xref: /openbmc/linux/sound/drivers/serial-u16550.c (revision 95e9fd10)
1 /*
2  *   serial.c
3  *   Copyright (c) by Jaroslav Kysela <perex@perex.cz>,
4  *                    Isaku Yamahata <yamahata@private.email.ne.jp>,
5  *		      George Hansper <ghansper@apana.org.au>,
6  *		      Hannu Savolainen
7  *
8  *   This code is based on the code from ALSA 0.5.9, but heavily rewritten.
9  *
10  *   This program is free software; you can redistribute it and/or modify
11  *   it under the terms of the GNU General Public License as published by
12  *   the Free Software Foundation; either version 2 of the License, or
13  *   (at your option) any later version.
14  *
15  *   This program is distributed in the hope that it will be useful,
16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *   GNU General Public License for more details.
19  *
20  *   You should have received a copy of the GNU General Public License
21  *   along with this program; if not, write to the Free Software
22  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
23  *
24  * Sat Mar 31 17:27:57 PST 2001 tim.mann@compaq.com
25  *      Added support for the Midiator MS-124T and for the MS-124W in
26  *      Single Addressed (S/A) or Multiple Burst (M/B) mode, with
27  *      power derived either parasitically from the serial port or
28  *      from a separate power supply.
29  *
30  *      More documentation can be found in serial-u16550.txt.
31  */
32 
33 #include <linux/init.h>
34 #include <linux/interrupt.h>
35 #include <linux/err.h>
36 #include <linux/platform_device.h>
37 #include <linux/slab.h>
38 #include <linux/ioport.h>
39 #include <linux/module.h>
40 #include <sound/core.h>
41 #include <sound/rawmidi.h>
42 #include <sound/initval.h>
43 
44 #include <linux/serial_reg.h>
45 #include <linux/jiffies.h>
46 
47 #include <asm/io.h>
48 
49 MODULE_DESCRIPTION("MIDI serial u16550");
50 MODULE_LICENSE("GPL");
51 MODULE_SUPPORTED_DEVICE("{{ALSA, MIDI serial u16550}}");
52 
53 #define SNDRV_SERIAL_SOUNDCANVAS 0 /* Roland Soundcanvas; F5 NN selects part */
54 #define SNDRV_SERIAL_MS124T 1      /* Midiator MS-124T */
55 #define SNDRV_SERIAL_MS124W_SA 2   /* Midiator MS-124W in S/A mode */
56 #define SNDRV_SERIAL_MS124W_MB 3   /* Midiator MS-124W in M/B mode */
57 #define SNDRV_SERIAL_GENERIC 4     /* Generic Interface */
58 #define SNDRV_SERIAL_MAX_ADAPTOR SNDRV_SERIAL_GENERIC
59 static char *adaptor_names[] = {
60 	"Soundcanvas",
61         "MS-124T",
62 	"MS-124W S/A",
63 	"MS-124W M/B",
64 	"Generic"
65 };
66 
67 #define SNDRV_SERIAL_NORMALBUFF 0 /* Normal blocking buffer operation */
68 #define SNDRV_SERIAL_DROPBUFF   1 /* Non-blocking discard operation */
69 
70 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
71 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
72 static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE; /* Enable this card */
73 static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT; /* 0x3f8,0x2f8,0x3e8,0x2e8 */
74 static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ; 	/* 3,4,5,7,9,10,11,14,15 */
75 static int speed[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 38400}; /* 9600,19200,38400,57600,115200 */
76 static int base[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 115200}; /* baud base */
77 static int outs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};	 /* 1 to 16 */
78 static int ins[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};	/* 1 to 16 */
79 static int adaptor[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = SNDRV_SERIAL_SOUNDCANVAS};
80 static bool droponfull[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS -1)] = SNDRV_SERIAL_NORMALBUFF };
81 
82 module_param_array(index, int, NULL, 0444);
83 MODULE_PARM_DESC(index, "Index value for Serial MIDI.");
84 module_param_array(id, charp, NULL, 0444);
85 MODULE_PARM_DESC(id, "ID string for Serial MIDI.");
86 module_param_array(enable, bool, NULL, 0444);
87 MODULE_PARM_DESC(enable, "Enable UART16550A chip.");
88 module_param_array(port, long, NULL, 0444);
89 MODULE_PARM_DESC(port, "Port # for UART16550A chip.");
90 module_param_array(irq, int, NULL, 0444);
91 MODULE_PARM_DESC(irq, "IRQ # for UART16550A chip.");
92 module_param_array(speed, int, NULL, 0444);
93 MODULE_PARM_DESC(speed, "Speed in bauds.");
94 module_param_array(base, int, NULL, 0444);
95 MODULE_PARM_DESC(base, "Base for divisor in bauds.");
96 module_param_array(outs, int, NULL, 0444);
97 MODULE_PARM_DESC(outs, "Number of MIDI outputs.");
98 module_param_array(ins, int, NULL, 0444);
99 MODULE_PARM_DESC(ins, "Number of MIDI inputs.");
100 module_param_array(droponfull, bool, NULL, 0444);
101 MODULE_PARM_DESC(droponfull, "Flag to enable drop-on-full buffer mode");
102 
103 module_param_array(adaptor, int, NULL, 0444);
104 MODULE_PARM_DESC(adaptor, "Type of adaptor.");
105 
106 /*#define SNDRV_SERIAL_MS124W_MB_NOCOMBO 1*/  /* Address outs as 0-3 instead of bitmap */
107 
108 #define SNDRV_SERIAL_MAX_OUTS	16		/* max 64, min 16 */
109 #define SNDRV_SERIAL_MAX_INS	16		/* max 64, min 16 */
110 
111 #define TX_BUFF_SIZE		(1<<15)		/* Must be 2^n */
112 #define TX_BUFF_MASK		(TX_BUFF_SIZE - 1)
113 
114 #define SERIAL_MODE_NOT_OPENED 		(0)
115 #define SERIAL_MODE_INPUT_OPEN		(1 << 0)
116 #define SERIAL_MODE_OUTPUT_OPEN		(1 << 1)
117 #define SERIAL_MODE_INPUT_TRIGGERED	(1 << 2)
118 #define SERIAL_MODE_OUTPUT_TRIGGERED	(1 << 3)
119 
120 struct snd_uart16550 {
121 	struct snd_card *card;
122 	struct snd_rawmidi *rmidi;
123 	struct snd_rawmidi_substream *midi_output[SNDRV_SERIAL_MAX_OUTS];
124 	struct snd_rawmidi_substream *midi_input[SNDRV_SERIAL_MAX_INS];
125 
126 	int filemode;		/* open status of file */
127 
128 	spinlock_t open_lock;
129 
130 	int irq;
131 
132 	unsigned long base;
133 	struct resource *res_base;
134 
135 	unsigned int speed;
136 	unsigned int speed_base;
137 	unsigned char divisor;
138 
139 	unsigned char old_divisor_lsb;
140 	unsigned char old_divisor_msb;
141 	unsigned char old_line_ctrl_reg;
142 
143 	/* parameter for using of write loop */
144 	short int fifo_limit;	/* used in uart16550 */
145         short int fifo_count;	/* used in uart16550 */
146 
147 	/* type of adaptor */
148 	int adaptor;
149 
150 	/* inputs */
151 	int prev_in;
152 	unsigned char rstatus;
153 
154 	/* outputs */
155 	int prev_out;
156 	unsigned char prev_status[SNDRV_SERIAL_MAX_OUTS];
157 
158 	/* write buffer and its writing/reading position */
159 	unsigned char tx_buff[TX_BUFF_SIZE];
160 	int buff_in_count;
161         int buff_in;
162         int buff_out;
163         int drop_on_full;
164 
165 	/* wait timer */
166 	unsigned int timer_running:1;
167 	struct timer_list buffer_timer;
168 
169 };
170 
171 static struct platform_device *devices[SNDRV_CARDS];
172 
173 static inline void snd_uart16550_add_timer(struct snd_uart16550 *uart)
174 {
175 	if (!uart->timer_running) {
176 		/* timer 38600bps * 10bit * 16byte */
177 		uart->buffer_timer.expires = jiffies + (HZ+255)/256;
178 		uart->timer_running = 1;
179 		add_timer(&uart->buffer_timer);
180 	}
181 }
182 
183 static inline void snd_uart16550_del_timer(struct snd_uart16550 *uart)
184 {
185 	if (uart->timer_running) {
186 		del_timer(&uart->buffer_timer);
187 		uart->timer_running = 0;
188 	}
189 }
190 
191 /* This macro is only used in snd_uart16550_io_loop */
192 static inline void snd_uart16550_buffer_output(struct snd_uart16550 *uart)
193 {
194 	unsigned short buff_out = uart->buff_out;
195 	if (uart->buff_in_count > 0) {
196 		outb(uart->tx_buff[buff_out], uart->base + UART_TX);
197 		uart->fifo_count++;
198 		buff_out++;
199 		buff_out &= TX_BUFF_MASK;
200 		uart->buff_out = buff_out;
201 		uart->buff_in_count--;
202 	}
203 }
204 
205 /* This loop should be called with interrupts disabled
206  * We don't want to interrupt this,
207  * as we're already handling an interrupt
208  */
209 static void snd_uart16550_io_loop(struct snd_uart16550 * uart)
210 {
211 	unsigned char c, status;
212 	int substream;
213 
214 	/* recall previous stream */
215 	substream = uart->prev_in;
216 
217 	/* Read Loop */
218 	while ((status = inb(uart->base + UART_LSR)) & UART_LSR_DR) {
219 		/* while receive data ready */
220 		c = inb(uart->base + UART_RX);
221 
222 		/* keep track of last status byte */
223 		if (c & 0x80)
224 			uart->rstatus = c;
225 
226 		/* handle stream switch */
227 		if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
228 			if (uart->rstatus == 0xf5) {
229 				if (c <= SNDRV_SERIAL_MAX_INS && c > 0)
230 					substream = c - 1;
231 				if (c != 0xf5)
232 					/* prevent future bytes from being
233 					   interpreted as streams */
234 					uart->rstatus = 0;
235 			} else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN)
236 				   && uart->midi_input[substream])
237 				snd_rawmidi_receive(uart->midi_input[substream],
238 						    &c, 1);
239 		} else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN) &&
240 			   uart->midi_input[substream])
241 			snd_rawmidi_receive(uart->midi_input[substream], &c, 1);
242 
243 		if (status & UART_LSR_OE)
244 			snd_printk(KERN_WARNING
245 				   "%s: Overrun on device at 0x%lx\n",
246 			       uart->rmidi->name, uart->base);
247 	}
248 
249 	/* remember the last stream */
250 	uart->prev_in = substream;
251 
252 	/* no need of check SERIAL_MODE_OUTPUT_OPEN because if not,
253 	   buffer is never filled. */
254 	/* Check write status */
255 	if (status & UART_LSR_THRE)
256 		uart->fifo_count = 0;
257 	if (uart->adaptor == SNDRV_SERIAL_MS124W_SA
258 	   || uart->adaptor == SNDRV_SERIAL_GENERIC) {
259 		/* Can't use FIFO, must send only when CTS is true */
260 		status = inb(uart->base + UART_MSR);
261 		while (uart->fifo_count == 0 && (status & UART_MSR_CTS) &&
262 		       uart->buff_in_count > 0) {
263 		       snd_uart16550_buffer_output(uart);
264 		       status = inb(uart->base + UART_MSR);
265 		}
266 	} else {
267 		/* Write loop */
268 		while (uart->fifo_count < uart->fifo_limit /* Can we write ? */
269 		       && uart->buff_in_count > 0)	/* Do we want to? */
270 			snd_uart16550_buffer_output(uart);
271 	}
272 	if (uart->irq < 0 && uart->buff_in_count > 0)
273 		snd_uart16550_add_timer(uart);
274 }
275 
276 /* NOTES ON SERVICING INTERUPTS
277  * ---------------------------
278  * After receiving a interrupt, it is important to indicate to the UART that
279  * this has been done.
280  * For a Rx interrupt, this is done by reading the received byte.
281  * For a Tx interrupt this is done by either:
282  * a) Writing a byte
283  * b) Reading the IIR
284  * It is particularly important to read the IIR if a Tx interrupt is received
285  * when there is no data in tx_buff[], as in this case there no other
286  * indication that the interrupt has been serviced, and it remains outstanding
287  * indefinitely. This has the curious side effect that and no further interrupts
288  * will be generated from this device AT ALL!!.
289  * It is also desirable to clear outstanding interrupts when the device is
290  * opened/closed.
291  *
292  *
293  * Note that some devices need OUT2 to be set before they will generate
294  * interrupts at all. (Possibly tied to an internal pull-up on CTS?)
295  */
296 static irqreturn_t snd_uart16550_interrupt(int irq, void *dev_id)
297 {
298 	struct snd_uart16550 *uart;
299 
300 	uart = dev_id;
301 	spin_lock(&uart->open_lock);
302 	if (uart->filemode == SERIAL_MODE_NOT_OPENED) {
303 		spin_unlock(&uart->open_lock);
304 		return IRQ_NONE;
305 	}
306 	/* indicate to the UART that the interrupt has been serviced */
307 	inb(uart->base + UART_IIR);
308 	snd_uart16550_io_loop(uart);
309 	spin_unlock(&uart->open_lock);
310 	return IRQ_HANDLED;
311 }
312 
313 /* When the polling mode, this function calls snd_uart16550_io_loop. */
314 static void snd_uart16550_buffer_timer(unsigned long data)
315 {
316 	unsigned long flags;
317 	struct snd_uart16550 *uart;
318 
319 	uart = (struct snd_uart16550 *)data;
320 	spin_lock_irqsave(&uart->open_lock, flags);
321 	snd_uart16550_del_timer(uart);
322 	snd_uart16550_io_loop(uart);
323 	spin_unlock_irqrestore(&uart->open_lock, flags);
324 }
325 
326 /*
327  *  this method probes, if an uart sits on given port
328  *  return 0 if found
329  *  return negative error if not found
330  */
331 static int __devinit snd_uart16550_detect(struct snd_uart16550 *uart)
332 {
333 	unsigned long io_base = uart->base;
334 	int ok;
335 	unsigned char c;
336 
337 	/* Do some vague tests for the presence of the uart */
338 	if (io_base == 0 || io_base == SNDRV_AUTO_PORT) {
339 		return -ENODEV;	/* Not configured */
340 	}
341 
342 	uart->res_base = request_region(io_base, 8, "Serial MIDI");
343 	if (uart->res_base == NULL) {
344 		snd_printk(KERN_ERR "u16550: can't grab port 0x%lx\n", io_base);
345 		return -EBUSY;
346 	}
347 
348 	/* uart detected unless one of the following tests should fail */
349 	ok = 1;
350 	/* 8 data-bits, 1 stop-bit, parity off, DLAB = 0 */
351 	outb(UART_LCR_WLEN8, io_base + UART_LCR); /* Line Control Register */
352 	c = inb(io_base + UART_IER);
353 	/* The top four bits of the IER should always == 0 */
354 	if ((c & 0xf0) != 0)
355 		ok = 0;		/* failed */
356 
357 	outb(0xaa, io_base + UART_SCR);
358 	/* Write arbitrary data into the scratch reg */
359 	c = inb(io_base + UART_SCR);
360 	/* If it comes back, it's OK */
361 	if (c != 0xaa)
362 		ok = 0;		/* failed */
363 
364 	outb(0x55, io_base + UART_SCR);
365 	/* Write arbitrary data into the scratch reg */
366 	c = inb(io_base + UART_SCR);
367 	/* If it comes back, it's OK */
368 	if (c != 0x55)
369 		ok = 0;		/* failed */
370 
371 	return ok;
372 }
373 
374 static void snd_uart16550_do_open(struct snd_uart16550 * uart)
375 {
376 	char byte;
377 
378 	/* Initialize basic variables */
379 	uart->buff_in_count = 0;
380 	uart->buff_in = 0;
381 	uart->buff_out = 0;
382 	uart->fifo_limit = 1;
383 	uart->fifo_count = 0;
384 	uart->timer_running = 0;
385 
386 	outb(UART_FCR_ENABLE_FIFO	/* Enable FIFO's (if available) */
387 	     | UART_FCR_CLEAR_RCVR	/* Clear receiver FIFO */
388 	     | UART_FCR_CLEAR_XMIT	/* Clear transmitter FIFO */
389 	     | UART_FCR_TRIGGER_4	/* Set FIFO trigger at 4-bytes */
390 	/* NOTE: interrupt generated after T=(time)4-bytes
391 	 * if less than UART_FCR_TRIGGER bytes received
392 	 */
393 	     ,uart->base + UART_FCR);	/* FIFO Control Register */
394 
395 	if ((inb(uart->base + UART_IIR) & 0xf0) == 0xc0)
396 		uart->fifo_limit = 16;
397 	if (uart->divisor != 0) {
398 		uart->old_line_ctrl_reg = inb(uart->base + UART_LCR);
399 		outb(UART_LCR_DLAB	/* Divisor latch access bit */
400 		     ,uart->base + UART_LCR);	/* Line Control Register */
401 		uart->old_divisor_lsb = inb(uart->base + UART_DLL);
402 		uart->old_divisor_msb = inb(uart->base + UART_DLM);
403 
404 		outb(uart->divisor
405 		     ,uart->base + UART_DLL);	/* Divisor Latch Low */
406 		outb(0
407 		     ,uart->base + UART_DLM);	/* Divisor Latch High */
408 		/* DLAB is reset to 0 in next outb() */
409 	}
410 	/* Set serial parameters (parity off, etc) */
411 	outb(UART_LCR_WLEN8	/* 8 data-bits */
412 	     | 0		/* 1 stop-bit */
413 	     | 0		/* parity off */
414 	     | 0		/* DLAB = 0 */
415 	     ,uart->base + UART_LCR);	/* Line Control Register */
416 
417 	switch (uart->adaptor) {
418 	default:
419 		outb(UART_MCR_RTS	/* Set Request-To-Send line active */
420 		     | UART_MCR_DTR	/* Set Data-Terminal-Ready line active */
421 		     | UART_MCR_OUT2	/* Set OUT2 - not always required, but when
422 					 * it is, it is ESSENTIAL for enabling interrupts
423 				 */
424 		     ,uart->base + UART_MCR);	/* Modem Control Register */
425 		break;
426 	case SNDRV_SERIAL_MS124W_SA:
427 	case SNDRV_SERIAL_MS124W_MB:
428 		/* MS-124W can draw power from RTS and DTR if they
429 		   are in opposite states. */
430 		outb(UART_MCR_RTS | (0&UART_MCR_DTR) | UART_MCR_OUT2,
431 		     uart->base + UART_MCR);
432 		break;
433 	case SNDRV_SERIAL_MS124T:
434 		/* MS-124T can draw power from RTS and/or DTR (preferably
435 		   both) if they are both asserted. */
436 		outb(UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2,
437 		     uart->base + UART_MCR);
438 		break;
439 	}
440 
441 	if (uart->irq < 0) {
442 		byte = (0 & UART_IER_RDI)	/* Disable Receiver data interrupt */
443 		    |(0 & UART_IER_THRI)	/* Disable Transmitter holding register empty interrupt */
444 		    ;
445 	} else if (uart->adaptor == SNDRV_SERIAL_MS124W_SA) {
446 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
447 		    | UART_IER_MSI	/* Enable Modem status interrupt */
448 		    ;
449 	} else if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
450 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
451 		    | UART_IER_MSI	/* Enable Modem status interrupt */
452 		    | UART_IER_THRI	/* Enable Transmitter holding register empty interrupt */
453 		    ;
454 	} else {
455 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
456 		    | UART_IER_THRI	/* Enable Transmitter holding register empty interrupt */
457 		    ;
458 	}
459 	outb(byte, uart->base + UART_IER);	/* Interrupt enable Register */
460 
461 	inb(uart->base + UART_LSR);	/* Clear any pre-existing overrun indication */
462 	inb(uart->base + UART_IIR);	/* Clear any pre-existing transmit interrupt */
463 	inb(uart->base + UART_RX);	/* Clear any pre-existing receive interrupt */
464 }
465 
466 static void snd_uart16550_do_close(struct snd_uart16550 * uart)
467 {
468 	if (uart->irq < 0)
469 		snd_uart16550_del_timer(uart);
470 
471 	/* NOTE: may need to disable interrupts before de-registering out handler.
472 	 * For now, the consequences are harmless.
473 	 */
474 
475 	outb((0 & UART_IER_RDI)		/* Disable Receiver data interrupt */
476 	     |(0 & UART_IER_THRI)	/* Disable Transmitter holding register empty interrupt */
477 	     ,uart->base + UART_IER);	/* Interrupt enable Register */
478 
479 	switch (uart->adaptor) {
480 	default:
481 		outb((0 & UART_MCR_RTS)		/* Deactivate Request-To-Send line  */
482 		     |(0 & UART_MCR_DTR)	/* Deactivate Data-Terminal-Ready line */
483 		     |(0 & UART_MCR_OUT2)	/* Deactivate OUT2 */
484 		     ,uart->base + UART_MCR);	/* Modem Control Register */
485 	  break;
486 	case SNDRV_SERIAL_MS124W_SA:
487 	case SNDRV_SERIAL_MS124W_MB:
488 		/* MS-124W can draw power from RTS and DTR if they
489 		   are in opposite states; leave it powered. */
490 		outb(UART_MCR_RTS | (0&UART_MCR_DTR) | (0&UART_MCR_OUT2),
491 		     uart->base + UART_MCR);
492 		break;
493 	case SNDRV_SERIAL_MS124T:
494 		/* MS-124T can draw power from RTS and/or DTR (preferably
495 		   both) if they are both asserted; leave it powered. */
496 		outb(UART_MCR_RTS | UART_MCR_DTR | (0&UART_MCR_OUT2),
497 		     uart->base + UART_MCR);
498 		break;
499 	}
500 
501 	inb(uart->base + UART_IIR);	/* Clear any outstanding interrupts */
502 
503 	/* Restore old divisor */
504 	if (uart->divisor != 0) {
505 		outb(UART_LCR_DLAB		/* Divisor latch access bit */
506 		     ,uart->base + UART_LCR);	/* Line Control Register */
507 		outb(uart->old_divisor_lsb
508 		     ,uart->base + UART_DLL);	/* Divisor Latch Low */
509 		outb(uart->old_divisor_msb
510 		     ,uart->base + UART_DLM);	/* Divisor Latch High */
511 		/* Restore old LCR (data bits, stop bits, parity, DLAB) */
512 		outb(uart->old_line_ctrl_reg
513 		     ,uart->base + UART_LCR);	/* Line Control Register */
514 	}
515 }
516 
517 static int snd_uart16550_input_open(struct snd_rawmidi_substream *substream)
518 {
519 	unsigned long flags;
520 	struct snd_uart16550 *uart = substream->rmidi->private_data;
521 
522 	spin_lock_irqsave(&uart->open_lock, flags);
523 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
524 		snd_uart16550_do_open(uart);
525 	uart->filemode |= SERIAL_MODE_INPUT_OPEN;
526 	uart->midi_input[substream->number] = substream;
527 	spin_unlock_irqrestore(&uart->open_lock, flags);
528 	return 0;
529 }
530 
531 static int snd_uart16550_input_close(struct snd_rawmidi_substream *substream)
532 {
533 	unsigned long flags;
534 	struct snd_uart16550 *uart = substream->rmidi->private_data;
535 
536 	spin_lock_irqsave(&uart->open_lock, flags);
537 	uart->filemode &= ~SERIAL_MODE_INPUT_OPEN;
538 	uart->midi_input[substream->number] = NULL;
539 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
540 		snd_uart16550_do_close(uart);
541 	spin_unlock_irqrestore(&uart->open_lock, flags);
542 	return 0;
543 }
544 
545 static void snd_uart16550_input_trigger(struct snd_rawmidi_substream *substream,
546 					int up)
547 {
548 	unsigned long flags;
549 	struct snd_uart16550 *uart = substream->rmidi->private_data;
550 
551 	spin_lock_irqsave(&uart->open_lock, flags);
552 	if (up)
553 		uart->filemode |= SERIAL_MODE_INPUT_TRIGGERED;
554 	else
555 		uart->filemode &= ~SERIAL_MODE_INPUT_TRIGGERED;
556 	spin_unlock_irqrestore(&uart->open_lock, flags);
557 }
558 
559 static int snd_uart16550_output_open(struct snd_rawmidi_substream *substream)
560 {
561 	unsigned long flags;
562 	struct snd_uart16550 *uart = substream->rmidi->private_data;
563 
564 	spin_lock_irqsave(&uart->open_lock, flags);
565 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
566 		snd_uart16550_do_open(uart);
567 	uart->filemode |= SERIAL_MODE_OUTPUT_OPEN;
568 	uart->midi_output[substream->number] = substream;
569 	spin_unlock_irqrestore(&uart->open_lock, flags);
570 	return 0;
571 };
572 
573 static int snd_uart16550_output_close(struct snd_rawmidi_substream *substream)
574 {
575 	unsigned long flags;
576 	struct snd_uart16550 *uart = substream->rmidi->private_data;
577 
578 	spin_lock_irqsave(&uart->open_lock, flags);
579 	uart->filemode &= ~SERIAL_MODE_OUTPUT_OPEN;
580 	uart->midi_output[substream->number] = NULL;
581 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
582 		snd_uart16550_do_close(uart);
583 	spin_unlock_irqrestore(&uart->open_lock, flags);
584 	return 0;
585 };
586 
587 static inline int snd_uart16550_buffer_can_write(struct snd_uart16550 *uart,
588 						 int Num)
589 {
590 	if (uart->buff_in_count + Num < TX_BUFF_SIZE)
591 		return 1;
592 	else
593 		return 0;
594 }
595 
596 static inline int snd_uart16550_write_buffer(struct snd_uart16550 *uart,
597 					     unsigned char byte)
598 {
599 	unsigned short buff_in = uart->buff_in;
600 	if (uart->buff_in_count < TX_BUFF_SIZE) {
601 		uart->tx_buff[buff_in] = byte;
602 		buff_in++;
603 		buff_in &= TX_BUFF_MASK;
604 		uart->buff_in = buff_in;
605 		uart->buff_in_count++;
606 		if (uart->irq < 0) /* polling mode */
607 			snd_uart16550_add_timer(uart);
608 		return 1;
609 	} else
610 		return 0;
611 }
612 
613 static int snd_uart16550_output_byte(struct snd_uart16550 *uart,
614 				     struct snd_rawmidi_substream *substream,
615 				     unsigned char midi_byte)
616 {
617 	if (uart->buff_in_count == 0                    /* Buffer empty? */
618 	    && ((uart->adaptor != SNDRV_SERIAL_MS124W_SA &&
619 	    uart->adaptor != SNDRV_SERIAL_GENERIC) ||
620 		(uart->fifo_count == 0                  /* FIFO empty? */
621 		 && (inb(uart->base + UART_MSR) & UART_MSR_CTS)))) { /* CTS? */
622 
623 	        /* Tx Buffer Empty - try to write immediately */
624 		if ((inb(uart->base + UART_LSR) & UART_LSR_THRE) != 0) {
625 		        /* Transmitter holding register (and Tx FIFO) empty */
626 		        uart->fifo_count = 1;
627 			outb(midi_byte, uart->base + UART_TX);
628 		} else {
629 		        if (uart->fifo_count < uart->fifo_limit) {
630 			        uart->fifo_count++;
631 				outb(midi_byte, uart->base + UART_TX);
632 			} else {
633 			        /* Cannot write (buffer empty) -
634 				 * put char in buffer */
635 				snd_uart16550_write_buffer(uart, midi_byte);
636 			}
637 		}
638 	} else {
639 		if (!snd_uart16550_write_buffer(uart, midi_byte)) {
640 			snd_printk(KERN_WARNING
641 				   "%s: Buffer overrun on device at 0x%lx\n",
642 				   uart->rmidi->name, uart->base);
643 			return 0;
644 		}
645 	}
646 
647 	return 1;
648 }
649 
650 static void snd_uart16550_output_write(struct snd_rawmidi_substream *substream)
651 {
652 	unsigned long flags;
653 	unsigned char midi_byte, addr_byte;
654 	struct snd_uart16550 *uart = substream->rmidi->private_data;
655 	char first;
656 	static unsigned long lasttime = 0;
657 
658 	/* Interrupts are disabled during the updating of the tx_buff,
659 	 * since it is 'bad' to have two processes updating the same
660 	 * variables (ie buff_in & buff_out)
661 	 */
662 
663 	spin_lock_irqsave(&uart->open_lock, flags);
664 
665 	if (uart->irq < 0)	/* polling */
666 		snd_uart16550_io_loop(uart);
667 
668 	if (uart->adaptor == SNDRV_SERIAL_MS124W_MB) {
669 		while (1) {
670 			/* buffer full? */
671 			/* in this mode we need two bytes of space */
672 			if (uart->buff_in_count > TX_BUFF_SIZE - 2)
673 				break;
674 			if (snd_rawmidi_transmit(substream, &midi_byte, 1) != 1)
675 				break;
676 #ifdef SNDRV_SERIAL_MS124W_MB_NOCOMBO
677 			/* select exactly one of the four ports */
678 			addr_byte = (1 << (substream->number + 4)) | 0x08;
679 #else
680 			/* select any combination of the four ports */
681 			addr_byte = (substream->number << 4) | 0x08;
682 			/* ...except none */
683 			if (addr_byte == 0x08)
684 				addr_byte = 0xf8;
685 #endif
686 			snd_uart16550_output_byte(uart, substream, addr_byte);
687 			/* send midi byte */
688 			snd_uart16550_output_byte(uart, substream, midi_byte);
689 		}
690 	} else {
691 		first = 0;
692 		while (snd_rawmidi_transmit_peek(substream, &midi_byte, 1) == 1) {
693 			/* Also send F5 after 3 seconds with no data
694 			 * to handle device disconnect */
695 			if (first == 0 &&
696 			    (uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS ||
697 			     uart->adaptor == SNDRV_SERIAL_GENERIC) &&
698 			    (uart->prev_out != substream->number ||
699 			     time_after(jiffies, lasttime + 3*HZ))) {
700 
701 				if (snd_uart16550_buffer_can_write(uart, 3)) {
702 					/* Roland Soundcanvas part selection */
703 					/* If this substream of the data is
704 					 * different previous substream
705 					 * in this uart, send the change part
706 					 * event
707 					 */
708 					uart->prev_out = substream->number;
709 					/* change part */
710 					snd_uart16550_output_byte(uart, substream,
711 								  0xf5);
712 					/* data */
713 					snd_uart16550_output_byte(uart, substream,
714 								  uart->prev_out + 1);
715 					/* If midi_byte is a data byte,
716 					 * send the previous status byte */
717 					if (midi_byte < 0x80 &&
718 					    uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS)
719 						snd_uart16550_output_byte(uart, substream, uart->prev_status[uart->prev_out]);
720 				} else if (!uart->drop_on_full)
721 					break;
722 
723 			}
724 
725 			/* send midi byte */
726 			if (!snd_uart16550_output_byte(uart, substream, midi_byte) &&
727 			    !uart->drop_on_full )
728 				break;
729 
730 			if (midi_byte >= 0x80 && midi_byte < 0xf0)
731 				uart->prev_status[uart->prev_out] = midi_byte;
732 			first = 1;
733 
734 			snd_rawmidi_transmit_ack( substream, 1 );
735 		}
736 		lasttime = jiffies;
737 	}
738 	spin_unlock_irqrestore(&uart->open_lock, flags);
739 }
740 
741 static void snd_uart16550_output_trigger(struct snd_rawmidi_substream *substream,
742 					 int up)
743 {
744 	unsigned long flags;
745 	struct snd_uart16550 *uart = substream->rmidi->private_data;
746 
747 	spin_lock_irqsave(&uart->open_lock, flags);
748 	if (up)
749 		uart->filemode |= SERIAL_MODE_OUTPUT_TRIGGERED;
750 	else
751 		uart->filemode &= ~SERIAL_MODE_OUTPUT_TRIGGERED;
752 	spin_unlock_irqrestore(&uart->open_lock, flags);
753 	if (up)
754 		snd_uart16550_output_write(substream);
755 }
756 
757 static struct snd_rawmidi_ops snd_uart16550_output =
758 {
759 	.open =		snd_uart16550_output_open,
760 	.close =	snd_uart16550_output_close,
761 	.trigger =	snd_uart16550_output_trigger,
762 };
763 
764 static struct snd_rawmidi_ops snd_uart16550_input =
765 {
766 	.open =		snd_uart16550_input_open,
767 	.close =	snd_uart16550_input_close,
768 	.trigger =	snd_uart16550_input_trigger,
769 };
770 
771 static int snd_uart16550_free(struct snd_uart16550 *uart)
772 {
773 	if (uart->irq >= 0)
774 		free_irq(uart->irq, uart);
775 	release_and_free_resource(uart->res_base);
776 	kfree(uart);
777 	return 0;
778 };
779 
780 static int snd_uart16550_dev_free(struct snd_device *device)
781 {
782 	struct snd_uart16550 *uart = device->device_data;
783 	return snd_uart16550_free(uart);
784 }
785 
786 static int __devinit snd_uart16550_create(struct snd_card *card,
787 				       unsigned long iobase,
788 				       int irq,
789 				       unsigned int speed,
790 				       unsigned int base,
791 				       int adaptor,
792 				       int droponfull,
793 				       struct snd_uart16550 **ruart)
794 {
795 	static struct snd_device_ops ops = {
796 		.dev_free =	snd_uart16550_dev_free,
797 	};
798 	struct snd_uart16550 *uart;
799 	int err;
800 
801 
802 	if ((uart = kzalloc(sizeof(*uart), GFP_KERNEL)) == NULL)
803 		return -ENOMEM;
804 	uart->adaptor = adaptor;
805 	uart->card = card;
806 	spin_lock_init(&uart->open_lock);
807 	uart->irq = -1;
808 	uart->base = iobase;
809 	uart->drop_on_full = droponfull;
810 
811 	if ((err = snd_uart16550_detect(uart)) <= 0) {
812 		printk(KERN_ERR "no UART detected at 0x%lx\n", iobase);
813 		snd_uart16550_free(uart);
814 		return -ENODEV;
815 	}
816 
817 	if (irq >= 0 && irq != SNDRV_AUTO_IRQ) {
818 		if (request_irq(irq, snd_uart16550_interrupt,
819 				0, "Serial MIDI", uart)) {
820 			snd_printk(KERN_WARNING
821 				   "irq %d busy. Using Polling.\n", irq);
822 		} else {
823 			uart->irq = irq;
824 		}
825 	}
826 	uart->divisor = base / speed;
827 	uart->speed = base / (unsigned int)uart->divisor;
828 	uart->speed_base = base;
829 	uart->prev_out = -1;
830 	uart->prev_in = 0;
831 	uart->rstatus = 0;
832 	memset(uart->prev_status, 0x80, sizeof(unsigned char) * SNDRV_SERIAL_MAX_OUTS);
833 	init_timer(&uart->buffer_timer);
834 	uart->buffer_timer.function = snd_uart16550_buffer_timer;
835 	uart->buffer_timer.data = (unsigned long)uart;
836 	uart->timer_running = 0;
837 
838 	/* Register device */
839 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, uart, &ops)) < 0) {
840 		snd_uart16550_free(uart);
841 		return err;
842 	}
843 
844 	switch (uart->adaptor) {
845 	case SNDRV_SERIAL_MS124W_SA:
846 	case SNDRV_SERIAL_MS124W_MB:
847 		/* MS-124W can draw power from RTS and DTR if they
848 		   are in opposite states. */
849 		outb(UART_MCR_RTS | (0&UART_MCR_DTR), uart->base + UART_MCR);
850 		break;
851 	case SNDRV_SERIAL_MS124T:
852 		/* MS-124T can draw power from RTS and/or DTR (preferably
853 		   both) if they are asserted. */
854 		outb(UART_MCR_RTS | UART_MCR_DTR, uart->base + UART_MCR);
855 		break;
856 	default:
857 		break;
858 	}
859 
860 	if (ruart)
861 		*ruart = uart;
862 
863 	return 0;
864 }
865 
866 static void __devinit snd_uart16550_substreams(struct snd_rawmidi_str *stream)
867 {
868 	struct snd_rawmidi_substream *substream;
869 
870 	list_for_each_entry(substream, &stream->substreams, list) {
871 		sprintf(substream->name, "Serial MIDI %d", substream->number + 1);
872 	}
873 }
874 
875 static int __devinit snd_uart16550_rmidi(struct snd_uart16550 *uart, int device,
876 				      int outs, int ins,
877 				      struct snd_rawmidi **rmidi)
878 {
879 	struct snd_rawmidi *rrawmidi;
880 	int err;
881 
882 	err = snd_rawmidi_new(uart->card, "UART Serial MIDI", device,
883 			      outs, ins, &rrawmidi);
884 	if (err < 0)
885 		return err;
886 	snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_INPUT,
887 			    &snd_uart16550_input);
888 	snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
889 			    &snd_uart16550_output);
890 	strcpy(rrawmidi->name, "Serial MIDI");
891 	snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT]);
892 	snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT]);
893 	rrawmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
894 			       SNDRV_RAWMIDI_INFO_INPUT |
895 			       SNDRV_RAWMIDI_INFO_DUPLEX;
896 	rrawmidi->private_data = uart;
897 	if (rmidi)
898 		*rmidi = rrawmidi;
899 	return 0;
900 }
901 
902 static int __devinit snd_serial_probe(struct platform_device *devptr)
903 {
904 	struct snd_card *card;
905 	struct snd_uart16550 *uart;
906 	int err;
907 	int dev = devptr->id;
908 
909 	switch (adaptor[dev]) {
910 	case SNDRV_SERIAL_SOUNDCANVAS:
911 		ins[dev] = 1;
912 		break;
913 	case SNDRV_SERIAL_MS124T:
914 	case SNDRV_SERIAL_MS124W_SA:
915 		outs[dev] = 1;
916 		ins[dev] = 1;
917 		break;
918 	case SNDRV_SERIAL_MS124W_MB:
919 		outs[dev] = 16;
920 		ins[dev] = 1;
921 		break;
922 	case SNDRV_SERIAL_GENERIC:
923 		break;
924 	default:
925 		snd_printk(KERN_ERR
926 			   "Adaptor type is out of range 0-%d (%d)\n",
927 			   SNDRV_SERIAL_MAX_ADAPTOR, adaptor[dev]);
928 		return -ENODEV;
929 	}
930 
931 	if (outs[dev] < 1 || outs[dev] > SNDRV_SERIAL_MAX_OUTS) {
932 		snd_printk(KERN_ERR
933 			   "Count of outputs is out of range 1-%d (%d)\n",
934 			   SNDRV_SERIAL_MAX_OUTS, outs[dev]);
935 		return -ENODEV;
936 	}
937 
938 	if (ins[dev] < 1 || ins[dev] > SNDRV_SERIAL_MAX_INS) {
939 		snd_printk(KERN_ERR
940 			   "Count of inputs is out of range 1-%d (%d)\n",
941 			   SNDRV_SERIAL_MAX_INS, ins[dev]);
942 		return -ENODEV;
943 	}
944 
945 	err  = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
946 	if (err < 0)
947 		return err;
948 
949 	strcpy(card->driver, "Serial");
950 	strcpy(card->shortname, "Serial MIDI (UART16550A)");
951 
952 	if ((err = snd_uart16550_create(card,
953 					port[dev],
954 					irq[dev],
955 					speed[dev],
956 					base[dev],
957 					adaptor[dev],
958 					droponfull[dev],
959 					&uart)) < 0)
960 		goto _err;
961 
962 	err = snd_uart16550_rmidi(uart, 0, outs[dev], ins[dev], &uart->rmidi);
963 	if (err < 0)
964 		goto _err;
965 
966 	sprintf(card->longname, "%s [%s] at %#lx, irq %d",
967 		card->shortname,
968 		adaptor_names[uart->adaptor],
969 		uart->base,
970 		uart->irq);
971 
972 	snd_card_set_dev(card, &devptr->dev);
973 
974 	if ((err = snd_card_register(card)) < 0)
975 		goto _err;
976 
977 	platform_set_drvdata(devptr, card);
978 	return 0;
979 
980  _err:
981 	snd_card_free(card);
982 	return err;
983 }
984 
985 static int __devexit snd_serial_remove(struct platform_device *devptr)
986 {
987 	snd_card_free(platform_get_drvdata(devptr));
988 	platform_set_drvdata(devptr, NULL);
989 	return 0;
990 }
991 
992 #define SND_SERIAL_DRIVER	"snd_serial_u16550"
993 
994 static struct platform_driver snd_serial_driver = {
995 	.probe		= snd_serial_probe,
996 	.remove		= __devexit_p( snd_serial_remove),
997 	.driver		= {
998 		.name	= SND_SERIAL_DRIVER,
999 		.owner	= THIS_MODULE,
1000 	},
1001 };
1002 
1003 static void snd_serial_unregister_all(void)
1004 {
1005 	int i;
1006 
1007 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1008 		platform_device_unregister(devices[i]);
1009 	platform_driver_unregister(&snd_serial_driver);
1010 }
1011 
1012 static int __init alsa_card_serial_init(void)
1013 {
1014 	int i, cards, err;
1015 
1016 	if ((err = platform_driver_register(&snd_serial_driver)) < 0)
1017 		return err;
1018 
1019 	cards = 0;
1020 	for (i = 0; i < SNDRV_CARDS; i++) {
1021 		struct platform_device *device;
1022 		if (! enable[i])
1023 			continue;
1024 		device = platform_device_register_simple(SND_SERIAL_DRIVER,
1025 							 i, NULL, 0);
1026 		if (IS_ERR(device))
1027 			continue;
1028 		if (!platform_get_drvdata(device)) {
1029 			platform_device_unregister(device);
1030 			continue;
1031 		}
1032 		devices[i] = device;
1033 		cards++;
1034 	}
1035 	if (! cards) {
1036 #ifdef MODULE
1037 		printk(KERN_ERR "serial midi soundcard not found or device busy\n");
1038 #endif
1039 		snd_serial_unregister_all();
1040 		return -ENODEV;
1041 	}
1042 	return 0;
1043 }
1044 
1045 static void __exit alsa_card_serial_exit(void)
1046 {
1047 	snd_serial_unregister_all();
1048 }
1049 
1050 module_init(alsa_card_serial_init)
1051 module_exit(alsa_card_serial_exit)
1052