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