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Subject[PATCH v1] irqchip/irq-sifive-plic: Add syscore callbacks for hibernation
Date
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..80306de45d2b 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;
+ u32 *priority_reg;
};

struct plic_handler {
@@ -79,10 +82,13 @@ struct plic_handler {
raw_spinlock_t enable_lock;
void __iomem *enable_base;
struct plic_priv *priv;
+ /* To record interrupts that are enabled before suspend. */
+ u32 enable_reg[MAX_DEVICES / 32];
};
static int plic_parent_irq __ro_after_init;
static bool plic_cpuhp_setup_done __ro_after_init;
static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
+static struct plic_priv *priv_data;

static int plic_irq_set_type(struct irq_data *d, unsigned int type);

@@ -229,6 +235,78 @@ static int plic_irq_set_type(struct irq_data *d, unsigned int type)
return IRQ_SET_MASK_OK;
}

+static void plic_irq_resume(void)
+{
+ unsigned int i, cpu;
+ u32 __iomem *reg;
+
+ for (i = 0; i < priv_data->nr_irqs; i++)
+ writel(priv_data->priority_reg[i],
+ priv_data->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;
+
+ for (i = 0; i < DIV_ROUND_UP(priv_data->nr_irqs, 32); i++) {
+ reg = handler->enable_base + i * sizeof(u32);
+ raw_spin_lock(&handler->enable_lock);
+ writel(handler->enable_reg[i], reg);
+ raw_spin_unlock(&handler->enable_lock);
+ }
+ }
+}
+
+static int plic_irq_suspend(void)
+{
+ unsigned int i, cpu;
+ u32 __iomem *reg;
+
+ for (i = 0; i < priv_data->nr_irqs; i++)
+ priv_data->priority_reg[i] =
+ readl(priv_data->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;
+
+ for (i = 0; i < DIV_ROUND_UP(priv_data->nr_irqs, 32); i++) {
+ reg = handler->enable_base + i * sizeof(u32);
+ raw_spin_lock(&handler->enable_lock);
+ handler->enable_reg[i] = readl(reg);
+ raw_spin_unlock(&handler->enable_lock);
+ }
+ }
+
+ return 0;
+}
+
+static struct syscore_ops plic_irq_syscore_ops = {
+ .suspend = plic_irq_suspend,
+ .resume = plic_irq_resume,
+};
+
+static void plic_irq_pm_init(void)
+{
+ unsigned int cpu;
+
+ for_each_cpu(cpu, cpu_present_mask) {
+ struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu);
+
+ if (!handler->present)
+ continue;
+
+ memset(&handler->enable_reg[0], 0,
+ sizeof(handler->enable_reg));
+ }
+
+ register_syscore_ops(&plic_irq_syscore_ops);
+}
+
static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
@@ -351,6 +429,7 @@ static int __init __plic_init(struct device_node *node,
return -ENOMEM;

priv->plic_quirks = plic_quirks;
+ priv_data = priv;

priv->regs = of_iomap(node, 0);
if (WARN_ON(!priv->regs)) {
@@ -363,15 +442,21 @@ static int __init __plic_init(struct device_node *node,
if (WARN_ON(!nr_irqs))
goto out_iounmap;

+ priv->nr_irqs = nr_irqs;
+
+ priv->priority_reg = kcalloc(nr_irqs, sizeof(u32), GFP_KERNEL);
+ if (!priv->priority_reg)
+ 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;
@@ -461,11 +546,15 @@ static int __init __plic_init(struct device_node *node,
plic_starting_cpu, plic_dying_cpu);
plic_cpuhp_setup_done = true;
}
+ plic_irq_pm_init();

pr_info("%pOFP: mapped %d interrupts with %d handlers for"
" %d contexts.\n", node, nr_irqs, nr_handlers, nr_contexts);
return 0;

+out_free_priority_reg:
+ kfree(priv->priority_reg);
+
out_iounmap:
iounmap(priv->regs);
out_free_priv:
--
2.39.0
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