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

[Anup Patel]

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 <a...@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;
 
-- 
2.17.1