The T-HEAD PLIC ignores additional edges seen while an edge-triggered
interrupt is being handled. Because of this behavior, the driver needs
to complete edge-triggered interrupts in the .irq_ack callback before
handling them, instead of in the .irq_eoi callback afterward. Otherwise,
it could miss some interrupts.
Co-developed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---
Changes in v1:
- Use a flag for enabling the changes instead of a variant ID
- Use handle_edge_irq instead of handle_fasteoi_ack_irq
- Do not set the handler name, as RISC-V selects GENERIC_IRQ_SHOW_LEVEL
drivers/irqchip/irq-sifive-plic.c | 76 +++++++++++++++++++++++++++++--
1 file changed, 71 insertions(+), 5 deletions(-)
diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index 90515865af08..462a93b4b088 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -69,6 +69,7 @@ struct plic_priv {
struct cpumask lmask;
struct irq_domain *irqdomain;
void __iomem *regs;
+ bool needs_edge_handling;
};
struct plic_handler {
@@ -86,6 +87,9 @@ static int plic_parent_irq __ro_after_init;
static bool plic_cpuhp_setup_done __ro_after_init;
static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
+static struct irq_chip plic_edge_chip;
+static struct irq_chip plic_chip;
+
static void __plic_toggle(void __iomem *enable_base, int hwirq, int enable)
{
u32 __iomem *reg = enable_base + (hwirq / 32) * sizeof(u32);
@@ -181,6 +185,40 @@ static void plic_irq_eoi(struct irq_data *d)
}
}
+static int plic_irq_set_type(struct irq_data *d, unsigned int flow_type)
+{
+ struct plic_priv *priv = irq_data_get_irq_chip_data(d);
+
+ if (!priv->needs_edge_handling)
+ return IRQ_SET_MASK_OK_NOCOPY;
+
+ switch (flow_type) {
+ case IRQ_TYPE_EDGE_RISING:
+ irq_set_chip_handler_name_locked(d, &plic_edge_chip,
+ handle_edge_irq, NULL);
+ break;
+ case IRQ_TYPE_LEVEL_HIGH:
+ irq_set_chip_handler_name_locked(d, &plic_chip,
+ handle_fasteoi_irq, NULL);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return IRQ_SET_MASK_OK;
+}
+
+static struct irq_chip plic_edge_chip = {
+ .name = "PLIC",
+ .irq_ack = plic_irq_eoi,
+ .irq_mask = plic_irq_mask,
+ .irq_unmask = plic_irq_unmask,
+#ifdef CONFIG_SMP
+ .irq_set_affinity = plic_set_affinity,
+#endif
+ .irq_set_type = plic_irq_set_type,
+};
+
static struct irq_chip plic_chip = {
.name = "PLIC",
.irq_mask = plic_irq_mask,
@@ -189,8 +227,22 @@ static struct irq_chip plic_chip = {
#ifdef CONFIG_SMP
.irq_set_affinity = plic_set_affinity,
#endif
+ .irq_set_type = plic_irq_set_type,
};
+static int plic_irq_domain_translate(struct irq_domain *d,
+ struct irq_fwspec *fwspec,
+ unsigned long *hwirq,
+ unsigned int *type)
+{
+ struct plic_priv *priv = d->host_data;
+
+ if (priv->needs_edge_handling)
+ return irq_domain_translate_twocell(d, fwspec, hwirq, type);
+ else
+ return irq_domain_translate_onecell(d, fwspec, hwirq, type);
+}
+
static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
@@ -211,7 +263,7 @@ static int plic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
unsigned int type;
struct irq_fwspec *fwspec = arg;
- ret = irq_domain_translate_onecell(domain, fwspec, &hwirq, &type);
+ ret = plic_irq_domain_translate(domain, fwspec, &hwirq, &type);
if (ret)
return ret;
@@ -225,7 +277,7 @@ static int plic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
}
static const struct irq_domain_ops plic_irqdomain_ops = {
- .translate = irq_domain_translate_onecell,
+ .translate = plic_irq_domain_translate,
.alloc = plic_irq_domain_alloc,
.free = irq_domain_free_irqs_top,
};
@@ -286,8 +338,9 @@ static int plic_starting_cpu(unsigned int cpu)
return 0;
}
-static int __init plic_init(struct device_node *node,
- struct device_node *parent)
+static int __init __plic_init(struct device_node *node,
+ struct device_node *parent,
+ bool needs_edge_handling)
{
int error = 0, nr_contexts, nr_handlers = 0, i;
u32 nr_irqs;
@@ -298,6 +351,8 @@ static int __init plic_init(struct device_node *node,
if (!priv)
return -ENOMEM;
+ priv->needs_edge_handling = needs_edge_handling;
+
priv->regs = of_iomap(node, 0);
if (WARN_ON(!priv->regs)) {
error = -EIO;
@@ -415,6 +470,17 @@ static int __init plic_init(struct device_node *node,
return error;
}
+static int __init plic_init(struct device_node *node,
+ struct device_node *parent)
+{
+ return __plic_init(node, parent, false);
+}
IRQCHIP_DECLARE(sifive_plic, "sifive,plic-1.0.0", plic_init);
IRQCHIP_DECLARE(riscv_plic0, "riscv,plic0", plic_init); /* for legacy systems */
-IRQCHIP_DECLARE(thead_c900_plic, "thead,c900-plic", plic_init); /* for firmware driver */
+
+static int __init plic_edge_init(struct device_node *node,
+ struct device_node *parent)
+{
+ return __plic_init(node, parent, true);
+}
+IRQCHIP_DECLARE(thead_c900_plic, "thead,c900-plic", plic_edge_init);
--
2.35.1
