xref: /openbmc/linux/sound/drivers/serial-u16550.c (revision 762f99f4f3cb41a775b5157dd761217beba65873)
1  // SPDX-License-Identifier: GPL-2.0-or-later
2  /*
3   *   serial.c
4   *   Copyright (c) by Jaroslav Kysela <perex@perex.cz>,
5   *                    Isaku Yamahata <yamahata@private.email.ne.jp>,
6   *		      George Hansper <ghansper@apana.org.au>,
7   *		      Hannu Savolainen
8   *
9   *   This code is based on the code from ALSA 0.5.9, but heavily rewritten.
10   *
11   * Sat Mar 31 17:27:57 PST 2001 tim.mann@compaq.com
12   *      Added support for the Midiator MS-124T and for the MS-124W in
13   *      Single Addressed (S/A) or Multiple Burst (M/B) mode, with
14   *      power derived either parasitically from the serial port or
15   *      from a separate power supply.
16   *
17   *      More documentation can be found in serial-u16550.txt.
18   */
19  
20  #include <linux/init.h>
21  #include <linux/interrupt.h>
22  #include <linux/err.h>
23  #include <linux/platform_device.h>
24  #include <linux/slab.h>
25  #include <linux/ioport.h>
26  #include <linux/module.h>
27  #include <linux/io.h>
28  #include <sound/core.h>
29  #include <sound/rawmidi.h>
30  #include <sound/initval.h>
31  
32  #include <linux/serial_reg.h>
33  #include <linux/jiffies.h>
34  
35  MODULE_DESCRIPTION("MIDI serial u16550");
36  MODULE_LICENSE("GPL");
37  
38  #define SNDRV_SERIAL_SOUNDCANVAS 0 /* Roland Soundcanvas; F5 NN selects part */
39  #define SNDRV_SERIAL_MS124T 1      /* Midiator MS-124T */
40  #define SNDRV_SERIAL_MS124W_SA 2   /* Midiator MS-124W in S/A mode */
41  #define SNDRV_SERIAL_MS124W_MB 3   /* Midiator MS-124W in M/B mode */
42  #define SNDRV_SERIAL_GENERIC 4     /* Generic Interface */
43  #define SNDRV_SERIAL_MAX_ADAPTOR SNDRV_SERIAL_GENERIC
44  static const char * const adaptor_names[] = {
45  	"Soundcanvas",
46          "MS-124T",
47  	"MS-124W S/A",
48  	"MS-124W M/B",
49  	"Generic"
50  };
51  
52  #define SNDRV_SERIAL_NORMALBUFF 0 /* Normal blocking buffer operation */
53  #define SNDRV_SERIAL_DROPBUFF   1 /* Non-blocking discard operation */
54  
55  static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
56  static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
57  static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE; /* Enable this card */
58  static long port[SNDRV_CARDS] = SNDRV_DEFAULT_PORT; /* 0x3f8,0x2f8,0x3e8,0x2e8 */
59  static int irq[SNDRV_CARDS] = SNDRV_DEFAULT_IRQ; 	/* 3,4,5,7,9,10,11,14,15 */
60  static int speed[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 38400}; /* 9600,19200,38400,57600,115200 */
61  static int base[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 115200}; /* baud base */
62  static int outs[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};	 /* 1 to 16 */
63  static int ins[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = 1};	/* 1 to 16 */
64  static int adaptor[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS - 1)] = SNDRV_SERIAL_SOUNDCANVAS};
65  static bool droponfull[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS -1)] = SNDRV_SERIAL_NORMALBUFF };
66  
67  module_param_array(index, int, NULL, 0444);
68  MODULE_PARM_DESC(index, "Index value for Serial MIDI.");
69  module_param_array(id, charp, NULL, 0444);
70  MODULE_PARM_DESC(id, "ID string for Serial MIDI.");
71  module_param_array(enable, bool, NULL, 0444);
72  MODULE_PARM_DESC(enable, "Enable UART16550A chip.");
73  module_param_hw_array(port, long, ioport, NULL, 0444);
74  MODULE_PARM_DESC(port, "Port # for UART16550A chip.");
75  module_param_hw_array(irq, int, irq, NULL, 0444);
76  MODULE_PARM_DESC(irq, "IRQ # for UART16550A chip.");
77  module_param_array(speed, int, NULL, 0444);
78  MODULE_PARM_DESC(speed, "Speed in bauds.");
79  module_param_array(base, int, NULL, 0444);
80  MODULE_PARM_DESC(base, "Base for divisor in bauds.");
81  module_param_array(outs, int, NULL, 0444);
82  MODULE_PARM_DESC(outs, "Number of MIDI outputs.");
83  module_param_array(ins, int, NULL, 0444);
84  MODULE_PARM_DESC(ins, "Number of MIDI inputs.");
85  module_param_array(droponfull, bool, NULL, 0444);
86  MODULE_PARM_DESC(droponfull, "Flag to enable drop-on-full buffer mode");
87  
88  module_param_array(adaptor, int, NULL, 0444);
89  MODULE_PARM_DESC(adaptor, "Type of adaptor.");
90  
91  /*#define SNDRV_SERIAL_MS124W_MB_NOCOMBO 1*/  /* Address outs as 0-3 instead of bitmap */
92  
93  #define SNDRV_SERIAL_MAX_OUTS	16		/* max 64, min 16 */
94  #define SNDRV_SERIAL_MAX_INS	16		/* max 64, min 16 */
95  
96  #define TX_BUFF_SIZE		(1<<15)		/* Must be 2^n */
97  #define TX_BUFF_MASK		(TX_BUFF_SIZE - 1)
98  
99  #define SERIAL_MODE_NOT_OPENED 		(0)
100  #define SERIAL_MODE_INPUT_OPEN		(1 << 0)
101  #define SERIAL_MODE_OUTPUT_OPEN		(1 << 1)
102  #define SERIAL_MODE_INPUT_TRIGGERED	(1 << 2)
103  #define SERIAL_MODE_OUTPUT_TRIGGERED	(1 << 3)
104  
105  struct snd_uart16550 {
106  	struct snd_card *card;
107  	struct snd_rawmidi *rmidi;
108  	struct snd_rawmidi_substream *midi_output[SNDRV_SERIAL_MAX_OUTS];
109  	struct snd_rawmidi_substream *midi_input[SNDRV_SERIAL_MAX_INS];
110  
111  	int filemode;		/* open status of file */
112  
113  	spinlock_t open_lock;
114  
115  	int irq;
116  
117  	unsigned long base;
118  
119  	unsigned int speed;
120  	unsigned int speed_base;
121  	unsigned char divisor;
122  
123  	unsigned char old_divisor_lsb;
124  	unsigned char old_divisor_msb;
125  	unsigned char old_line_ctrl_reg;
126  
127  	/* parameter for using of write loop */
128  	short int fifo_limit;	/* used in uart16550 */
129          short int fifo_count;	/* used in uart16550 */
130  
131  	/* type of adaptor */
132  	int adaptor;
133  
134  	/* inputs */
135  	int prev_in;
136  	unsigned char rstatus;
137  
138  	/* outputs */
139  	int prev_out;
140  	unsigned char prev_status[SNDRV_SERIAL_MAX_OUTS];
141  
142  	/* write buffer and its writing/reading position */
143  	unsigned char tx_buff[TX_BUFF_SIZE];
144  	int buff_in_count;
145          int buff_in;
146          int buff_out;
147          int drop_on_full;
148  
149  	/* wait timer */
150  	unsigned int timer_running:1;
151  	struct timer_list buffer_timer;
152  
153  };
154  
155  static struct platform_device *devices[SNDRV_CARDS];
156  
snd_uart16550_add_timer(struct snd_uart16550 * uart)157  static inline void snd_uart16550_add_timer(struct snd_uart16550 *uart)
158  {
159  	if (!uart->timer_running) {
160  		/* timer 38600bps * 10bit * 16byte */
161  		mod_timer(&uart->buffer_timer, jiffies + (HZ + 255) / 256);
162  		uart->timer_running = 1;
163  	}
164  }
165  
snd_uart16550_del_timer(struct snd_uart16550 * uart)166  static inline void snd_uart16550_del_timer(struct snd_uart16550 *uart)
167  {
168  	if (uart->timer_running) {
169  		del_timer(&uart->buffer_timer);
170  		uart->timer_running = 0;
171  	}
172  }
173  
174  /* This macro is only used in snd_uart16550_io_loop */
snd_uart16550_buffer_output(struct snd_uart16550 * uart)175  static inline void snd_uart16550_buffer_output(struct snd_uart16550 *uart)
176  {
177  	unsigned short buff_out = uart->buff_out;
178  	if (uart->buff_in_count > 0) {
179  		outb(uart->tx_buff[buff_out], uart->base + UART_TX);
180  		uart->fifo_count++;
181  		buff_out++;
182  		buff_out &= TX_BUFF_MASK;
183  		uart->buff_out = buff_out;
184  		uart->buff_in_count--;
185  	}
186  }
187  
188  /* This loop should be called with interrupts disabled
189   * We don't want to interrupt this,
190   * as we're already handling an interrupt
191   */
snd_uart16550_io_loop(struct snd_uart16550 * uart)192  static void snd_uart16550_io_loop(struct snd_uart16550 * uart)
193  {
194  	unsigned char c, status;
195  	int substream;
196  
197  	/* recall previous stream */
198  	substream = uart->prev_in;
199  
200  	/* Read Loop */
201  	while ((status = inb(uart->base + UART_LSR)) & UART_LSR_DR) {
202  		/* while receive data ready */
203  		c = inb(uart->base + UART_RX);
204  
205  		/* keep track of last status byte */
206  		if (c & 0x80)
207  			uart->rstatus = c;
208  
209  		/* handle stream switch */
210  		if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
211  			if (uart->rstatus == 0xf5) {
212  				if (c <= SNDRV_SERIAL_MAX_INS && c > 0)
213  					substream = c - 1;
214  				if (c != 0xf5)
215  					/* prevent future bytes from being
216  					   interpreted as streams */
217  					uart->rstatus = 0;
218  			} else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN)
219  				   && uart->midi_input[substream])
220  				snd_rawmidi_receive(uart->midi_input[substream],
221  						    &c, 1);
222  		} else if ((uart->filemode & SERIAL_MODE_INPUT_OPEN) &&
223  			   uart->midi_input[substream])
224  			snd_rawmidi_receive(uart->midi_input[substream], &c, 1);
225  
226  		if (status & UART_LSR_OE)
227  			snd_printk(KERN_WARNING
228  				   "%s: Overrun on device at 0x%lx\n",
229  			       uart->rmidi->name, uart->base);
230  	}
231  
232  	/* remember the last stream */
233  	uart->prev_in = substream;
234  
235  	/* no need of check SERIAL_MODE_OUTPUT_OPEN because if not,
236  	   buffer is never filled. */
237  	/* Check write status */
238  	if (status & UART_LSR_THRE)
239  		uart->fifo_count = 0;
240  	if (uart->adaptor == SNDRV_SERIAL_MS124W_SA
241  	   || uart->adaptor == SNDRV_SERIAL_GENERIC) {
242  		/* Can't use FIFO, must send only when CTS is true */
243  		status = inb(uart->base + UART_MSR);
244  		while (uart->fifo_count == 0 && (status & UART_MSR_CTS) &&
245  		       uart->buff_in_count > 0) {
246  		       snd_uart16550_buffer_output(uart);
247  		       status = inb(uart->base + UART_MSR);
248  		}
249  	} else {
250  		/* Write loop */
251  		while (uart->fifo_count < uart->fifo_limit /* Can we write ? */
252  		       && uart->buff_in_count > 0)	/* Do we want to? */
253  			snd_uart16550_buffer_output(uart);
254  	}
255  	if (uart->irq < 0 && uart->buff_in_count > 0)
256  		snd_uart16550_add_timer(uart);
257  }
258  
259  /* NOTES ON SERVICING INTERUPTS
260   * ---------------------------
261   * After receiving a interrupt, it is important to indicate to the UART that
262   * this has been done.
263   * For a Rx interrupt, this is done by reading the received byte.
264   * For a Tx interrupt this is done by either:
265   * a) Writing a byte
266   * b) Reading the IIR
267   * It is particularly important to read the IIR if a Tx interrupt is received
268   * when there is no data in tx_buff[], as in this case there no other
269   * indication that the interrupt has been serviced, and it remains outstanding
270   * indefinitely. This has the curious side effect that and no further interrupts
271   * will be generated from this device AT ALL!!.
272   * It is also desirable to clear outstanding interrupts when the device is
273   * opened/closed.
274   *
275   *
276   * Note that some devices need OUT2 to be set before they will generate
277   * interrupts at all. (Possibly tied to an internal pull-up on CTS?)
278   */
snd_uart16550_interrupt(int irq,void * dev_id)279  static irqreturn_t snd_uart16550_interrupt(int irq, void *dev_id)
280  {
281  	struct snd_uart16550 *uart;
282  
283  	uart = dev_id;
284  	spin_lock(&uart->open_lock);
285  	if (uart->filemode == SERIAL_MODE_NOT_OPENED) {
286  		spin_unlock(&uart->open_lock);
287  		return IRQ_NONE;
288  	}
289  	/* indicate to the UART that the interrupt has been serviced */
290  	inb(uart->base + UART_IIR);
291  	snd_uart16550_io_loop(uart);
292  	spin_unlock(&uart->open_lock);
293  	return IRQ_HANDLED;
294  }
295  
296  /* When the polling mode, this function calls snd_uart16550_io_loop. */
snd_uart16550_buffer_timer(struct timer_list * t)297  static void snd_uart16550_buffer_timer(struct timer_list *t)
298  {
299  	unsigned long flags;
300  	struct snd_uart16550 *uart;
301  
302  	uart = from_timer(uart, t, buffer_timer);
303  	spin_lock_irqsave(&uart->open_lock, flags);
304  	snd_uart16550_del_timer(uart);
305  	snd_uart16550_io_loop(uart);
306  	spin_unlock_irqrestore(&uart->open_lock, flags);
307  }
308  
309  /*
310   *  this method probes, if an uart sits on given port
311   *  return 0 if found
312   *  return negative error if not found
313   */
snd_uart16550_detect(struct snd_uart16550 * uart)314  static int snd_uart16550_detect(struct snd_uart16550 *uart)
315  {
316  	unsigned long io_base = uart->base;
317  	int ok;
318  	unsigned char c;
319  
320  	/* Do some vague tests for the presence of the uart */
321  	if (io_base == 0 || io_base == SNDRV_AUTO_PORT) {
322  		return -ENODEV;	/* Not configured */
323  	}
324  
325  	if (!devm_request_region(uart->card->dev, io_base, 8, "Serial MIDI")) {
326  		snd_printk(KERN_ERR "u16550: can't grab port 0x%lx\n", io_base);
327  		return -EBUSY;
328  	}
329  
330  	/* uart detected unless one of the following tests should fail */
331  	ok = 1;
332  	/* 8 data-bits, 1 stop-bit, parity off, DLAB = 0 */
333  	outb(UART_LCR_WLEN8, io_base + UART_LCR); /* Line Control Register */
334  	c = inb(io_base + UART_IER);
335  	/* The top four bits of the IER should always == 0 */
336  	if ((c & 0xf0) != 0)
337  		ok = 0;		/* failed */
338  
339  	outb(0xaa, io_base + UART_SCR);
340  	/* Write arbitrary data into the scratch reg */
341  	c = inb(io_base + UART_SCR);
342  	/* If it comes back, it's OK */
343  	if (c != 0xaa)
344  		ok = 0;		/* failed */
345  
346  	outb(0x55, io_base + UART_SCR);
347  	/* Write arbitrary data into the scratch reg */
348  	c = inb(io_base + UART_SCR);
349  	/* If it comes back, it's OK */
350  	if (c != 0x55)
351  		ok = 0;		/* failed */
352  
353  	return ok;
354  }
355  
snd_uart16550_do_open(struct snd_uart16550 * uart)356  static void snd_uart16550_do_open(struct snd_uart16550 * uart)
357  {
358  	char byte;
359  
360  	/* Initialize basic variables */
361  	uart->buff_in_count = 0;
362  	uart->buff_in = 0;
363  	uart->buff_out = 0;
364  	uart->fifo_limit = 1;
365  	uart->fifo_count = 0;
366  	uart->timer_running = 0;
367  
368  	outb(UART_FCR_ENABLE_FIFO	/* Enable FIFO's (if available) */
369  	     | UART_FCR_CLEAR_RCVR	/* Clear receiver FIFO */
370  	     | UART_FCR_CLEAR_XMIT	/* Clear transmitter FIFO */
371  	     | UART_FCR_TRIGGER_4	/* Set FIFO trigger at 4-bytes */
372  	/* NOTE: interrupt generated after T=(time)4-bytes
373  	 * if less than UART_FCR_TRIGGER bytes received
374  	 */
375  	     ,uart->base + UART_FCR);	/* FIFO Control Register */
376  
377  	if ((inb(uart->base + UART_IIR) & 0xf0) == 0xc0)
378  		uart->fifo_limit = 16;
379  	if (uart->divisor != 0) {
380  		uart->old_line_ctrl_reg = inb(uart->base + UART_LCR);
381  		outb(UART_LCR_DLAB	/* Divisor latch access bit */
382  		     ,uart->base + UART_LCR);	/* Line Control Register */
383  		uart->old_divisor_lsb = inb(uart->base + UART_DLL);
384  		uart->old_divisor_msb = inb(uart->base + UART_DLM);
385  
386  		outb(uart->divisor
387  		     ,uart->base + UART_DLL);	/* Divisor Latch Low */
388  		outb(0
389  		     ,uart->base + UART_DLM);	/* Divisor Latch High */
390  		/* DLAB is reset to 0 in next outb() */
391  	}
392  	/* Set serial parameters (parity off, etc) */
393  	outb(UART_LCR_WLEN8	/* 8 data-bits */
394  	     | 0		/* 1 stop-bit */
395  	     | 0		/* parity off */
396  	     | 0		/* DLAB = 0 */
397  	     ,uart->base + UART_LCR);	/* Line Control Register */
398  
399  	switch (uart->adaptor) {
400  	default:
401  		outb(UART_MCR_RTS	/* Set Request-To-Send line active */
402  		     | UART_MCR_DTR	/* Set Data-Terminal-Ready line active */
403  		     | UART_MCR_OUT2	/* Set OUT2 - not always required, but when
404  					 * it is, it is ESSENTIAL for enabling interrupts
405  				 */
406  		     ,uart->base + UART_MCR);	/* Modem Control Register */
407  		break;
408  	case SNDRV_SERIAL_MS124W_SA:
409  	case SNDRV_SERIAL_MS124W_MB:
410  		/* MS-124W can draw power from RTS and DTR if they
411  		   are in opposite states. */
412  		outb(UART_MCR_RTS | (0&UART_MCR_DTR) | UART_MCR_OUT2,
413  		     uart->base + UART_MCR);
414  		break;
415  	case SNDRV_SERIAL_MS124T:
416  		/* MS-124T can draw power from RTS and/or DTR (preferably
417  		   both) if they are both asserted. */
418  		outb(UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2,
419  		     uart->base + UART_MCR);
420  		break;
421  	}
422  
423  	if (uart->irq < 0) {
424  		byte = (0 & UART_IER_RDI)	/* Disable Receiver data interrupt */
425  		    |(0 & UART_IER_THRI)	/* Disable Transmitter holding register empty interrupt */
426  		    ;
427  	} else if (uart->adaptor == SNDRV_SERIAL_MS124W_SA) {
428  		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
429  		    | UART_IER_MSI	/* Enable Modem status interrupt */
430  		    ;
431  	} else if (uart->adaptor == SNDRV_SERIAL_GENERIC) {
432  		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
433  		    | UART_IER_MSI	/* Enable Modem status interrupt */
434  		    | UART_IER_THRI	/* Enable Transmitter holding register empty interrupt */
435  		    ;
436  	} else {
437  		byte = UART_IER_RDI	/* Enable Receiver data interrupt */
438  		    | UART_IER_THRI	/* Enable Transmitter holding register empty interrupt */
439  		    ;
440  	}
441  	outb(byte, uart->base + UART_IER);	/* Interrupt enable Register */
442  
443  	inb(uart->base + UART_LSR);	/* Clear any pre-existing overrun indication */
444  	inb(uart->base + UART_IIR);	/* Clear any pre-existing transmit interrupt */
445  	inb(uart->base + UART_RX);	/* Clear any pre-existing receive interrupt */
446  }
447  
snd_uart16550_do_close(struct snd_uart16550 * uart)448  static void snd_uart16550_do_close(struct snd_uart16550 * uart)
449  {
450  	if (uart->irq < 0)
451  		snd_uart16550_del_timer(uart);
452  
453  	/* NOTE: may need to disable interrupts before de-registering out handler.
454  	 * For now, the consequences are harmless.
455  	 */
456  
457  	outb((0 & UART_IER_RDI)		/* Disable Receiver data interrupt */
458  	     |(0 & UART_IER_THRI)	/* Disable Transmitter holding register empty interrupt */
459  	     ,uart->base + UART_IER);	/* Interrupt enable Register */
460  
461  	switch (uart->adaptor) {
462  	default:
463  		outb((0 & UART_MCR_RTS)		/* Deactivate Request-To-Send line  */
464  		     |(0 & UART_MCR_DTR)	/* Deactivate Data-Terminal-Ready line */
465  		     |(0 & UART_MCR_OUT2)	/* Deactivate OUT2 */
466  		     ,uart->base + UART_MCR);	/* Modem Control Register */
467  	  break;
468  	case SNDRV_SERIAL_MS124W_SA:
469  	case SNDRV_SERIAL_MS124W_MB:
470  		/* MS-124W can draw power from RTS and DTR if they
471  		   are in opposite states; leave it powered. */
472  		outb(UART_MCR_RTS | (0&UART_MCR_DTR) | (0&UART_MCR_OUT2),
473  		     uart->base + UART_MCR);
474  		break;
475  	case SNDRV_SERIAL_MS124T:
476  		/* MS-124T can draw power from RTS and/or DTR (preferably
477  		   both) if they are both asserted; leave it powered. */
478  		outb(UART_MCR_RTS | UART_MCR_DTR | (0&UART_MCR_OUT2),
479  		     uart->base + UART_MCR);
480  		break;
481  	}
482  
483  	inb(uart->base + UART_IIR);	/* Clear any outstanding interrupts */
484  
485  	/* Restore old divisor */
486  	if (uart->divisor != 0) {
487  		outb(UART_LCR_DLAB		/* Divisor latch access bit */
488  		     ,uart->base + UART_LCR);	/* Line Control Register */
489  		outb(uart->old_divisor_lsb
490  		     ,uart->base + UART_DLL);	/* Divisor Latch Low */
491  		outb(uart->old_divisor_msb
492  		     ,uart->base + UART_DLM);	/* Divisor Latch High */
493  		/* Restore old LCR (data bits, stop bits, parity, DLAB) */
494  		outb(uart->old_line_ctrl_reg
495  		     ,uart->base + UART_LCR);	/* Line Control Register */
496  	}
497  }
498  
snd_uart16550_input_open(struct snd_rawmidi_substream * substream)499  static int snd_uart16550_input_open(struct snd_rawmidi_substream *substream)
500  {
501  	unsigned long flags;
502  	struct snd_uart16550 *uart = substream->rmidi->private_data;
503  
504  	spin_lock_irqsave(&uart->open_lock, flags);
505  	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
506  		snd_uart16550_do_open(uart);
507  	uart->filemode |= SERIAL_MODE_INPUT_OPEN;
508  	uart->midi_input[substream->number] = substream;
509  	spin_unlock_irqrestore(&uart->open_lock, flags);
510  	return 0;
511  }
512  
snd_uart16550_input_close(struct snd_rawmidi_substream * substream)513  static int snd_uart16550_input_close(struct snd_rawmidi_substream *substream)
514  {
515  	unsigned long flags;
516  	struct snd_uart16550 *uart = substream->rmidi->private_data;
517  
518  	spin_lock_irqsave(&uart->open_lock, flags);
519  	uart->filemode &= ~SERIAL_MODE_INPUT_OPEN;
520  	uart->midi_input[substream->number] = NULL;
521  	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
522  		snd_uart16550_do_close(uart);
523  	spin_unlock_irqrestore(&uart->open_lock, flags);
524  	return 0;
525  }
526  
snd_uart16550_input_trigger(struct snd_rawmidi_substream * substream,int up)527  static void snd_uart16550_input_trigger(struct snd_rawmidi_substream *substream,
528  					int up)
529  {
530  	unsigned long flags;
531  	struct snd_uart16550 *uart = substream->rmidi->private_data;
532  
533  	spin_lock_irqsave(&uart->open_lock, flags);
534  	if (up)
535  		uart->filemode |= SERIAL_MODE_INPUT_TRIGGERED;
536  	else
537  		uart->filemode &= ~SERIAL_MODE_INPUT_TRIGGERED;
538  	spin_unlock_irqrestore(&uart->open_lock, flags);
539  }
540  
snd_uart16550_output_open(struct snd_rawmidi_substream * substream)541  static int snd_uart16550_output_open(struct snd_rawmidi_substream *substream)
542  {
543  	unsigned long flags;
544  	struct snd_uart16550 *uart = substream->rmidi->private_data;
545  
546  	spin_lock_irqsave(&uart->open_lock, flags);
547  	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
548  		snd_uart16550_do_open(uart);
549  	uart->filemode |= SERIAL_MODE_OUTPUT_OPEN;
550  	uart->midi_output[substream->number] = substream;
551  	spin_unlock_irqrestore(&uart->open_lock, flags);
552  	return 0;
553  };
554  
snd_uart16550_output_close(struct snd_rawmidi_substream * substream)555  static int snd_uart16550_output_close(struct snd_rawmidi_substream *substream)
556  {
557  	unsigned long flags;
558  	struct snd_uart16550 *uart = substream->rmidi->private_data;
559  
560  	spin_lock_irqsave(&uart->open_lock, flags);
561  	uart->filemode &= ~SERIAL_MODE_OUTPUT_OPEN;
562  	uart->midi_output[substream->number] = NULL;
563  	if (uart->filemode == SERIAL_MODE_NOT_OPENED)
564  		snd_uart16550_do_close(uart);
565  	spin_unlock_irqrestore(&uart->open_lock, flags);
566  	return 0;
567  };
568  
snd_uart16550_buffer_can_write(struct snd_uart16550 * uart,int Num)569  static inline int snd_uart16550_buffer_can_write(struct snd_uart16550 *uart,
570  						 int Num)
571  {
572  	if (uart->buff_in_count + Num < TX_BUFF_SIZE)
573  		return 1;
574  	else
575  		return 0;
576  }
577  
snd_uart16550_write_buffer(struct snd_uart16550 * uart,unsigned char byte)578  static inline int snd_uart16550_write_buffer(struct snd_uart16550 *uart,
579  					     unsigned char byte)
580  {
581  	unsigned short buff_in = uart->buff_in;
582  	if (uart->buff_in_count < TX_BUFF_SIZE) {
583  		uart->tx_buff[buff_in] = byte;
584  		buff_in++;
585  		buff_in &= TX_BUFF_MASK;
586  		uart->buff_in = buff_in;
587  		uart->buff_in_count++;
588  		if (uart->irq < 0) /* polling mode */
589  			snd_uart16550_add_timer(uart);
590  		return 1;
591  	} else
592  		return 0;
593  }
594  
snd_uart16550_output_byte(struct snd_uart16550 * uart,struct snd_rawmidi_substream * substream,unsigned char midi_byte)595  static int snd_uart16550_output_byte(struct snd_uart16550 *uart,
596  				     struct snd_rawmidi_substream *substream,
597  				     unsigned char midi_byte)
598  {
599  	if (uart->buff_in_count == 0                    /* Buffer empty? */
600  	    && ((uart->adaptor != SNDRV_SERIAL_MS124W_SA &&
601  	    uart->adaptor != SNDRV_SERIAL_GENERIC) ||
602  		(uart->fifo_count == 0                  /* FIFO empty? */
603  		 && (inb(uart->base + UART_MSR) & UART_MSR_CTS)))) { /* CTS? */
604  
605  	        /* Tx Buffer Empty - try to write immediately */
606  		if ((inb(uart->base + UART_LSR) & UART_LSR_THRE) != 0) {
607  		        /* Transmitter holding register (and Tx FIFO) empty */
608  		        uart->fifo_count = 1;
609  			outb(midi_byte, uart->base + UART_TX);
610  		} else {
611  		        if (uart->fifo_count < uart->fifo_limit) {
612  			        uart->fifo_count++;
613  				outb(midi_byte, uart->base + UART_TX);
614  			} else {
615  			        /* Cannot write (buffer empty) -
616  				 * put char in buffer */
617  				snd_uart16550_write_buffer(uart, midi_byte);
618  			}
619  		}
620  	} else {
621  		if (!snd_uart16550_write_buffer(uart, midi_byte)) {
622  			snd_printk(KERN_WARNING
623  				   "%s: Buffer overrun on device at 0x%lx\n",
624  				   uart->rmidi->name, uart->base);
625  			return 0;
626  		}
627  	}
628  
629  	return 1;
630  }
631  
snd_uart16550_output_write(struct snd_rawmidi_substream * substream)632  static void snd_uart16550_output_write(struct snd_rawmidi_substream *substream)
633  {
634  	unsigned long flags;
635  	unsigned char midi_byte, addr_byte;
636  	struct snd_uart16550 *uart = substream->rmidi->private_data;
637  	char first;
638  	static unsigned long lasttime = 0;
639  
640  	/* Interrupts are disabled during the updating of the tx_buff,
641  	 * since it is 'bad' to have two processes updating the same
642  	 * variables (ie buff_in & buff_out)
643  	 */
644  
645  	spin_lock_irqsave(&uart->open_lock, flags);
646  
647  	if (uart->irq < 0)	/* polling */
648  		snd_uart16550_io_loop(uart);
649  
650  	if (uart->adaptor == SNDRV_SERIAL_MS124W_MB) {
651  		while (1) {
652  			/* buffer full? */
653  			/* in this mode we need two bytes of space */
654  			if (uart->buff_in_count > TX_BUFF_SIZE - 2)
655  				break;
656  			if (snd_rawmidi_transmit(substream, &midi_byte, 1) != 1)
657  				break;
658  #ifdef SNDRV_SERIAL_MS124W_MB_NOCOMBO
659  			/* select exactly one of the four ports */
660  			addr_byte = (1 << (substream->number + 4)) | 0x08;
661  #else
662  			/* select any combination of the four ports */
663  			addr_byte = (substream->number << 4) | 0x08;
664  			/* ...except none */
665  			if (addr_byte == 0x08)
666  				addr_byte = 0xf8;
667  #endif
668  			snd_uart16550_output_byte(uart, substream, addr_byte);
669  			/* send midi byte */
670  			snd_uart16550_output_byte(uart, substream, midi_byte);
671  		}
672  	} else {
673  		first = 0;
674  		while (snd_rawmidi_transmit_peek(substream, &midi_byte, 1) == 1) {
675  			/* Also send F5 after 3 seconds with no data
676  			 * to handle device disconnect */
677  			if (first == 0 &&
678  			    (uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS ||
679  			     uart->adaptor == SNDRV_SERIAL_GENERIC) &&
680  			    (uart->prev_out != substream->number ||
681  			     time_after(jiffies, lasttime + 3*HZ))) {
682  
683  				if (snd_uart16550_buffer_can_write(uart, 3)) {
684  					/* Roland Soundcanvas part selection */
685  					/* If this substream of the data is
686  					 * different previous substream
687  					 * in this uart, send the change part
688  					 * event
689  					 */
690  					uart->prev_out = substream->number;
691  					/* change part */
692  					snd_uart16550_output_byte(uart, substream,
693  								  0xf5);
694  					/* data */
695  					snd_uart16550_output_byte(uart, substream,
696  								  uart->prev_out + 1);
697  					/* If midi_byte is a data byte,
698  					 * send the previous status byte */
699  					if (midi_byte < 0x80 &&
700  					    uart->adaptor == SNDRV_SERIAL_SOUNDCANVAS)
701  						snd_uart16550_output_byte(uart, substream, uart->prev_status[uart->prev_out]);
702  				} else if (!uart->drop_on_full)
703  					break;
704  
705  			}
706  
707  			/* send midi byte */
708  			if (!snd_uart16550_output_byte(uart, substream, midi_byte) &&
709  			    !uart->drop_on_full )
710  				break;
711  
712  			if (midi_byte >= 0x80 && midi_byte < 0xf0)
713  				uart->prev_status[uart->prev_out] = midi_byte;
714  			first = 1;
715  
716  			snd_rawmidi_transmit_ack( substream, 1 );
717  		}
718  		lasttime = jiffies;
719  	}
720  	spin_unlock_irqrestore(&uart->open_lock, flags);
721  }
722  
snd_uart16550_output_trigger(struct snd_rawmidi_substream * substream,int up)723  static void snd_uart16550_output_trigger(struct snd_rawmidi_substream *substream,
724  					 int up)
725  {
726  	unsigned long flags;
727  	struct snd_uart16550 *uart = substream->rmidi->private_data;
728  
729  	spin_lock_irqsave(&uart->open_lock, flags);
730  	if (up)
731  		uart->filemode |= SERIAL_MODE_OUTPUT_TRIGGERED;
732  	else
733  		uart->filemode &= ~SERIAL_MODE_OUTPUT_TRIGGERED;
734  	spin_unlock_irqrestore(&uart->open_lock, flags);
735  	if (up)
736  		snd_uart16550_output_write(substream);
737  }
738  
739  static const struct snd_rawmidi_ops snd_uart16550_output =
740  {
741  	.open =		snd_uart16550_output_open,
742  	.close =	snd_uart16550_output_close,
743  	.trigger =	snd_uart16550_output_trigger,
744  };
745  
746  static const struct snd_rawmidi_ops snd_uart16550_input =
747  {
748  	.open =		snd_uart16550_input_open,
749  	.close =	snd_uart16550_input_close,
750  	.trigger =	snd_uart16550_input_trigger,
751  };
752  
snd_uart16550_create(struct snd_card * card,unsigned long iobase,int irq,unsigned int speed,unsigned int base,int adaptor,int droponfull,struct snd_uart16550 ** ruart)753  static int snd_uart16550_create(struct snd_card *card,
754  				unsigned long iobase,
755  				int irq,
756  				unsigned int speed,
757  				unsigned int base,
758  				int adaptor,
759  				int droponfull,
760  				struct snd_uart16550 **ruart)
761  {
762  	struct snd_uart16550 *uart;
763  	int err;
764  
765  
766  	uart = devm_kzalloc(card->dev, sizeof(*uart), GFP_KERNEL);
767  	if (!uart)
768  		return -ENOMEM;
769  	uart->adaptor = adaptor;
770  	uart->card = card;
771  	spin_lock_init(&uart->open_lock);
772  	uart->irq = -1;
773  	uart->base = iobase;
774  	uart->drop_on_full = droponfull;
775  
776  	err = snd_uart16550_detect(uart);
777  	if (err <= 0) {
778  		printk(KERN_ERR "no UART detected at 0x%lx\n", iobase);
779  		return -ENODEV;
780  	}
781  
782  	if (irq >= 0 && irq != SNDRV_AUTO_IRQ) {
783  		if (devm_request_irq(card->dev, irq, snd_uart16550_interrupt,
784  				     0, "Serial MIDI", uart)) {
785  			snd_printk(KERN_WARNING
786  				   "irq %d busy. Using Polling.\n", irq);
787  		} else {
788  			uart->irq = irq;
789  		}
790  	}
791  	uart->divisor = base / speed;
792  	uart->speed = base / (unsigned int)uart->divisor;
793  	uart->speed_base = base;
794  	uart->prev_out = -1;
795  	uart->prev_in = 0;
796  	uart->rstatus = 0;
797  	memset(uart->prev_status, 0x80, sizeof(unsigned char) * SNDRV_SERIAL_MAX_OUTS);
798  	timer_setup(&uart->buffer_timer, snd_uart16550_buffer_timer, 0);
799  	uart->timer_running = 0;
800  
801  	switch (uart->adaptor) {
802  	case SNDRV_SERIAL_MS124W_SA:
803  	case SNDRV_SERIAL_MS124W_MB:
804  		/* MS-124W can draw power from RTS and DTR if they
805  		   are in opposite states. */
806  		outb(UART_MCR_RTS | (0&UART_MCR_DTR), uart->base + UART_MCR);
807  		break;
808  	case SNDRV_SERIAL_MS124T:
809  		/* MS-124T can draw power from RTS and/or DTR (preferably
810  		   both) if they are asserted. */
811  		outb(UART_MCR_RTS | UART_MCR_DTR, uart->base + UART_MCR);
812  		break;
813  	default:
814  		break;
815  	}
816  
817  	if (ruart)
818  		*ruart = uart;
819  
820  	return 0;
821  }
822  
snd_uart16550_substreams(struct snd_rawmidi_str * stream)823  static void snd_uart16550_substreams(struct snd_rawmidi_str *stream)
824  {
825  	struct snd_rawmidi_substream *substream;
826  
827  	list_for_each_entry(substream, &stream->substreams, list) {
828  		sprintf(substream->name, "Serial MIDI %d", substream->number + 1);
829  	}
830  }
831  
snd_uart16550_rmidi(struct snd_uart16550 * uart,int device,int outs,int ins,struct snd_rawmidi ** rmidi)832  static int snd_uart16550_rmidi(struct snd_uart16550 *uart, int device,
833  			       int outs, int ins,
834  			       struct snd_rawmidi **rmidi)
835  {
836  	struct snd_rawmidi *rrawmidi;
837  	int err;
838  
839  	err = snd_rawmidi_new(uart->card, "UART Serial MIDI", device,
840  			      outs, ins, &rrawmidi);
841  	if (err < 0)
842  		return err;
843  	snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_INPUT,
844  			    &snd_uart16550_input);
845  	snd_rawmidi_set_ops(rrawmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
846  			    &snd_uart16550_output);
847  	strcpy(rrawmidi->name, "Serial MIDI");
848  	snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_OUTPUT]);
849  	snd_uart16550_substreams(&rrawmidi->streams[SNDRV_RAWMIDI_STREAM_INPUT]);
850  	rrawmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT |
851  			       SNDRV_RAWMIDI_INFO_INPUT |
852  			       SNDRV_RAWMIDI_INFO_DUPLEX;
853  	rrawmidi->private_data = uart;
854  	if (rmidi)
855  		*rmidi = rrawmidi;
856  	return 0;
857  }
858  
snd_serial_probe(struct platform_device * devptr)859  static int snd_serial_probe(struct platform_device *devptr)
860  {
861  	struct snd_card *card;
862  	struct snd_uart16550 *uart;
863  	int err;
864  	int dev = devptr->id;
865  
866  	switch (adaptor[dev]) {
867  	case SNDRV_SERIAL_SOUNDCANVAS:
868  		ins[dev] = 1;
869  		break;
870  	case SNDRV_SERIAL_MS124T:
871  	case SNDRV_SERIAL_MS124W_SA:
872  		outs[dev] = 1;
873  		ins[dev] = 1;
874  		break;
875  	case SNDRV_SERIAL_MS124W_MB:
876  		outs[dev] = 16;
877  		ins[dev] = 1;
878  		break;
879  	case SNDRV_SERIAL_GENERIC:
880  		break;
881  	default:
882  		snd_printk(KERN_ERR
883  			   "Adaptor type is out of range 0-%d (%d)\n",
884  			   SNDRV_SERIAL_MAX_ADAPTOR, adaptor[dev]);
885  		return -ENODEV;
886  	}
887  
888  	if (outs[dev] < 1 || outs[dev] > SNDRV_SERIAL_MAX_OUTS) {
889  		snd_printk(KERN_ERR
890  			   "Count of outputs is out of range 1-%d (%d)\n",
891  			   SNDRV_SERIAL_MAX_OUTS, outs[dev]);
892  		return -ENODEV;
893  	}
894  
895  	if (ins[dev] < 1 || ins[dev] > SNDRV_SERIAL_MAX_INS) {
896  		snd_printk(KERN_ERR
897  			   "Count of inputs is out of range 1-%d (%d)\n",
898  			   SNDRV_SERIAL_MAX_INS, ins[dev]);
899  		return -ENODEV;
900  	}
901  
902  	err  = snd_devm_card_new(&devptr->dev, index[dev], id[dev], THIS_MODULE,
903  				 0, &card);
904  	if (err < 0)
905  		return err;
906  
907  	strcpy(card->driver, "Serial");
908  	strcpy(card->shortname, "Serial MIDI (UART16550A)");
909  
910  	err = snd_uart16550_create(card, port[dev], irq[dev], speed[dev],
911  				   base[dev], adaptor[dev], droponfull[dev],
912  				   &uart);
913  	if (err < 0)
914  		return err;
915  
916  	err = snd_uart16550_rmidi(uart, 0, outs[dev], ins[dev], &uart->rmidi);
917  	if (err < 0)
918  		return err;
919  
920  	sprintf(card->longname, "%s [%s] at %#lx, irq %d",
921  		card->shortname,
922  		adaptor_names[uart->adaptor],
923  		uart->base,
924  		uart->irq);
925  
926  	err = snd_card_register(card);
927  	if (err < 0)
928  		return err;
929  
930  	platform_set_drvdata(devptr, card);
931  	return 0;
932  }
933  
934  #define SND_SERIAL_DRIVER	"snd_serial_u16550"
935  
936  static struct platform_driver snd_serial_driver = {
937  	.probe		= snd_serial_probe,
938  	.driver		= {
939  		.name	= SND_SERIAL_DRIVER,
940  	},
941  };
942  
snd_serial_unregister_all(void)943  static void snd_serial_unregister_all(void)
944  {
945  	int i;
946  
947  	for (i = 0; i < ARRAY_SIZE(devices); ++i)
948  		platform_device_unregister(devices[i]);
949  	platform_driver_unregister(&snd_serial_driver);
950  }
951  
alsa_card_serial_init(void)952  static int __init alsa_card_serial_init(void)
953  {
954  	int i, cards, err;
955  
956  	err = platform_driver_register(&snd_serial_driver);
957  	if (err < 0)
958  		return err;
959  
960  	cards = 0;
961  	for (i = 0; i < SNDRV_CARDS; i++) {
962  		struct platform_device *device;
963  		if (! enable[i])
964  			continue;
965  		device = platform_device_register_simple(SND_SERIAL_DRIVER,
966  							 i, NULL, 0);
967  		if (IS_ERR(device))
968  			continue;
969  		if (!platform_get_drvdata(device)) {
970  			platform_device_unregister(device);
971  			continue;
972  		}
973  		devices[i] = device;
974  		cards++;
975  	}
976  	if (! cards) {
977  #ifdef MODULE
978  		printk(KERN_ERR "serial midi soundcard not found or device busy\n");
979  #endif
980  		snd_serial_unregister_all();
981  		return -ENODEV;
982  	}
983  	return 0;
984  }
985  
alsa_card_serial_exit(void)986  static void __exit alsa_card_serial_exit(void)
987  {
988  	snd_serial_unregister_all();
989  }
990  
991  module_init(alsa_card_serial_init)
992  module_exit(alsa_card_serial_exit)
993