[PATCH 1/2] irqchip/sifive-plic: Fix duplicate mask/unmask for claim/complete

From: guoren
Date: Mon Oct 11 2021 - 09:24:57 EST


From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>

PLIC only has enable-registers not mask/unmask registers. Mixing
mask/unmask with irq_eoi is wrong, because readl(claim) could mask
irq by hardware. We only need mask/unmask to fixup the hardware
which couldn't claim + mask correctly.

If hardware supports claim + mask, it would cause unnecessary
mask/umak operations.

Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Anup Patel <anup@xxxxxxxxxxxxxx>
Cc: Atish Patra <atish.patra@xxxxxxx>
---
drivers/irqchip/irq-sifive-plic.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index cf74cfa82045..0fa46912f452 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -64,6 +64,7 @@ struct plic_priv {
struct cpumask lmask;
struct irq_domain *irqdomain;
void __iomem *regs;
+ bool claim_mask_support;
};

struct plic_handler {
@@ -111,7 +112,7 @@ static inline void plic_irq_toggle(const struct cpumask *mask,
}
}

-static void plic_irq_unmask(struct irq_data *d)
+static void plic_irq_enable(struct irq_data *d)
{
struct cpumask amask;
unsigned int cpu;
@@ -125,7 +126,7 @@ static void plic_irq_unmask(struct irq_data *d)
plic_irq_toggle(cpumask_of(cpu), d, 1);
}

-static void plic_irq_mask(struct irq_data *d)
+static void plic_irq_disable(struct irq_data *d)
{
struct plic_priv *priv = irq_data_get_irq_chip_data(d);

@@ -168,8 +169,8 @@ static void plic_irq_eoi(struct irq_data *d)

static struct irq_chip plic_chip = {
.name = "SiFive PLIC",
- .irq_mask = plic_irq_mask,
- .irq_unmask = plic_irq_unmask,
+ .irq_enable = plic_irq_enable,
+ .irq_disable = plic_irq_disable,
.irq_eoi = plic_irq_eoi,
#ifdef CONFIG_SMP
.irq_set_affinity = plic_set_affinity,
@@ -181,6 +182,11 @@ static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
{
struct plic_priv *priv = d->host_data;

+ if (!priv->claim_mask_support) {
+ plic_chip.irq_mask = plic_irq_disable;
+ plic_chip.irq_unmask = plic_irq_enable;
+ }
+
irq_domain_set_info(d, irq, hwirq, &plic_chip, d->host_data,
handle_fasteoi_irq, NULL, NULL);
irq_set_noprobe(irq);
@@ -298,6 +304,8 @@ static int __init plic_init(struct device_node *node,
if (WARN_ON(!nr_contexts))
goto out_iounmap;

+ priv->claim_mask_support = of_property_read_bool(node, "claim-mask-support");
+
error = -ENOMEM;
priv->irqdomain = irq_domain_add_linear(node, nr_irqs + 1,
&plic_irqdomain_ops, priv);
--
2.25.1