Currently, the implementation of the RISC-V INTC driver uses the
interrupt cause as the hardware interrupt number, with a maximum of
64 interrupts. However, the platform can expand the interrupt number
further for custom local interrupts.

To fully utilize the available local interrupt sources, switch
to using irq_domain_create_tree() that creates the radix tree
map, add global variables (riscv_intc_nr_irqs, riscv_intc_custom_base
and riscv_intc_custom_nr_irqs) to determine the valid range of local
interrupt number (hwirq).

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Randolph <randolph@andestech.com>
---
Changes v1 -> v2:
  - Fixed irq mapping failure checking (suggested by Clément and Anup)
Changes v2 -> v3:
  - No change
Changes v3 -> v4: (Suggested by Thomas [1])
  - Use pr_warn_ratelimited instead
  - Fix coding style and commit message
Changes v4 -> v5: (Suggested by Thomas)
  - Fix commit message
Changes v5 -> v6: (Suggested by Anup [2])
  - Add riscv_intc_* global variables for checking range in riscv_intc_domain_alloc()
  - Advertise the number of interrupts allowed
Changes v6 -> v7:
  - No functional change

[1] https://patchwork.kernel.org/project/linux-riscv/patch/20231023004100.2663486-3-peterlin@andestech.com/#25573085
[2] https://patchwork.kernel.org/project/linux-riscv/patch/20231213070301.1684751-3-peterlin@andestech.com/#25636589
---
 drivers/irqchip/irq-riscv-intc.c | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index e8d01b14ccdd..b13a16b164c9 100644
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -19,15 +19,17 @@
 #include <linux/smp.h>
 
 static struct irq_domain *intc_domain;
+static unsigned int riscv_intc_nr_irqs __ro_after_init;
+static unsigned int riscv_intc_custom_base __ro_after_init;
+static unsigned int riscv_intc_custom_nr_irqs __ro_after_init;
 
 static asmlinkage void riscv_intc_irq(struct pt_regs *regs)
 {
 	unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG;
 
-	if (unlikely(cause >= BITS_PER_LONG))
-		panic("unexpected interrupt cause");
-
-	generic_handle_domain_irq(intc_domain, cause);
+	if (generic_handle_domain_irq(intc_domain, cause))
+		pr_warn_ratelimited("Failed to handle interrupt (cause: %ld)\n",
+				    cause);
 }
 
 /*
@@ -93,6 +95,14 @@ static int riscv_intc_domain_alloc(struct irq_domain *domain,
 	if (ret)
 		return ret;
 
+	/*
+	 * Only allow hwirq for which we have corresponding standard or
+	 * custom interrupt enable register.
+	 */
+	if ((riscv_intc_nr_irqs <= hwirq && hwirq < riscv_intc_custom_base) ||
+	    (riscv_intc_custom_base + riscv_intc_custom_nr_irqs) <= hwirq)
+		return -EINVAL;
+
 	for (i = 0; i < nr_irqs; i++) {
 		ret = riscv_intc_domain_map(domain, virq + i, hwirq + i);
 		if (ret)
@@ -117,8 +127,7 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn)
 {
 	int rc;
 
-	intc_domain = irq_domain_create_linear(fn, BITS_PER_LONG,
-					       &riscv_intc_domain_ops, NULL);
+	intc_domain = irq_domain_create_tree(fn, &riscv_intc_domain_ops, NULL);
 	if (!intc_domain) {
 		pr_err("unable to add IRQ domain\n");
 		return -ENXIO;
@@ -132,7 +141,10 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn)
 
 	riscv_set_intc_hwnode_fn(riscv_intc_hwnode);
 
-	pr_info("%d local interrupts mapped\n", BITS_PER_LONG);
+	pr_info("%d local interrupts mapped\n", riscv_intc_nr_irqs);
+	if (riscv_intc_custom_nr_irqs)
+		pr_info("%d custom local interrupts mapped\n",
+			riscv_intc_custom_nr_irqs);
 
 	return 0;
 }
@@ -166,6 +178,10 @@ static int __init riscv_intc_init(struct device_node *node,
 		return 0;
 	}
 
+	riscv_intc_nr_irqs = BITS_PER_LONG;
+	riscv_intc_custom_base = riscv_intc_nr_irqs;
+	riscv_intc_custom_nr_irqs = 0;
+
 	return riscv_intc_init_common(of_node_to_fwnode(node));
 }
 
-- 
2.34.1

On Wed, Jan 10, 2024 at 1:10 PM Yu Chien Peter Lin
<peterlin@andestech.com> wrote:
>
> Currently, the implementation of the RISC-V INTC driver uses the
> interrupt cause as the hardware interrupt number, with a maximum of
> 64 interrupts. However, the platform can expand the interrupt number
> further for custom local interrupts.
>
> To fully utilize the available local interrupt sources, switch
> to using irq_domain_create_tree() that creates the radix tree
> map, add global variables (riscv_intc_nr_irqs, riscv_intc_custom_base
> and riscv_intc_custom_nr_irqs) to determine the valid range of local
> interrupt number (hwirq).
>
> Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
> Reviewed-by: Randolph <randolph@andestech.com>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
> Changes v1 -> v2:
>   - Fixed irq mapping failure checking (suggested by Clément and Anup)
> Changes v2 -> v3:
>   - No change
> Changes v3 -> v4: (Suggested by Thomas [1])
>   - Use pr_warn_ratelimited instead
>   - Fix coding style and commit message
> Changes v4 -> v5: (Suggested by Thomas)
>   - Fix commit message
> Changes v5 -> v6: (Suggested by Anup [2])
>   - Add riscv_intc_* global variables for checking range in riscv_intc_domain_alloc()
>   - Advertise the number of interrupts allowed
> Changes v6 -> v7:
>   - No functional change
>
> [1] https://patchwork.kernel.org/project/linux-riscv/patch/20231023004100.2663486-3-peterlin@andestech.com/#25573085
> [2] https://patchwork.kernel.org/project/linux-riscv/patch/20231213070301.1684751-3-peterlin@andestech.com/#25636589
> ---
>  drivers/irqchip/irq-riscv-intc.c | 30 +++++++++++++++++++++++-------
>  1 file changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
> index e8d01b14ccdd..b13a16b164c9 100644
> --- a/drivers/irqchip/irq-riscv-intc.c
> +++ b/drivers/irqchip/irq-riscv-intc.c
> @@ -19,15 +19,17 @@
>  #include <linux/smp.h>
>
>  static struct irq_domain *intc_domain;
> +static unsigned int riscv_intc_nr_irqs __ro_after_init;
> +static unsigned int riscv_intc_custom_base __ro_after_init;
> +static unsigned int riscv_intc_custom_nr_irqs __ro_after_init;
>
>  static asmlinkage void riscv_intc_irq(struct pt_regs *regs)
>  {
>         unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG;
>
> -       if (unlikely(cause >= BITS_PER_LONG))
> -               panic("unexpected interrupt cause");
> -
> -       generic_handle_domain_irq(intc_domain, cause);
> +       if (generic_handle_domain_irq(intc_domain, cause))
> +               pr_warn_ratelimited("Failed to handle interrupt (cause: %ld)\n",
> +                                   cause);
>  }
>
>  /*
> @@ -93,6 +95,14 @@ static int riscv_intc_domain_alloc(struct irq_domain *domain,
>         if (ret)
>                 return ret;
>
> +       /*
> +        * Only allow hwirq for which we have corresponding standard or
> +        * custom interrupt enable register.
> +        */
> +       if ((riscv_intc_nr_irqs <= hwirq && hwirq < riscv_intc_custom_base) ||
> +           (riscv_intc_custom_base + riscv_intc_custom_nr_irqs) <= hwirq)
> +               return -EINVAL;
> +
>         for (i = 0; i < nr_irqs; i++) {
>                 ret = riscv_intc_domain_map(domain, virq + i, hwirq + i);
>                 if (ret)
> @@ -117,8 +127,7 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn)
>  {
>         int rc;
>
> -       intc_domain = irq_domain_create_linear(fn, BITS_PER_LONG,
> -                                              &riscv_intc_domain_ops, NULL);
> +       intc_domain = irq_domain_create_tree(fn, &riscv_intc_domain_ops, NULL);
>         if (!intc_domain) {
>                 pr_err("unable to add IRQ domain\n");
>                 return -ENXIO;
> @@ -132,7 +141,10 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn)
>
>         riscv_set_intc_hwnode_fn(riscv_intc_hwnode);
>
> -       pr_info("%d local interrupts mapped\n", BITS_PER_LONG);
> +       pr_info("%d local interrupts mapped\n", riscv_intc_nr_irqs);
> +       if (riscv_intc_custom_nr_irqs)
> +               pr_info("%d custom local interrupts mapped\n",
> +                       riscv_intc_custom_nr_irqs);
>
>         return 0;
>  }
> @@ -166,6 +178,10 @@ static int __init riscv_intc_init(struct device_node *node,
>                 return 0;
>         }
>
> +       riscv_intc_nr_irqs = BITS_PER_LONG;
> +       riscv_intc_custom_base = riscv_intc_nr_irqs;
> +       riscv_intc_custom_nr_irqs = 0;
> +
>         return riscv_intc_init_common(of_node_to_fwnode(node));
>  }
>
> --
> 2.34.1
>

On Wed, Jan 10, 2024 at 7:11 AM Anup Patel <anup@brainfault.org> wrote:
>
> On Wed, Jan 10, 2024 at 1:10 PM Yu Chien Peter Lin
> <peterlin@andestech.com> wrote:
> >
> > Currently, the implementation of the RISC-V INTC driver uses the
> > interrupt cause as the hardware interrupt number, with a maximum of
> > 64 interrupts. However, the platform can expand the interrupt number
> > further for custom local interrupts.
> >
> > To fully utilize the available local interrupt sources, switch
> > to using irq_domain_create_tree() that creates the radix tree
> > map, add global variables (riscv_intc_nr_irqs, riscv_intc_custom_base
> > and riscv_intc_custom_nr_irqs) to determine the valid range of local
> > interrupt number (hwirq).
> >
> > Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
> > Reviewed-by: Randolph <randolph@andestech.com>
>
> Looks good to me.
>
> Reviewed-by: Anup Patel <anup@brainfault.org>
>
> Regards,
> Anup
>
> > ---
> > Changes v1 -> v2:
> >   - Fixed irq mapping failure checking (suggested by Clément and Anup)
> > Changes v2 -> v3:
> >   - No change
> > Changes v3 -> v4: (Suggested by Thomas [1])
> >   - Use pr_warn_ratelimited instead
> >   - Fix coding style and commit message
> > Changes v4 -> v5: (Suggested by Thomas)
> >   - Fix commit message
> > Changes v5 -> v6: (Suggested by Anup [2])
> >   - Add riscv_intc_* global variables for checking range in riscv_intc_domain_alloc()
> >   - Advertise the number of interrupts allowed
> > Changes v6 -> v7:
> >   - No functional change
> >
> > [1] https://patchwork.kernel.org/project/linux-riscv/patch/20231023004100.2663486-3-peterlin@andestech.com/#25573085
> > [2] https://patchwork.kernel.org/project/linux-riscv/patch/20231213070301.1684751-3-peterlin@andestech.com/#25636589
> > ---
> >  drivers/irqchip/irq-riscv-intc.c | 30 +++++++++++++++++++++++-------
> >  1 file changed, 23 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
> > index e8d01b14ccdd..b13a16b164c9 100644
> > --- a/drivers/irqchip/irq-riscv-intc.c
> > +++ b/drivers/irqchip/irq-riscv-intc.c
> > @@ -19,15 +19,17 @@
> >  #include <linux/smp.h>
> >
> >  static struct irq_domain *intc_domain;
> > +static unsigned int riscv_intc_nr_irqs __ro_after_init;
> > +static unsigned int riscv_intc_custom_base __ro_after_init;
> > +static unsigned int riscv_intc_custom_nr_irqs __ro_after_init;
> >
> >  static asmlinkage void riscv_intc_irq(struct pt_regs *regs)
> >  {
> >         unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG;
> >
> > -       if (unlikely(cause >= BITS_PER_LONG))
> > -               panic("unexpected interrupt cause");
> > -
> > -       generic_handle_domain_irq(intc_domain, cause);
> > +       if (generic_handle_domain_irq(intc_domain, cause))
> > +               pr_warn_ratelimited("Failed to handle interrupt (cause: %ld)\n",
> > +                                   cause);
> >  }
> >
> >  /*
> > @@ -93,6 +95,14 @@ static int riscv_intc_domain_alloc(struct irq_domain *domain,
> >         if (ret)
> >                 return ret;
> >
> > +       /*
> > +        * Only allow hwirq for which we have corresponding standard or
> > +        * custom interrupt enable register.
> > +        */
> > +       if ((riscv_intc_nr_irqs <= hwirq && hwirq < riscv_intc_custom_base) ||
> > +           (riscv_intc_custom_base + riscv_intc_custom_nr_irqs) <= hwirq)
> > +               return -EINVAL;
> > +
> >         for (i = 0; i < nr_irqs; i++) {
> >                 ret = riscv_intc_domain_map(domain, virq + i, hwirq + i);
> >                 if (ret)
> > @@ -117,8 +127,7 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn)
> >  {
> >         int rc;
> >
> > -       intc_domain = irq_domain_create_linear(fn, BITS_PER_LONG,
> > -                                              &riscv_intc_domain_ops, NULL);
> > +       intc_domain = irq_domain_create_tree(fn, &riscv_intc_domain_ops, NULL);
> >         if (!intc_domain) {
> >                 pr_err("unable to add IRQ domain\n");
> >                 return -ENXIO;
> > @@ -132,7 +141,10 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn)
> >
> >         riscv_set_intc_hwnode_fn(riscv_intc_hwnode);
> >
> > -       pr_info("%d local interrupts mapped\n", BITS_PER_LONG);
> > +       pr_info("%d local interrupts mapped\n", riscv_intc_nr_irqs);
> > +       if (riscv_intc_custom_nr_irqs)
> > +               pr_info("%d custom local interrupts mapped\n",
> > +                       riscv_intc_custom_nr_irqs);
> >
> >         return 0;
> >  }
> > @@ -166,6 +178,10 @@ static int __init riscv_intc_init(struct device_node *node,
> >                 return 0;
> >         }
> >
> > +       riscv_intc_nr_irqs = BITS_PER_LONG;
> > +       riscv_intc_custom_base = riscv_intc_nr_irqs;
> > +       riscv_intc_custom_nr_irqs = 0;
> > +
> >         return riscv_intc_init_common(of_node_to_fwnode(node));
> >  }
> >
> > --
> > 2.34.1
> >


Reviewed-by: Atish Patra <atishp@rivosinc.com>

-- 
Regards,
Atish