[PATCH v5] irqchip/irq-sifive-plic: Add syscore callbacks for hibernation

From: Mason Huo
Date: Mon Apr 03 2023 - 23:29:24 EST


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@xxxxxxxxxxxxxxxx>
Reviewed-by: Ley Foon Tan <leyfoon.tan@xxxxxxxxxxxxxxxx>
Reviewed-by: Sia Jee Heng <jeeheng.sia@xxxxxxxxxxxxxxxx>
Reported-by: Dan Carpenter <error27@xxxxxxxxx>
Link: https://lore.kernel.org/r/202302140709.CdkxgtPi-lkp@xxxxxxxxx/
---
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..e1484905b7bd 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 = BIT_WORD(i);
+ writel((priv->prio_save[index] & BIT_MASK(i)) ? 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),
+ sizeof(*handler->enable_save), 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:
--
2.39.2