[PATCH 3/6] irqchip: irq-mvebu-gicp: new driver for Marvell GICP

This commit adds a simple driver for the Marvell GICP, a hardware unit
that converts memory writes into GIC SPI interrupts. The driver doesn't
do anything but clear all interrupts at boot time, to avoid spurious
interrupts left by the firmware.

The GICP registers are directly written to in hardware by the ICU unit,
which is configured in a separate driver.

Signed-off-by: Thomas Petazzoni <redacted>
---
 drivers/irqchip/Kconfig          |  3 +++
 drivers/irqchip/Makefile         |  1 +
 drivers/irqchip/irq-mvebu-gicp.c | 53 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 57 insertions(+)
 create mode 100644 drivers/irqchip/irq-mvebu-gicp.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 478f8ac..e527ee5 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig

@@ -268,6 +268,9 @@ config IRQ_MXS
 	select IRQ_DOMAIN
 	select STMP_DEVICE
 
+config MVEBU_GICP
+	bool
+
 config MVEBU_ODMI
 	bool
 	select GENERIC_MSI_IRQ_DOMAIN

diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index b64c59b..11eb858 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile

@@ -69,6 +69,7 @@ obj-$(CONFIG_ARCH_SA1100)		+= irq-sa11x0.o
 obj-$(CONFIG_INGENIC_IRQ)		+= irq-ingenic.o
 obj-$(CONFIG_IMX_GPCV2)			+= irq-imx-gpcv2.o
 obj-$(CONFIG_PIC32_EVIC)		+= irq-pic32-evic.o
+obj-$(CONFIG_MVEBU_GICP)		+= irq-mvebu-gicp.o
 obj-$(CONFIG_MVEBU_ODMI)		+= irq-mvebu-odmi.o
 obj-$(CONFIG_MVEBU_PIC)			+= irq-mvebu-pic.o
 obj-$(CONFIG_LS_SCFG_MSI)		+= irq-ls-scfg-msi.o

diff --git a/drivers/irqchip/irq-mvebu-gicp.c b/drivers/irqchip/irq-mvebu-gicp.c
new file mode 100644
index 0000000..4effed4
--- /dev/null
+++ b/drivers/irqchip/irq-mvebu-gicp.c

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2017 Marvell
+ *
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * 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/platform_device.h>
+
+#define GICP_SETSPI_NSR_OFFSET	0x0
+#define GICP_CLRSPI_NSR_OFFSET	0x8
+
+#define GICP_INT_COUNT		128
+
+static int mvebu_gicp_probe(struct platform_device *pdev)
+{
+	void __iomem *regs;
+	struct resource *res;
+	int i;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	regs = ioremap(res->start, resource_size(res));
+	if (!regs)
+		return -ENOMEM;
+
+	for (i = 0; i < GICP_INT_COUNT; i++)
+		writel(i, regs + GICP_CLRSPI_NSR_OFFSET);