Add NI_IRQ_RESOLVER

MAINTAINERS

@@ -17699,6 +17699,12 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next
 F:	drivers/mtd/nand/
 F:	include/linux/mtd/*nand*.h
 
+NATIONAL INSTRUMENTS DEVICETREE IRQ RESOLVER
+M:	Alison Montag <[email protected]>
+S:	Maintained
+F:	drivers/misc/niirqresolver.c
+F:	include/linux/niirqresolver.h
+
 NATIONAL INSTRUMENTS SERIAL DRIVER
 M:	Chaitanya Vadrevu <[email protected]>
 L:	[email protected]

arch/arm/configs/nati_bluefin_defconfig

@@ -82,6 +82,7 @@ CONFIG_BLK_DEV_LOOP=y
 CONFIG_BLK_DEV_RAM=y
 CONFIG_BLK_DEV_RAM_SIZE=16384
 CONFIG_SRAM=y
+CONFIG_NI_IRQ_RESOLVER=y
 CONFIG_EEPROM_AT24=y
 CONFIG_EEPROM_AT25=y
 CONFIG_SCSI=y

arch/arm/configs/nati_slsc_defconfig

@@ -71,6 +71,7 @@ CONFIG_BLK_DEV_LOOP=y
 CONFIG_BLK_DEV_RAM=y
 CONFIG_BLK_DEV_RAM_SIZE=16384
 CONFIG_SRAM=y
+CONFIG_NI_IRQ_RESOLVER=y
 CONFIG_EEPROM_AT24=y
 CONFIG_EEPROM_AT25=y
 CONFIG_EEPROM_93CX6=m

arch/arm/configs/nati_zynq_defconfig

@@ -179,6 +179,7 @@ CONFIG_BLK_DEV_RAM_SIZE=16384
 CONFIG_FPGA_PERIPHERAL=y
 CONFIG_NIZYNQ_CPLD=y
 CONFIG_SRAM=y
+CONFIG_NI_IRQ_RESOLVER=y
 CONFIG_EEPROM_AT24=y
 CONFIG_EEPROM_AT25=y
 CONFIG_SCSI=y

drivers/misc/Kconfig

@@ -694,6 +694,16 @@ config NI_WATCHDOG
 
 	  If unsure, say N (but it's safe to say "Y").
 
+config NI_IRQ_RESOLVER
+	bool "NI interrupt resolver"
+	depends on ARCH_ZYNQ
+	help
+	  Resolves the Linux virtual IRQ for the HW interrupts.
+	  Required for NI-RIO Zynq HW on kernels where the
+	  GIC allocates virtual IRQs dynamically.
+
+	  If unsure, say Y on NI-RIO Zynq targets.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"

drivers/misc/Makefile

@@ -79,3 +79,4 @@ obj-$(CONFIG_MISC_RP1)		+= rp1/
 obj-$(CONFIG_NI_RT_FEATURES)	+= nirtfeatures.o
 obj-$(CONFIG_NI_WATCHDOG)	+= niwatchdog.o
 obj-$(CONFIG_FPGA_PERIPHERAL)   += fpgaperipheral.o
+obj-$(CONFIG_NI_IRQ_RESOLVER)	+= niirqresolver.o

drivers/misc/niirqresolver.c

@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic devicetree interrupt specifier -> Linux virq resolver.
+ *
+ * This file has no knowledge of any specific device, board, or interrupt
+ * controller: the caller supplies the controller's devicetree "compatible"
+ * string and its raw, controller-specific interrupt specifier cells (for
+ * example <type, spi-number, trigger-flags> for an ARM GIC).
+ */
+
+#include <linux/export.h>
+#include <linux/niirqresolver.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/types.h>
+
+/**
+ * ni_of_resolve_irq - resolve a Linux virq from a devicetree interrupt specifier
+ * @compatible: devicetree "compatible" string of the interrupt controller node
+ * @args: raw interrupt specifier cells, controller-specific
+ * @args_count: number of valid entries in @args (must not exceed MAX_PHANDLE_ARGS)
+ *
+ * Finds the first devicetree node matching @compatible and asks its
+ * irqdomain to map @args to a Linux virq. Repeated calls with the same
+ * arguments return the same virq.
+ *
+ * Return: the Linux virtual IRQ number, or 0 if it could not be resolved
+ * (no matching node, args_count out of range, or the domain couldn't map it).
+ */
+unsigned int ni_of_resolve_irq(const char *compatible, const unsigned int *args,
+				unsigned int args_count)
+{
+	struct device_node *node;
+	struct of_phandle_args irq_spec;
+	unsigned int virq;
+	unsigned int i;
+
+	if (args_count > MAX_PHANDLE_ARGS)
+		return 0;
+
+	node = of_find_compatible_node(NULL, NULL, compatible);
+	if (!node)
+		return 0;
+
+	irq_spec.np = node;
+	irq_spec.args_count = args_count;
+	for (i = 0; i < args_count; i++)
+		irq_spec.args[i] = args[i];
+
+	virq = irq_create_of_mapping(&irq_spec);
+
+	of_node_put(node);
+
+	return virq;
+}
+EXPORT_SYMBOL(ni_of_resolve_irq);

include/linux/niirqresolver.h

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Generic devicetree interrupt specifier -> Linux virq resolver.
+ *
+ * Public declaration for the NI IRQ resolver implemented in
+ * drivers/misc/niirqresolver.c.
+ */
+
+#ifndef _LINUX_NIIRQRESOLVER_H_
+#define _LINUX_NIIRQRESOLVER_H_
+
+/**
+ * ni_of_resolve_irq - resolve a Linux virq from a devicetree interrupt specifier
+ * @compatible: devicetree "compatible" string of the interrupt controller node
+ * @args: raw interrupt specifier cells, controller-specific
+ * @args_count: number of valid entries in @args (must not exceed MAX_PHANDLE_ARGS)
+ *
+ * Return: the Linux virtual IRQ number, or 0 if it could not be resolved.
+ */
+unsigned int ni_of_resolve_irq(const char *compatible, const unsigned int *args,
+			       unsigned int args_count);
+
+#endif /* _LINUX_NIIRQRESOLVER_H_ */