[PATCH/RFC 3/6] staging: board: Add support for translating hwirq to virq numbers

[Geert Uytterhoeven <geert+renesas@glider.be>]

As of commit 9a1091ef0017c40a ("irqchip: gic: Support hierarchy irq
domain."), GIC IRQ numbers are virtual, breaking hardcoded hardware IRQ
numbers in platform device resources.

Add support for translating hardware IRQ numbers to virtual IRQ numbers,
and fixing up platform device resources with hardcoded IRQ numbers.

Add a copyright header, including the original author.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/staging/board/board.c | 66 +++++++++++++++++++++++++++++++++++++++++++
 drivers/staging/board/board.h |  5 ++++
 2 files changed, 71 insertions(+)

diff --git a/drivers/staging/board/board.c b/drivers/staging/board/board.c
index d5a6abc845191c93..b84ac2837a20bf06 100644
--- a/drivers/staging/board/board.c
+++ b/drivers/staging/board/board.c
@@ -1,10 +1,27 @@
+/*
+ * Copyright (C) 2014 Magnus Damm
+ * Copyright (C) 2015 Glider bvba
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#define pr_fmt(fmt)	"board_staging: "  fmt
+
 #include <linux/init.h>
+#include <linux/irq.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/of_irq.h>
+
 #include "board.h"
 
+static struct device_node *irqc_node __initdata;
+static unsigned int irqc_base __initdata;
+
 static bool find_by_address(u64 base_address)
 {
 	struct device_node *dn = of_find_all_nodes(NULL);
@@ -38,3 +55,52 @@ bool __init board_staging_dt_node_available(const struct resource *resource,
 
 	return false; /* Nothing found */
 }
+
+int __init board_staging_setup_hwirq_xlate(const char *irqc_match,
+					   unsigned int base)
+{
+	irqc_node = of_find_compatible_node(NULL, NULL, irqc_match);
+
+	WARN_ON(!irqc_node);
+	if (!irqc_node)
+		return -ENOENT;
+
+	irqc_base = base;
+	return 0;
+}
+
+static unsigned int __init xlate_hwirq(unsigned int hwirq)
+{
+	struct of_phandle_args irq_data;
+	unsigned int irq;
+
+	if (!irqc_node)
+		return hwirq;
+
+	irq_data.np = irqc_node;
+	irq_data.args_count = 3;
+	irq_data.args[0] = 0;
+	irq_data.args[1] = hwirq - irqc_base;
+	irq_data.args[2] = IRQ_TYPE_LEVEL_HIGH;
+
+	irq = irq_create_of_mapping(&irq_data);
+	if (WARN_ON(!irq))
+		irq = hwirq;
+
+	return irq;
+}
+
+void __init board_staging_fixup_irq_resources(struct resource *res,
+					      unsigned int nres)
+{
+	unsigned int i;
+
+	for (i = 0; i < nres; i++)
+		if (res[i].flags = IORESOURCE_IRQ) {
+			unsigned int hwirq = res[i].start;
+			unsigned int virq = xlate_hwirq(hwirq);
+
+			pr_debug("hwirq %u -> virq %u\n", hwirq, virq);
+			res[i].start = virq;
+		}
+}
diff --git a/drivers/staging/board/board.h b/drivers/staging/board/board.h
index e9c914985d4acb36..4cedc3c46e287eb7 100644
--- a/drivers/staging/board/board.h
+++ b/drivers/staging/board/board.h
@@ -1,10 +1,15 @@
 #ifndef __BOARD_H__
 #define __BOARD_H__
+
 #include <linux/init.h>
 #include <linux/of.h>
 
+struct resource;
+
 bool board_staging_dt_node_available(const struct resource *resource,
 				     unsigned int num_resources);
+int board_staging_setup_hwirq_xlate(const char *irqc_match, unsigned int base);
+void board_staging_fixup_irq_resources(struct resource *res, unsigned int nres);
 
 #define board_staging(str, fn)			\
 static int __init runtime_board_check(void)	\
-- 
1.9.1