sh: intc: Split up the INTC code.

This splits up the sh intc core in to something more vaguely resembling
a subsystem. Most of the functionality was alread fairly well
compartmentalized, and there were only a handful of interdependencies
that needed to be resolved in the process.

This also serves as future-proofing for the genirq and sparseirq rework,
which will make some of the split out functionality wholly generic,
allowing things to be killed off in place with minimal migration pain.

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

1 files changed, 83 insertions, 0 deletions

diff --git a/drivers/sh/intc/userimask.c b/drivers/sh/intc/userimask.c
new file mode 100644
index 000000000000..e32304b66cf1
--- /dev/null
+++ b/drivers/sh/intc/userimask.c
@@ -0,0 +1,83 @@
+/*
+ * Support for hardware-assisted userspace interrupt masking.
+ *
+ * Copyright (C) 2010  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/errno.h>
+#include <linux/sysdev.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <asm/sizes.h>
+#include "internals.h"
+
+static void __iomem *uimask;
+
+static ssize_t
+show_intc_userimask(struct sysdev_class *cls,
+                    struct sysdev_class_attribute *attr, char *buf)
+{
+        return sprintf(buf, "%d\n", (__raw_readl(uimask) >> 4) & 0xf);
+}
+
+static ssize_t
+store_intc_userimask(struct sysdev_class *cls,
+                     struct sysdev_class_attribute *attr,
+                     const char *buf, size_t count)
+{
+        unsigned long level;
+
+        level = simple_strtoul(buf, NULL, 10);
+
+        /*
+         * Minimal acceptable IRQ levels are in the 2 - 16 range, but
+         * these are chomped so as to not interfere with normal IRQs.
+         *
+         * Level 1 is a special case on some CPUs in that it's not
+         * directly settable, but given that USERIMASK cuts off below a
+         * certain level, we don't care about this limitation here.
+         * Level 0 on the other hand equates to user masking disabled.
+         *
+         * We use the default priority level as a cut off so that only
+         * special case opt-in IRQs can be mangled.
+         */
+        if (level >= intc_get_dfl_prio_level())
+                return -EINVAL;
+
+        __raw_writel(0xa5 << 24 | level << 4, uimask);
+
+        return count;
+}
+
+static SYSDEV_CLASS_ATTR(userimask, S_IRUSR | S_IWUSR,
+                         show_intc_userimask, store_intc_userimask);
+
+
+static int __init userimask_sysdev_init(void)
+{
+        if (unlikely(!uimask))
+                return -ENXIO;
+
+        return sysdev_class_create_file(&intc_sysdev_class, &attr_userimask);
+}
+late_initcall(userimask_sysdev_init);
+
+int register_intc_userimask(unsigned long addr)
+{
+        if (unlikely(uimask))
+                return -EBUSY;
+
+        uimask = ioremap_nocache(addr, SZ_4K);
+        if (unlikely(!uimask))
+                return -ENOMEM;
+
+        pr_info("userimask support registered for levels 0 -> %d\n",
+                intc_get_dfl_prio_level() - 1);
+
+        return 0;
+}