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>

3 files changed, 187 insertions, 0 deletions

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index bbb746e35500..131f18562d7d 100644
--- a/drivers/irqchip/Kconfig
+++ b/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
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 62a13e5ef98f..7fba336c4daf 100644
--- a/drivers/irqchip/Makefile
+++ b/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
diff --git a/drivers/irqchip/irq-or1k-pic.c b/drivers/irqchip/irq-or1k-pic.c
new file mode 100644
index 000000000000..17ff033d9925
--- /dev/null
+++ b/drivers/irqchip/irq-or1k-pic.c
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
+ * Copyright (C) 2014 Stefan Kristansson <stefan.kristiansson@saunalahti.fi>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+
+#include "irqchip.h"
+
+/* OR1K PIC implementation */
+
+struct or1k_pic_dev {
+	struct irq_chip chip;
+	irq_flow_handler_t handle;
+	unsigned long flags;
+};
+
+/*
+ * 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)
+{
+	mtspr(SPR_PICSR, (1UL << data->hwirq));
+}
+
+static void or1k_pic_mask_ack(struct irq_data *data)
+{
+	mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
+	mtspr(SPR_PICSR, (1UL << data->hwirq));
+}
+
+/*
+ * 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
+ */
+static void or1k_pic_or1200_ack(struct irq_data *data)
+{
+	mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
+}
+
+static void or1k_pic_or1200_mask_ack(struct irq_data *data)
+{
+	mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
+	mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
+}
+
+static struct or1k_pic_dev or1k_pic_level = {
+	.chip = {
+		.name = "or1k-PIC-level",
+		.irq_unmask = or1k_pic_unmask,
+		.irq_mask = or1k_pic_mask,
+		.irq_mask_ack = or1k_pic_mask,
+	},
+	.handle = handle_level_irq,
+	.flags = IRQ_LEVEL | IRQ_NOPROBE,
+};
+
+static struct or1k_pic_dev or1k_pic_edge = {
+	.chip = {
+		.name = "or1k-PIC-edge",
+		.irq_unmask = or1k_pic_unmask,
+		.irq_mask = or1k_pic_mask,
+		.irq_ack = or1k_pic_ack,
+		.irq_mask_ack = or1k_pic_mask_ack,
+	},
+	.handle = handle_edge_irq,
+	.flags = IRQ_LEVEL | IRQ_NOPROBE,
+};
+
+static struct or1k_pic_dev or1k_pic_or1200 = {
+	.chip = {
+		.name = "or1200-PIC",
+		.irq_unmask = or1k_pic_unmask,
+		.irq_mask = or1k_pic_mask,
+		.irq_ack = or1k_pic_or1200_ack,
+		.irq_mask_ack = or1k_pic_or1200_mask_ack,
+	},
+	.handle = handle_level_irq,
+	.flags = IRQ_LEVEL | IRQ_NOPROBE,
+};
+
+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 void or1k_pic_handle_irq(struct pt_regs *regs)
+{
+	int irq = -1;
+
+	while ((irq = pic_get_irq(irq + 1)) != NO_IRQ)
+		handle_IRQ(irq, regs);
+}
+
+static int or1k_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
+{
+	struct or1k_pic_dev *pic = d->host_data;
+
+	irq_set_chip_and_handler(irq, &pic->chip, pic->handle);
+	irq_set_status_flags(irq, pic->flags);
+
+	return 0;
+}
+
+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 int __init or1k_pic_init(struct device_node *node,
+				 struct or1k_pic_dev *pic)
+{
+	/* Disable all interrupts until explicitly requested */
+	mtspr(SPR_PICMR, (0UL));
+
+	root_domain = irq_domain_add_linear(node, 32, &or1k_irq_domain_ops,
+					    pic);
+
+	set_handle_irq(or1k_pic_handle_irq);
+
+	return 0;
+}
+
+static int __init or1k_pic_or1200_init(struct device_node *node,
+				       struct device_node *parent)
+{
+	return or1k_pic_init(node, &or1k_pic_or1200);
+}
+IRQCHIP_DECLARE(or1k_pic_or1200, "opencores,or1200-pic", or1k_pic_or1200_init);
+IRQCHIP_DECLARE(or1k_pic, "opencores,or1k-pic", or1k_pic_or1200_init);
+
+static int __init or1k_pic_level_init(struct device_node *node,
+				      struct device_node *parent)
+{
+	return or1k_pic_init(node, &or1k_pic_level);
+}
+IRQCHIP_DECLARE(or1k_pic_level, "opencores,or1k-pic-level",
+		or1k_pic_level_init);
+
+static int __init or1k_pic_edge_init(struct device_node *node,
+				     struct device_node *parent)
+{
+	return or1k_pic_init(node, &or1k_pic_edge);
+}
+IRQCHIP_DECLARE(or1k_pic_edge, "opencores,or1k-pic-edge", or1k_pic_edge_init);