init

kernel/modules/ec-reboot/Makefile

@@ -0,0 +1,13 @@
+ifneq ($(KERNELRELEASE),)
+obj-m += ec-reboot.o
+ec-reboot-objs := ec_reboot.o
+else
+KERNEL_DIR ?= /lib/modules/$(shell uname -r)/build
+PWD := $(shell pwd)
+
+all:
+	$(MAKE) -C $(KERNEL_DIR) M=$(PWD) modules
+
+clean:
+	$(MAKE) -C $(KERNEL_DIR) M=$(PWD) clean
+endif

kernel/modules/ec-reboot/ec_reboot.c

@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+#include <linux/kobject.h>
+#include <linux/surface_aggregator/controller.h>
+
+static ssize_t reboot_store(struct kobject *kobj, struct kobj_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct ssam_controller *ctrl;
+	struct ssam_request rqst = {};
+	int ret;
+
+	if (count < 1 || buf[0] != '1')
+		return -EINVAL;
+
+	ctrl = ssam_get_controller();
+	if (!ctrl)
+		return -ENODEV;
+
+	rqst.target_category = 0x01;
+	rqst.target_id = 0x01;
+	rqst.command_id = 0x14;
+	rqst.instance_id = 0x00;
+	rqst.flags = 0;
+	rqst.length = 0;
+	rqst.payload = NULL;
+
+	ret = ssam_request_do_sync(ctrl, &rqst, NULL);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static struct kobj_attribute reboot_attr = __ATTR_WO(reboot);
+
+static struct attribute *ec_reboot_attrs[] = {
+	&reboot_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ec_reboot_group = {
+	.attrs = ec_reboot_attrs,
+};
+
+static struct kobject *ec_reboot_kobj;
+
+static int __init ec_reboot_init(void)
+{
+	int ret;
+
+	ec_reboot_kobj = kobject_create_and_add("ec_reboot", kernel_kobj);
+	if (!ec_reboot_kobj)
+		return -ENOMEM;
+
+	ret = sysfs_create_group(ec_reboot_kobj, &ec_reboot_group);
+	if (ret)
+		kobject_put(ec_reboot_kobj);
+
+	return ret;
+}
+
+static void __exit ec_reboot_exit(void)
+{
+	kobject_put(ec_reboot_kobj);
+}
+
+module_init(ec_reboot_init);
+module_exit(ec_reboot_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("EC hard reset via SSAM");