xref: /openbmc/linux/sound/drivers/serial-u16550.c (revision 4f6cce39)
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 <linux/io.h>
41 #include <sound/core.h>
42 #include <sound/rawmidi.h>
43 #include <sound/initval.h>
44 
45 #include <linux/serial_reg.h>
46 #include <linux/jiffies.h>
47 
48 MODULE_DESCRIPTION("MIDI serial u16550");
49 MODULE_LICENSE("GPL");
50 MODULE_SUPPORTED_DEVICE("{{ALSA, MIDI serial u16550}}");
51 
52 #define SNDRV_SERIAL_SOUNDCANVAS 0 /* Roland Soundcanvas; F5 NN selects part */
53 #define SNDRV_SERIAL_MS124T 1      /* Midiator MS-124T */
54 #define SNDRV_SERIAL_MS124W_SA 2   /* Midiator MS-124W in S/A mode */
55 #define SNDRV_SERIAL_MS124W_MB 3   /* Midiator MS-124W in M/B mode */
56 #define SNDRV_SERIAL_GENERIC 4     /* Generic Interface */
57 #define SNDRV_SERIAL_MAX_ADAPTOR SNDRV_SERIAL_GENERIC
58 static char *adaptor_names[] = {
59 	"Soundcanvas",
60         "MS-124T",
61 	"MS-124W S/A",
62 	"MS-124W M/B",
63 	"Generic"
64 };
65 
66 #define SNDRV_SERIAL_NORMALBUFF 0 /* Normal blocking buffer operation */
67 #define SNDRV_SERIAL_DROPBUFF   1 /* Non-blocking discard operation */
68 
69 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
70 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
71 static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE; /* Enable this card */
72 static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT; /* 0x3f8,0x2f8,0x3e8,0x2e8 */
73 static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ; 	/* 3,4,5,7,9,10,11,14,15 */
74 static int speed[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 38400}; /* 9600,19200,38400,57600,115200 */
75 static int base[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 115200}; /* baud base */
76 static int outs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};	 /* 1 to 16 */
77 static int ins[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};	/* 1 to 16 */
78 static int adaptor[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = SNDRV_SERIAL_SOUNDCANVAS};
79 static bool droponfull[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS -1)] = SNDRV_SERIAL_NORMALBUFF };
80 
81 module_param_array(index, int, NULL, 0444);
82 MODULE_PARM_DESC(index, "Index value for Serial MIDI.");
83 module_param_array(id, charp, NULL, 0444);
84 MODULE_PARM_DESC(id, "ID string for Serial MIDI.");
85 module_param_array(enable, bool, NULL, 0444);
86 MODULE_PARM_DESC(enable, "Enable UART16550A chip.");
87 module_param_array(port, long, NULL, 0444);
88 MODULE_PARM_DESC(port, "Port # for UART16550A chip.");
89 module_param_array(irq, int, NULL, 0444);
90 MODULE_PARM_DESC(irq, "IRQ # for UART16550A chip.");
91 module_param_array(speed, int, NULL, 0444);
92 MODULE_PARM_DESC(speed, "Speed in bauds.");
93 module_param_array(base, int, NULL, 0444);
94 MODULE_PARM_DESC(base, "Base for divisor in bauds.");
95 module_param_array(outs, int, NULL, 0444);
96 MODULE_PARM_DESC(outs, "Number of MIDI outputs.");
97 module_param_array(ins, int, NULL, 0444);
98 MODULE_PARM_DESC(ins, "Number of MIDI inputs.");
99 module_param_array(droponfull, bool, NULL, 0444);
100 MODULE_PARM_DESC(droponfull, "Flag to enable drop-on-full buffer mode");
101 
102 module_param_array(adaptor, int, NULL, 0444);
103 MODULE_PARM_DESC(adaptor, "Type of adaptor.");
104 
105 /*#define SNDRV_SERIAL_MS124W_MB_NOCOMBO 1*/  /* Address outs as 0-3 instead of bitmap */
106 
107 #define SNDRV_SERIAL_MAX_OUTS	16		/* max 64, min 16 */
108 #define SNDRV_SERIAL_MAX_INS	16		/* max 64, min 16 */
109 
110 #define TX_BUFF_SIZE		(1<<15)		/* Must be 2^n */
111 #define TX_BUFF_MASK		(TX_BUFF_SIZE - 1)
112 
113 #define SERIAL_MODE_NOT_OPENED 		(0)
114 #define SERIAL_MODE_INPUT_OPEN		(1 << 0)
115 #define SERIAL_MODE_OUTPUT_OPEN		(1 << 1)
116 #define SERIAL_MODE_INPUT_TRIGGERED	(1 << 2)
117 #define SERIAL_MODE_OUTPUT_TRIGGERED	(1 << 3)
118 
119 struct snd_uart16550 {
120 	struct snd_card *card;
121 	struct snd_rawmidi *rmidi;
122 	struct snd_rawmidi_substream *midi_output[SNDRV_SERIAL_MAX_OUTS];
123 	struct snd_rawmidi_substream *midi_input[SNDRV_SERIAL_MAX_INS];
124 
125 	int filemode;		/* open status of file */
126 
127 	spinlock_t open_lock;
128 
129 	int irq;
130 
131 	unsigned long base;
132 	struct resource *res_base;
133 
134 	unsigned int speed;
135 	unsigned int speed_base;
136 	unsigned char divisor;
137 
138 	unsigned char old_divisor_lsb;
139 	unsigned char old_divisor_msb;
140 	unsigned char old_line_ctrl_reg;
141 
142 	/* parameter for using of write loop */
143 	short int fifo_limit;	/* used in uart16550 */
144         short int fifo_count;	/* used in uart16550 */
145 
146 	/* type of adaptor */
147 	int adaptor;
148 
149 	/* inputs */
150 	int prev_in;
151 	unsigned char rstatus;
152 
153 	/* outputs */
154 	int prev_out;
155 	unsigned char prev_status[SNDRV_SERIAL_MAX_OUTS];
156 
157 	/* write buffer and its writing/reading position */
158 	unsigned char tx_buff[TX_BUFF_SIZE];
159 	int buff_in_count;
160         int buff_in;
161         int buff_out;
162         int drop_on_full;
163 
164 	/* wait timer */
165 	unsigned int timer_running:1;
166 	struct timer_list buffer_timer;
167 
168 };
169 
170 static struct platform_device *devices[SNDRV_CARDS];
171 
172 static inline void snd_uart16550_add_timer(struct snd_uart16550 *uart)
173 {
174 	if (!uart->timer_running) {
175 		/* timer 38600bps * 10bit * 16byte */
176 		mod_timer(&uart->buffer_timer, jiffies + (HZ + 255) / 256);
177 		uart->timer_running = 1;
178 	}
179 }
180 
181 static inline void snd_uart16550_del_timer(struct snd_uart16550 *uart)
182 {
183 	if (uart->timer_running) {
184 		del_timer(&uart->buffer_timer);
185 		uart->timer_running = 0;
186 	}
187 }
188 
189 /* This macro is only used in snd_uart16550_io_loop */
190 static inline void snd_uart16550_buffer_output(struct snd_uart16550 *uart)
191 {
192 	unsigned short buff_out = uart->buff_out;
193 	if (uart->buff_in_count > 0) {
194 		outb(uart->tx_buff[buff_out], uart->base + UART_TX);
195 		uart->fifo_count++;
196 		buff_out++;
197 		buff_out &= TX_BUFF_MASK;
198 		uart->buff_out = buff_out;
199 		uart->buff_in_count--;
200 	}
201 }
202 
203 /* This loop should be called with interrupts disabled
204  * We don't want to interrupt this,
205  * as we're already handling an interrupt
206  */
207 static void snd_uart16550_io_loop(struct snd_uart16550 * uart)
208 {
209 	unsigned char c, status;
210 	int substream;
211 
212 	/* recall previous stream */
213 	substream = uart->prev_in;
214 
215 	/* Read Loop */
216 	while ((status = inb(uart->base + UART_LSR)) & UART_LSR_DR) {
217 		/* while receive data ready */
218 		c = inb(uart->base + UART_RX);
219 
220 		/* keep track of last status byte */
221 		if (c & 0x80)
222 			uart->rstatus = c;
223 
224 		/* handle stream switch */
225 		if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
226 			if (uart->rstatus == 0xf5) {
227 				if (c <= SNDRV_SERIAL_MAX_INS && c > 0)
228 					substream = c - 1;
229 				if (c != 0xf5)
230 					/* prevent future bytes from being
231 					   interpreted as streams */
232 					uart->rstatus = 0;
233 			} else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN)
234 				   && uart->midi_input[substream])
235 				snd_rawmidi_receive(uart->midi_input[substream],
236 						    &c, 1);
237 		} else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN) &&
238 			   uart->midi_input[substream])
239 			snd_rawmidi_receive(uart->midi_input[substream], &c, 1);
240 
241 		if (status & UART_LSR_OE)
242 			snd_printk(KERN_WARNING
243 				   "%s: Overrun on device at 0x%lx\n",
244 			       uart->rmidi->name, uart->base);
245 	}
246 
247 	/* remember the last stream */
248 	uart->prev_in = substream;
249 
250 	/* no need of check SERIAL_MODE_OUTPUT_OPEN because if not,
251 	   buffer is never filled. */
252 	/* Check write status */
253 	if (status & UART_LSR_THRE)
254 		uart->fifo_count = 0;
255 	if (uart->adaptor == SNDRV_SERIAL_MS124W_SA
256 	   || uart->adaptor == SNDRV_SERIAL_GENERIC) {
257 		/* Can't use FIFO, must send only when CTS is true */
258 		status = inb(uart->base + UART_MSR);
259 		while (uart->fifo_count == 0 && (status & UART_MSR_CTS) &&
260 		       uart->buff_in_count > 0) {
261 		       snd_uart16550_buffer_output(uart);
262 		       status = inb(uart->base + UART_MSR);
263 		}
264 	} else {
265 		/* Write loop */
266 		while (uart->fifo_count < uart->fifo_limit /* Can we write ? */
267 		       && uart->buff_in_count > 0)	/* Do we want to? */
268 			snd_uart16550_buffer_output(uart);
269 	}
270 	if (uart->irq < 0 && uart->buff_in_count > 0)
271 		snd_uart16550_add_timer(uart);
272 }
273 
274 /* NOTES ON SERVICING INTERUPTS
275  * ---------------------------
276  * After receiving a interrupt, it is important to indicate to the UART that
277  * this has been done.
278  * For a Rx interrupt, this is done by reading the received byte.
279  * For a Tx interrupt this is done by either:
280  * a) Writing a byte
281  * b) Reading the IIR
282  * It is particularly important to read the IIR if a Tx interrupt is received
283  * when there is no data in tx_buff[], as in this case there no other
284  * indication that the interrupt has been serviced, and it remains outstanding
285  * indefinitely. This has the curious side effect that and no further interrupts
286  * will be generated from this device AT ALL!!.
287  * It is also desirable to clear outstanding interrupts when the device is
288  * opened/closed.
289  *
290  *
291  * Note that some devices need OUT2 to be set before they will generate
292  * interrupts at all. (Possibly tied to an internal pull-up on CTS?)
293  */
294 static irqreturn_t snd_uart16550_interrupt(int irq, void *dev_id)
295 {
296 	struct snd_uart16550 *uart;
297 
298 	uart = dev_id;
299 	spin_lock(&uart->open_lock);
300 	if (uart->filemode == SERIAL_MODE_NOT_OPENED) {
301 		spin_unlock(&uart->open_lock);
302 		return IRQ_NONE;
303 	}
304 	/* indicate to the UART that the interrupt has been serviced */
305 	inb(uart->base + UART_IIR);
306 	snd_uart16550_io_loop(uart);
307 	spin_unlock(&uart->open_lock);
308 	return IRQ_HANDLED;
309 }
310 
311 /* When the polling mode, this function calls snd_uart16550_io_loop. */
312 static void snd_uart16550_buffer_timer(unsigned long data)
313 {
314 	unsigned long flags;
315 	struct snd_uart16550 *uart;
316 
317 	uart = (struct snd_uart16550 *)data;
318 	spin_lock_irqsave(&uart->open_lock, flags);
319 	snd_uart16550_del_timer(uart);
320 	snd_uart16550_io_loop(uart);
321 	spin_unlock_irqrestore(&uart->open_lock, flags);
322 }
323 
324 /*
325  *  this method probes, if an uart sits on given port
326  *  return 0 if found
327  *  return negative error if not found
328  */
329 static int snd_uart16550_detect(struct snd_uart16550 *uart)
330 {
331 	unsigned long io_base = uart->base;
332 	int ok;
333 	unsigned char c;
334 
335 	/* Do some vague tests for the presence of the uart */
336 	if (io_base == 0 || io_base == SNDRV_AUTO_PORT) {
337 		return -ENODEV;	/* Not configured */
338 	}
339 
340 	uart->res_base = request_region(io_base, 8, "Serial MIDI");
341 	if (uart->res_base == NULL) {
342 		snd_printk(KERN_ERR "u16550: can't grab port 0x%lx\n", io_base);
343 		return -EBUSY;
344 	}
345 
346 	/* uart detected unless one of the following tests should fail */
347 	ok = 1;
348 	/* 8 data-bits, 1 stop-bit, parity off, DLAB = 0 */
349 	outb(UART_LCR_WLEN8, io_base + UART_LCR); /* Line Control Register */
350 	c = inb(io_base + UART_IER);
351 	/* The top four bits of the IER should always == 0 */
352 	if ((c & 0xf0) != 0)
353 		ok = 0;		/* failed */
354 
355 	outb(0xaa, io_base + UART_SCR);
356 	/* Write arbitrary data into the scratch reg */
357 	c = inb(io_base + UART_SCR);
358 	/* If it comes back, it's OK */
359 	if (c != 0xaa)
360 		ok = 0;		/* failed */
361 
362 	outb(0x55, io_base + UART_SCR);
363 	/* Write arbitrary data into the scratch reg */
364 	c = inb(io_base + UART_SCR);
365 	/* If it comes back, it's OK */
366 	if (c != 0x55)
367 		ok = 0;		/* failed */
368 
369 	return ok;
370 }
371 
372 static void snd_uart16550_do_open(struct snd_uart16550 * uart)
373 {
374 	char byte;
375 
376 	/* Initialize basic variables */
377 	uart->buff_in_count = 0;
378 	uart->buff_in = 0;
379 	uart->buff_out = 0;
380 	uart->fifo_limit = 1;
381 	uart->fifo_count = 0;
382 	uart->timer_running = 0;
383 
384 	outb(UART_FCR_ENABLE_FIFO	/* Enable FIFO's (if available) */
385 	     | UART_FCR_CLEAR_RCVR	/* Clear receiver FIFO */
386 	     | UART_FCR_CLEAR_XMIT	/* Clear transmitter FIFO */
387 	     | UART_FCR_TRIGGER_4	/* Set FIFO trigger at 4-bytes */
388 	/* NOTE: interrupt generated after T=(time)4-bytes
389 	 * if less than UART_FCR_TRIGGER bytes received
390 	 */
391 	     ,uart->base + UART_FCR);	/* FIFO Control Register */
392 
393 	if ((inb(uart->base + UART_IIR) & 0xf0) == 0xc0)
394 		uart->fifo_limit = 16;
395 	if (uart->divisor != 0) {
396 		uart->old_line_ctrl_reg = inb(uart->base + UART_LCR);
397 		outb(UART_LCR_DLAB	/* Divisor latch access bit */
398 		     ,uart->base + UART_LCR);	/* Line Control Register */
399 		uart->old_divisor_lsb = inb(uart->base + UART_DLL);
400 		uart->old_divisor_msb = inb(uart->base + UART_DLM);
401 
402 		outb(uart->divisor
403 		     ,uart->base + UART_DLL);	/* Divisor Latch Low */
404 		outb(0
405 		     ,uart->base + UART_DLM);	/* Divisor Latch High */
406 		/* DLAB is reset to 0 in next outb() */
407 	}
408 	/* Set serial parameters (parity off, etc) */
409 	outb(UART_LCR_WLEN8	/* 8 data-bits */
410 	     | 0		/* 1 stop-bit */
411 	     | 0		/* parity off */
412 	     | 0		/* DLAB = 0 */
413 	     ,uart->base + UART_LCR);	/* Line Control Register */
414 
415 	switch (uart->adaptor) {
416 	default:
417 		outb(UART_MCR_RTS	/* Set Request-To-Send line active */
418 		     | UART_MCR_DTR	/* Set Data-Terminal-Ready line active */
419 		     | UART_MCR_OUT2	/* Set OUT2 - not always required, but when
420 					 * it is, it is ESSENTIAL for enabling interrupts
421 				 */
422 		     ,uart->base + UART_MCR);	/* Modem Control Register */
423 		break;
424 	case SNDRV_SERIAL_MS124W_SA:
425 	case SNDRV_SERIAL_MS124W_MB:
426 		/* MS-124W can draw power from RTS and DTR if they
427 		   are in opposite states. */
428 		outb(UART_MCR_RTS | (0&UART_MCR_DTR) | UART_MCR_OUT2,
429 		     uart->base + UART_MCR);
430 		break;
431 	case SNDRV_SERIAL_MS124T:
432 		/* MS-124T can draw power from RTS and/or DTR (preferably
433 		   both) if they are both asserted. */
434 		outb(UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2,
435 		     uart->base + UART_MCR);
436 		break;
437 	}
438 
439 	if (uart->irq < 0) {
440 		byte = (0 & UART_IER_RDI)	/* Disable Receiver data interrupt */
441 		    |(0 & UART_IER_THRI)	/* Disable Transmitter holding register empty interrupt */
442 		    ;
443 	} else if (uart->adaptor == SNDRV_SERIAL_MS124W_SA) {
444 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
445 		    | UART_IER_MSI	/* Enable Modem status interrupt */
446 		    ;
447 	} else if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
448 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
449 		    | UART_IER_MSI	/* Enable Modem status interrupt */
450 		    | UART_IER_THRI	/* Enable Transmitter holding register empty interrupt */
451 		    ;
452 	} else {
453 		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
454 		    | UART_IER_THRI	/* Enable Transmitter holding register empty interrupt */
455 		    ;
456 	}
457 	outb(byte, uart->base + UART_IER);	/* Interrupt enable Register */
458 
459 	inb(uart->base + UART_LSR);	/* Clear any pre-existing overrun indication */
460 	inb(uart->base + UART_IIR);	/* Clear any pre-existing transmit interrupt */
461 	inb(uart->base + UART_RX);	/* Clear any pre-existing receive interrupt */
462 }
463 
464 static void snd_uart16550_do_close(struct snd_uart16550 * uart)
465 {
466 	if (uart->irq < 0)
467 		snd_uart16550_del_timer(uart);
468 
469 	/* NOTE: may need to disable interrupts before de-registering out handler.
470 	 * For now, the consequences are harmless.
471 	 */
472 
473 	outb((0 & UART_IER_RDI)		/* Disable Receiver data interrupt */
474 	     |(0 & UART_IER_THRI)	/* Disable Transmitter holding register empty interrupt */
475 	     ,uart->base + UART_IER);	/* Interrupt enable Register */
476 
477 	switch (uart->adaptor) {
478 	default:
479 		outb((0 & UART_MCR_RTS)		/* Deactivate Request-To-Send line  */
480 		     |(0 & UART_MCR_DTR)	/* Deactivate Data-Terminal-Ready line */
481 		     |(0 & UART_MCR_OUT2)	/* Deactivate OUT2 */
482 		     ,uart->base + UART_MCR);	/* Modem Control Register */
483 	  break;
484 	case SNDRV_SERIAL_MS124W_SA:
485 	case SNDRV_SERIAL_MS124W_MB:
486 		/* MS-124W can draw power from RTS and DTR if they
487 		   are in opposite states; leave it powered. */
488 		outb(UART_MCR_RTS | (0&UART_MCR_DTR) | (0&UART_MCR_OUT2),
489 		     uart->base + UART_MCR);
490 		break;
491 	case SNDRV_SERIAL_MS124T:
492 		/* MS-124T can draw power from RTS and/or DTR (preferably
493 		   both) if they are both asserted; leave it powered. */
494 		outb(UART_MCR_RTS | UART_MCR_DTR | (0&UART_MCR_OUT2),
495 		     uart->base + UART_MCR);
496 		break;
497 	}
498 
499 	inb(uart->base + UART_IIR);	/* Clear any outstanding interrupts */
500 
501 	/* Restore old divisor */
502 	if (uart->divisor != 0) {
503 		outb(UART_LCR_DLAB		/* Divisor latch access bit */
504 		     ,uart->base + UART_LCR);	/* Line Control Register */
505 		outb(uart->old_divisor_lsb
506 		     ,uart->base + UART_DLL);	/* Divisor Latch Low */
507 		outb(uart->old_divisor_msb
508 		     ,uart->base + UART_DLM);	/* Divisor Latch High */
509 		/* Restore old LCR (data bits, stop bits, parity, DLAB) */
510 		outb(uart->old_line_ctrl_reg
511 		     ,uart->base + UART_LCR);	/* Line Control Register */
512 	}
513 }
514 
515 static int snd_uart16550_input_open(struct snd_rawmidi_substream *substream)
516 {
517 	unsigned long flags;
518 	struct snd_uart16550 *uart = substream->rmidi->private_data;
519 
520 	spin_lock_irqsave(&uart->open_lock, flags);
521 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
522 		snd_uart16550_do_open(uart);
523 	uart->filemode |= SERIAL_MODE_INPUT_OPEN;
524 	uart->midi_input[substream->number] = substream;
525 	spin_unlock_irqrestore(&uart->open_lock, flags);
526 	return 0;
527 }
528 
529 static int snd_uart16550_input_close(struct snd_rawmidi_substream *substream)
530 {
531 	unsigned long flags;
532 	struct snd_uart16550 *uart = substream->rmidi->private_data;
533 
534 	spin_lock_irqsave(&uart->open_lock, flags);
535 	uart->filemode &= ~SERIAL_MODE_INPUT_OPEN;
536 	uart->midi_input[substream->number] = NULL;
537 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
538 		snd_uart16550_do_close(uart);
539 	spin_unlock_irqrestore(&uart->open_lock, flags);
540 	return 0;
541 }
542 
543 static void snd_uart16550_input_trigger(struct snd_rawmidi_substream *substream,
544 					int up)
545 {
546 	unsigned long flags;
547 	struct snd_uart16550 *uart = substream->rmidi->private_data;
548 
549 	spin_lock_irqsave(&uart->open_lock, flags);
550 	if (up)
551 		uart->filemode |= SERIAL_MODE_INPUT_TRIGGERED;
552 	else
553 		uart->filemode &= ~SERIAL_MODE_INPUT_TRIGGERED;
554 	spin_unlock_irqrestore(&uart->open_lock, flags);
555 }
556 
557 static int snd_uart16550_output_open(struct snd_rawmidi_substream *substream)
558 {
559 	unsigned long flags;
560 	struct snd_uart16550 *uart = substream->rmidi->private_data;
561 
562 	spin_lock_irqsave(&uart->open_lock, flags);
563 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
564 		snd_uart16550_do_open(uart);
565 	uart->filemode |= SERIAL_MODE_OUTPUT_OPEN;
566 	uart->midi_output[substream->number] = substream;
567 	spin_unlock_irqrestore(&uart->open_lock, flags);
568 	return 0;
569 };
570 
571 static int snd_uart16550_output_close(struct snd_rawmidi_substream *substream)
572 {
573 	unsigned long flags;
574 	struct snd_uart16550 *uart = substream->rmidi->private_data;
575 
576 	spin_lock_irqsave(&uart->open_lock, flags);
577 	uart->filemode &= ~SERIAL_MODE_OUTPUT_OPEN;
578 	uart->midi_output[substream->number] = NULL;
579 	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
580 		snd_uart16550_do_close(uart);
581 	spin_unlock_irqrestore(&uart->open_lock, flags);
582 	return 0;
583 };
584 
585 static inline int snd_uart16550_buffer_can_write(struct snd_uart16550 *uart,
586 						 int Num)
587 {
588 	if (uart->buff_in_count + Num < TX_BUFF_SIZE)
589 		return 1;
590 	else
591 		return 0;
592 }
593 
594 static inline int snd_uart16550_write_buffer(struct snd_uart16550 *uart,
595 					     unsigned char byte)
596 {
597 	unsigned short buff_in = uart->buff_in;
598 	if (uart->buff_in_count < TX_BUFF_SIZE) {
599 		uart->tx_buff[buff_in] = byte;
600 		buff_in++;
601 		buff_in &= TX_BUFF_MASK;
602 		uart->buff_in = buff_in;
603 		uart->buff_in_count++;
604 		if (uart->irq < 0) /* polling mode */
605 			snd_uart16550_add_timer(uart);
606 		return 1;
607 	} else
608 		return 0;
609 }
610 
611 static int snd_uart16550_output_byte(struct snd_uart16550 *uart,
612 				     struct snd_rawmidi_substream *substream,
613 				     unsigned char midi_byte)
614 {
615 	if (uart->buff_in_count == 0                    /* Buffer empty? */
616 	    && ((uart->adaptor != SNDRV_SERIAL_MS124W_SA &&
617 	    uart->adaptor != SNDRV_SERIAL_GENERIC) ||
618 		(uart->fifo_count == 0                  /* FIFO empty? */
619 		 && (inb(uart->base + UART_MSR) & UART_MSR_CTS)))) { /* CTS? */
620 
621 	        /* Tx Buffer Empty - try to write immediately */
622 		if ((inb(uart->base + UART_LSR) & UART_LSR_THRE) != 0) {
623 		        /* Transmitter holding register (and Tx FIFO) empty */
624 		        uart->fifo_count = 1;
625 			outb(midi_byte, uart->base + UART_TX);
626 		} else {
627 		        if (uart->fifo_count < uart->fifo_limit) {
628 			        uart->fifo_count++;
629 				outb(midi_byte, uart->base + UART_TX);
630 			} else {
631 			        /* Cannot write (buffer empty) -
632 				 * put char in buffer */
633 				snd_uart16550_write_buffer(uart, midi_byte);
634 			}
635 		}
636 	} else {
637 		if (!snd_uart16550_write_buffer(uart, midi_byte)) {
638 			snd_printk(KERN_WARNING
639 				   "%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 const 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 const 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 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 				0, "Serial MIDI", uart)) {
818 			snd_printk(KERN_WARNING
819 				   "irq %d busy. Using Polling.\n", irq);
820 		} else {
821 			uart->irq = irq;
822 		}
823 	}
824 	uart->divisor = base / speed;
825 	uart->speed = base / (unsigned int)uart->divisor;
826 	uart->speed_base = base;
827 	uart->prev_out = -1;
828 	uart->prev_in = 0;
829 	uart->rstatus = 0;
830 	memset(uart->prev_status, 0x80, sizeof(unsigned char) * SNDRV_SERIAL_MAX_OUTS);
831 	setup_timer(&uart->buffer_timer, snd_uart16550_buffer_timer,
832 		    (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 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 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 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(KERN_ERR
923 			   "Adaptor type is out of range 0-%d (%d)\n",
924 			   SNDRV_SERIAL_MAX_ADAPTOR, adaptor[dev]);
925 		return -ENODEV;
926 	}
927 
928 	if (outs[dev] < 1 || outs[dev] > SNDRV_SERIAL_MAX_OUTS) {
929 		snd_printk(KERN_ERR
930 			   "Count of outputs is out of range 1-%d (%d)\n",
931 			   SNDRV_SERIAL_MAX_OUTS, outs[dev]);
932 		return -ENODEV;
933 	}
934 
935 	if (ins[dev] < 1 || ins[dev] > SNDRV_SERIAL_MAX_INS) {
936 		snd_printk(KERN_ERR
937 			   "Count of inputs is out of range 1-%d (%d)\n",
938 			   SNDRV_SERIAL_MAX_INS, ins[dev]);
939 		return -ENODEV;
940 	}
941 
942 	err  = snd_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
943 			    0, &card);
944 	if (err < 0)
945 		return err;
946 
947 	strcpy(card->driver, "Serial");
948 	strcpy(card->shortname, "Serial MIDI (UART16550A)");
949 
950 	if ((err = snd_uart16550_create(card,
951 					port[dev],
952 					irq[dev],
953 					speed[dev],
954 					base[dev],
955 					adaptor[dev],
956 					droponfull[dev],
957 					&uart)) < 0)
958 		goto _err;
959 
960 	err = snd_uart16550_rmidi(uart, 0, outs[dev], ins[dev], &uart->rmidi);
961 	if (err < 0)
962 		goto _err;
963 
964 	sprintf(card->longname, "%s [%s] at %#lx, irq %d",
965 		card->shortname,
966 		adaptor_names[uart->adaptor],
967 		uart->base,
968 		uart->irq);
969 
970 	if ((err = snd_card_register(card)) < 0)
971 		goto _err;
972 
973 	platform_set_drvdata(devptr, card);
974 	return 0;
975 
976  _err:
977 	snd_card_free(card);
978 	return err;
979 }
980 
981 static int snd_serial_remove(struct platform_device *devptr)
982 {
983 	snd_card_free(platform_get_drvdata(devptr));
984 	return 0;
985 }
986 
987 #define SND_SERIAL_DRIVER	"snd_serial_u16550"
988 
989 static struct platform_driver snd_serial_driver = {
990 	.probe		= snd_serial_probe,
991 	.remove		=  snd_serial_remove,
992 	.driver		= {
993 		.name	= SND_SERIAL_DRIVER,
994 	},
995 };
996 
997 static void snd_serial_unregister_all(void)
998 {
999 	int i;
1000 
1001 	for (i = 0; i < ARRAY_SIZE(devices); ++i)
1002 		platform_device_unregister(devices[i]);
1003 	platform_driver_unregister(&snd_serial_driver);
1004 }
1005 
1006 static int __init alsa_card_serial_init(void)
1007 {
1008 	int i, cards, err;
1009 
1010 	if ((err = platform_driver_register(&snd_serial_driver)) < 0)
1011 		return err;
1012 
1013 	cards = 0;
1014 	for (i = 0; i < SNDRV_CARDS; i++) {
1015 		struct platform_device *device;
1016 		if (! enable[i])
1017 			continue;
1018 		device = platform_device_register_simple(SND_SERIAL_DRIVER,
1019 							 i, NULL, 0);
1020 		if (IS_ERR(device))
1021 			continue;
1022 		if (!platform_get_drvdata(device)) {
1023 			platform_device_unregister(device);
1024 			continue;
1025 		}
1026 		devices[i] = device;
1027 		cards++;
1028 	}
1029 	if (! cards) {
1030 #ifdef MODULE
1031 		printk(KERN_ERR "serial midi soundcard not found or device busy\n");
1032 #endif
1033 		snd_serial_unregister_all();
1034 		return -ENODEV;
1035 	}
1036 	return 0;
1037 }
1038 
1039 static void __exit alsa_card_serial_exit(void)
1040 {
1041 	snd_serial_unregister_all();
1042 }
1043 
1044 module_init(alsa_card_serial_init)
1045 module_exit(alsa_card_serial_exit)
1046