irqchip/irq-bcm7038-l1: Add PM support

The current L1 controller does not mask any interrupts when dropping
into suspend. This mean we can receive unexpected wake up sources.
Modified the BCM7038 L1 controller to mask the all non-wake interrupts
before dropping into suspend.

Signed-off-by: Justin Chen <justinpopo6@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20191024201415.23454-2-f.fainelli@gmail.com

drivers/irqchip/irq-bcm7038-l1.c

@@ -27,6 +27,7 @@
 #include <linux/types.h>
 #include <linux/irqchip.h>
 #include <linux/irqchip/chained_irq.h>
+#include <linux/syscore_ops.h>
 
 #define IRQS_PER_WORD		32
 #define REG_BYTES_PER_IRQ_WORD	(sizeof(u32) * 4)
@@ -39,6 +40,10 @@ struct bcm7038_l1_chip {
 	unsigned int		n_words;
 	struct irq_domain	*domain;
 	struct bcm7038_l1_cpu	*cpus[NR_CPUS];
+#ifdef CONFIG_PM_SLEEP
+	struct list_head	list;
+	u32			wake_mask[MAX_WORDS];
+#endif
 	u8			affinity[MAX_WORDS * IRQS_PER_WORD];
 };
 
@@ -287,6 +292,77 @@ static int __init bcm7038_l1_init_one(struct device_node *dn,
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+/*
+ * We keep a list of bcm7038_l1_chip used for suspend/resume. This hack is
+ * used because the struct chip_type suspend/resume hooks are not called
+ * unless chip_type is hooked onto a generic_chip. Since this driver does
+ * not use generic_chip, we need to manually hook our resume/suspend to
+ * syscore_ops.
+ */
+static LIST_HEAD(bcm7038_l1_intcs_list);
+static DEFINE_RAW_SPINLOCK(bcm7038_l1_intcs_lock);
+
+static int bcm7038_l1_suspend(void)
+{
+	struct bcm7038_l1_chip *intc;
+	int boot_cpu, word;
+
+	/* Wakeup interrupt should only come from the boot cpu */
+	boot_cpu = cpu_logical_map(0);
+
+	list_for_each_entry(intc, &bcm7038_l1_intcs_list, list) {
+		for (word = 0; word < intc->n_words; word++) {
+			l1_writel(~intc->wake_mask[word],
+				intc->cpus[boot_cpu]->map_base + reg_mask_set(intc, word));
+			l1_writel(intc->wake_mask[word],
+				intc->cpus[boot_cpu]->map_base + reg_mask_clr(intc, word));
+		}
+	}
+
+	return 0;
+}
+
+static void bcm7038_l1_resume(void)
+{
+	struct bcm7038_l1_chip *intc;
+	int boot_cpu, word;
+
+	boot_cpu = cpu_logical_map(0);
+
+	list_for_each_entry(intc, &bcm7038_l1_intcs_list, list) {
+		for (word = 0; word < intc->n_words; word++) {
+			l1_writel(intc->cpus[boot_cpu]->mask_cache[word],
+				intc->cpus[boot_cpu]->map_base + reg_mask_set(intc, word));
+			l1_writel(~intc->cpus[boot_cpu]->mask_cache[word],
+				intc->cpus[boot_cpu]->map_base + reg_mask_clr(intc, word));
+		}
+	}
+}
+
+static struct syscore_ops bcm7038_l1_syscore_ops = {
+	.suspend	= bcm7038_l1_suspend,
+	.resume		= bcm7038_l1_resume,
+};
+
+static int bcm7038_l1_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
+	unsigned long flags;
+	u32 word = d->hwirq / IRQS_PER_WORD;
+	u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
+
+	raw_spin_lock_irqsave(&intc->lock, flags);
+	if (on)
+		intc->wake_mask[word] |= mask;
+	else
+		intc->wake_mask[word] &= ~mask;
+	raw_spin_unlock_irqrestore(&intc->lock, flags);
+
+	return 0;
+}
+#endif
+
 static struct irq_chip bcm7038_l1_irq_chip = {
 	.name			= "bcm7038-l1",
 	.irq_mask		= bcm7038_l1_mask,
@@ -295,6 +371,9 @@ static struct irq_chip bcm7038_l1_irq_chip = {
 #ifdef CONFIG_SMP
 	.irq_cpu_offline	= bcm7038_l1_cpu_offline,
 #endif
+#ifdef CONFIG_PM_SLEEP
+	.irq_set_wake		= bcm7038_l1_set_wake,
+#endif
 };
 
 static int bcm7038_l1_map(struct irq_domain *d, unsigned int virq,
@@ -340,6 +419,16 @@ int __init bcm7038_l1_of_init(struct device_node *dn,
 		goto out_unmap;
 	}
 
+#ifdef CONFIG_PM_SLEEP
+	/* Add bcm7038_l1_chip into a list */
+	raw_spin_lock(&bcm7038_l1_intcs_lock);
+	list_add_tail(&intc->list, &bcm7038_l1_intcs_list);
+	raw_spin_unlock(&bcm7038_l1_intcs_lock);
+
+	if (list_is_singular(&bcm7038_l1_intcs_list))
+		register_syscore_ops(&bcm7038_l1_syscore_ops);
+#endif
+
 	pr_info("registered BCM7038 L1 intc (%pOF, IRQs: %d)\n",
 		dn, IRQS_PER_WORD * intc->n_words);