genirq: Expand generic show_interrupts()

Some archs want to print extra information for certain irq_chips which
is per irq and not per chip. Allow them to provide a chip callback to
print the chip name and the extra information.

PowerPC wants to print the LEVEL/EDGE type information. Make it configurable.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/irq.h

@@ -28,6 +28,7 @@
 #include <asm/ptrace.h>
 #include <asm/irq_regs.h>
 
+struct seq_file;
 struct irq_desc;
 struct irq_data;
 typedef	void (*irq_flow_handler_t)(unsigned int irq,
@@ -270,6 +271,7 @@ static inline bool irqd_can_move_in_process_context(struct irq_data *d)
  * @irq_set_wake:	enable/disable power-management wake-on of an IRQ
  * @irq_bus_lock:	function to lock access to slow bus (i2c) chips
  * @irq_bus_sync_unlock:function to sync and unlock slow bus (i2c) chips
+ * @irq_print_chip:	optional to print special chip info in show_interrupts
  * @flags:		chip specific flags
  *
  * @release:		release function solely used by UML
@@ -317,6 +319,8 @@ struct irq_chip {
 	void		(*irq_bus_lock)(struct irq_data *data);
 	void		(*irq_bus_sync_unlock)(struct irq_data *data);
 
+	void		(*irq_print_chip)(struct irq_data *data, struct seq_file *p);
+
 	unsigned long	flags;
 
 	/* Currently used only by UML, might disappear one day.*/

kernel/irq/Kconfig

@@ -31,6 +31,10 @@ config GENERIC_IRQ_PROBE
 config GENERIC_IRQ_SHOW
        bool
 
+# Print level/edge extra information
+config GENERIC_IRQ_SHOW_LEVEL
+       bool
+
 # Support for delayed migration from interrupt context
 config GENERIC_PENDING_IRQ
 	bool

kernel/irq/proc.c

@@ -404,7 +404,20 @@ int show_interrupts(struct seq_file *p, void *v)
 	seq_printf(p, "%*d: ", prec, i);
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
-	seq_printf(p, " %8s", desc->irq_data.chip->name);
+
+	if (desc->irq_data.chip) {
+		if (desc->irq_data.chip->irq_print_chip)
+			desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
+		else if (desc->irq_data.chip->name)
+			seq_printf(p, " %8s", desc->irq_data.chip->name);
+		else
+			seq_printf(p, " %8s", "-");
+	} else {
+		seq_printf(p, " %8s", "None");
+	}
+#ifdef CONFIG_GENIRC_IRQ_SHOW_LEVEL
+	seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
+#endif
 	if (desc->name)
 		seq_printf(p, "-%-8s", desc->name);