[PATCH v2 3/4] irqchip: sifive-plic: Differentiate between PLIC handler and context

Anup Patel
2018-11-27T10:04:05Z

We explicitly differentiate between PLIC handler and context because
PLIC context is for given mode of HART whereas PLIC handler is per-CPU
software construct meant for handling interrupts from a particular
PLIC context.

Signed-off-by: Anup Patel <anup@brainfault.org>
---
drivers/irqchip/irq-sifive-plic.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index 95b4b92ca9b8..ffd4deaca057 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -66,8 +66,8 @@ static DEFINE_PER_CPU(struct plic_handler, plic_handlers);

struct plic_hw {
u32 nr_irqs;
+ u32 nr_contexts;
u32 nr_handlers;
- u32 nr_mapped;
void __iomem *regs;
struct irq_domain *irqdomain;
};
@@ -191,10 +191,10 @@ static int __init plic_init(struct device_node *node,
if (WARN_ON(!plic.nr_irqs))
goto out_iounmap;

- plic.nr_handlers = of_irq_count(node);
- if (WARN_ON(!plic.nr_handlers))
+ plic.nr_contexts = of_irq_count(node);
+ if (WARN_ON(!plic.nr_contexts))
goto out_iounmap;
- if (WARN_ON(plic.nr_handlers < num_possible_cpus()))
+ if (WARN_ON(plic.nr_contexts < num_possible_cpus()))
goto out_iounmap;

plic.irqdomain = irq_domain_add_linear(node, plic.nr_irqs + 1,
@@ -202,7 +202,7 @@ static int __init plic_init(struct device_node *node,
if (WARN_ON(!plic.irqdomain))
goto out_iounmap;

- for (i = 0; i < plic.nr_handlers; i++) {
+ for (i = 0; i < plic.nr_contexts; i++) {
struct of_phandle_args parent;
struct plic_handler *handler;
irq_hw_number_t hwirq;
@@ -225,6 +225,11 @@ static int __init plic_init(struct device_node *node,

cpu = riscv_hartid_to_cpuid(hartid);
handler = per_cpu_ptr(&plic_handlers, cpu);
+ if (handler->present) {
+ pr_warn("handler not available for context %d.\n", i);
+ continue;
+ }
+
handler->present = true;
handler->hart_base =
plic.regs + CONTEXT_BASE + i * CONTEXT_PER_HART;
@@ -237,11 +242,11 @@ static int __init plic_init(struct device_node *node,
for (hwirq = 1; hwirq <= plic.nr_irqs; hwirq++)
plic_toggle(handler, hwirq, 0);

- plic.nr_mapped++;
+ plic.nr_handlers++;
}

- pr_info("mapped %d interrupts to %d (out of %d) handlers.\n",
- plic.nr_irqs, plic.nr_mapped, plic.nr_handlers);
+ pr_info("mapped %d interrupts with %d handlers for %d contexts.\n",
+ plic.nr_irqs, plic.nr_handlers, plic.nr_contexts);
set_handle_irq(plic_handle_irq);
return 0;