[PATCH 02/17] irqchip: Add PLX Technology RPS IRQ Controller

[Neil Armstrong]

Add PLX Technology RPS IRQ Controller as irqchip driver.

CC: Ma Haijun <mahaijuns@xxxxxxxxx>
Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
 drivers/irqchip/Kconfig   |   5 ++
 drivers/irqchip/Makefile  |   1 +
 drivers/irqchip/irq-rps.c | 128 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 134 insertions(+)
 create mode 100644 drivers/irqchip/irq-rps.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index fb50911..7892c1a 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -135,6 +135,11 @@ config PIC32_EVIC
 	select GENERIC_IRQ_CHIP
 	select IRQ_DOMAIN
 
+config PLXTECH_RPS
+	bool
+	select GENERIC_IRQ_CHIP
+	select IRQ_DOMAIN
+
 config RENESAS_INTC_IRQPIN
 	bool
 	select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 18caacb..3eec3a0 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_I8259)			+= irq-i8259.o
 obj-$(CONFIG_IMGPDC_IRQ)		+= irq-imgpdc.o
 obj-$(CONFIG_IRQ_MIPS_CPU)		+= irq-mips-cpu.o
 obj-$(CONFIG_SIRF_IRQ)			+= irq-sirfsoc.o
+obj-$(CONFIG_PLXTECH_RPS)		+= irq-rps.o
 obj-$(CONFIG_RENESAS_INTC_IRQPIN)	+= irq-renesas-intc-irqpin.o
 obj-$(CONFIG_RENESAS_IRQC)		+= irq-renesas-irqc.o
 obj-$(CONFIG_VERSATILE_FPGA_IRQ)	+= irq-versatile-fpga.o
diff --git a/drivers/irqchip/irq-rps.c b/drivers/irqchip/irq-rps.c
new file mode 100644
index 0000000..bcd4a31
--- /dev/null
+++ b/drivers/irqchip/irq-rps.c
@@ -0,0 +1,128 @@
+/*
+ * drivers/irqchip/irq-rps.c
+ *
+ * Copyright (C) 2009 Oxford Semiconductor Ltd
+ * Copyright (C) 2013 Ma Haijun <mahaijuns@xxxxxxxxx>
+ * Copyright (C) 2016 Neil Armstrong <narmstrong@xxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/version.h>
+#include <linux/irqchip.h>
+
+#include <asm/exception.h>
+
+struct rps_chip_data {
+	void __iomem *base;
+	struct irq_domain *domain;
+} rps_data;
+
+enum {
+	RPS_IRQ_COUNT = 32,
+
+	RPS_STATUS = 0,
+	RPS_RAW_STATUS = 4,
+	RPS_UNMASK = 8,
+	RPS_MASK = 0xc,
+};
+
+/* Routines to acknowledge, disable and enable interrupts */
+static void rps_mask_irq(struct irq_data *d)
+{
+	u32 mask = BIT(d->hwirq);
+
+	iowrite32(mask, rps_data.base + RPS_MASK);
+}
+
+static void rps_unmask_irq(struct irq_data *d)
+{
+	u32 mask = BIT(d->hwirq);
+
+	iowrite32(mask, rps_data.base + RPS_UNMASK);
+}
+
+static void rps_ack_irq(struct irq_data *d)
+{
+	/* NOP */
+}
+
+static void __exception_irq_entry handle_irq(struct pt_regs *regs)
+{
+	u32 irqstat;
+	int hwirq;
+
+	irqstat = ioread32(rps_data.base + RPS_STATUS);
+	hwirq = __ffs(irqstat);
+
+	do {
+		handle_IRQ(irq_find_mapping(rps_data.domain, hwirq), regs);
+
+		irqstat = ioread32(rps_data.base + RPS_STATUS);
+		hwirq = __ffs(irqstat);
+	} while (irqstat);
+}
+
+int __init rps_of_init(struct device_node *node, struct device_node *parent)
+{
+	int ret;
+	struct irq_chip_generic *gc;
+
+	if (WARN_ON(!node))
+		return -ENODEV;
+
+	rps_data.base = of_iomap(node, 0);
+	WARN(!rps_data.base, "unable to map rps registers\n");
+
+	rps_data.domain = irq_domain_add_linear(node, RPS_IRQ_COUNT,
+						&irq_generic_chip_ops,
+						NULL);
+	if (!rps_data.domain) {
+		pr_err("%s: could add irq domain\n",
+		       node->full_name);
+		return -ENOMEM;
+	}
+
+	ret = irq_alloc_domain_generic_chips(rps_data.domain, RPS_IRQ_COUNT, 1,
+					     "RPS", handle_level_irq,
+					     0, 0, IRQ_GC_INIT_NESTED_LOCK);
+	if (ret) {
+		pr_err("%s: could not allocate generic chip\n",
+		       node->full_name);
+		irq_domain_remove(rps_data.domain);
+		return -EINVAL;
+	}
+
+	gc = irq_get_domain_generic_chip(rps_data.domain, 0);
+	gc->chip_types[0].chip.irq_ack = rps_ack_irq;
+	gc->chip_types[0].chip.irq_mask = rps_mask_irq;
+	gc->chip_types[0].chip.irq_unmask = rps_unmask_irq;
+
+	/* Disable all IRQs */
+	iowrite32(~0, rps_data.base + RPS_MASK);
+
+	set_handle_irq(handle_irq);
+
+	pr_info("Registered %d rps interrupts\n", RPS_IRQ_COUNT);
+
+	return 0;
+}
+
+IRQCHIP_DECLARE(nas782x, "plxtech,nas782x-rps", rps_of_init);
-- 
1.9.1