irqchip: or1k-pic: Migrate from arch/openrisc/

In addition to consolidating the or1k-pic with other interrupt
controllers, this makes OpenRISC less tied to its on-cpu
interrupt controller.

All or1k-pic specific parts are moved out of irq.c and into
drivers/irqchip/irq-or1k-pic.c

In that transition, the functionality have been divided into
three chip variants.
One that handles level triggered interrupts, one that handles edge
triggered interrupts and one that handles the interrupt
controller that is present in the or1200 OpenRISC cpu
implementation.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Link: https://lkml.kernel.org/r/1401136302-27654-1-git-send-email-stefan.kristiansson@saunalahti.fi
Acked-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

Documentation/devicetree/bindings/interrupt-controller/opencores,or1k-pic.txt

@@ -0,0 +1,23 @@
+OpenRISC 1000 Programmable Interrupt Controller
+
+Required properties:
+
+- compatible : should be "opencores,or1k-pic-level" for variants with
+  level triggered interrupt lines, "opencores,or1k-pic-edge" for variants with
+  edge triggered interrupt lines or "opencores,or1200-pic" for machines
+  with the non-spec compliant or1200 type implementation.
+
+  "opencores,or1k-pic" is also provided as an alias to "opencores,or1200-pic",
+  but this is only for backwards compatibility.
+
+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt source. The value shall be 1.
+
+Example:
+
+intc: interrupt-controller {
+	compatible = "opencores,or1k-pic-level";
+	interrupt-controller;
+	#interrupt-cells = <1>;
+};

arch/openrisc/Kconfig

@@ -22,6 +22,7 @@ config OPENRISC
 	select GENERIC_STRNLEN_USER
 	select MODULES_USE_ELF_RELA
 	select HAVE_DEBUG_STACKOVERFLOW
+	select OR1K_PIC
 
 config MMU
 	def_bool y

arch/openrisc/include/asm/irq.h

@@ -24,4 +24,7 @@
 
 #define NO_IRQ		(-1)
 
+void handle_IRQ(unsigned int, struct pt_regs *);
+extern void set_handle_irq(void (*handle_irq)(struct pt_regs *));
+
 #endif /* __ASM_OPENRISC_IRQ_H__ */

arch/openrisc/kernel/irq.c

@@ -16,11 +16,10 @@
 
 #include <linux/interrupt.h>
 #include <linux/init.h>
-#include <linux/of.h>
 #include <linux/ftrace.h>
 #include <linux/irq.h>
+#include <linux/irqchip.h>
 #include <linux/export.h>
-#include <linux/irqdomain.h>
 #include <linux/irqflags.h>
 
 /* read interrupt enabled status */
@@ -37,150 +36,31 @@ void arch_local_irq_restore(unsigned long flags)
 }
 EXPORT_SYMBOL(arch_local_irq_restore);
 
-
-/* OR1K PIC implementation */
-
-/* We're a couple of cycles faster than the generic implementations with
- * these 'fast' versions.
- */
-
-static void or1k_pic_mask(struct irq_data *data)
-{
-	mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
-}
-
-static void or1k_pic_unmask(struct irq_data *data)
-{
-	mtspr(SPR_PICMR, mfspr(SPR_PICMR) | (1UL << data->hwirq));
-}
-
-static void or1k_pic_ack(struct irq_data *data)
-{
-	/* EDGE-triggered interrupts need to be ack'ed in order to clear
-	 * the latch.
-	 * LEVEL-triggered interrupts do not need to be ack'ed; however,
-	 * ack'ing the interrupt has no ill-effect and is quicker than
-	 * trying to figure out what type it is...
-	 */
-
-	/* The OpenRISC 1000 spec says to write a 1 to the bit to ack the
-	 * interrupt, but the OR1200 does this backwards and requires a 0
-	 * to be written...
-	 */
-
-#ifdef CONFIG_OR1K_1200
-	/* There are two oddities with the OR1200 PIC implementation:
-	 * i)  LEVEL-triggered interrupts are latched and need to be cleared
-	 * ii) the interrupt latch is cleared by writing a 0 to the bit,
-	 *     as opposed to a 1 as mandated by the spec
-	 */
-
-	mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
-#else
-	WARN(1, "Interrupt handling possibly broken\n");
-	mtspr(SPR_PICSR, (1UL << data->hwirq));
-#endif
-}
-
-static void or1k_pic_mask_ack(struct irq_data *data)
-{
-	/* Comments for pic_ack apply here, too */
-
-#ifdef CONFIG_OR1K_1200
-	mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
-	mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
-#else
-	WARN(1, "Interrupt handling possibly broken\n");
-	mtspr(SPR_PICMR, (1UL << data->hwirq));
-	mtspr(SPR_PICSR, (1UL << data->hwirq));
-#endif
-}
-
-#if 0
-static int or1k_pic_set_type(struct irq_data *data, unsigned int flow_type)
-{
-	/* There's nothing to do in the PIC configuration when changing
-	 * flow type.  Level and edge-triggered interrupts are both
-	 * supported, but it's PIC-implementation specific which type
-	 * is handled. */
-
-	return irq_setup_alt_chip(data, flow_type);
-}
-#endif
-
-static struct irq_chip or1k_dev = {
-	.name = "or1k-PIC",
-	.irq_unmask = or1k_pic_unmask,
-	.irq_mask = or1k_pic_mask,
-	.irq_ack = or1k_pic_ack,
-	.irq_mask_ack = or1k_pic_mask_ack,
-};
-
-static struct irq_domain *root_domain;
-
-static inline int pic_get_irq(int first)
-{
-	int hwirq;
-
-	hwirq = ffs(mfspr(SPR_PICSR) >> first);
-	if (!hwirq)
-		return NO_IRQ;
-	else
-		hwirq = hwirq + first -1;
-
-	return irq_find_mapping(root_domain, hwirq);
-}
-
-
-static int or1k_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
+void __init init_IRQ(void)
 {
-	irq_set_chip_and_handler_name(irq, &or1k_dev,
-				      handle_level_irq, "level");
-	irq_set_status_flags(irq, IRQ_LEVEL | IRQ_NOPROBE);
-
-	return 0;
+	irqchip_init();
 }
 
-static const struct irq_domain_ops or1k_irq_domain_ops = {
-	.xlate = irq_domain_xlate_onecell,
-	.map = or1k_map,
-};
-
-/*
- * This sets up the IRQ domain for the PIC built in to the OpenRISC
- * 1000 CPU.  This is the "root" domain as these are the interrupts
- * that directly trigger an exception in the CPU.
- */
-static void __init or1k_irq_init(void)
-{
-	struct device_node *intc = NULL;
-
-	/* The interrupt controller device node is mandatory */
-	intc = of_find_compatible_node(NULL, NULL, "opencores,or1k-pic");
-	BUG_ON(!intc);
-
-	/* Disable all interrupts until explicitly requested */
-	mtspr(SPR_PICMR, (0UL));
-
-	root_domain = irq_domain_add_linear(intc, 32,
-					    &or1k_irq_domain_ops, NULL);
-}
+static void (*handle_arch_irq)(struct pt_regs *);
 
-void __init init_IRQ(void)
+void __init set_handle_irq(void (*handle_irq)(struct pt_regs *))
 {
-	or1k_irq_init();
+	handle_arch_irq = handle_irq;
 }
 
-void __irq_entry do_IRQ(struct pt_regs *regs)
+void handle_IRQ(unsigned int irq, struct pt_regs *regs)
 {
-	int irq = -1;
 	struct pt_regs *old_regs = set_irq_regs(regs);
 
 	irq_enter();
 
-	while ((irq = pic_get_irq(irq + 1)) != NO_IRQ)
-		generic_handle_irq(irq);
+	generic_handle_irq(irq);
 
 	irq_exit();
 	set_irq_regs(old_regs);
 }
+
+void __irq_entry do_IRQ(struct pt_regs *regs)
+{
+	handle_arch_irq(regs);
+}

drivers/irqchip/Kconfig

@@ -53,6 +53,10 @@ config CLPS711X_IRQCHIP
 	select SPARSE_IRQ
 	default y
 
+config OR1K_PIC
+	bool
+	select IRQ_DOMAIN
+
 config ORION_IRQCHIP
 	bool
 	select IRQ_DOMAIN

drivers/irqchip/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_METAG)			+= irq-metag-ext.o
 obj-$(CONFIG_METAG_PERFCOUNTER_IRQS)	+= irq-metag.o
 obj-$(CONFIG_ARCH_MOXART)		+= irq-moxart.o
 obj-$(CONFIG_CLPS711X_IRQCHIP)		+= irq-clps711x.o
+obj-$(CONFIG_OR1K_PIC)			+= irq-or1k-pic.o
 obj-$(CONFIG_ORION_IRQCHIP)		+= irq-orion.o
 obj-$(CONFIG_ARCH_SUNXI)		+= irq-sun4i.o
 obj-$(CONFIG_ARCH_SUNXI)		+= irq-sunxi-nmi.o