sh: x3proto: ILSEL IRQ support.

This adds functionality for the on-board ILSEL IRQs that chain
IRL mode events. Many on-board devices (ethernet, usb, etc.) rely
on ILSEL IRQs directly.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 152 insertions, 1 deletions

diff --git a/arch/sh/boards/renesas/x3proto/Makefile b/arch/sh/boards/renesas/x3proto/Makefile
index 2b9dba458932..983e4551fecf 100644
--- a/arch/sh/boards/renesas/x3proto/Makefile
+++ b/arch/sh/boards/renesas/x3proto/Makefile
@@ -1 +1 @@
-obj-y += setup.o
+obj-y += setup.o ilsel.o
diff --git a/arch/sh/boards/renesas/x3proto/ilsel.c b/arch/sh/boards/renesas/x3proto/ilsel.c
new file mode 100644
index 000000000000..ff9c7edf1b6f
--- /dev/null
+++ b/arch/sh/boards/renesas/x3proto/ilsel.c
@@ -0,0 +1,151 @@
+/*
+ * arch/sh/boards/renesas/x3proto/ilsel.c
+ *
+ * Helper routines for SH-X3 proto board ILSEL.
+ *
+ * Copyright (C) 2007 Paul Mundt
+ *
+ * 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.
+ */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bitmap.h>
+#include <linux/io.h>
+#include <asm/ilsel.h>
+
+/*
+ * ILSEL is split across:
+ *
+ *	ILSEL0 - 0xb8100004 [ Levels  1 -  4 ]
+ *	ILSEL1 - 0xb8100006 [ Levels  5 -  8 ]
+ *	ILSEL2 - 0xb8100008 [ Levels  9 - 12 ]
+ *	ILSEL3 - 0xb810000a [ Levels 13 - 15 ]
+ *
+ * With each level being relative to an ilsel_source_t.
+ */
+#define ILSEL_BASE	0xb8100004
+#define ILSEL_LEVELS	15
+
+/*
+ * ILSEL level map, in descending order from the highest level down.
+ *
+ * Supported levels are 1 - 15 spread across ILSEL0 - ILSEL4, mapping
+ * directly to IRLs. As the IRQs are numbered in reverse order relative
+ * to the interrupt level, the level map is carefully managed to ensure a
+ * 1:1 mapping between the bit position and the IRQ number.
+ *
+ * This careful constructions allows ilsel_enable*() to be referenced
+ * directly for hooking up an ILSEL set and getting back an IRQ which can
+ * subsequently be used for internal accounting in the (optional) disable
+ * path.
+ */
+static unsigned long ilsel_level_map;
+
+static inline unsigned int ilsel_offset(unsigned int bit)
+{
+	return ILSEL_LEVELS - bit - 1;
+}
+
+static inline unsigned long mk_ilsel_addr(unsigned int bit)
+{
+	return ILSEL_BASE + ((ilsel_offset(bit) >> 1) & ~0x1);
+}
+
+static inline unsigned int mk_ilsel_shift(unsigned int bit)
+{
+	return (ilsel_offset(bit) & 0x3) << 2;
+}
+
+static void __ilsel_enable(ilsel_source_t set, unsigned int bit)
+{
+	unsigned int tmp, shift;
+	unsigned long addr;
+
+	addr = mk_ilsel_addr(bit);
+	shift = mk_ilsel_shift(bit);
+
+	pr_debug("%s: bit#%d: addr - 0x%08lx (shift %d, set %d)\n",
+		 __FUNCTION__, bit, addr, shift, set);
+
+	tmp = ctrl_inw(addr);
+	tmp &= ~(0xf << shift);
+	tmp |= set << shift;
+	ctrl_outw(tmp, addr);
+}
+
+/**
+ * ilsel_enable - Enable an ILSEL set.
+ * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h).
+ *
+ * Enables a given non-aliased ILSEL source (<= ILSEL_KEY) at the highest
+ * available interrupt level. Callers should take care to order callsites
+ * noting descending interrupt levels. Aliasing FPGA and external board
+ * IRQs need to use ilsel_enable_fixed().
+ *
+ * The return value is an IRQ number that can later be taken down with
+ * ilsel_disable().
+ */
+int ilsel_enable(ilsel_source_t set)
+{
+	unsigned int bit;
+
+	/* Aliased sources must use ilsel_enable_fixed() */
+	BUG_ON(set > ILSEL_KEY);
+
+	do {
+		bit = find_first_zero_bit(&ilsel_level_map, ILSEL_LEVELS);
+	} while (test_and_set_bit(bit, &ilsel_level_map));
+
+	__ilsel_enable(set, bit);
+
+	return bit;
+}
+EXPORT_SYMBOL_GPL(ilsel_enable);
+
+/**
+ * ilsel_enable_fixed - Enable an ILSEL set at a fixed interrupt level
+ * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h).
+ * @level: Interrupt level (1 - 15)
+ *
+ * Enables a given ILSEL source at a fixed interrupt level. Necessary
+ * both for level reservation as well as for aliased sources that only
+ * exist on special ILSEL#s.
+ *
+ * Returns an IRQ number (as ilsel_enable()).
+ */
+int ilsel_enable_fixed(ilsel_source_t set, unsigned int level)
+{
+	unsigned int bit = ilsel_offset(level - 1);
+
+	if (test_and_set_bit(bit, &ilsel_level_map))
+		return -EBUSY;
+
+	__ilsel_enable(set, bit);
+
+	return bit;
+}
+EXPORT_SYMBOL_GPL(ilsel_enable_fixed);
+
+/**
+ * ilsel_disable - Disable an ILSEL set
+ * @irq: Bit position for ILSEL set value (retval from enable routines)
+ *
+ * Disable a previously enabled ILSEL set.
+ */
+void ilsel_disable(unsigned int irq)
+{
+	unsigned long addr;
+	unsigned int tmp;
+
+	addr = mk_ilsel_addr(bit);
+
+	tmp = ctrl_inw(addr);
+	tmp &= ~(0xf << mk_ilsel_shift(bit));
+	ctrl_outw(tmp, addr);
+
+	clear_bit(bit, &ilsel_level_map);
+}
+EXPORT_SYMBOL_GPL(ilsel_disable);