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1// SPDX-License-Identifier: GPL-2.0+
2/*
3** mux.c:
4** serial driver for the Mux console found in some PA-RISC servers.
5**
6** (c) Copyright 2002 Ryan Bradetich
7** (c) Copyright 2002 Hewlett-Packard Company
8**
9** This Driver currently only supports the console (port 0) on the MUX.
10** Additional work will be needed on this driver to enable the full
11** functionality of the MUX.
12**
13*/
14
15#include <linux/module.h>
16#include <linux/ioport.h>
17#include <linux/init.h>
18#include <linux/serial.h>
19#include <linux/tty.h>
20#include <linux/tty_flip.h>
21#include <linux/console.h>
22#include <linux/delay.h> /* for udelay */
23#include <linux/device.h>
24#include <linux/io.h>
25#include <asm/irq.h>
26#include <asm/parisc-device.h>
27
28#include <linux/sysrq.h>
29#include <linux/serial_core.h>
30
31#define MUX_OFFSET 0x800
32#define MUX_LINE_OFFSET 0x80
33
34#define MUX_FIFO_SIZE 255
35#define MUX_POLL_DELAY (30 * HZ / 1000)
36
37#define IO_DATA_REG_OFFSET 0x3c
38#define IO_DCOUNT_REG_OFFSET 0x40
39
40#define MUX_EOFIFO(status) ((status & 0xF000) == 0xF000)
41#define MUX_STATUS(status) ((status & 0xF000) == 0x8000)
42#define MUX_BREAK(status) ((status & 0xF000) == 0x2000)
43
44#define MUX_NR 256
45static unsigned int port_cnt __read_mostly;
46struct mux_port {
47 struct uart_port port;
48 int enabled;
49};
50static struct mux_port mux_ports[MUX_NR];
51
52static struct uart_driver mux_driver = {
53 .owner = THIS_MODULE,
54 .driver_name = "ttyB",
55 .dev_name = "ttyB",
56 .major = MUX_MAJOR,
57 .minor = 0,
58 .nr = MUX_NR,
59};
60
61static struct timer_list mux_timer;
62
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)
65
66/**
67 * get_mux_port_count - Get the number of available ports on the Mux.
68 * @dev: The parisc device.
69 *
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
73 * are connected. This function can override the IODC and
74 * return the true port count.
75 */
76static int __init get_mux_port_count(struct parisc_device *dev)
77{
78 int status;
79 u8 iodc_data[32];
80 unsigned long bytecnt;
81
82 /* If this is the built-in Mux for the K-Class (Eole CAP/MUX),
83 * we only need to allocate resources for 1 port since the
84 * other 7 ports are not connected.
85 */
86 if(dev->id.hversion == 0x15)
87 return 1;
88
89 status = pdc_iodc_read(&bytecnt, dev->hpa.start, 0, iodc_data, 32);
90 BUG_ON(status != PDC_OK);
91
92 /* Return the number of ports specified in the iodc data. */
93 return ((((iodc_data)[4] & 0xf0) >> 4) * 8) + 8;
94}
95
96/**
97 * mux_tx_empty - Check if the transmitter fifo is empty.
98 * @port: Ptr to the uart_port.
99 *
100 * This function test if the transmitter fifo for the port
101 * described by 'port' is empty. If it is empty, this function
102 * should return TIOCSER_TEMT, otherwise return 0.
103 */
104static unsigned int mux_tx_empty(struct uart_port *port)
105{
106 return UART_GET_FIFO_CNT(port) ? 0 : TIOCSER_TEMT;
107}
108
109/**
110 * mux_set_mctrl - Set the current state of the modem control inputs.
111 * @ports: Ptr to the uart_port.
112 * @mctrl: Modem control bits.
113 *
114 * The Serial MUX does not support CTS, DCD or DSR so this function
115 * is ignored.
116 */
117static void mux_set_mctrl(struct uart_port *port, unsigned int mctrl)
118{
119}
120
121/**
122 * mux_get_mctrl - Returns the current state of modem control inputs.
123 * @port: Ptr to the uart_port.
124 *
125 * The Serial MUX does not support CTS, DCD or DSR so these lines are
126 * treated as permanently active.
127 */
128static unsigned int mux_get_mctrl(struct uart_port *port)
129{
130 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
131}
132
133/**
134 * mux_stop_tx - Stop transmitting characters.
135 * @port: Ptr to the uart_port.
136 *
137 * The Serial MUX does not support this function.
138 */
139static void mux_stop_tx(struct uart_port *port)
140{
141}
142
143/**
144 * mux_start_tx - Start transmitting characters.
145 * @port: Ptr to the uart_port.
146 *
147 * The Serial Mux does not support this function.
148 */
149static void mux_start_tx(struct uart_port *port)
150{
151}
152
153/**
154 * mux_stop_rx - Stop receiving characters.
155 * @port: Ptr to the uart_port.
156 *
157 * The Serial Mux does not support this function.
158 */
159static void mux_stop_rx(struct uart_port *port)
160{
161}
162
163/**
164 * mux_break_ctl - Control the transmitssion of a break signal.
165 * @port: Ptr to the uart_port.
166 * @break_state: Raise/Lower the break signal.
167 *
168 * The Serial Mux does not support this function.
169 */
170static void mux_break_ctl(struct uart_port *port, int break_state)
171{
172}
173
174static void mux_tx_done(struct uart_port *port)
175{
176 /* FIXME js: really needs to wait? */
177 while (UART_GET_FIFO_CNT(port))
178 udelay(1);
179}
180
181/**
182 * mux_write - Write chars to the mux fifo.
183 * @port: Ptr to the uart_port.
184 *
185 * This function writes all the data from the uart buffer to
186 * the mux fifo.
187 */
188static void mux_write(struct uart_port *port)
189{
190 u8 ch;
191
192 uart_port_tx_limited(port, ch,
193 port->fifosize - UART_GET_FIFO_CNT(port),
194 true,
195 UART_PUT_CHAR(port, ch),
196 mux_tx_done(port));
197}
198
199/**
200 * mux_read - Read chars from the mux fifo.
201 * @port: Ptr to the uart_port.
202 *
203 * This reads all available data from the mux's fifo and pushes
204 * the data to the tty layer.
205 */
206static void mux_read(struct uart_port *port)
207{
208 struct tty_port *tport = &port->state->port;
209 int data;
210 __u32 start_count = port->icount.rx;
211
212 while(1) {
213 data = __raw_readl(port->membase + IO_DATA_REG_OFFSET);
214
215 if (MUX_STATUS(data))
216 continue;
217
218 if (MUX_EOFIFO(data))
219 break;
220
221 port->icount.rx++;
222
223 if (MUX_BREAK(data)) {
224 port->icount.brk++;
225 if(uart_handle_break(port))
226 continue;
227 }
228
229 if (uart_handle_sysrq_char(port, data & 0xffu))
230 continue;
231
232 tty_insert_flip_char(tport, data & 0xFF, TTY_NORMAL);
233 }
234
235 if (start_count != port->icount.rx)
236 tty_flip_buffer_push(tport);
237}
238
239/**
240 * mux_startup - Initialize the port.
241 * @port: Ptr to the uart_port.
242 *
243 * Grab any resources needed for this port and start the
244 * mux timer.
245 */
246static int mux_startup(struct uart_port *port)
247{
248 mux_ports[port->line].enabled = 1;
249 return 0;
250}
251
252/**
253 * mux_shutdown - Disable the port.
254 * @port: Ptr to the uart_port.
255 *
256 * Release any resources needed for the port.
257 */
258static void mux_shutdown(struct uart_port *port)
259{
260 mux_ports[port->line].enabled = 0;
261}
262
263/**
264 * mux_set_termios - Chane port parameters.
265 * @port: Ptr to the uart_port.
266 * @termios: new termios settings.
267 * @old: old termios settings.
268 *
269 * The Serial Mux does not support this function.
270 */
271static void
272mux_set_termios(struct uart_port *port, struct ktermios *termios,
273 const struct ktermios *old)
274{
275}
276
277/**
278 * mux_type - Describe the port.
279 * @port: Ptr to the uart_port.
280 *
281 * Return a pointer to a string constant describing the
282 * specified port.
283 */
284static const char *mux_type(struct uart_port *port)
285{
286 return "Mux";
287}
288
289/**
290 * mux_release_port - Release memory and IO regions.
291 * @port: Ptr to the uart_port.
292 *
293 * Release any memory and IO region resources currently in use by
294 * the port.
295 */
296static void mux_release_port(struct uart_port *port)
297{
298}
299
300/**
301 * mux_request_port - Request memory and IO regions.
302 * @port: Ptr to the uart_port.
303 *
304 * Request any memory and IO region resources required by the port.
305 * If any fail, no resources should be registered when this function
306 * returns, and it should return -EBUSY on failure.
307 */
308static int mux_request_port(struct uart_port *port)
309{
310 return 0;
311}
312
313/**
314 * mux_config_port - Perform port autoconfiguration.
315 * @port: Ptr to the uart_port.
316 * @type: Bitmask of required configurations.
317 *
318 * Perform any autoconfiguration steps for the port. This function is
319 * called if the UPF_BOOT_AUTOCONF flag is specified for the port.
320 * [Note: This is required for now because of a bug in the Serial core.
321 * rmk has already submitted a patch to linus, should be available for
322 * 2.5.47.]
323 */
324static void mux_config_port(struct uart_port *port, int type)
325{
326 port->type = PORT_MUX;
327}
328
329/**
330 * mux_verify_port - Verify the port information.
331 * @port: Ptr to the uart_port.
332 * @ser: Ptr to the serial information.
333 *
334 * Verify the new serial port information contained within serinfo is
335 * suitable for this port type.
336 */
337static int mux_verify_port(struct uart_port *port, struct serial_struct *ser)
338{
339 if(port->membase == NULL)
340 return -EINVAL;
341
342 return 0;
343}
344
345/**
346 * mux_poll - Mux poll function.
347 * @unused: Unused variable
348 *
349 * This function periodically polls the Serial MUX to check for new data.
350 */
351static void mux_poll(struct timer_list *unused)
352{
353 int i;
354
355 for(i = 0; i < port_cnt; ++i) {
356 if(!mux_ports[i].enabled)
357 continue;
358
359 mux_read(&mux_ports[i].port);
360 mux_write(&mux_ports[i].port);
361 }
362
363 mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY);
364}
365
366
367#ifdef CONFIG_SERIAL_MUX_CONSOLE
368static void mux_console_write(struct console *co, const char *s, unsigned count)
369{
370 /* Wait until the FIFO drains. */
371 while(UART_GET_FIFO_CNT(&mux_ports[0].port))
372 udelay(1);
373
374 while(count--) {
375 if(*s == '\n') {
376 UART_PUT_CHAR(&mux_ports[0].port, '\r');
377 }
378 UART_PUT_CHAR(&mux_ports[0].port, *s++);
379 }
380
381}
382
383static int mux_console_setup(struct console *co, char *options)
384{
385 return 0;
386}
387
388static struct console mux_console = {
389 .name = "ttyB",
390 .write = mux_console_write,
391 .device = uart_console_device,
392 .setup = mux_console_setup,
393 .flags = CON_ENABLED | CON_PRINTBUFFER,
394 .index = 0,
395 .data = &mux_driver,
396};
397
398#define MUX_CONSOLE &mux_console
399#else
400#define MUX_CONSOLE NULL
401#endif
402
403static const struct uart_ops mux_pops = {
404 .tx_empty = mux_tx_empty,
405 .set_mctrl = mux_set_mctrl,
406 .get_mctrl = mux_get_mctrl,
407 .stop_tx = mux_stop_tx,
408 .start_tx = mux_start_tx,
409 .stop_rx = mux_stop_rx,
410 .break_ctl = mux_break_ctl,
411 .startup = mux_startup,
412 .shutdown = mux_shutdown,
413 .set_termios = mux_set_termios,
414 .type = mux_type,
415 .release_port = mux_release_port,
416 .request_port = mux_request_port,
417 .config_port = mux_config_port,
418 .verify_port = mux_verify_port,
419};
420
421/**
422 * mux_probe - Determine if the Serial Mux should claim this device.
423 * @dev: The parisc device.
424 *
425 * Deterimine if the Serial Mux should claim this chip (return 0)
426 * or not (return 1).
427 */
428static int __init mux_probe(struct parisc_device *dev)
429{
430 int i, status;
431
432 int port_count = get_mux_port_count(dev);
433 printk(KERN_INFO "Serial mux driver (%d ports) Revision: 0.6\n", port_count);
434
435 dev_set_drvdata(&dev->dev, (void *)(long)port_count);
436 request_mem_region(dev->hpa.start + MUX_OFFSET,
437 port_count * MUX_LINE_OFFSET, "Mux");
438
439 if(!port_cnt) {
440 mux_driver.cons = MUX_CONSOLE;
441
442 status = uart_register_driver(&mux_driver);
443 if(status) {
444 printk(KERN_ERR "Serial mux: Unable to register driver.\n");
445 return 1;
446 }
447 }
448
449 for(i = 0; i < port_count; ++i, ++port_cnt) {
450 struct uart_port *port = &mux_ports[port_cnt].port;
451 port->iobase = 0;
452 port->mapbase = dev->hpa.start + MUX_OFFSET +
453 (i * MUX_LINE_OFFSET);
454 port->membase = ioremap(port->mapbase, MUX_LINE_OFFSET);
455 port->iotype = UPIO_MEM;
456 port->type = PORT_MUX;
457 port->irq = 0;
458 port->uartclk = 0;
459 port->fifosize = MUX_FIFO_SIZE;
460 port->ops = &mux_pops;
461 port->flags = UPF_BOOT_AUTOCONF;
462 port->line = port_cnt;
463 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MUX_CONSOLE);
464
465 spin_lock_init(&port->lock);
466
467 status = uart_add_one_port(&mux_driver, port);
468 BUG_ON(status);
469 }
470
471 return 0;
472}
473
474static void __exit mux_remove(struct parisc_device *dev)
475{
476 int i, j;
477 int port_count = (long)dev_get_drvdata(&dev->dev);
478
479 /* Find Port 0 for this card in the mux_ports list. */
480 for(i = 0; i < port_cnt; ++i) {
481 if(mux_ports[i].port.mapbase == dev->hpa.start + MUX_OFFSET)
482 break;
483 }
484 BUG_ON(i + port_count > port_cnt);
485
486 /* Release the resources associated with each port on the device. */
487 for(j = 0; j < port_count; ++j, ++i) {
488 struct uart_port *port = &mux_ports[i].port;
489
490 uart_remove_one_port(&mux_driver, port);
491 if(port->membase)
492 iounmap(port->membase);
493 }
494
495 release_mem_region(dev->hpa.start + MUX_OFFSET, port_count * MUX_LINE_OFFSET);
496}
497
498/* Hack. This idea was taken from the 8250_gsc.c on how to properly order
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.
502 *
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.
505 */
506static const struct parisc_device_id builtin_mux_tbl[] __initconst = {
507 { HPHW_A_DIRECT, HVERSION_REV_ANY_ID, 0x15, 0x0000D }, /* All K-class */
508 { HPHW_A_DIRECT, HVERSION_REV_ANY_ID, 0x44, 0x0000D }, /* E35, E45, and E55 */
509 { 0, }
510};
511
512static const struct parisc_device_id mux_tbl[] __initconst = {
513 { HPHW_A_DIRECT, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x0000D },
514 { 0, }
515};
516
517MODULE_DEVICE_TABLE(parisc, builtin_mux_tbl);
518MODULE_DEVICE_TABLE(parisc, mux_tbl);
519
520static struct parisc_driver builtin_serial_mux_driver __refdata = {
521 .name = "builtin_serial_mux",
522 .id_table = builtin_mux_tbl,
523 .probe = mux_probe,
524 .remove = __exit_p(mux_remove),
525};
526
527static struct parisc_driver serial_mux_driver __refdata = {
528 .name = "serial_mux",
529 .id_table = mux_tbl,
530 .probe = mux_probe,
531 .remove = __exit_p(mux_remove),
532};
533
534/**
535 * mux_init - Serial MUX initialization procedure.
536 *
537 * Register the Serial MUX driver.
538 */
539static int __init mux_init(void)
540{
541 register_parisc_driver(&builtin_serial_mux_driver);
542 register_parisc_driver(&serial_mux_driver);
543
544 if(port_cnt > 0) {
545 /* Start the Mux timer */
546 timer_setup(&mux_timer, mux_poll, 0);
547 mod_timer(&mux_timer, jiffies + MUX_POLL_DELAY);
548
549#ifdef CONFIG_SERIAL_MUX_CONSOLE
550 register_console(&mux_console);
551#endif
552 }
553
554 return 0;
555}
556
557/**
558 * mux_exit - Serial MUX cleanup procedure.
559 *
560 * Unregister the Serial MUX driver from the tty layer.
561 */
562static void __exit mux_exit(void)
563{
564 /* Delete the Mux timer. */
565 if(port_cnt > 0) {
566 timer_delete_sync(&mux_timer);
567#ifdef CONFIG_SERIAL_MUX_CONSOLE
568 unregister_console(&mux_console);
569#endif
570 }
571
572 unregister_parisc_driver(&builtin_serial_mux_driver);
573 unregister_parisc_driver(&serial_mux_driver);
574 uart_unregister_driver(&mux_driver);
575}
576
577module_init(mux_init);
578module_exit(mux_exit);
579
580MODULE_AUTHOR("Ryan Bradetich");
581MODULE_DESCRIPTION("Serial MUX driver");
582MODULE_LICENSE("GPL");
583MODULE_ALIAS_CHARDEV_MAJOR(MUX_MAJOR);