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>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Atish Patra <atishp@rivosinc.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 the range of valid
interrupt number in riscv_intc_domain_alloc()
- Advertise the number of interrupts allowed
Changes v6 -> v7:
- No functional change
Changes v7 -> v8:
- Include Reviewed-by tags from Anup and Atish
[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 Mon, Jan 29 2024 at 17:25, Yu Chien Peter Lin wrote:
> 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);
Either let the cause stick out or you need brackets. See:
https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#bracket-rules
> }
>
> /*
> @@ -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;
Duh. This mix of ordering required to read this 3 times. What's wrong
with writing this consistently:
if ((hwirq >= riscv_intc_nr_irqs && hwirq < riscv_intc_custom_base) ||
(hwirq >= iscv_intc_custom_base + riscv_intc_custom_nr_irqs)
return -EINVAL;
Hmm?
> - 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);
See bracket rules.
> 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;
Why don't you initialize the static variables with constants right away?
> + riscv_intc_custom_nr_irqs = 0;
It's already 0, no?
> return riscv_intc_init_common(of_node_to_fwnode(node));
> }
Thanks,
tglx
Hi Thomas,
On Tue, Feb 13, 2024 at 11:04:53AM +0100, Thomas Gleixner wrote:
> On Mon, Jan 29 2024 at 17:25, Yu Chien Peter Lin wrote:
> > 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);
>
> Either let the cause stick out or you need brackets. See:
>
> https://www.kernel.org/doc/html/latest/process/maintainer-tip.html#bracket-rules
>
> > }
> >
> > /*
> > @@ -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;
>
> Duh. This mix of ordering required to read this 3 times. What's wrong
> with writing this consistently:
>
> if ((hwirq >= riscv_intc_nr_irqs && hwirq < riscv_intc_custom_base) ||
> (hwirq >= iscv_intc_custom_base + riscv_intc_custom_nr_irqs)
> return -EINVAL;
>
> Hmm?
>
> > - 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);
>
> See bracket rules.
>
> > 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;
>
> Why don't you initialize the static variables with constants right away?
>
> > + riscv_intc_custom_nr_irqs = 0;
>
> It's already 0, no?
>
> > return riscv_intc_init_common(of_node_to_fwnode(node));
> > }
>
> Thanks,
>
> tglx
Thanks for pointing these out, I'll fix them in PATCH v9.
Regards,
Peter Lin
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