genirq: Add chip suspend and resume callbacks

These callbacks are only called in the syscore suspend/resume code on
interrupt chips which have been registered via the generic irq chip
mechanism. Calling those callbacks per irq would be rather icky, but
with the generic irq chip mechanism we can call this per registered
chip.

Signed-off-by: Thomas Gleixner <[e-mail]>
Cc: [e-mail]

include/linux/irq.h

···
  * @irq_bus_sync_unlock:function to sync and unlock slow bus (i2c) chips
  * @irq_cpu_online:	configure an interrupt source for a secondary CPU
  * @irq_cpu_offline:	un-configure an interrupt source for a secondary CPU
+ * @irq_suspend:	function called from core code on suspend once per chip
+ * @irq_resume:		function called from core code on resume once per chip
+ * @irq_pm_shutdown:	function called from core code on shutdown once per chip
  * @irq_print_chip:	optional to print special chip info in show_interrupts
  * @flags:		chip specific flags
  *
···
 
 	void		(*irq_cpu_online)(struct irq_data *data);
 	void		(*irq_cpu_offline)(struct irq_data *data);
+
+	void		(*irq_suspend)(struct irq_data *data);
+	void		(*irq_resume)(struct irq_data *data);
+	void		(*irq_pm_shutdown)(struct irq_data *data);
 
 	void		(*irq_print_chip)(struct irq_data *data, struct seq_file *p);
 
···
  * @wake_active:	Interrupt is marked as an wakeup from suspend source
  * @num_ct:		Number of available irq_chip_type instances (usually 1)
  * @private:		Private data for non generic chip callbacks
+ * @list:		List head for keeping track of instances
  * @chip_types:		Array of interrupt irq_chip_types
  *
  * Note, that irq_chip_generic can have multiple irq_chip_type
···
 	u32			wake_active;
 	unsigned int		num_ct;
 	void			*private;
+	struct list_head	list;
 	struct irq_chip_type	chip_types[0];
 };
 
···
 			    enum irq_gc_flags flags, unsigned int clr,
 			    unsigned int set);
 int irq_setup_alt_chip(struct irq_data *d, unsigned int type);
+void irq_remove_generic_chip(struct irq_chip_generic *gc, u32 msk,
+			     unsigned int clr, unsigned int set);
 
 static inline struct irq_chip_type *irq_data_get_chip_type(struct irq_data *d)
 {

kernel/irq/generic-chip.c

···
 #include <linux/slab.h>
 #include <linux/interrupt.h>
 #include <linux/kernel_stat.h>
+#include <linux/syscore_ops.h>
 
 #include "internals.h"
+
+static LIST_HEAD(gc_list);
+static DEFINE_RAW_SPINLOCK(gc_lock);
 
 static inline struct irq_chip_regs *cur_regs(struct irq_data *d)
 {
···
 	struct irq_chip_type *ct = gc->chip_types;
 	unsigned int i;
 
+	raw_spin_lock(&gc_lock);
+	list_add_tail(&gc->list, &gc_list);
+	raw_spin_unlock(&gc_lock);
+
 	/* Init mask cache ? */
 	if (flags & IRQ_GC_INIT_MASK_CACHE)
 		gc->mask_cache = irq_reg_readl(gc->reg_base + ct->regs.mask);
···
 	}
 	return -EINVAL;
 }
+
+/**
+ * irq_remove_generic_chip - Remove a chip
+ * @gc:		Generic irq chip holding all data
+ * @msk:	Bitmask holding the irqs to initialize relative to gc->irq_base
+ * @clr:	IRQ_* bits to clear
+ * @set:	IRQ_* bits to set
+ *
+ * Remove up to 32 interrupts starting from gc->irq_base.
+ */
+void irq_remove_generic_chip(struct irq_chip_generic *gc, u32 msk,
+			     unsigned int clr, unsigned int set)
+{
+	unsigned int i = gc->irq_base;
+
+	raw_spin_lock(&gc_lock);
+	list_del(&gc->list);
+	raw_spin_unlock(&gc_lock);
+
+	for (; msk; msk >>= 1, i++) {
+		if (!msk & 0x01)
+			continue;
+
+		/* Remove handler first. That will mask the irq line */
+		irq_set_handler(i, NULL);
+		irq_set_chip(i, &no_irq_chip);
+		irq_set_chip_data(i, NULL);
+		irq_modify_status(i, clr, set);
+	}
+}
+
+#ifdef CONFIG_PM
+static int irq_gc_suspend(void)
+{
+	struct irq_chip_generic *gc;
+
+	list_for_each_entry(gc, &gc_list, list) {
+		struct irq_chip_type *ct = gc->chip_types;
+
+		if (ct->chip.irq_suspend)
+			ct->chip.irq_suspend(irq_get_irq_data(gc->irq_base));
+	}
+	return 0;
+}
+
+static void irq_gc_resume(void)
+{
+	struct irq_chip_generic *gc;
+
+	list_for_each_entry(gc, &gc_list, list) {
+		struct irq_chip_type *ct = gc->chip_types;
+
+		if (ct->chip.irq_resume)
+			ct->chip.irq_resume(irq_get_irq_data(gc->irq_base));
+	}
+}
+#else
+#define irq_gc_suspend NULL
+#define irq_gc_resume NULL
+#endif
+
+static void irq_gc_shutdown(void)
+{
+	struct irq_chip_generic *gc;
+
+	list_for_each_entry(gc, &gc_list, list) {
+		struct irq_chip_type *ct = gc->chip_types;
+
+		if (ct->chip.irq_pm_shutdown)
+			ct->chip.irq_pm_shutdown(irq_get_irq_data(gc->irq_base));
+	}
+}
+
+static struct syscore_ops irq_gc_syscore_ops = {
+	.suspend = irq_gc_suspend,
+	.resume = irq_gc_resume,
+	.shutdown = irq_gc_shutdown,
+};
+
+static int __init irq_gc_init_ops(void)
+{
+	register_syscore_ops(&irq_gc_syscore_ops);
+	return 0;
+}
+device_initcall(irq_gc_init_ops);