1 // SPDX-License-Identifier: GPL-2.0+
3 ** mux.c:
4 **	serial driver for the Mux console found in some PA-RISC servers.
7 **	(c) Copyright 2002 Hewlett-Packard Company
9 ** This Driver currently only supports the console (port 0) on the MUX.
11 ** functionality of the MUX.
18 #include <linux/serial.h>
26 #include <asm/parisc-device.h>
63 #define UART_PUT_CHAR(p, c) __raw_writel((c), (p)->membase + IO_DATA_REG_OFFSET)
64 #define UART_GET_FIFO_CNT(p) __raw_readl((p)->membase + IO_DCOUNT_REG_OFFSET)
67  * get_mux_port_count - Get the number of available ports on the Mux.
70  * This function is used to determine the number of ports the Mux
71  * supports.  The IODC data reports the number of ports the Mux
72  * can support, but there are cases where not all the Mux ports
82 	/* If this is the built-in Mux for the K-Class (Eole CAP/MUX),  in get_mux_port_count()
86 	if(dev->id.hversion == 0x15)  in get_mux_port_count()
89 	status = pdc_iodc_read(&bytecnt, dev->hpa.start, 0, iodc_data, 32);  in get_mux_port_count()
97  * mux_tx_empty - Check if the transmitter fifo is empty.
110  * mux_set_mctrl - Set the current state of the modem control inputs.
114  * The Serial MUX does not support CTS, DCD or DSR so this function
122  * mux_get_mctrl - Returns the current state of modem control inputs.
125  * The Serial MUX does not support CTS, DCD or DSR so these lines are
134  * mux_stop_tx - Stop transmitting characters.
137  * The Serial MUX does not support this function.
144  * mux_start_tx - Start transmitting characters.
147  * The Serial Mux does not support this function.
154  * mux_stop_rx - Stop receiving characters.
157  * The Serial Mux does not support this function.
164  * mux_break_ctl - Control the transmitssion of a break signal.
168  * The Serial Mux does not support this function.
182  * mux_write - Write chars to the mux fifo.
186  * the mux fifo.
193 		port->fifosize - UART_GET_FIFO_CNT(port),  in mux_write()
200  * mux_read - Read chars from the mux fifo.
203  * This reads all available data from the mux's fifo and pushes
208 	struct tty_port *tport = &port->state->port;  in mux_read()
210 	__u32 start_count = port->icount.rx;  in mux_read()
213 		data = __raw_readl(port->membase + IO_DATA_REG_OFFSET);  in mux_read()
221 		port->icount.rx++;  in mux_read()
224 			port->icount.brk++;  in mux_read()
235 	if (start_count != port->icount.rx)  in mux_read()
240  * mux_startup - Initialize the port.
244  * mux timer.
248 	mux_ports[port->line].enabled = 1;  in mux_startup()
253  * mux_shutdown - Disable the port.
260 	mux_ports[port->line].enabled = 0;  in mux_shutdown()
264  * mux_set_termios - Chane port parameters.
269  * The Serial Mux does not support this function.
278  * mux_type - Describe the port.
286 	return "Mux";  in mux_type()
290  * mux_release_port - Release memory and IO regions.
301  * mux_request_port - Request memory and IO regions.
306  * returns, and it should return -EBUSY on failure.
314  * mux_config_port - Perform port autoconfiguration.
320  * [Note: This is required for now because of a bug in the Serial core.
326 	port->type = PORT_MUX;  in mux_config_port()
330  * mux_verify_port - Verify the port information.
332  * @ser: Ptr to the serial information.
334  * Verify the new serial port information contained within serinfo is
339 	if(port->membase == NULL)  in mux_verify_port()
340 		return -EINVAL;  in mux_verify_port()
346  * mux_drv_poll - Mux poll function.
349  * This function periodically polls the Serial MUX to check for new data.
374 	while(count--) {  in mux_console_write()
422  * mux_probe - Determine if the Serial Mux should claim this device.
425  * Deterimine if the Serial Mux should claim this chip (return 0)
433 	printk(KERN_INFO "Serial mux driver (%d ports) Revision: 0.6\n", port_count);  in mux_probe()
435 	dev_set_drvdata(&dev->dev, (void *)(long)port_count);  in mux_probe()
436 	request_mem_region(dev->hpa.start + MUX_OFFSET,  in mux_probe()
437                            port_count * MUX_LINE_OFFSET, "Mux");  in mux_probe()
444 			printk(KERN_ERR "Serial mux: Unable to register driver.\n");  in mux_probe()
451 		port->iobase	= 0;  in mux_probe()
452 		port->mapbase	= dev->hpa.start + MUX_OFFSET +  in mux_probe()
454 		port->membase	= ioremap(port->mapbase, MUX_LINE_OFFSET);  in mux_probe()
455 		port->iotype	= UPIO_MEM;  in mux_probe()
456 		port->type	= PORT_MUX;  in mux_probe()
457 		port->irq	= 0;  in mux_probe()
458 		port->uartclk	= 0;  in mux_probe()
459 		port->fifosize	= MUX_FIFO_SIZE;  in mux_probe()
460 		port->ops	= &mux_pops;  in mux_probe()
461 		port->flags	= UPF_BOOT_AUTOCONF;  in mux_probe()
462 		port->line	= port_cnt;  in mux_probe()
463 		port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MUX_CONSOLE);  in mux_probe()
465 		spin_lock_init(&port->lock);  in mux_probe()
477 	int port_count = (long)dev_get_drvdata(&dev->dev);  in mux_remove()
481 		if(mux_ports[i].port.mapbase == dev->hpa.start + MUX_OFFSET)  in mux_remove()
491 		if(port->membase)  in mux_remove()
492 			iounmap(port->membase);  in mux_remove()
495 	release_mem_region(dev->hpa.start + MUX_OFFSET, port_count * MUX_LINE_OFFSET);  in mux_remove()
499  * the serial port detection in the proper order.   The idea is we always
500  * want the builtin mux to be detected before addin mux cards, so we
501  * specifically probe for the builtin mux cards first.
503  * This table only contains the parisc_device_id of known builtin mux
504  * devices.  All other mux cards will be detected by the generic mux_tbl.
507 	{ HPHW_A_DIRECT, HVERSION_REV_ANY_ID, 0x15, 0x0000D }, /* All K-class */
535  * mux_init - Serial MUX initialization procedure.
537  * Register the Serial MUX driver.
545 		/* Start the Mux timer */  in mux_init()
558  * mux_exit - Serial MUX cleanup procedure.
560  * Unregister the Serial MUX driver from the tty layer.
564 	/* Delete the Mux timer. */  in mux_exit()
581 MODULE_DESCRIPTION("Serial MUX driver");