winesync: Introduce the winesync driver and character device

drivers/misc/Kconfig

@@ -483,6 +483,17 @@ config OPEN_DICE
 
 	  If unsure, say N.
 
+config WINESYNC
+	tristate "Synchronization primitives for Wine"
+	help
+	  This module provides kernel support for synchronization primitives
+	  used by Wine. It is not a hardware driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called winesync.
+
+	  If unsure, say N.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"

drivers/misc/Makefile

@@ -58,5 +58,6 @@ obj-$(CONFIG_HABANA_AI)		+= habanalabs/
 obj-$(CONFIG_UACCE)		+= uacce/
 obj-$(CONFIG_XILINX_SDFEC)	+= xilinx_sdfec.o
 obj-$(CONFIG_HISI_HIKEY_USB)	+= hisi_hikey_usb.o
+obj-$(CONFIG_WINESYNC)		+= winesync.o
 obj-$(CONFIG_HI6421V600_IRQ)	+= hi6421v600-irq.o
 obj-$(CONFIG_OPEN_DICE)		+= open-dice.o

drivers/misc/winesync.c

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * winesync.c - Kernel driver for Wine synchronization primitives
+ *
+ * Copyright (C) 2021 Zebediah Figura
+ */
+
+#include <linux/fs.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+
+#define WINESYNC_NAME	"winesync"
+
+static int winesync_char_open(struct inode *inode, struct file *file)
+{
+	return nonseekable_open(inode, file);
+}
+
+static int winesync_char_release(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+static long winesync_char_ioctl(struct file *file, unsigned int cmd,
+				unsigned long parm)
+{
+	switch (cmd) {
+	default:
+		return -ENOSYS;
+	}
+}
+
+static const struct file_operations winesync_fops = {
+	.owner		= THIS_MODULE,
+	.open		= winesync_char_open,
+	.release	= winesync_char_release,
+	.unlocked_ioctl	= winesync_char_ioctl,
+	.compat_ioctl	= winesync_char_ioctl,
+	.llseek		= no_llseek,
+};
+
+static struct miscdevice winesync_misc = {
+	.minor		= MISC_DYNAMIC_MINOR,
+	.name		= WINESYNC_NAME,
+	.fops		= &winesync_fops,
+};
+
+static int __init winesync_init(void)
+{
+	return misc_register(&winesync_misc);
+}
+
+static void __exit winesync_exit(void)
+{
+	misc_deregister(&winesync_misc);
+}
+
+module_init(winesync_init);
+module_exit(winesync_exit);
+
+MODULE_AUTHOR("Zebediah Figura");
+MODULE_DESCRIPTION("Kernel driver for Wine synchronization primitives");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("devname:" WINESYNC_NAME);