drivers/tty/ehv_bytechan.c

2 /* ePAPR hypervisor byte channel device driver
8  * This driver support three distinct interfaces, all of which are related to
11  * 1) An early-console (udbg) driver.  This provides early console output
15  * 2) A normal console driver.  Output is sent to the byte channel designated
16  * for stdout in the device tree.  The console driver is for handling kernel
19  * 3) A tty driver, which is used to handle user-space input and output.  The
336 	pr_info("ehv-bc: registered console driver for byte channel %u\n",
537  * This is actually a contract between the driver and the tty layer outlining
538  * how much write room the driver can guarantee will be sent OR BUFFERED.  This
539  * driver MUST honor the return value.
558  * so the driver should stop sending it data.  The easiest way to do this is to
577  * tty layer's input buffers now have more room, so the driver can resume
599  * TTY driver operations
741 	.driver = {
750  * ehv_bc_init - ePAPR hypervisor byte channel driver initialization
752  * This function is called when this driver is loaded.
756 	struct tty_driver *driver;
761 	pr_info("ePAPR hypervisor byte channel driver\n");
779 	driver = tty_alloc_driver(count, TTY_DRIVER_REAL_RAW |
781 	if (IS_ERR(driver)) {
782 		ret = PTR_ERR(driver);
786 	driver->driver_name = "ehv-bc";
787 	driver->name = ehv_bc_console.name;
788 	driver->type = TTY_DRIVER_TYPE_CONSOLE;
789 	driver->subtype = SYSTEM_TYPE_CONSOLE;
790 	driver->init_termios = tty_std_termios;
791 	tty_set_operations(driver, &ehv_bc_ops);
793 	ret = tty_register_driver(driver);
795 		pr_err("ehv-bc: could not register tty driver (ret=%i)\n", ret);
799 	ehv_bc_driver = driver;
803 		pr_err("ehv-bc: could not register platform driver (ret=%i)\n",
812 	tty_unregister_driver(driver);
814 	tty_driver_kref_put(driver);