[PATCH 04/17] irqchip/sifive-plic: set max threshold for ignored handlers

From: Christoph Hellwig
Date: Mon Jun 24 2019 - 01:43:35 EST


When running in M-mode we still the S-mode plic handlers in the DT.
Ignore them by setting the maximum threshold.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
drivers/irqchip/irq-sifive-plic.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index cf755964f2f8..c72c036aea76 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -244,6 +244,7 @@ static int __init plic_init(struct device_node *node,
struct plic_handler *handler;
irq_hw_number_t hwirq;
int cpu, hartid;
+ u32 threshold = 0;

if (of_irq_parse_one(node, i, &parent)) {
pr_err("failed to parse parent for context %d.\n", i);
@@ -266,10 +267,16 @@ static int __init plic_init(struct device_node *node,
continue;
}

+ /*
+ * When running in M-mode we need to ignore the S-mode handler.
+ * Here we assume it always comes later, but that might be a
+ * little fragile.
+ */
handler = per_cpu_ptr(&plic_handlers, cpu);
if (handler->present) {
pr_warn("handler already present for context %d.\n", i);
- continue;
+ threshold = 0xffffffff;
+ goto done;
}

handler->present = true;
@@ -279,8 +286,9 @@ static int __init plic_init(struct device_node *node,
handler->enable_base =
plic_regs + ENABLE_BASE + i * ENABLE_PER_HART;

+done:
/* priority must be > threshold to trigger an interrupt */
- writel(0, handler->hart_base + CONTEXT_THRESHOLD);
+ writel(threshold, handler->hart_base + CONTEXT_THRESHOLD);
for (hwirq = 1; hwirq <= nr_irqs; hwirq++)
plic_toggle(handler, hwirq, 0);
nr_handlers++;
--
2.20.1