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Linux/sound/drivers/serial-u16550.c

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

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