xref: /linux/sound/drivers/serial-u16550.c (revision c1f3ee120bb61045b1c0a3ead620d1d65af47130)
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/moduleparam.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 int 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 int 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("%s: Overrun on device at 0x%lx\n",
245 			       uart->rmidi->name, uart->base);
246 	}
247 
248 	/* remember the last stream */
249 	uart->prev_in = substream;
250 
251 	/* no need of check SERIAL_MODE_OUTPUT_OPEN because if not,
252 	   buffer is never filled. */
253 	/* Check write status */
254 	if (status & UART_LSR_THRE)
255 		uart->fifo_count = 0;
256 	if (uart->adaptor == SNDRV_SERIAL_MS124W_SA
257 	   || uart->adaptor == SNDRV_SERIAL_GENERIC) {
258 		/* Can't use FIFO, must send only when CTS is true */
259 		status = inb(uart->base + UART_MSR);
260 		while (uart->fifo_count == 0 && (status & UART_MSR_CTS) &&
261 		       uart->buff_in_count > 0) {
262 		       snd_uart16550_buffer_output(uart);
263 		       status = inb(uart->base + UART_MSR);
264 		}
265 	} else {
266 		/* Write loop */
267 		while (uart->fifo_count < uart->fifo_limit /* Can we write ? */
268 		       && uart->buff_in_count > 0)	/* Do we want to? */
269 			snd_uart16550_buffer_output(uart);
270 	}
271 	if (uart->irq < 0 && uart->buff_in_count > 0)
272 		snd_uart16550_add_timer(uart);
273 }
274 
275 /* NOTES ON SERVICING INTERUPTS
276  * ---------------------------
277  * After receiving a interrupt, it is important to indicate to the UART that
278  * this has been done.
279  * For a Rx interrupt, this is done by reading the received byte.
280  * For a Tx interrupt this is done by either:
281  * a) Writing a byte
282  * b) Reading the IIR
283  * It is particularly important to read the IIR if a Tx interrupt is received
284  * when there is no data in tx_buff[], as in this case there no other
285  * indication that the interrupt has been serviced, and it remains outstanding
286  * indefinitely. This has the curious side effect that and no further interrupts
287  * will be generated from this device AT ALL!!.
288  * It is also desirable to clear outstanding interrupts when the device is
289  * opened/closed.
290  *
291  *
292  * Note that some devices need OUT2 to be set before they will generate
293  * interrupts at all. (Possibly tied to an internal pull-up on CTS?)
294  */
295 static irqreturn_t snd_uart16550_interrupt(int irq, void *dev_id)
296 {
297 	struct snd_uart16550 *uart;
298 
299 	uart = dev_id;
300 	spin_lock(&uart->open_lock);
301 	if (uart->filemode == SERIAL_MODE_NOT_OPENED) {
302 		spin_unlock(&uart->open_lock);
303 		return IRQ_NONE;
304 	}
305 	/* indicate to the UART that the interrupt has been serviced */
306 	inb(uart->base + UART_IIR);
307 	snd_uart16550_io_loop(uart);
308 	spin_unlock(&uart->open_lock);
309 	return IRQ_HANDLED;
310 }
311 
312 /* When the polling mode, this function calls snd_uart16550_io_loop. */
313 static void snd_uart16550_buffer_timer(unsigned long data)
314 {
315 	unsigned long flags;
316 	struct snd_uart16550 *uart;
317 
318 	uart = (struct snd_uart16550 *)data;
319 	spin_lock_irqsave(&uart->open_lock, flags);
320 	snd_uart16550_del_timer(uart);
321 	snd_uart16550_io_loop(uart);
322 	spin_unlock_irqrestore(&uart->open_lock, flags);
323 }
324 
325 /*
326  *  this method probes, if an uart sits on given port
327  *  return 0 if found
328  *  return negative error if not found
329  */
330 static int __devinit snd_uart16550_detect(struct snd_uart16550 *uart)
331 {
332 	unsigned long io_base = uart->base;
333 	int ok;
334 	unsigned char c;
335 
336 	/* Do some vague tests for the presence of the uart */
337 	if (io_base == 0 || io_base == SNDRV_AUTO_PORT) {
338 		return -ENODEV;	/* Not configured */
339 	}
340 
341 	uart->res_base = request_region(io_base, 8, "Serial MIDI");
342 	if (uart->res_base == NULL) {
343 		snd_printk(KERN_ERR "u16550: can't grab port 0x%lx\n", io_base);
344 		return -EBUSY;
345 	}
346 
347 	/* uart detected unless one of the following tests should fail */
348 	ok = 1;
349 	/* 8 data-bits, 1 stop-bit, parity off, DLAB = 0 */
350 	outb(UART_LCR_WLEN8, io_base + UART_LCR); /* Line Control Register */
351 	c = inb(io_base + UART_IER);
352 	/* The top four bits of the IER should always == 0 */
353 	if ((c & 0xf0) != 0)
354 		ok = 0;		/* failed */
355 
356 	outb(0xaa, io_base + UART_SCR);
357 	/* Write arbitrary data into the scratch reg */
358 	c = inb(io_base + UART_SCR);
359 	/* If it comes back, it's OK */
360 	if (c != 0xaa)
361 		ok = 0;		/* failed */
362 
363 	outb(0x55, io_base + UART_SCR);
364 	/* Write arbitrary data into the scratch reg */
365 	c = inb(io_base + UART_SCR);
366 	/* If it comes back, it's OK */
367 	if (c != 0x55)
368 		ok = 0;		/* failed */
369 
370 	return ok;
371 }
372 
373 static void snd_uart16550_do_open(struct snd_uart16550 * uart)
374 {
375 	char byte;
376 
377 	/* Initialize basic variables */
378 	uart->buff_in_count = 0;
379 	uart->buff_in = 0;
380 	uart->buff_out = 0;
381 	uart->fifo_limit = 1;
382 	uart->fifo_count = 0;
383 	uart->timer_running = 0;
384 
385 	outb(UART_FCR_ENABLE_FIFO	/* Enable FIFO's (if available) */
386 	     | UART_FCR_CLEAR_RCVR	/* Clear receiver FIFO */
387 	     | UART_FCR_CLEAR_XMIT	/* Clear transmitter FIFO */
388 	     | UART_FCR_TRIGGER_4	/* Set FIFO trigger at 4-bytes */
389 	/* NOTE: interrupt generated after T=(time)4-bytes
390 	 * if less than UART_FCR_TRIGGER bytes received
391 	 */
392 	     ,uart->base + UART_FCR);	/* FIFO Control Register */
393 
394 	if ((inb(uart->base + UART_IIR) & 0xf0) == 0xc0)
395 		uart->fifo_limit = 16;
396 	if (uart->divisor != 0) {
397 		uart->old_line_ctrl_reg = inb(uart->base + UART_LCR);
398 		outb(UART_LCR_DLAB	/* Divisor latch access bit */
399 		     ,uart->base + UART_LCR);	/* Line Control Register */
400 		uart->old_divisor_lsb = inb(uart->base + UART_DLL);
401 		uart->old_divisor_msb = inb(uart->base + UART_DLM);
402 
403 		outb(uart->divisor
404 		     ,uart->base + UART_DLL);	/* Divisor Latch Low */
405 		outb(0
406 		     ,uart->base + UART_DLM);	/* Divisor Latch High */
407 		/* DLAB is reset to 0 in next outb() */
408 	}
409 	/* Set serial parameters (parity off, etc) */
410 	outb(UART_LCR_WLEN8	/* 8 data-bits */
411 	     | 0		/* 1 stop-bit */
412 	     | 0		/* parity off */
413 	     | 0		/* DLAB = 0 */
414 	     ,uart->base + UART_LCR);	/* Line Control Register */
415 
416 	switch (uart->adaptor) {
417 	default:
418 		outb(UART_MCR_RTS	/* Set Request-To-Send line active */
419 		     | UART_MCR_DTR	/* Set Data-Terminal-Ready line active */
420 		     | UART_MCR_OUT2	/* Set OUT2 - not always required, but when
421 					 * it is, it is ESSENTIAL for enabling interrupts
422 				 */
423 		     ,uart->base + UART_MCR);	/* Modem Control Register */
424 		break;
425 	case SNDRV_SERIAL_MS124W_SA:
426 	case SNDRV_SERIAL_MS124W_MB:
427 		/* MS-124W can draw power from RTS and DTR if they
428 		   are in opposite states. */
429 		outb(UART_MCR_RTS | (0&UART_MCR_DTR) | UART_MCR_OUT2,
430 		     uart->base + UART_MCR);
431 		break;
432 	case SNDRV_SERIAL_MS124T:
433 		/* MS-124T can draw power from RTS and/or DTR (preferably
434 		   both) if they are both asserted. */
435 		outb(UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2,
436 		     uart->base + UART_MCR);
437 		break;
438 	}
439 
440 	if (uart->irq < 0) {
441 		byte = (0 & UART_IER_RDI)	/* Disable Receiver data interrupt */
442 		    |(0 & UART_IER_THRI)	/* Disable Transmitter holding register empty interrupt */
443 		    ;
444 	} else if (uart->adaptor == SNDRV_SERIAL_MS124W_SA) {
445 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
446 		    | UART_IER_MSI	/* Enable Modem status interrupt */
447 		    ;
448 	} else if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
449 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
450 		    | UART_IER_MSI	/* Enable Modem status interrupt */
451 		    | UART_IER_THRI	/* Enable Transmitter holding register empty interrupt */
452 		    ;
453 	} else {
454 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
455 		    | UART_IER_THRI	/* Enable Transmitter holding register empty interrupt */
456 		    ;
457 	}
458 	outb(byte, uart->base + UART_IER);	/* Interrupt enable Register */
459 
460 	inb(uart->base + UART_LSR);	/* Clear any pre-existing overrun indication */
461 	inb(uart->base + UART_IIR);	/* Clear any pre-existing transmit interrupt */
462 	inb(uart->base + UART_RX);	/* Clear any pre-existing receive interrupt */
463 }
464 
465 static void snd_uart16550_do_close(struct snd_uart16550 * uart)
466 {
467 	if (uart->irq < 0)
468 		snd_uart16550_del_timer(uart);
469 
470 	/* NOTE: may need to disable interrupts before de-registering out handler.
471 	 * For now, the consequences are harmless.
472 	 */
473 
474 	outb((0 & UART_IER_RDI)		/* Disable Receiver data interrupt */
475 	     |(0 & UART_IER_THRI)	/* Disable Transmitter holding register empty interrupt */
476 	     ,uart->base + UART_IER);	/* Interrupt enable Register */
477 
478 	switch (uart->adaptor) {
479 	default:
480 		outb((0 & UART_MCR_RTS)		/* Deactivate Request-To-Send line  */
481 		     |(0 & UART_MCR_DTR)	/* Deactivate Data-Terminal-Ready line */
482 		     |(0 & UART_MCR_OUT2)	/* Deactivate OUT2 */
483 		     ,uart->base + UART_MCR);	/* Modem Control Register */
484 	  break;
485 	case SNDRV_SERIAL_MS124W_SA:
486 	case SNDRV_SERIAL_MS124W_MB:
487 		/* MS-124W can draw power from RTS and DTR if they
488 		   are in opposite states; leave it powered. */
489 		outb(UART_MCR_RTS | (0&UART_MCR_DTR) | (0&UART_MCR_OUT2),
490 		     uart->base + UART_MCR);
491 		break;
492 	case SNDRV_SERIAL_MS124T:
493 		/* MS-124T can draw power from RTS and/or DTR (preferably
494 		   both) if they are both asserted; leave it powered. */
495 		outb(UART_MCR_RTS | UART_MCR_DTR | (0&UART_MCR_OUT2),
496 		     uart->base + UART_MCR);
497 		break;
498 	}
499 
500 	inb(uart->base + UART_IIR);	/* Clear any outstanding interrupts */
501 
502 	/* Restore old divisor */
503 	if (uart->divisor != 0) {
504 		outb(UART_LCR_DLAB		/* Divisor latch access bit */
505 		     ,uart->base + UART_LCR);	/* Line Control Register */
506 		outb(uart->old_divisor_lsb
507 		     ,uart->base + UART_DLL);	/* Divisor Latch Low */
508 		outb(uart->old_divisor_msb
509 		     ,uart->base + UART_DLM);	/* Divisor Latch High */
510 		/* Restore old LCR (data bits, stop bits, parity, DLAB) */
511 		outb(uart->old_line_ctrl_reg
512 		     ,uart->base + UART_LCR);	/* Line Control Register */
513 	}
514 }
515 
516 static int snd_uart16550_input_open(struct snd_rawmidi_substream *substream)
517 {
518 	unsigned long flags;
519 	struct snd_uart16550 *uart = substream->rmidi->private_data;
520 
521 	spin_lock_irqsave(&uart->open_lock, flags);
522 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
523 		snd_uart16550_do_open(uart);
524 	uart->filemode |= SERIAL_MODE_INPUT_OPEN;
525 	uart->midi_input[substream->number] = substream;
526 	spin_unlock_irqrestore(&uart->open_lock, flags);
527 	return 0;
528 }
529 
530 static int snd_uart16550_input_close(struct snd_rawmidi_substream *substream)
531 {
532 	unsigned long flags;
533 	struct snd_uart16550 *uart = substream->rmidi->private_data;
534 
535 	spin_lock_irqsave(&uart->open_lock, flags);
536 	uart->filemode &= ~SERIAL_MODE_INPUT_OPEN;
537 	uart->midi_input[substream->number] = NULL;
538 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
539 		snd_uart16550_do_close(uart);
540 	spin_unlock_irqrestore(&uart->open_lock, flags);
541 	return 0;
542 }
543 
544 static void snd_uart16550_input_trigger(struct snd_rawmidi_substream *substream,
545 					int up)
546 {
547 	unsigned long flags;
548 	struct snd_uart16550 *uart = substream->rmidi->private_data;
549 
550 	spin_lock_irqsave(&uart->open_lock, flags);
551 	if (up)
552 		uart->filemode |= SERIAL_MODE_INPUT_TRIGGERED;
553 	else
554 		uart->filemode &= ~SERIAL_MODE_INPUT_TRIGGERED;
555 	spin_unlock_irqrestore(&uart->open_lock, flags);
556 }
557 
558 static int snd_uart16550_output_open(struct snd_rawmidi_substream *substream)
559 {
560 	unsigned long flags;
561 	struct snd_uart16550 *uart = substream->rmidi->private_data;
562 
563 	spin_lock_irqsave(&uart->open_lock, flags);
564 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
565 		snd_uart16550_do_open(uart);
566 	uart->filemode |= SERIAL_MODE_OUTPUT_OPEN;
567 	uart->midi_output[substream->number] = substream;
568 	spin_unlock_irqrestore(&uart->open_lock, flags);
569 	return 0;
570 };
571 
572 static int snd_uart16550_output_close(struct snd_rawmidi_substream *substream)
573 {
574 	unsigned long flags;
575 	struct snd_uart16550 *uart = substream->rmidi->private_data;
576 
577 	spin_lock_irqsave(&uart->open_lock, flags);
578 	uart->filemode &= ~SERIAL_MODE_OUTPUT_OPEN;
579 	uart->midi_output[substream->number] = NULL;
580 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
581 		snd_uart16550_do_close(uart);
582 	spin_unlock_irqrestore(&uart->open_lock, flags);
583 	return 0;
584 };
585 
586 static inline int snd_uart16550_buffer_can_write(struct snd_uart16550 *uart,
587 						 int Num)
588 {
589 	if (uart->buff_in_count + Num < TX_BUFF_SIZE)
590 		return 1;
591 	else
592 		return 0;
593 }
594 
595 static inline int snd_uart16550_write_buffer(struct snd_uart16550 *uart,
596 					     unsigned char byte)
597 {
598 	unsigned short buff_in = uart->buff_in;
599 	if (uart->buff_in_count < TX_BUFF_SIZE) {
600 		uart->tx_buff[buff_in] = byte;
601 		buff_in++;
602 		buff_in &= TX_BUFF_MASK;
603 		uart->buff_in = buff_in;
604 		uart->buff_in_count++;
605 		if (uart->irq < 0) /* polling mode */
606 			snd_uart16550_add_timer(uart);
607 		return 1;
608 	} else
609 		return 0;
610 }
611 
612 static int snd_uart16550_output_byte(struct snd_uart16550 *uart,
613 				     struct snd_rawmidi_substream *substream,
614 				     unsigned char midi_byte)
615 {
616 	if (uart->buff_in_count == 0                    /* Buffer empty? */
617 	    && ((uart->adaptor != SNDRV_SERIAL_MS124W_SA &&
618 	    uart->adaptor != SNDRV_SERIAL_GENERIC) ||
619 		(uart->fifo_count == 0                  /* FIFO empty? */
620 		 && (inb(uart->base + UART_MSR) & UART_MSR_CTS)))) { /* CTS? */
621 
622 	        /* Tx Buffer Empty - try to write immediately */
623 		if ((inb(uart->base + UART_LSR) & UART_LSR_THRE) != 0) {
624 		        /* Transmitter holding register (and Tx FIFO) empty */
625 		        uart->fifo_count = 1;
626 			outb(midi_byte, uart->base + UART_TX);
627 		} else {
628 		        if (uart->fifo_count < uart->fifo_limit) {
629 			        uart->fifo_count++;
630 				outb(midi_byte, uart->base + UART_TX);
631 			} else {
632 			        /* Cannot write (buffer empty) -
633 				 * put char in buffer */
634 				snd_uart16550_write_buffer(uart, midi_byte);
635 			}
636 		}
637 	} else {
638 		if (!snd_uart16550_write_buffer(uart, midi_byte)) {
639 			snd_printk("%s: Buffer overrun on device at 0x%lx\n",
640 				   uart->rmidi->name, uart->base);
641 			return 0;
642 		}
643 	}
644 
645 	return 1;
646 }
647 
648 static void snd_uart16550_output_write(struct snd_rawmidi_substream *substream)
649 {
650 	unsigned long flags;
651 	unsigned char midi_byte, addr_byte;
652 	struct snd_uart16550 *uart = substream->rmidi->private_data;
653 	char first;
654 	static unsigned long lasttime = 0;
655 
656 	/* Interrupts are disabled during the updating of the tx_buff,
657 	 * since it is 'bad' to have two processes updating the same
658 	 * variables (ie buff_in & buff_out)
659 	 */
660 
661 	spin_lock_irqsave(&uart->open_lock, flags);
662 
663 	if (uart->irq < 0)	/* polling */
664 		snd_uart16550_io_loop(uart);
665 
666 	if (uart->adaptor == SNDRV_SERIAL_MS124W_MB) {
667 		while (1) {
668 			/* buffer full? */
669 			/* in this mode we need two bytes of space */
670 			if (uart->buff_in_count > TX_BUFF_SIZE - 2)
671 				break;
672 			if (snd_rawmidi_transmit(substream, &midi_byte, 1) != 1)
673 				break;
674 #ifdef SNDRV_SERIAL_MS124W_MB_NOCOMBO
675 			/* select exactly one of the four ports */
676 			addr_byte = (1 << (substream->number + 4)) | 0x08;
677 #else
678 			/* select any combination of the four ports */
679 			addr_byte = (substream->number << 4) | 0x08;
680 			/* ...except none */
681 			if (addr_byte == 0x08)
682 				addr_byte = 0xf8;
683 #endif
684 			snd_uart16550_output_byte(uart, substream, addr_byte);
685 			/* send midi byte */
686 			snd_uart16550_output_byte(uart, substream, midi_byte);
687 		}
688 	} else {
689 		first = 0;
690 		while (snd_rawmidi_transmit_peek(substream, &midi_byte, 1) == 1) {
691 			/* Also send F5 after 3 seconds with no data
692 			 * to handle device disconnect */
693 			if (first == 0 &&
694 			    (uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS ||
695 			     uart->adaptor == SNDRV_SERIAL_GENERIC) &&
696 			    (uart->prev_out != substream->number ||
697 			     time_after(jiffies, lasttime + 3*HZ))) {
698 
699 				if (snd_uart16550_buffer_can_write(uart, 3)) {
700 					/* Roland Soundcanvas part selection */
701 					/* If this substream of the data is
702 					 * different previous substream
703 					 * in this uart, send the change part
704 					 * event
705 					 */
706 					uart->prev_out = substream->number;
707 					/* change part */
708 					snd_uart16550_output_byte(uart, substream,
709 								  0xf5);
710 					/* data */
711 					snd_uart16550_output_byte(uart, substream,
712 								  uart->prev_out + 1);
713 					/* If midi_byte is a data byte,
714 					 * send the previous status byte */
715 					if (midi_byte < 0x80 &&
716 					    uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS)
717 						snd_uart16550_output_byte(uart, substream, uart->prev_status[uart->prev_out]);
718 				} else if (!uart->drop_on_full)
719 					break;
720 
721 			}
722 
723 			/* send midi byte */
724 			if (!snd_uart16550_output_byte(uart, substream, midi_byte) &&
725 			    !uart->drop_on_full )
726 				break;
727 
728 			if (midi_byte >= 0x80 && midi_byte < 0xf0)
729 				uart->prev_status[uart->prev_out] = midi_byte;
730 			first = 1;
731 
732 			snd_rawmidi_transmit_ack( substream, 1 );
733 		}
734 		lasttime = jiffies;
735 	}
736 	spin_unlock_irqrestore(&uart->open_lock, flags);
737 }
738 
739 static void snd_uart16550_output_trigger(struct snd_rawmidi_substream *substream,
740 					 int up)
741 {
742 	unsigned long flags;
743 	struct snd_uart16550 *uart = substream->rmidi->private_data;
744 
745 	spin_lock_irqsave(&uart->open_lock, flags);
746 	if (up)
747 		uart->filemode |= SERIAL_MODE_OUTPUT_TRIGGERED;
748 	else
749 		uart->filemode &= ~SERIAL_MODE_OUTPUT_TRIGGERED;
750 	spin_unlock_irqrestore(&uart->open_lock, flags);
751 	if (up)
752 		snd_uart16550_output_write(substream);
753 }
754 
755 static struct snd_rawmidi_ops snd_uart16550_output =
756 {
757 	.open =		snd_uart16550_output_open,
758 	.close =	snd_uart16550_output_close,
759 	.trigger =	snd_uart16550_output_trigger,
760 };
761 
762 static struct snd_rawmidi_ops snd_uart16550_input =
763 {
764 	.open =		snd_uart16550_input_open,
765 	.close =	snd_uart16550_input_close,
766 	.trigger =	snd_uart16550_input_trigger,
767 };
768 
769 static int snd_uart16550_free(struct snd_uart16550 *uart)
770 {
771 	if (uart->irq >= 0)
772 		free_irq(uart->irq, uart);
773 	release_and_free_resource(uart->res_base);
774 	kfree(uart);
775 	return 0;
776 };
777 
778 static int snd_uart16550_dev_free(struct snd_device *device)
779 {
780 	struct snd_uart16550 *uart = device->device_data;
781 	return snd_uart16550_free(uart);
782 }
783 
784 static int __devinit snd_uart16550_create(struct snd_card *card,
785 				       unsigned long iobase,
786 				       int irq,
787 				       unsigned int speed,
788 				       unsigned int base,
789 				       int adaptor,
790 				       int droponfull,
791 				       struct snd_uart16550 **ruart)
792 {
793 	static struct snd_device_ops ops = {
794 		.dev_free =	snd_uart16550_dev_free,
795 	};
796 	struct snd_uart16550 *uart;
797 	int err;
798 
799 
800 	if ((uart = kzalloc(sizeof(*uart), GFP_KERNEL)) == NULL)
801 		return -ENOMEM;
802 	uart->adaptor = adaptor;
803 	uart->card = card;
804 	spin_lock_init(&uart->open_lock);
805 	uart->irq = -1;
806 	uart->base = iobase;
807 	uart->drop_on_full = droponfull;
808 
809 	if ((err = snd_uart16550_detect(uart)) <= 0) {
810 		printk(KERN_ERR "no UART detected at 0x%lx\n", iobase);
811 		snd_uart16550_free(uart);
812 		return -ENODEV;
813 	}
814 
815 	if (irq >= 0 && irq != SNDRV_AUTO_IRQ) {
816 		if (request_irq(irq, snd_uart16550_interrupt,
817 				IRQF_DISABLED, "Serial MIDI", uart)) {
818 			snd_printk("irq %d busy. Using Polling.\n", irq);
819 		} else {
820 			uart->irq = irq;
821 		}
822 	}
823 	uart->divisor = base / speed;
824 	uart->speed = base / (unsigned int)uart->divisor;
825 	uart->speed_base = base;
826 	uart->prev_out = -1;
827 	uart->prev_in = 0;
828 	uart->rstatus = 0;
829 	memset(uart->prev_status, 0x80, sizeof(unsigned char) * SNDRV_SERIAL_MAX_OUTS);
830 	init_timer(&uart->buffer_timer);
831 	uart->buffer_timer.function = snd_uart16550_buffer_timer;
832 	uart->buffer_timer.data = (unsigned long)uart;
833 	uart->timer_running = 0;
834 
835 	/* Register device */
836 	if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, uart, &ops)) < 0) {
837 		snd_uart16550_free(uart);
838 		return err;
839 	}
840 
841 	switch (uart->adaptor) {
842 	case SNDRV_SERIAL_MS124W_SA:
843 	case SNDRV_SERIAL_MS124W_MB:
844 		/* MS-124W can draw power from RTS and DTR if they
845 		   are in opposite states. */
846 		outb(UART_MCR_RTS | (0&UART_MCR_DTR), uart->base + UART_MCR);
847 		break;
848 	case SNDRV_SERIAL_MS124T:
849 		/* MS-124T can draw power from RTS and/or DTR (preferably
850 		   both) if they are asserted. */
851 		outb(UART_MCR_RTS | UART_MCR_DTR, uart->base + UART_MCR);
852 		break;
853 	default:
854 		break;
855 	}
856 
857 	if (ruart)
858 		*ruart = uart;
859 
860 	return 0;
861 }
862 
863 static void __devinit snd_uart16550_substreams(struct snd_rawmidi_str *stream)
864 {
865 	struct snd_rawmidi_substream *substream;
866 
867 	list_for_each_entry(substream, &stream->substreams, list) {
868 		sprintf(substream->name, "Serial MIDI %d", substream->number + 1);
869 	}
870 }
871 
872 static int __devinit snd_uart16550_rmidi(struct snd_uart16550 *uart, int device,
873 				      int outs, int ins,
874 				      struct snd_rawmidi **rmidi)
875 {
876 	struct snd_rawmidi *rrawmidi;
877 	int err;
878 
879 	err = snd_rawmidi_new(uart->card, "UART Serial MIDI", device,
880 			      outs, ins, &rrawmidi);
881 	if (err < 0)
882 		return err;
883 	snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_INPUT,
884 			    &snd_uart16550_input);
885 	snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
886 			    &snd_uart16550_output);
887 	strcpy(rrawmidi->name, "Serial MIDI");
888 	snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT]);
889 	snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT]);
890 	rrawmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
891 			       SNDRV_RAWMIDI_INFO_INPUT |
892 			       SNDRV_RAWMIDI_INFO_DUPLEX;
893 	rrawmidi->private_data = uart;
894 	if (rmidi)
895 		*rmidi = rrawmidi;
896 	return 0;
897 }
898 
899 static int __devinit snd_serial_probe(struct platform_device *devptr)
900 {
901 	struct snd_card *card;
902 	struct snd_uart16550 *uart;
903 	int err;
904 	int dev = devptr->id;
905 
906 	switch (adaptor[dev]) {
907 	case SNDRV_SERIAL_SOUNDCANVAS:
908 		ins[dev] = 1;
909 		break;
910 	case SNDRV_SERIAL_MS124T:
911 	case SNDRV_SERIAL_MS124W_SA:
912 		outs[dev] = 1;
913 		ins[dev] = 1;
914 		break;
915 	case SNDRV_SERIAL_MS124W_MB:
916 		outs[dev] = 16;
917 		ins[dev] = 1;
918 		break;
919 	case SNDRV_SERIAL_GENERIC:
920 		break;
921 	default:
922 		snd_printk("Adaptor type is out of range 0-%d (%d)\n",
923 			   SNDRV_SERIAL_MAX_ADAPTOR, adaptor[dev]);
924 		return -ENODEV;
925 	}
926 
927 	if (outs[dev] < 1 || outs[dev] > SNDRV_SERIAL_MAX_OUTS) {
928 		snd_printk("Count of outputs is out of range 1-%d (%d)\n",
929 			   SNDRV_SERIAL_MAX_OUTS, outs[dev]);
930 		return -ENODEV;
931 	}
932 
933 	if (ins[dev] < 1 || ins[dev] > SNDRV_SERIAL_MAX_INS) {
934 		snd_printk("Count of inputs is out of range 1-%d (%d)\n",
935 			   SNDRV_SERIAL_MAX_INS, ins[dev]);
936 		return -ENODEV;
937 	}
938 
939 	card  = snd_card_new(index[dev], id[dev], THIS_MODULE, 0);
940 	if (card == NULL)
941 		return -ENOMEM;
942 
943 	strcpy(card->driver, "Serial");
944 	strcpy(card->shortname, "Serial MIDI (UART16550A)");
945 
946 	if ((err = snd_uart16550_create(card,
947 					port[dev],
948 					irq[dev],
949 					speed[dev],
950 					base[dev],
951 					adaptor[dev],
952 					droponfull[dev],
953 					&uart)) < 0)
954 		goto _err;
955 
956 	err = snd_uart16550_rmidi(uart, 0, outs[dev], ins[dev], &uart->rmidi);
957 	if (err < 0)
958 		goto _err;
959 
960 	sprintf(card->longname, "%s at 0x%lx, irq %d speed %d div %d outs %d ins %d adaptor %s droponfull %d",
961 		card->shortname,
962 		uart->base,
963 		uart->irq,
964 		uart->speed,
965 		(int)uart->divisor,
966 		outs[dev],
967 		ins[dev],
968 		adaptor_names[uart->adaptor],
969 		uart->drop_on_full);
970 
971 	snd_card_set_dev(card, &devptr->dev);
972 
973 	if ((err = snd_card_register(card)) < 0)
974 		goto _err;
975 
976 	platform_set_drvdata(devptr, card);
977 	return 0;
978 
979  _err:
980 	snd_card_free(card);
981 	return err;
982 }
983 
984 static int __devexit snd_serial_remove(struct platform_device *devptr)
985 {
986 	snd_card_free(platform_get_drvdata(devptr));
987 	platform_set_drvdata(devptr, NULL);
988 	return 0;
989 }
990 
991 #define SND_SERIAL_DRIVER	"snd_serial_u16550"
992 
993 static struct platform_driver snd_serial_driver = {
994 	.probe		= snd_serial_probe,
995 	.remove		= __devexit_p( snd_serial_remove),
996 	.driver		= {
997 		.name	= SND_SERIAL_DRIVER
998 	},
999 };
1000 
1001 static void snd_serial_unregister_all(void)
1002 {
1003 	int i;
1004 
1005 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1006 		platform_device_unregister(devices[i]);
1007 	platform_driver_unregister(&snd_serial_driver);
1008 }
1009 
1010 static int __init alsa_card_serial_init(void)
1011 {
1012 	int i, cards, err;
1013 
1014 	if ((err = platform_driver_register(&snd_serial_driver)) < 0)
1015 		return err;
1016 
1017 	cards = 0;
1018 	for (i = 0; i < SNDRV_CARDS; i++) {
1019 		struct platform_device *device;
1020 		if (! enable[i])
1021 			continue;
1022 		device = platform_device_register_simple(SND_SERIAL_DRIVER,
1023 							 i, NULL, 0);
1024 		if (IS_ERR(device))
1025 			continue;
1026 		if (!platform_get_drvdata(device)) {
1027 			platform_device_unregister(device);
1028 			continue;
1029 		}
1030 		devices[i] = device;
1031 		cards++;
1032 	}
1033 	if (! cards) {
1034 #ifdef MODULE
1035 		printk(KERN_ERR "serial midi soundcard not found or device busy\n");
1036 #endif
1037 		snd_serial_unregister_all();
1038 		return -ENODEV;
1039 	}
1040 	return 0;
1041 }
1042 
1043 static void __exit alsa_card_serial_exit(void)
1044 {
1045 	snd_serial_unregister_all();
1046 }
1047 
1048 module_init(alsa_card_serial_init)
1049 module_exit(alsa_card_serial_exit)
1050