Fixed MTP to work with TWRP

drivers/gud/gud-exynos8890/sec-os-ctrl/Kconfig

@@ -0,0 +1,10 @@
+#
+# Secure OS control configuration
+#
+config SECURE_OS_CONTROL
+	bool "Secure OS control"
+	depends on MOBICORE_DRIVER
+	---help---
+	  Enable Secure OS control sysfs.
+	  It can migrate a core that executes secure OS tasks
+	  and check a current core on secure OS.

drivers/gud/gud-exynos8890/sec-os-ctrl/Makefile

@@ -0,0 +1,11 @@
+#
+# Makefile for Secure OS control sysfs
+#
+obj-$(CONFIG_SECURE_OS_CONTROL) += sec_os_ctrl.o
+
+# MobiCore kernel driver path
+GUD_ROOT_FOLDER := drivers/gud/
+
+# Includes MobiCore kernel driver
+ccflags-y += -I$(GUD_ROOT_FOLDER)/MobiCoreDriver
+ccflags-y += -I$(GUD_ROOT_FOLDER)/MobiCoreDriver/public

drivers/gud/gud-exynos8890/sec-os-ctrl/sec_os_ctrl.c

@@ -0,0 +1,119 @@
+/* drivers/gud/sec-os-ctrl/sec_os_ctrl.c
+ *
+ * Secure OS control driver for Samsung Exynos
+ *
+ * Copyright (c) 2014 Samsung Electronics
+ * http://www.samsungsemi.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/sysfs.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+
+#define DEFAULT_LITTLE_CORE	1
+#define DEFAULT_BIG_CORE	4
+#define ASCII_TO_DIGIT_NUM(ascii)	(ascii - '0')
+
+static unsigned int current_core, new_core;
+static DEFINE_MUTEX(sec_os_ctrl_lock);
+
+int mc_switch_core(uint32_t core_num);
+uint32_t mc_active_core(void);
+
+static struct bus_type sec_os_ctrl_subsys = {
+	.name = "sec_os_ctrl",
+	.dev_name = "sec_os_ctrl",
+};
+
+/* Migrate Secure OS */
+static ssize_t migrate_os_store(struct kobject *kobj,
+		struct kobj_attribute *attr, const char *buf, size_t count)
+{
+	int ret = 0;
+	unsigned int core_num = 0;
+
+	/* Select only big or LITTLE */
+	if ((buf[0] != 'L') && (buf[0] != 'b')) {
+		pr_err("Invalid core number\n");
+		return count;
+	}
+
+	/* Derive core number */
+	core_num = ASCII_TO_DIGIT_NUM(buf[1]);
+	if (buf[0] == 'L') {
+		if ((buf[1] == 0xA) || (buf[1] == 0x0)) {	/* if LF(Line Feed, 0xA) or NULL(0x0) */
+			new_core = DEFAULT_LITTLE_CORE;
+		} else if ((core_num >= 0) && (core_num < 4)) {	/* From core 0 to core 3 */
+			new_core = core_num;
+		} else {
+			pr_err("[LITTLE] Enter correct core number(0~3)\n");
+			return count;
+		}
+	} else if (buf[0] == 'b') {
+		if ((buf[1] == 0xA) || (buf[1] == 0x0)) {	/* if LF(Line Feed, 0xA) or NULL(0x0) */
+			new_core = DEFAULT_BIG_CORE;
+		} else if ((core_num >= 0) && (core_num < 4)) {	/* From core 0 to core 3 */
+			new_core = core_num + 4;
+		} else {
+			pr_err("[big] Enter correct core number(0~3)\n");
+			return count;
+		}
+	}
+	pr_info("Secure OS will be migrated into core [%d]\n", new_core);
+
+	if (mutex_lock_interruptible(&sec_os_ctrl_lock)) {
+		pr_err("Fail to get lock\n");
+		return count;
+	}
+	ret = mc_switch_core(new_core);
+	mutex_unlock(&sec_os_ctrl_lock);
+	if (ret != 0) {
+		pr_err("Secure OS migration is failed!\n");
+		pr_err("Return value = %d\n", ret);
+		return count;
+	}
+
+	return count;
+}
+
+/* The current core where Secure OS is on */
+static ssize_t current_core_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	current_core = mc_active_core();
+
+	return sprintf(buf, "Secure OS is on core [%c%d]\n",
+			(current_core < 4) ? 'L' : 'b', (current_core & 3));
+}
+
+static struct kobj_attribute migrate_os_attr =
+	__ATTR(migrate_os, 0600, NULL, migrate_os_store);
+
+static struct kobj_attribute current_core_attr =
+	__ATTR(current_core, 0600, current_core_show, NULL);
+
+static struct attribute *sec_os_ctrl_sysfs_attrs[] = {
+	&migrate_os_attr.attr,
+	&current_core_attr.attr,
+	NULL,
+};
+
+static struct attribute_group sec_os_ctrl_sysfs_group = {
+	.attrs = sec_os_ctrl_sysfs_attrs,
+};
+
+static const struct attribute_group *sec_os_ctrl_sysfs_groups[] = {
+	&sec_os_ctrl_sysfs_group,
+	NULL,
+};
+
+static int __init sec_os_ctrl_init(void)
+{
+	return subsys_system_register(&sec_os_ctrl_subsys, sec_os_ctrl_sysfs_groups);
+}
+late_initcall(sec_os_ctrl_init);