[PATCH 05/13] irqchip: add initial support for ompic

[Stafford Horne <shorne-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

From: Stefan Kristiansson <stefan.kristiansson-MbMCFXIvDHJFcC0YU169RA@public.gmane.org>

IPI driver for OpenRISC Multicore programmable interrupt controller as
described in the Multicore support section of the OpenRISC 1.2
proposed architecture specification:

  https://github.com/stffrdhrn/doc/raw/arch-1.2-proposal/openrisc-arch-1.2-rev0.pdf

Each OpenRISC core contains a full interrupt controller which is used in
the SMP architecture for interrupt balancing.  This IPI device is the
only external device required for enabling SMP on OpenRISC.

Pending ops are stored in a memory bit mask which can allow multiple
pending operations to be set and serviced at a time. This is mostly
borrowed from the alpha IPI implementation.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson-MbMCFXIvDHJFcC0YU169RA@public.gmane.org>
[shorne-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org: converted ops to bitmask, wrote commit message]
Signed-off-by: Stafford Horne <shorne-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 .../bindings/interrupt-controller/ompic.txt        |  22 ++++
 arch/openrisc/Kconfig                              |   1 +
 drivers/irqchip/Kconfig                            |   4 +
 drivers/irqchip/Makefile                           |   1 +
 drivers/irqchip/irq-ompic.c                        | 117 +++++++++++++++++++++
 5 files changed, 145 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/ompic.txt
 create mode 100644 drivers/irqchip/irq-ompic.c

diff --git a/Documentation/devicetree/bindings/interrupt-controller/ompic.txt b/Documentation/devicetree/bindings/interrupt-controller/ompic.txt
new file mode 100644
index 000000000000..4176ecc3366d
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/ompic.txt
@@ -0,0 +1,22 @@
+OpenRISC Multicore Programmable Interrupt Controller
+
+Required properties:
+
+- compatible : This should be "ompic"
+- reg : Specifies base physical address and size of the register space. The
+  size can be arbitrary based on the number of cores the controller has
+  been configured to handle, typically 8 bytes per core.
+- 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.
+- interrupts : Specifies the interrupt line to which the ompic is wired.
+
+Example:
+
+ompic: ompic {
+	compatible = "ompic";
+	reg = <0x98000000 16>;
+	#interrupt-cells = <1>;
+	interrupt-controller;
+	interrupts = <1>;
+};
diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
index 214c837ce597..dd7e55e7e42d 100644
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -30,6 +30,7 @@ config OPENRISC
 	select NO_BOOTMEM
 	select ARCH_USE_QUEUED_SPINLOCKS
 	select ARCH_USE_QUEUED_RWLOCKS
+	select OMPIC if SMP
 
 config CPU_BIG_ENDIAN
 	def_bool y
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index f1fd5f44d1d4..3fa60e6667a7 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -145,6 +145,10 @@ config CLPS711X_IRQCHIP
 	select SPARSE_IRQ
 	default y
 
+config OMPIC
+	bool
+	select IRQ_DOMAIN
+
 config OR1K_PIC
 	bool
 	select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index e88d856cc09c..123047d7a20d 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_DW_APB_ICTL)		+= irq-dw-apb-ictl.o
 obj-$(CONFIG_METAG)			+= irq-metag-ext.o
 obj-$(CONFIG_METAG_PERFCOUNTER_IRQS)	+= irq-metag.o
 obj-$(CONFIG_CLPS711X_IRQCHIP)		+= irq-clps711x.o
+obj-$(CONFIG_OMPIC)			+= irq-ompic.o
 obj-$(CONFIG_OR1K_PIC)			+= irq-or1k-pic.o
 obj-$(CONFIG_ORION_IRQCHIP)		+= irq-orion.o
 obj-$(CONFIG_OMAP_IRQCHIP)		+= irq-omap-intc.o
diff --git a/drivers/irqchip/irq-ompic.c b/drivers/irqchip/irq-ompic.c
new file mode 100644
index 000000000000..438819f8a5a7
--- /dev/null
+++ b/drivers/irqchip/irq-ompic.c
@@ -0,0 +1,117 @@
+/*
+ * Open Multi-Processor Interrupt Controller driver
+ *
+ * Copyright (C) 2014 Stefan Kristiansson <stefan.kristiansson-MbMCFXIvDHJFcC0YU169RA@public.gmane.org>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_address.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/delay.h>
+
+#include <linux/irqchip.h>
+
+#define OMPIC_IPI_BASE			0x0
+#define OMPIC_IPI_CTRL(cpu)		(OMPIC_IPI_BASE + 0x0 + (cpu)*8)
+#define OMPIC_IPI_STAT(cpu)		(OMPIC_IPI_BASE + 0x4 + (cpu)*8)
+
+#define OMPIC_IPI_CTRL_IRQ_ACK		(1 << 31)
+#define OMPIC_IPI_CTRL_IRQ_GEN		(1 << 30)
+#define OMPIC_IPI_CTRL_DST(cpu)		(((cpu) & 0x3fff) << 16)
+
+#define OMPIC_IPI_STAT_IRQ_PENDING	(1 << 30)
+
+#define OMPIC_IPI_DATA(x)		((x) & 0xffff)
+
+static struct {
+	unsigned long ops;
+} ipi_data[NR_CPUS];
+
+static void __iomem *ompic_base;
+
+static inline u32 ompic_readreg(void __iomem *base, loff_t offset)
+{
+	return ioread32be(base + offset);
+}
+
+static void ompic_writereg(void __iomem *base, loff_t offset, u32 data)
+{
+	iowrite32be(data, base + offset);
+}
+
+#ifdef CONFIG_SMP
+void ompic_raise_softirq(const struct cpumask *mask, unsigned int irq)
+{
+	unsigned int dst_cpu;
+	unsigned int src_cpu = smp_processor_id();
+
+	for_each_cpu(dst_cpu, mask) {
+		set_bit(irq, &ipi_data[dst_cpu].ops);
+
+		ompic_writereg(ompic_base, OMPIC_IPI_CTRL(src_cpu),
+			       OMPIC_IPI_CTRL_IRQ_GEN |
+			       OMPIC_IPI_CTRL_DST(dst_cpu) |
+			       OMPIC_IPI_DATA(1));
+	}
+}
+#endif
+
+irqreturn_t ompic_ipi_handler(int irq, void *dev_id)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned long *pending_ops = &ipi_data[cpu].ops;
+	unsigned long ops;
+
+	ompic_writereg(ompic_base, OMPIC_IPI_CTRL(cpu), OMPIC_IPI_CTRL_IRQ_ACK);
+	while ((ops = xchg(pending_ops, 0)) != 0) {
+		do {
+			unsigned long ipi;
+
+			ipi = ops & -ops;
+			ops &= ~ipi;
+			ipi = __ffs(ipi);
+
+			handle_IPI(ipi);
+		} while (ops);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static struct irqaction ompi_ipi_irqaction = {
+	.handler =      ompic_ipi_handler,
+	.flags =        IRQF_PERCPU,
+	.name =         "ompic_ipi",
+};
+
+#ifdef CONFIG_OF
+int __init ompic_of_init(struct device_node *node, struct device_node *parent)
+{
+	int irq;
+
+	if (WARN_ON(!node))
+		return -ENODEV;
+
+	memset(ipi_data, 0, sizeof(ipi_data));
+
+	ompic_base = of_iomap(node, 0);
+
+	irq = irq_of_parse_and_map(node, 0);
+	setup_irq(irq, &ompi_ipi_irqaction);
+
+#ifdef CONFIG_SMP
+	set_smp_cross_call(ompic_raise_softirq);
+#endif
+
+	return 0;
+}
+IRQCHIP_DECLARE(ompic, "ompic", ompic_of_init);
+#endif
-- 
2.13.5

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html