ARM: Add fiq_glue

Change-Id: I27d2554e07d9de204e0a06696d38db51608d9f6b
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Colin Cross <ccross@android.com>

1 files changed, 92 insertions, 0 deletions

diff --git a/arch/arm/common/fiq_glue_setup.c b/arch/arm/common/fiq_glue_setup.c
new file mode 100644
index 000000000000..f878ea079b4d
--- /dev/null
+++ b/arch/arm/common/fiq_glue_setup.c
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2010 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/percpu.h>
+#include <linux/slab.h>
+#include <asm/fiq.h>
+#include <asm/fiq_glue.h>
+
+extern unsigned char fiq_glue, fiq_glue_end;
+extern void fiq_glue_setup(void *func, void *data, void *sp);
+
+static struct fiq_handler fiq_debbuger_fiq_handler = {
+	.name = "fiq_glue",
+};
+static __percpu void *fiq_stack;
+static struct fiq_glue_handler *current_handler;
+static DEFINE_MUTEX(fiq_glue_lock);
+
+static void fiq_glue_setup_helper(void *info)
+{
+	struct fiq_glue_handler *handler = info;
+	fiq_glue_setup(handler->fiq, handler,
+		__this_cpu_ptr(fiq_stack) + THREAD_START_SP);
+}
+
+int fiq_glue_register_handler(struct fiq_glue_handler *handler)
+{
+	int ret;
+
+	if (!handler || !handler->fiq)
+		return -EINVAL;
+
+	mutex_lock(&fiq_glue_lock);
+	if (fiq_stack) {
+		ret = -EBUSY;
+		goto err_busy;
+	}
+
+	fiq_stack = __alloc_percpu(THREAD_SIZE, L1_CACHE_BYTES);
+	if (WARN_ON(!fiq_stack)) {
+		ret = -ENOMEM;
+		goto err_alloc_fiq_stack;
+	}
+
+	ret = claim_fiq(&fiq_debbuger_fiq_handler);
+	if (WARN_ON(ret))
+		goto err_claim_fiq;
+
+	current_handler = handler;
+	on_each_cpu(fiq_glue_setup_helper, handler, true);
+	set_fiq_handler(&fiq_glue, &fiq_glue_end - &fiq_glue);
+
+err_claim_fiq:
+	if (ret) {
+		free_percpu(fiq_stack);
+		fiq_stack = NULL;
+	}
+err_alloc_fiq_stack:
+err_busy:
+	mutex_unlock(&fiq_glue_lock);
+	return ret;
+}
+
+/**
+ * fiq_glue_resume - Restore fiqs after suspend or low power idle states
+ *
+ * This must be called before calling local_fiq_enable after returning from a
+ * power state where the fiq mode registers were lost. If a driver provided
+ * a resume hook when it registered the handler it will be called.
+ */
+
+void fiq_glue_resume(void)
+{
+	if (!current_handler)
+		return;
+	fiq_glue_setup(current_handler->fiq, current_handler,
+			__this_cpu_ptr(fiq_stack) + THREAD_START_SP);
+	if (current_handler->resume)
+		current_handler->resume(current_handler);
+}
+