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.
175  * mux_write - Write chars to the mux fifo.
179  * the mux fifo.
184 	struct circ_buf *xmit = &port->state->xmit;  in mux_write()
186 	if(port->x_char) {  in mux_write()
187 		UART_PUT_CHAR(port, port->x_char);  in mux_write()
188 		port->icount.tx++;  in mux_write()
189 		port->x_char = 0;  in mux_write()
198 	count = (port->fifosize) - UART_GET_FIFO_CNT(port);  in mux_write()
200 		UART_PUT_CHAR(port, xmit->buf[xmit->tail]);  in mux_write()
201 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);  in mux_write()
202 		port->icount.tx++;  in mux_write()
206 	} while(--count > 0);  in mux_write()
219  * mux_read - Read chars from the mux fifo.
222  * This reads all available data from the mux's fifo and pushes
227 	struct tty_port *tport = &port->state->port;  in mux_read()
229 	__u32 start_count = port->icount.rx;  in mux_read()
232 		data = __raw_readl(port->membase + IO_DATA_REG_OFFSET);  in mux_read()
240 		port->icount.rx++;  in mux_read()
243 			port->icount.brk++;  in mux_read()
254 	if (start_count != port->icount.rx)  in mux_read()
259  * mux_startup - Initialize the port.
263  * mux timer.
267 	mux_ports[port->line].enabled = 1;  in mux_startup()
272  * mux_shutdown - Disable the port.
279 	mux_ports[port->line].enabled = 0;  in mux_shutdown()
283  * mux_set_termios - Chane port parameters.
288  * The Serial Mux does not support this function.
297  * mux_type - Describe the port.
305 	return "Mux";  in mux_type()
309  * mux_release_port - Release memory and IO regions.
320  * mux_request_port - Request memory and IO regions.
325  * returns, and it should return -EBUSY on failure.
333  * mux_config_port - Perform port autoconfiguration.
339  * [Note: This is required for now because of a bug in the Serial core.
345 	port->type = PORT_MUX;  in mux_config_port()
349  * mux_verify_port - Verify the port information.
351  * @ser: Ptr to the serial information.
353  * Verify the new serial port information contained within serinfo is
358 	if(port->membase == NULL)  in mux_verify_port()
359 		return -EINVAL;  in mux_verify_port()
365  * mux_drv_poll - Mux poll function.
368  * This function periodically polls the Serial MUX to check for new data.
393 	while(count--) {  in mux_console_write()
441  * mux_probe - Determine if the Serial Mux should claim this device.
444  * Deterimine if the Serial Mux should claim this chip (return 0)
452 	printk(KERN_INFO "Serial mux driver (%d ports) Revision: 0.6\n", port_count);  in mux_probe()
454 	dev_set_drvdata(&dev->dev, (void *)(long)port_count);  in mux_probe()
455 	request_mem_region(dev->hpa.start + MUX_OFFSET,  in mux_probe()
456                            port_count * MUX_LINE_OFFSET, "Mux");  in mux_probe()
463 			printk(KERN_ERR "Serial mux: Unable to register driver.\n");  in mux_probe()
470 		port->iobase	= 0;  in mux_probe()
471 		port->mapbase	= dev->hpa.start + MUX_OFFSET +  in mux_probe()
473 		port->membase	= ioremap(port->mapbase, MUX_LINE_OFFSET);  in mux_probe()
474 		port->iotype	= UPIO_MEM;  in mux_probe()
475 		port->type	= PORT_MUX;  in mux_probe()
476 		port->irq	= 0;  in mux_probe()
477 		port->uartclk	= 0;  in mux_probe()
478 		port->fifosize	= MUX_FIFO_SIZE;  in mux_probe()
479 		port->ops	= &mux_pops;  in mux_probe()
480 		port->flags	= UPF_BOOT_AUTOCONF;  in mux_probe()
481 		port->line	= port_cnt;  in mux_probe()
482 		port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MUX_CONSOLE);  in mux_probe()
484 		/* The port->timeout needs to match what is present in  in mux_probe()
489 		port->timeout   = HZ / 50;  in mux_probe()
490 		spin_lock_init(&port->lock);  in mux_probe()
502 	int port_count = (long)dev_get_drvdata(&dev->dev);  in mux_remove()
506 		if(mux_ports[i].port.mapbase == dev->hpa.start + MUX_OFFSET)  in mux_remove()
516 		if(port->membase)  in mux_remove()
517 			iounmap(port->membase);  in mux_remove()
520 	release_mem_region(dev->hpa.start + MUX_OFFSET, port_count * MUX_LINE_OFFSET);  in mux_remove()
525  * the serial port detection in the proper order.   The idea is we always
526  * want the builtin mux to be detected before addin mux cards, so we
527  * specifically probe for the builtin mux cards first.
529  * This table only contains the parisc_device_id of known builtin mux
530  * devices.  All other mux cards will be detected by the generic mux_tbl.
533 	{ HPHW_A_DIRECT, HVERSION_REV_ANY_ID, 0x15, 0x0000D }, /* All K-class */
561  * mux_init - Serial MUX initialization procedure.
563  * Register the Serial MUX driver.
571 		/* Start the Mux timer */  in mux_init()
584  * mux_exit - Serial MUX cleanup procedure.
586  * Unregister the Serial MUX driver from the tty layer.
590 	/* Delete the Mux timer. */  in mux_exit()
607 MODULE_DESCRIPTION("Serial MUX driver");