sparc64: vcc: TTY driver initialization and cleanup

Allocate and register TTY driver during module init. Cleanup
TTY driver during module exit.
Signed-off-by: NJagannathan Raman <jag.raman@oracle.com>
Reviewed-by: NLiam Merwick <liam.merwick@oracle.com>
Reviewed-by: NShannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/tty/vcc.c

@@ -4,15 +4,26 @@
  */
 
 #include <linux/module.h>
+#include <linux/tty.h>
 
 #define DRV_MODULE_NAME		"vcc"
 #define DRV_MODULE_VERSION	"1.1"
 #define DRV_MODULE_RELDATE	"July 1, 2017"
 
+static char version[] =
+	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")";
+
 MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_MODULE_VERSION);
 
+#define VCC_MAX_PORTS		1024
+#define VCC_MINOR_START		0	/* must be zero */
+
+static const char vcc_driver_name[] = "vcc";
+static const char vcc_device_node[] = "vcc";
+static struct tty_driver *vcc_tty_driver;
+
 int vcc_dbg;
 int vcc_dbg_ldc;
 int vcc_dbg_vio;
@@ -46,13 +57,83 @@ module_param(vcc_dbg_vio, uint, 0664);
 		}						\
 	} while (0)						\
 
-static int __init vcc_init(void)
+/* Note: Be careful when adding flags to this line discipline.  Don't
+ * add anything that will cause echoing or we'll go into recursive
+ * loop echoing chars back and forth with the console drivers.
+ */
+static struct ktermios vcc_tty_termios = {
+	.c_iflag = IGNBRK | IGNPAR,
+	.c_oflag = OPOST,
+	.c_cflag = B38400 | CS8 | CREAD | HUPCL,
+	.c_cc = INIT_C_CC,
+	.c_ispeed = 38400,
+	.c_ospeed = 38400
+};
+
+static const struct tty_operations vcc_ops;
+
+#define VCC_TTY_FLAGS   (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
+
+static int vcc_tty_init(void)
 {
+	int rv;
+
+	pr_info("VCC: %s\n", version);
+
+	vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
+	if (!vcc_tty_driver) {
+		pr_err("VCC: TTY driver alloc failed\n");
+		return -ENOMEM;
+	}
+
+	vcc_tty_driver->driver_name = vcc_driver_name;
+	vcc_tty_driver->name = vcc_device_node;
+
+	vcc_tty_driver->minor_start = VCC_MINOR_START;
+	vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
+	vcc_tty_driver->init_termios = vcc_tty_termios;
+
+	tty_set_operations(vcc_tty_driver, &vcc_ops);
+
+	rv = tty_register_driver(vcc_tty_driver);
+	if (rv) {
+		pr_err("VCC: TTY driver registration failed\n");
+		put_tty_driver(vcc_tty_driver);
+		vcc_tty_driver = NULL;
+		return rv;
+	}
+
+	vccdbg("VCC: TTY driver registered\n");
+
 	return 0;
 }
 
+static void vcc_tty_exit(void)
+{
+	tty_unregister_driver(vcc_tty_driver);
+	put_tty_driver(vcc_tty_driver);
+	vccdbg("VCC: TTY driver unregistered\n");
+
+	vcc_tty_driver = NULL;
+}
+
+static int __init vcc_init(void)
+{
+	int rv;
+
+	rv = vcc_tty_init();
+	if (rv) {
+		pr_err("VCC: TTY init failed\n");
+		return rv;
+	}
+
+	return rv;
+}
+
 static void __exit vcc_exit(void)
 {
+	vcc_tty_exit();
+	vccdbg("VCC: TTY driver unregistered\n");
 }
 
 module_init(vcc_init);