1/*
2** mux.c:
3**	serial driver for the Mux console found in some PA-RISC servers.
4**
5**	(c) Copyright 2002 Ryan Bradetich
6**	(c) Copyright 2002 Hewlett-Packard Company
7**
8** This program is free software; you can redistribute it and/or modify
9** it under the terms of the GNU General Public License as published by
10** the Free Software Foundation; either version 2 of the License, or
11** (at your option) any later version.
12**
13** This Driver currently only supports the console (port 0) on the MUX.
14** Additional work will be needed on this driver to enable the full
15** functionality of the MUX.
16**
17*/
18
19#include <linux/module.h>
20#include <linux/tty.h>
21#include <linux/ioport.h>
22#include <linux/init.h>
23#include <linux/serial.h>
24#include <linux/console.h>
25#include <linux/slab.h>
26#include <linux/delay.h> /* for udelay */
27#include <linux/device.h>
28#include <asm/io.h>
29#include <asm/irq.h>
30#include <asm/parisc-device.h>
31
32#ifdef CONFIG_MAGIC_SYSRQ
33#include <linux/sysrq.h>
34#define SUPPORT_SYSRQ
35#endif
36
37#include <linux/serial_core.h>
38
39#define MUX_OFFSET 0x800
40#define MUX_LINE_OFFSET 0x80
41
42#define MUX_FIFO_SIZE 255
43#define MUX_POLL_DELAY (30 * HZ / 1000)
44
45#define IO_DATA_REG_OFFSET 0x3c
46#define IO_DCOUNT_REG_OFFSET 0x40
47
48#define MUX_EOFIFO(status) ((status & 0xF000) == 0xF000)
49#define MUX_STATUS(status) ((status & 0xF000) == 0x8000)
50#define MUX_BREAK(status) ((status & 0xF000) == 0x2000)
51
52#define MUX_NR 256
53static unsigned int port_cnt __read_mostly;
54struct mux_port {
55	struct uart_port port;
56	int enabled;
57};
58static struct mux_port mux_ports[MUX_NR];
59
60static struct uart_driver mux_driver = {
61	.owner = THIS_MODULE,
62	.driver_name = "ttyB",
63	.dev_name = "ttyB",
64	.major = MUX_MAJOR,
65	.minor = 0,
66	.nr = MUX_NR,
67};
68
69static struct timer_list mux_timer;
70
71#define UART_PUT_CHAR(p, c) __raw_writel((c), (p)->membase + IO_DATA_REG_OFFSET)
72#define UART_GET_FIFO_CNT(p) __raw_readl((p)->membase + IO_DCOUNT_REG_OFFSET)
73
74/**
75 * get_mux_port_count - Get the number of available ports on the Mux.
76 * @dev: The parisc device.
77 *
78 * This function is used to determine the number of ports the Mux
79 * supports.  The IODC data reports the number of ports the Mux
80 * can support, but there are cases where not all the Mux ports
81 * are connected.  This function can override the IODC and
82 * return the true port count.
83 */
84static int __init get_mux_port_count(struct parisc_device *dev)
85{
86	int status;
87	u8 iodc_data[32];
88	unsigned long bytecnt;
89
90	/* If this is the built-in Mux for the K-Class (Eole CAP/MUX),
91	 * we only need to allocate resources for 1 port since the
92	 * other 7 ports are not connected.
93	 */
94	if(dev->id.hversion == 0x15)
95		return 1;
96
97	status = pdc_iodc_read(&bytecnt, dev->hpa.start, 0, iodc_data, 32);
98	BUG_ON(status != PDC_OK);
99
100	/* Return the number of ports specified in the iodc data. */
101	return ((((iodc_data)[4] & 0xf0) >> 4) * 8) + 8;
102}
103
104/**
105 * mux_tx_empty - Check if the transmitter fifo is empty.
106 * @port: Ptr to the uart_port.
107 *
108 * This function test if the transmitter fifo for the port
109 * described by 'port' is empty.  If it is empty, this function
110 * should return TIOCSER_TEMT, otherwise return 0.
111 */
112static unsigned int mux_tx_empty(struct uart_port *port)
113{
114	return UART_GET_FIFO_CNT(port) ? 0 : TIOCSER_TEMT;
115}
116
117/**
118 * mux_set_mctrl - Set the current state of the modem control inputs.
119 * @ports: Ptr to the uart_port.
120 * @mctrl: Modem control bits.
121 *
122 * The Serial MUX does not support CTS, DCD or DSR so this function
123 * is ignored.
124 */
125static void mux_set_mctrl(struct uart_port *port, unsigned int mctrl)
126{
127}
128
129/**
130 * mux_get_mctrl - Returns the current state of modem control inputs.
131 * @port: Ptr to the uart_port.
132 *
133 * The Serial MUX does not support CTS, DCD or DSR so these lines are
134 * treated as permanently active.
135 */
136static unsigned int mux_get_mctrl(struct uart_port *port)
137{
138	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
139}
140
141/**
142 * mux_stop_tx - Stop transmitting characters.
143 * @port: Ptr to the uart_port.
144 *
145 * The Serial MUX does not support this function.
146 */
147static void mux_stop_tx(struct uart_port *port)
148{
149}
150
151/**
152 * mux_start_tx - Start transmitting characters.
153 * @port: Ptr to the uart_port.
154 *
155 * The Serial Mux does not support this function.
156 */
157static void mux_start_tx(struct uart_port *port)
158{
159}
160
161/**
162 * mux_stop_rx - Stop receiving characters.
163 * @port: Ptr to the uart_port.
164 *
165 * The Serial Mux does not support this function.
166 */
167static void mux_stop_rx(struct uart_port *port)
168{
169}
170
171/**
172 * mux_enable_ms - Enable modum status interrupts.
173 * @port: Ptr to the uart_port.
174 *
175 * The Serial Mux does not support this function.
176 */
177static void mux_enable_ms(struct uart_port *port)
178{
179}
180
181/**
182 * mux_break_ctl - Control the transmitssion of a break signal.
183 * @port: Ptr to the uart_port.
184 * @break_state: Raise/Lower the break signal.
185 *
186 * The Serial Mux does not support this function.
187 */
188static void mux_break_ctl(struct uart_port *port, int break_state)
189{
190}
191
192/**
193 * mux_write - Write chars to the mux fifo.
194 * @port: Ptr to the uart_port.
195 *
196 * This function writes all the data from the uart buffer to
197 * the mux fifo.
198 */
199static void mux_write(struct uart_port *port)
200{
201	int count;
202	struct circ_buf *xmit = &port->info->xmit;
203
204	if(port->x_char) {
205		UART_PUT_CHAR(port, port->x_char);
206		port->icount.tx++;
207		port->x_char = 0;
208		return;
209	}
210
211	if(uart_circ_empty(xmit) || uart_tx_stopped(port)) {
212		mux_stop_tx(port);
213		return;
214	}
215
216	count = (port->fifosize) - UART_GET_FIFO_CNT(port);
217	do {
218		UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
219		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
220		port->icount.tx++;
221		if(uart_circ_empty(xmit))
222			break;
223
224	} while(--count > 0);
225
226	while(UART_GET_FIFO_CNT(port))
227		udelay(1);
228
229	if(uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
230		uart_write_wakeup(port);
231
232	if (uart_circ_empty(xmit))
233		mux_stop_tx(port);
234}
235
236/**
237 * mux_read - Read chars from the mux fifo.
238 * @port: Ptr to the uart_port.
239 *
240 * This reads all available data from the mux's fifo and pushes
241 * the data to the tty layer.
242 */
243static void mux_read(struct uart_port *port)
244{
245	int data;
246	struct tty_struct *tty = port->info->tty;
247	__u32 start_count = port->icount.rx;
248
249	while(1) {
250		data = __raw_readl(port->membase + IO_DATA_REG_OFFSET);
251
252		if (MUX_STATUS(data))
253			continue;
254
255		if (MUX_EOFIFO(data))
256			break;
257
258		port->icount.rx++;
259
260		if (MUX_BREAK(data)) {
261			port->icount.brk++;
262			if(uart_handle_break(port))
263				continue;
264		}
265
266		if (uart_handle_sysrq_char(port, data & 0xffu))
267			continue;
268
269		tty_insert_flip_char(tty, data & 0xFF, TTY_NORMAL);
270	}
271
272	if (start_count != port->icount.rx) {
273		tty_flip_buffer_push(tty);
274	}
275}
276
277/**
278 * mux_startup - Initialize the port.
279 * @port: Ptr to the uart_port.
280 *
281 * Grab any resources needed for this port and start the
282 * mux timer.
283 */
284static int mux_startup(struct uart_port *port)
285{
286	mux_ports[port->line].enabled = 1;
287	return 0;
288}
289
290/**
291 * mux_shutdown - Disable the port.
292 * @port: Ptr to the uart_port.
293 *
294 * Release any resources needed for the port.
295 */
296static void mux_shutdown(struct uart_port *port)
297{
298	mux_ports[port->line].enabled = 0;
299}
300
301/**
302 * mux_set_termios - Chane port parameters.
303 * @port: Ptr to the uart_port.
304 * @termios: new termios settings.
305 * @old: old termios settings.
306 *
307 * The Serial Mux does not support this function.
308 */
309static void
310mux_set_termios(struct uart_port *port, struct ktermios *termios,
311	        struct ktermios *old)
312{
313}
314
315/**
316 * mux_type - Describe the port.
317 * @port: Ptr to the uart_port.
318 *
319 * Return a pointer to a string constant describing the
320 * specified port.
321 */
322static const char *mux_type(struct uart_port *port)
323{
324	return "Mux";
325}
326
327/**
328 * mux_release_port - Release memory and IO regions.
329 * @port: Ptr to the uart_port.
330 *
331 * Release any memory and IO region resources currently in use by
332 * the port.
333 */
334static void mux_release_port(struct uart_port *port)
335{
336}
337
338/**
339 * mux_request_port - Request memory and IO regions.
340 * @port: Ptr to the uart_port.
341 *
342 * Request any memory and IO region resources required by the port.
343 * If any fail, no resources should be registered when this function
344 * returns, and it should return -EBUSY on failure.
345 */
346static int mux_request_port(struct uart_port *port)
347{
348	return 0;
349}
350
351/**
352 * mux_config_port - Perform port autoconfiguration.
353 * @port: Ptr to the uart_port.
354 * @type: Bitmask of required configurations.
355 *
356 * Perform any autoconfiguration steps for the port.  This function is
357 * called if the UPF_BOOT_AUTOCONF flag is specified for the port.
358 * [Note: This is required for now because of a bug in the Serial core.
359 *  rmk has already submitted a patch to linus, should be available for
360 *  2.5.47.]
361 */
362static void mux_config_port(struct uart_port *port, int type)
363{
364	port->type = PORT_MUX;
365}
366
367/**
368 * mux_verify_port - Verify the port information.
369 * @port: Ptr to the uart_port.
370 * @ser: Ptr to the serial information.
371 *
372 * Verify the new serial port information contained within serinfo is
373 * suitable for this port type.
374 */
375static int mux_verify_port(struct uart_port *port, struct serial_struct *ser)
376{
377	if(port->membase == NULL)
378		return -EINVAL;
379
380	return 0;
381}
382
383/**
384 * mux_drv_poll - Mux poll function.
385 * @unused: Unused variable
386 *
387 * This function periodically polls the Serial MUX to check for new data.
388 */
389static void mux_poll(unsigned long unused)
390{
391	int i;
392
393	for(i = 0; i < port_cnt; ++i) {
394		if(!mux_ports[i].enabled)
395			continue;
396
397		mux_read(&mux_ports[i].port);
398		mux_write(&mux_ports[i].port);
399	}
400
401	mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY);
402}
403
404
405#ifdef CONFIG_SERIAL_MUX_CONSOLE
406static void mux_console_write(struct console *co, const char *s, unsigned count)
407{
408	/* Wait until the FIFO drains. */
409	while(UART_GET_FIFO_CNT(&mux_ports[0].port))
410		udelay(1);
411
412	while(count--) {
413		if(*s == '\n') {
414			UART_PUT_CHAR(&mux_ports[0].port, '\r');
415		}
416		UART_PUT_CHAR(&mux_ports[0].port, *s++);
417	}
418
419}
420
421static int mux_console_setup(struct console *co, char *options)
422{
423        return 0;
424}
425
426struct tty_driver *mux_console_device(struct console *co, int *index)
427{
428        *index = co->index;
429	return mux_driver.tty_driver;
430}
431
432static struct console mux_console = {
433	.name =		"ttyB",
434	.write =	mux_console_write,
435	.device =	mux_console_device,
436	.setup =	mux_console_setup,
437	.flags =	CON_ENABLED | CON_PRINTBUFFER,
438	.index =	0,
439};
440
441#define MUX_CONSOLE	&mux_console
442#else
443#define MUX_CONSOLE	NULL
444#endif
445
446static struct uart_ops mux_pops = {
447	.tx_empty =		mux_tx_empty,
448	.set_mctrl =		mux_set_mctrl,
449	.get_mctrl =		mux_get_mctrl,
450	.stop_tx =		mux_stop_tx,
451	.start_tx =		mux_start_tx,
452	.stop_rx =		mux_stop_rx,
453	.enable_ms =		mux_enable_ms,
454	.break_ctl =		mux_break_ctl,
455	.startup =		mux_startup,
456	.shutdown =		mux_shutdown,
457	.set_termios =		mux_set_termios,
458	.type =			mux_type,
459	.release_port =		mux_release_port,
460	.request_port =		mux_request_port,
461	.config_port =		mux_config_port,
462	.verify_port =		mux_verify_port,
463};
464
465/**
466 * mux_probe - Determine if the Serial Mux should claim this device.
467 * @dev: The parisc device.
468 *
469 * Deterimine if the Serial Mux should claim this chip (return 0)
470 * or not (return 1).
471 */
472static int __init mux_probe(struct parisc_device *dev)
473{
474	int i, status;
475
476	int port_count = get_mux_port_count(dev);
477	printk(KERN_INFO "Serial mux driver (%d ports) Revision: 0.6\n", port_count);
478
479	dev_set_drvdata(&dev->dev, (void *)(long)port_count);
480	request_mem_region(dev->hpa.start + MUX_OFFSET,
481                           port_count * MUX_LINE_OFFSET, "Mux");
482
483	if(!port_cnt) {
484		mux_driver.cons = MUX_CONSOLE;
485
486		status = uart_register_driver(&mux_driver);
487		if(status) {
488			printk(KERN_ERR "Serial mux: Unable to register driver.\n");
489			return 1;
490		}
491	}
492
493	for(i = 0; i < port_count; ++i, ++port_cnt) {
494		struct uart_port *port = &mux_ports[port_cnt].port;
495		port->iobase	= 0;
496		port->mapbase	= dev->hpa.start + MUX_OFFSET +
497						(i * MUX_LINE_OFFSET);
498		port->membase	= ioremap_nocache(port->mapbase, MUX_LINE_OFFSET);
499		port->iotype	= UPIO_MEM;
500		port->type	= PORT_MUX;
501		port->irq	= NO_IRQ;
502		port->uartclk	= 0;
503		port->fifosize	= MUX_FIFO_SIZE;
504		port->ops	= &mux_pops;
505		port->flags	= UPF_BOOT_AUTOCONF;
506		port->line	= port_cnt;
507
508		/* The port->timeout needs to match what is present in
509		 * uart_wait_until_sent in serial_core.c.  Otherwise
510		 * the time spent in msleep_interruptable will be very
511		 * long, causing the appearance of a console hang.
512		 */
513		port->timeout   = HZ / 50;
514		spin_lock_init(&port->lock);
515
516		status = uart_add_one_port(&mux_driver, port);
517		BUG_ON(status);
518	}
519
520	return 0;
521}
522
523static int __devexit mux_remove(struct parisc_device *dev)
524{
525	int i, j;
526	int port_count = (long)dev_get_drvdata(&dev->dev);
527
528	/* Find Port 0 for this card in the mux_ports list. */
529	for(i = 0; i < port_cnt; ++i) {
530		if(mux_ports[i].port.mapbase == dev->hpa.start + MUX_OFFSET)
531			break;
532	}
533	BUG_ON(i + port_count > port_cnt);
534
535	/* Release the resources associated with each port on the device. */
536	for(j = 0; j < port_count; ++j, ++i) {
537		struct uart_port *port = &mux_ports[i].port;
538
539		uart_remove_one_port(&mux_driver, port);
540		if(port->membase)
541			iounmap(port->membase);
542	}
543
544	release_mem_region(dev->hpa.start + MUX_OFFSET, port_count * MUX_LINE_OFFSET);
545	return 0;
546}
547
548/* Hack.  This idea was taken from the 8250_gsc.c on how to properly order
549 * the serial port detection in the proper order.   The idea is we always
550 * want the builtin mux to be detected before addin mux cards, so we
551 * specifically probe for the builtin mux cards first.
552 *
553 * This table only contains the parisc_device_id of known builtin mux
554 * devices.  All other mux cards will be detected by the generic mux_tbl.
555 */
556static struct parisc_device_id builtin_mux_tbl[] = {
557	{ HPHW_A_DIRECT, HVERSION_REV_ANY_ID, 0x15, 0x0000D }, /* All K-class */
558	{ HPHW_A_DIRECT, HVERSION_REV_ANY_ID, 0x44, 0x0000D }, /* E35, E45, and E55 */
559	{ 0, }
560};
561
562static struct parisc_device_id mux_tbl[] = {
563	{ HPHW_A_DIRECT, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x0000D },
564	{ 0, }
565};
566
567MODULE_DEVICE_TABLE(parisc, builtin_mux_tbl);
568MODULE_DEVICE_TABLE(parisc, mux_tbl);
569
570static struct parisc_driver builtin_serial_mux_driver = {
571	.name =		"builtin_serial_mux",
572	.id_table =	builtin_mux_tbl,
573	.probe =	mux_probe,
574	.remove =       __devexit_p(mux_remove),
575};
576
577static struct parisc_driver serial_mux_driver = {
578	.name =		"serial_mux",
579	.id_table =	mux_tbl,
580	.probe =	mux_probe,
581	.remove =       __devexit_p(mux_remove),
582};
583
584/**
585 * mux_init - Serial MUX initalization procedure.
586 *
587 * Register the Serial MUX driver.
588 */
589static int __init mux_init(void)
590{
591	register_parisc_driver(&builtin_serial_mux_driver);
592	register_parisc_driver(&serial_mux_driver);
593
594	if(port_cnt > 0) {
595		/* Start the Mux timer */
596		init_timer(&mux_timer);
597		mux_timer.function = mux_poll;
598		mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY);
599
600#ifdef CONFIG_SERIAL_MUX_CONSOLE
601	        register_console(&mux_console);
602#endif
603	}
604
605	return 0;
606}
607
608/**
609 * mux_exit - Serial MUX cleanup procedure.
610 *
611 * Unregister the Serial MUX driver from the tty layer.
612 */
613static void __exit mux_exit(void)
614{
615	/* Delete the Mux timer. */
616	if(port_cnt > 0) {
617		del_timer(&mux_timer);
618#ifdef CONFIG_SERIAL_MUX_CONSOLE
619		unregister_console(&mux_console);
620#endif
621	}
622
623	unregister_parisc_driver(&builtin_serial_mux_driver);
624	unregister_parisc_driver(&serial_mux_driver);
625	uart_unregister_driver(&mux_driver);
626}
627
628module_init(mux_init);
629module_exit(mux_exit);
630
631MODULE_AUTHOR("Ryan Bradetich");
632MODULE_DESCRIPTION("Serial MUX driver");
633MODULE_LICENSE("GPL");
634MODULE_ALIAS_CHARDEV_MAJOR(MUX_MAJOR);
635