sh: intc: initial irqdomain support.

Trivial support for irq domains, using either a linear map or radix tree
depending on the vector layout.

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

1 files changed, 68 insertions, 0 deletions

diff --git a/drivers/sh/intc/irqdomain.c b/drivers/sh/intc/irqdomain.c
new file mode 100644
index 000000000000..3968f1c3c5c3
--- /dev/null
+++ b/drivers/sh/intc/irqdomain.c
@@ -0,0 +1,68 @@
+/*
+ * IRQ domain support for SH INTC subsystem
+ *
+ * Copyright (C) 2012  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.
+ */
+#define pr_fmt(fmt) "intc: " fmt
+
+#include <linux/irqdomain.h>
+#include <linux/sh_intc.h>
+#include <linux/export.h>
+#include "internals.h"
+
+/**
+ * intc_irq_domain_evt_xlate() - Generic xlate for vectored IRQs.
+ *
+ * This takes care of exception vector to hwirq translation through
+ * by way of evt2irq() translation.
+ *
+ * Note: For platforms that use a flat vector space without INTEVT this
+ * basically just mimics irq_domain_xlate_onecell() by way of a nopped
+ * out evt2irq() implementation.
+ */
+static int intc_evt_xlate(struct irq_domain *d, struct device_node *ctrlr,
+                          const u32 *intspec, unsigned int intsize,
+                          unsigned long *out_hwirq, unsigned int *out_type)
+{
+        if (WARN_ON(intsize < 1))
+                return -EINVAL;
+
+        *out_hwirq = evt2irq(intspec[0]);
+        *out_type = IRQ_TYPE_NONE;
+
+        return 0;
+}
+
+static const struct irq_domain_ops intc_evt_ops = {
+        .xlate          = intc_evt_xlate,
+};
+
+void __init intc_irq_domain_init(struct intc_desc_int *d,
+                                 struct intc_hw_desc *hw)
+{
+        unsigned int irq_base, irq_end;
+
+        /*
+         * Quick linear revmap check
+         */
+        irq_base = evt2irq(hw->vectors[0].vect);
+        irq_end = evt2irq(hw->vectors[hw->nr_vectors - 1].vect);
+
+        /*
+         * Linear domains have a hard-wired assertion that IRQs start at
+         * 0 in order to make some performance optimizations. Lamely
+         * restrict the linear case to these conditions here, taking the
+         * tree penalty for linear cases with non-zero hwirq bases.
+         */
+        if (irq_base == 0 && irq_end == (irq_base + hw->nr_vectors - 1))
+                d->domain = irq_domain_add_linear(NULL, hw->nr_vectors,
+                                                  &intc_evt_ops, NULL);
+        else
+                d->domain = irq_domain_add_tree(NULL, &intc_evt_ops, NULL);
+
+        BUG_ON(!d->domain);
+}