;
> > +     int rc = SBI_ENODEV;
> >
> > -static int (*ext_irqfn)(void) = default_irqfn;
> > +     sbi_list_for_each_entry(chip, &irqchip_list, node) {
> > +             if (!chip->process_hwirqs)
> > +                     continue;
> > +             if (!sbi_hartmask_test_hartindex(current_hartindex(), &chip->target_harts))
> > +                     continue;
> > +             rc = chip->process_hwirqs(chip);
> > +             if (rc)
> > +                     break;
> > +     }
> >
> > -int sbi_irqchip_process(void)
> > -{
> > -     return ext_irqfn();
> > +     return rc;
> >   }
> >
> > -void sbi_irqchip_add_device(struct sbi_irqchip_device *chip)
> > +int sbi_irqchip_add_device(struct sbi_irqchip_device *chip)
> >   {
> > -     sbi_list_add_tail(&chip->node, &irqchip_list);
> > +     struct sbi_irqchip_device *c;
> > +     struct sbi_hartmask hm;
> > +
> > +     if (!chip || !sbi_hartmask_weight(&chip->target_harts))
> > +             return SBI_EINVAL;
> > +
> > +     if (chip->process_hwirqs) {
> > +             sbi_list_for_each_entry(c, &irqchip_list, node) {
> > +                     if (!c->process_hwirqs)
> > +                             continue;
> > +                     sbi_hartmask_and(&hm, &c->target_harts, &chip->target_harts);
> > +                     if (sbi_hartmask_weight(&hm))
> > +                             return SBI_EINVAL;
>
> I tested this by registering a 'process_hwirqs' hook, but
> 'sbi_hartmask_weight' returns errors.

This loop ensures that irqchips which directly connect
to external interrupt line of harts (aka irqchips which
implement process_hwirqs) don't have overlapping
target_harts.

Regards,
Anup