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

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Date:   Mon, 22 Oct 2018 17:15:16 +0530
From:   Anup Patel <anup@...infault.org>
To:     Palmer Dabbelt <palmer@...ive.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>
Cc:     Atish Patra <atish.patra@....com>,
        Christoph Hellwig <hch@...radead.org>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Anup Patel <anup@...infault.org>
Subject: [PATCH 3/4] irqchip: sifive-plic: Differentiate between PLIC handler and context

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 to handling interrupts from a particular
PLIC context.

Signed-off-by: Anup Patel <anup@...infault.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 869355d2a713..eb9e8aee1a1a 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -64,8 +64,8 @@ struct plic_handler {
 
 struct plic_hw {
 	u32			nr_irqs;
+	u32			nr_contexts;
 	u32			nr_handlers;
-	u32			nr_mapped;
 	void __iomem		*regs;
 	struct plic_handler	*handlers;
 	struct irq_domain	*irqdomain;
@@ -190,10 +190,10 @@ 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;
 
 	error = -ENOMEM;
@@ -206,7 +206,7 @@ static int __init plic_init(struct device_node *node,
 	if (WARN_ON(!plic.irqdomain))
 		goto out_free_handlers;
 
-	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;
@@ -229,6 +229,11 @@ 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;
@@ -241,11 +246,11 @@ 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