genirq: Implement a generic interrupt chip

Implement a generic interrupt chip, which is configurable and is able
to handle the most common irq chip implementations.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by; Kevin Hilman <khilman@ti.com>

include/linux/irq.h

@@ -568,6 +568,141 @@ static inline int irq_reserve_irq(unsigned int irq)
 	return irq_reserve_irqs(irq, 1);
 }
 
+#ifndef irq_reg_writel
+# define irq_reg_writel(val, addr)	writel(val, addr)
+#endif
+#ifndef irq_reg_readl
+# define irq_reg_readl(addr)		readl(addr)
+#endif
+
+/**
+ * struct irq_chip_regs - register offsets for struct irq_gci
+ * @enable:	Enable register offset to reg_base
+ * @disable:	Disable register offset to reg_base
+ * @mask:	Mask register offset to reg_base
+ * @ack:	Ack register offset to reg_base
+ * @eoi:	Eoi register offset to reg_base
+ * @type:	Type configuration register offset to reg_base
+ * @polarity:	Polarity configuration register offset to reg_base
+ */
+struct irq_chip_regs {
+	unsigned long		enable;
+	unsigned long		disable;
+	unsigned long		mask;
+	unsigned long		ack;
+	unsigned long		eoi;
+	unsigned long		type;
+	unsigned long		polarity;
+};
+
+/**
+ * struct irq_chip_type - Generic interrupt chip instance for a flow type
+ * @chip:		The real interrupt chip which provides the callbacks
+ * @regs:		Register offsets for this chip
+ * @handler:		Flow handler associated with this chip
+ * @type:		Chip can handle these flow types
+ *
+ * A irq_generic_chip can have several instances of irq_chip_type when
+ * it requires different functions and register offsets for different
+ * flow types.
+ */
+struct irq_chip_type {
+	struct irq_chip		chip;
+	struct irq_chip_regs	regs;
+	irq_flow_handler_t	handler;
+	u32			type;
+};
+
+/**
+ * struct irq_chip_generic - Generic irq chip data structure
+ * @lock:		Lock to protect register and cache data access
+ * @reg_base:		Register base address (virtual)
+ * @irq_base:		Interrupt base nr for this chip
+ * @irq_cnt:		Number of interrupts handled by this chip
+ * @mask_cache:		Cached mask register
+ * @type_cache:		Cached type register
+ * @polarity_cache:	Cached polarity register
+ * @wake_enabled:	Interrupt can wakeup from suspend
+ * @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
+ * @chip_types:		Array of interrupt irq_chip_types
+ *
+ * Note, that irq_chip_generic can have multiple irq_chip_type
+ * implementations which can be associated to a particular irq line of
+ * an irq_chip_generic instance. That allows to share and protect
+ * state in an irq_chip_generic instance when we need to implement
+ * different flow mechanisms (level/edge) for it.
+ */
+struct irq_chip_generic {
+	raw_spinlock_t		lock;
+	void __iomem		*reg_base;
+	unsigned int		irq_base;
+	unsigned int		irq_cnt;
+	u32			mask_cache;
+	u32			type_cache;
+	u32			polarity_cache;
+	u32			wake_enabled;
+	u32			wake_active;
+	unsigned int		num_ct;
+	void			*private;
+	struct irq_chip_type	chip_types[0];
+};
+
+/**
+ * enum irq_gc_flags - Initialization flags for generic irq chips
+ * @IRQ_GC_INIT_MASK_CACHE:	Initialize the mask_cache by reading mask reg
+ * @IRQ_GC_INIT_NESTED_LOCK:	Set the lock class of the irqs to nested for
+ *				irq chips which need to call irq_set_wake() on
+ *				the parent irq. Usually GPIO implementations
+ */
+enum irq_gc_flags {
+	IRQ_GC_INIT_MASK_CACHE		= 1 << 0,
+	IRQ_GC_INIT_NESTED_LOCK		= 1 << 1,
+};
+
+/* Generic chip callback functions */
+void irq_gc_noop(struct irq_data *d);
+void irq_gc_mask_disable_reg(struct irq_data *d);
+void irq_gc_mask_set_bit(struct irq_data *d);
+void irq_gc_mask_clr_bit(struct irq_data *d);
+void irq_gc_unmask_enable_reg(struct irq_data *d);
+void irq_gc_ack(struct irq_data *d);
+void irq_gc_mask_disable_reg_and_ack(struct irq_data *d);
+void irq_gc_eoi(struct irq_data *d);
+int irq_gc_set_wake(struct irq_data *d, unsigned int on);
+
+/* Setup functions for irq_chip_generic */
+struct irq_chip_generic *
+irq_alloc_generic_chip(const char *name, int nr_ct, unsigned int irq_base,
+		       void __iomem *reg_base, irq_flow_handler_t handler);
+void irq_setup_generic_chip(struct irq_chip_generic *gc, u32 msk,
+			    enum irq_gc_flags flags, unsigned int clr,
+			    unsigned int set);
+int irq_setup_alt_chip(struct irq_data *d, unsigned int type);
+
+static inline struct irq_chip_type *irq_data_get_chip_type(struct irq_data *d)
+{
+	return container_of(d->chip, struct irq_chip_type, chip);
+}
+
+#define IRQ_MSK(n) (u32)((n) < 32 ? ((1 << (n)) - 1) : UINT_MAX)
+
+#ifdef CONFIG_SMP
+static inline void irq_gc_lock(struct irq_chip_generic *gc)
+{
+	raw_spin_lock(&gc->lock);
+}
+
+static inline void irq_gc_unlock(struct irq_chip_generic *gc)
+{
+	raw_spin_unlock(&gc->lock);
+}
+#else
+static inline void irq_gc_lock(struct irq_chip_generic *gc) { }
+static inline void irq_gc_unlock(struct irq_chip_generic *gc) { }
+#endif
+
 #endif /* CONFIG_GENERIC_HARDIRQS */
 
 #endif /* !CONFIG_S390 */

kernel/irq/Makefile

@@ -1,5 +1,6 @@
 
 obj-y := irqdesc.o handle.o manage.o spurious.o resend.o chip.o dummychip.o devres.o
+obj-y += generic-chip.o
 obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o