interconnect: Add debugfs test code

Allow setting constraints from userspace for more convenient testing.

Example usage:
	cd /sys/kernel/debug/interconnect-test/
	echo -n 3 > src_port
	echo -n 53 > dst_port
	echo -n 1 > get
	echo -n 80000000 > avg_bw
	echo -n 90000000 > peak_bw
	echo -n 1 > commit

Change-Id: I8a47c45a8060607470edc870b1eb4245bb7ffc54
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: David Dai <daidavid1@codeaurora.org>
Git-commit: 8b9e75c3e826f6a719ff02fa409f6b9c92aee66c
Git-repo: https://git.linaro.org/people/georgi.djakov/linux.git
Signed-off-by: Georgi Djakov <gdjako@codeaurora.org>

drivers/interconnect/Kconfig

@@ -11,6 +11,16 @@ menuconfig INTERCONNECT
 
 if INTERCONNECT
 
+menuconfig INTERCONNECT_TEST
+	tristate "Debugfs test"
+	depends on DEBUG_FS
+	help
+	  Expose the interconnect API to userspace for testing purposes. This
+	  will create /sys/kernel/debug/interconnect-test to allow requesting
+	  bandwidth between endpoints.
+
+	  If unsure, say no.
+
 source "drivers/interconnect/imx/Kconfig"
 source "drivers/interconnect/qcom/Kconfig"
 source "drivers/interconnect/samsung/Kconfig"

drivers/interconnect/Makefile

@@ -2,8 +2,10 @@
 
 CFLAGS_core.o				:= -I$(src)
 icc-core-objs				:= core.o bulk.o
+icc-test-objs				:= debugfs-test.o
 
 obj-$(CONFIG_INTERCONNECT)		+= icc-core.o
+obj-$(CONFIG_INTERCONNECT_TEST)		+= icc-test.o
 obj-$(CONFIG_INTERCONNECT_IMX)		+= imx/
 obj-$(CONFIG_INTERCONNECT_QCOM)		+= qcom/
 obj-$(CONFIG_INTERCONNECT_SAMSUNG)	+= samsung/

drivers/interconnect/debugfs-test.c

@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2017, Linaro Ltd.
+ *
+ * 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.
+ */
+#ifdef CONFIG_DEBUG_FS
+
+#include <linux/debugfs.h>
+#include <linux/interconnect.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/uaccess.h>
+
+static struct platform_device *icc_pdev;
+static struct dentry *debugfs_dir;
+static struct icc_path *path;
+static u32 src_port;
+static u32 dst_port;
+
+static u32 avg_bw;
+static u32 peak_bw;
+
+static ssize_t get_write_op(struct file *file, char const __user *buf,
+			    size_t count, loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(buf, count, 10, &val);
+	if (ret)
+		return ret;
+
+	path = icc_get(&icc_pdev->dev, src_port, dst_port);
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	*ppos += count;
+
+	return count;
+}
+
+static const struct file_operations get_fops = {
+	.owner = THIS_MODULE,
+	.write = get_write_op
+};
+
+static ssize_t commit_write_op(struct file *file, char const __user *buf,
+			       size_t count, loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(buf, count, 10, &val);
+	if (ret)
+		return ret;
+
+	if (IS_ERR(path))
+		return PTR_ERR(path);
+
+	ret = icc_set_bw(path, avg_bw, peak_bw);
+	if (ret)
+		return ret;
+
+	*ppos += count;
+
+	return count;
+}
+
+static const struct file_operations commit_fops = {
+	.owner = THIS_MODULE,
+	.write = commit_write_op
+};
+
+static void __exit icc_test_exit(void)
+{
+	if (!IS_ERR(path))
+		icc_put(path);
+
+	debugfs_remove_recursive(debugfs_dir);
+	platform_device_del(icc_pdev);
+	platform_device_put(icc_pdev);
+}
+
+static int __init icc_test_init(void)
+{
+	icc_pdev = platform_device_alloc("icc-test", PLATFORM_DEVID_AUTO);
+	platform_device_add(icc_pdev);
+
+	debugfs_dir = debugfs_create_dir("interconnect-test", NULL);
+	if (!debugfs_dir)
+		pr_err("interconnect: error creating debugfs directory\n");
+
+	debugfs_create_u32("src_port", 0600, debugfs_dir, &src_port);
+	debugfs_create_u32("dst_port", 0600, debugfs_dir, &dst_port);
+	debugfs_create_file("get", 0200, debugfs_dir, NULL, &get_fops);
+	debugfs_create_u32("avg_bw", 0600, debugfs_dir, &avg_bw);
+	debugfs_create_u32("peak_bw", 0600, debugfs_dir, &peak_bw);
+	debugfs_create_file("commit", 0200, debugfs_dir, NULL, &commit_fops);
+
+	return 0;
+}
+
+module_init(icc_test_init);
+module_exit(icc_test_exit);
+MODULE_LICENSE("GPL v2");
+
+#endif