[PATCH v3] irqchip/irq-sifive-plic: Add syscore callbacks for hibernation

* [PATCH v3] irqchip/irq-sifive-plic: Add syscore callbacks for hibernation
@ 2023-02-10 10:01 ` Mason Huo
  0 siblings, 0 replies; 10+ messages in thread
From: Mason Huo @ 2023-02-10 10:01 UTC (permalink / raw)
  To: Thomas Gleixner, Marc Zyngier, Palmer Dabbelt, Paul Walmsley
  Cc: linux-kernel, linux-riscv, Mason Huo, Ley Foon Tan, Sia Jee Heng

The priority and enable registers of plic will be reset
during hibernation power cycle in poweroff mode,
add the syscore callbacks to save/restore those registers.

Signed-off-by: Mason Huo <mason.huo@starfivetech.com>
Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
Reviewed-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
---
 drivers/irqchip/irq-sifive-plic.c | 93 ++++++++++++++++++++++++++++++-
 1 file changed, 91 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index ff47bd0dec45..f9d314afecf1 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -17,6 +17,7 @@
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
+#include <linux/syscore_ops.h>
 #include <asm/smp.h>
 
 /*
@@ -67,6 +68,8 @@ struct plic_priv {
 	struct irq_domain *irqdomain;
 	void __iomem *regs;
 	unsigned long plic_quirks;
+	unsigned int nr_irqs;
+	unsigned long *prio_save;
 };
 
 struct plic_handler {
@@ -78,6 +81,7 @@ struct plic_handler {
 	 */
 	raw_spinlock_t		enable_lock;
 	void __iomem		*enable_base;
+	u32			*enable_save;
 	struct plic_priv	*priv;
 };
 static int plic_parent_irq __ro_after_init;
@@ -229,6 +233,71 @@ static int plic_irq_set_type(struct irq_data *d, unsigned int type)
 	return IRQ_SET_MASK_OK;
 }
 
+static int plic_irq_suspend(void)
+{
+	unsigned int i, cpu;
+	u32 __iomem *reg;
+	struct plic_priv *priv;
+
+	priv = per_cpu_ptr(&plic_handlers, smp_processor_id())->priv;
+
+	for (i = 0; i < priv->nr_irqs; i++)
+		if (readl(priv->regs + PRIORITY_BASE + i * PRIORITY_PER_ID))
+			__set_bit(i, priv->prio_save);
+		else
+			__clear_bit(i, priv->prio_save);
+
+	for_each_cpu(cpu, cpu_present_mask) {
+		struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu);
+
+		if (!handler->present)
+			continue;
+
+		raw_spin_lock(&handler->enable_lock);
+		for (i = 0; i < DIV_ROUND_UP(priv->nr_irqs, 32); i++) {
+			reg = handler->enable_base + i * sizeof(u32);
+			handler->enable_save[i] = readl(reg);
+		}
+		raw_spin_unlock(&handler->enable_lock);
+	}
+
+	return 0;
+}
+
+static void plic_irq_resume(void)
+{
+	unsigned int i, index, cpu;
+	u32 __iomem *reg;
+	struct plic_priv *priv;
+
+	priv = per_cpu_ptr(&plic_handlers, smp_processor_id())->priv;
+
+	for (i = 0; i < priv->nr_irqs; i++) {
+		index = (i / BITS_PER_LONG);
+		writel((priv->prio_save[index] & BIT(i % BITS_PER_LONG)) ? 1 : 0,
+		       priv->regs + PRIORITY_BASE + i * PRIORITY_PER_ID);
+	}
+
+	for_each_cpu(cpu, cpu_present_mask) {
+		struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu);
+
+		if (!handler->present)
+			continue;
+
+		raw_spin_lock(&handler->enable_lock);
+		for (i = 0; i < DIV_ROUND_UP(priv->nr_irqs, 32); i++) {
+			reg = handler->enable_base + i * sizeof(u32);
+			writel(handler->enable_save[i], reg);
+		}
+		raw_spin_unlock(&handler->enable_lock);
+	}
+}
+
+static struct syscore_ops plic_irq_syscore_ops = {
+	.suspend	= plic_irq_suspend,
+	.resume		= plic_irq_resume,
+};
+
 static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
 			      irq_hw_number_t hwirq)
 {
@@ -345,6 +414,7 @@ static int __init __plic_init(struct device_node *node,
 	u32 nr_irqs;
 	struct plic_priv *priv;
 	struct plic_handler *handler;
+	unsigned int cpu;
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -363,15 +433,21 @@ static int __init __plic_init(struct device_node *node,
 	if (WARN_ON(!nr_irqs))
 		goto out_iounmap;
 
+	priv->nr_irqs = nr_irqs;
+
+	priv->prio_save = bitmap_alloc(nr_irqs, GFP_KERNEL);
+	if (!priv->prio_save)
+		goto out_free_priority_reg;
+
 	nr_contexts = of_irq_count(node);
 	if (WARN_ON(!nr_contexts))
-		goto out_iounmap;
+		goto out_free_priority_reg;
 
 	error = -ENOMEM;
 	priv->irqdomain = irq_domain_add_linear(node, nr_irqs + 1,
 			&plic_irqdomain_ops, priv);
 	if (WARN_ON(!priv->irqdomain))
-		goto out_iounmap;
+		goto out_free_priority_reg;
 
 	for (i = 0; i < nr_contexts; i++) {
 		struct of_phandle_args parent;
@@ -441,6 +517,11 @@ static int __init __plic_init(struct device_node *node,
 		handler->enable_base = priv->regs + CONTEXT_ENABLE_BASE +
 			i * CONTEXT_ENABLE_SIZE;
 		handler->priv = priv;
+
+		handler->enable_save =  kcalloc(DIV_ROUND_UP(nr_irqs, 32),
+						32, GFP_KERNEL);
+		if (!handler->enable_save)
+			goto out_free_enable_reg;
 done:
 		for (hwirq = 1; hwirq <= nr_irqs; hwirq++) {
 			plic_toggle(handler, hwirq, 0);
@@ -461,11 +542,19 @@ static int __init __plic_init(struct device_node *node,
 				  plic_starting_cpu, plic_dying_cpu);
 		plic_cpuhp_setup_done = true;
 	}
+	register_syscore_ops(&plic_irq_syscore_ops);
 
 	pr_info("%pOFP: mapped %d interrupts with %d handlers for"
 		" %d contexts.\n", node, nr_irqs, nr_handlers, nr_contexts);
 	return 0;
 
+out_free_enable_reg:
+	for_each_cpu(cpu, cpu_present_mask) {
+		handler = per_cpu_ptr(&plic_handlers, cpu);
+		kfree(handler->enable_save);
+	}
+out_free_priority_reg:
+	kfree(priv->prio_save);
 out_iounmap:
 	iounmap(priv->regs);
 out_free_priv:
-- 
2.39.0


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