Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  2  * sound/uart401.c
  3  *
  4  * MPU-401 UART driver (formerly uart401_midi.c)
  5  *
  6  *
  7  * Copyright (C) by Hannu Savolainen 1993-1997
  8  *
  9  * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
 10  * Version 2 (June 1991). See the "COPYING" file distributed with this software
 11  * for more info.
 12  *
 13  * Changes:
 14  *      Alan Cox                Reformatted, removed sound_mem usage, use normal Linux
 15  *                              interrupt allocation. Protect against bogus unload
 16  *                              Fixed to allow IRQ > 15
 17  *      Christoph Hellwig       Adapted to module_init/module_exit
 18  *      Arnaldo C. de Melo      got rid of check_region
 19  *
 20  * Status:
 21  *              Untested
 22  */
 23 
 24 #include <linux/init.h>
 25 #include <linux/interrupt.h>
 26 #include <linux/module.h>
 27 #include <linux/spinlock.h>
 28 #include "sound_config.h"
 29 
 30 #include "mpu401.h"
 31 
 32 typedef struct uart401_devc
 33 {
 34         int             base;
 35         int             irq;
 36         int            *osp;
 37         void            (*midi_input_intr) (int dev, unsigned char data);
 38         int             opened, disabled;
 39         volatile unsigned char input_byte;
 40         int             my_dev;
 41         int             share_irq;
 42         spinlock_t      lock;
 43 }
 44 uart401_devc;
 45 
 46 #define DATAPORT   (devc->base)
 47 #define COMDPORT   (devc->base+1)
 48 #define STATPORT   (devc->base+1)
 49 
 50 static int uart401_status(uart401_devc * devc)
 51 {
 52         return inb(STATPORT);
 53 }
 54 
 55 #define input_avail(devc) (!(uart401_status(devc)&INPUT_AVAIL))
 56 #define output_ready(devc)      (!(uart401_status(devc)&OUTPUT_READY))
 57 
 58 static void uart401_cmd(uart401_devc * devc, unsigned char cmd)
 59 {
 60         outb((cmd), COMDPORT);
 61 }
 62 
 63 static int uart401_read(uart401_devc * devc)
 64 {
 65         return inb(DATAPORT);
 66 }
 67 
 68 static void uart401_write(uart401_devc * devc, unsigned char byte)
 69 {
 70         outb((byte), DATAPORT);
 71 }
 72 
 73 #define OUTPUT_READY    0x40
 74 #define INPUT_AVAIL     0x80
 75 #define MPU_ACK         0xFE
 76 #define MPU_RESET       0xFF
 77 #define UART_MODE_ON    0x3F
 78 
 79 static int      reset_uart401(uart401_devc * devc);
 80 static void     enter_uart_mode(uart401_devc * devc);
 81 
 82 static void uart401_input_loop(uart401_devc * devc)
 83 {
 84         int work_limit=30000;
 85         
 86         while (input_avail(devc) && --work_limit)
 87         {
 88                 unsigned char   c = uart401_read(devc);
 89 
 90                 if (c == MPU_ACK)
 91                         devc->input_byte = c;
 92                 else if (devc->opened & OPEN_READ && devc->midi_input_intr)
 93                         devc->midi_input_intr(devc->my_dev, c);
 94         }
 95         if(work_limit==0)
 96                 printk(KERN_WARNING "Too much work in interrupt on uart401 (0x%X). UART jabbering ??\n", devc->base);
 97 }
 98 
 99 irqreturn_t uart401intr(int irq, void *dev_id, struct pt_regs *dummy)
100 {
101         uart401_devc *devc = dev_id;
102 
103         if (devc == NULL)
104         {
105                 printk(KERN_ERR "uart401: bad devc\n");
106                 return IRQ_NONE;
107         }
108 
109         if (input_avail(devc))
110                 uart401_input_loop(devc);
111         return IRQ_HANDLED;
112 }
113 
114 static int
115 uart401_open(int dev, int mode,
116              void            (*input) (int dev, unsigned char data),
117              void            (*output) (int dev)
118 )
119 {
120         uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;
121 
122         if (devc->opened)
123                 return -EBUSY;
124 
125         /* Flush the UART */
126         
127         while (input_avail(devc))
128                 uart401_read(devc);
129 
130         devc->midi_input_intr = input;
131         devc->opened = mode;
132         enter_uart_mode(devc);
133         devc->disabled = 0;
134 
135         return 0;
136 }
137 
138 static void uart401_close(int dev)
139 {
140         uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;
141 
142         reset_uart401(devc);
143         devc->opened = 0;
144 }
145 
146 static int uart401_out(int dev, unsigned char midi_byte)
147 {
148         int timeout;
149         unsigned long flags;
150         uart401_devc *devc = (uart401_devc *) midi_devs[dev]->devc;
151 
152         if (devc->disabled)
153                 return 1;
154         /*
155          * Test for input since pending input seems to block the output.
156          */
157 
158         spin_lock_irqsave(&devc->lock,flags);   
159         if (input_avail(devc))
160                 uart401_input_loop(devc);
161 
162         spin_unlock_irqrestore(&devc->lock,flags);
163 
164         /*
165          * Sometimes it takes about 13000 loops before the output becomes ready
166          * (After reset). Normally it takes just about 10 loops.
167          */
168 
169         for (timeout = 30000; timeout > 0 && !output_ready(devc); timeout--);
170 
171         if (!output_ready(devc))
172         {
173                   printk(KERN_WARNING "uart401: Timeout - Device not responding\n");
174                   devc->disabled = 1;
175                   reset_uart401(devc);
176                   enter_uart_mode(devc);
177                   return 1;
178         }
179         uart401_write(devc, midi_byte);
180         return 1;
181 }
182 
183 static inline int uart401_start_read(int dev)
184 {
185         return 0;
186 }
187 
188 static inline int uart401_end_read(int dev)
189 {
190         return 0;
191 }
192 
193 static inline void uart401_kick(int dev)
194 {
195 }
196 
197 static inline int uart401_buffer_status(int dev)
198 {
199         return 0;
200 }
201 
202 #define MIDI_SYNTH_NAME "MPU-401 UART"
203 #define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT
204 #include "midi_synth.h"
205 
206 static const struct midi_operations uart401_operations =
207 {
208         .owner          = THIS_MODULE,
209         .info           = {"MPU-401 (UART) MIDI", 0, 0, SNDCARD_MPU401},
210         .converter      = &std_midi_synth,
211         .in_info        = {0},
212         .open           = uart401_open,
213         .close          = uart401_close,
214         .outputc        = uart401_out,
215         .start_read     = uart401_start_read,
216         .end_read       = uart401_end_read,
217         .kick           = uart401_kick,
218         .buffer_status  = uart401_buffer_status,
219 };
220 
221 static void enter_uart_mode(uart401_devc * devc)
222 {
223         int ok, timeout;
224         unsigned long flags;
225 
226         spin_lock_irqsave(&devc->lock,flags);   
227         for (timeout = 30000; timeout > 0 && !output_ready(devc); timeout--);
228 
229         devc->input_byte = 0;
230         uart401_cmd(devc, UART_MODE_ON);
231 
232         ok = 0;
233         for (timeout = 50000; timeout > 0 && !ok; timeout--)
234                 if (devc->input_byte == MPU_ACK)
235                         ok = 1;
236                 else if (input_avail(devc))
237                         if (uart401_read(devc) == MPU_ACK)
238                                 ok = 1;
239 
240         spin_unlock_irqrestore(&devc->lock,flags);
241 }
242 
243 static int reset_uart401(uart401_devc * devc)
244 {
245         int ok, timeout, n;
246 
247         /*
248          * Send the RESET command. Try again if no success at the first time.
249          */
250 
251         ok = 0;
252 
253         for (n = 0; n < 2 && !ok; n++)
254         {
255                 for (timeout = 30000; timeout > 0 && !output_ready(devc); timeout--);
256                 devc->input_byte = 0;
257                 uart401_cmd(devc, MPU_RESET);
258 
259                 /*
260                  * Wait at least 25 msec. This method is not accurate so let's make the
261                  * loop bit longer. Cannot sleep since this is called during boot.
262                  */
263 
264                 for (timeout = 50000; timeout > 0 && !ok; timeout--)
265                 {
266                         if (devc->input_byte == MPU_ACK)        /* Interrupt */
267                                 ok = 1;
268                         else if (input_avail(devc))
269                         {
270                                 if (uart401_read(devc) == MPU_ACK)
271                                         ok = 1;
272                         }
273                 }
274         }
275 
276 
277         if (ok)
278         {
279                 DEB(printk("Reset UART401 OK\n"));
280         }
281         else
282                 DDB(printk("Reset UART401 failed - No hardware detected.\n"));
283 
284         if (ok)
285                 uart401_input_loop(devc);       /*
286                                                  * Flush input before enabling interrupts
287                                                  */
288 
289         return ok;
290 }
291 
292 int probe_uart401(struct address_info *hw_config, struct module *owner)
293 {
294         uart401_devc *devc;
295         char *name = "MPU-401 (UART) MIDI";
296         int ok = 0;
297         unsigned long flags;
298 
299         DDB(printk("Entered probe_uart401()\n"));
300 
301         /* Default to "not found" */
302         hw_config->slots[4] = -1;
303 
304         if (!request_region(hw_config->io_base, 4, "MPU-401 UART")) {
305                 printk(KERN_INFO "uart401: could not request_region(%d, 4)\n", hw_config->io_base);
306                 return 0;
307         }
308 
309         devc = kmalloc(sizeof(uart401_devc), GFP_KERNEL);
310         if (!devc) {
311                 printk(KERN_WARNING "uart401: Can't allocate memory\n");
312                 goto cleanup_region;
313         }
314 
315         devc->base = hw_config->io_base;
316         devc->irq = hw_config->irq;
317         devc->osp = hw_config->osp;
318         devc->midi_input_intr = NULL;
319         devc->opened = 0;
320         devc->input_byte = 0;
321         devc->my_dev = 0;
322         devc->share_irq = 0;
323         spin_lock_init(&devc->lock);
324 
325         spin_lock_irqsave(&devc->lock,flags);   
326         ok = reset_uart401(devc);
327         spin_unlock_irqrestore(&devc->lock,flags);
328 
329         if (!ok)
330                 goto cleanup_devc;
331 
332         if (hw_config->name)
333                 name = hw_config->name;
334 
335         if (devc->irq < 0) {
336                 devc->share_irq = 1;
337                 devc->irq *= -1;
338         } else
339                 devc->share_irq = 0;
340 
341         if (!devc->share_irq)
342                 if (request_irq(devc->irq, uart401intr, 0, "MPU-401 UART", devc) < 0) {
343                         printk(KERN_WARNING "uart401: Failed to allocate IRQ%d\n", devc->irq);
344                         devc->share_irq = 1;
345                 }
346         devc->my_dev = sound_alloc_mididev();
347         enter_uart_mode(devc);
348 
349         if (devc->my_dev == -1) {
350                 printk(KERN_INFO "uart401: Too many midi devices detected\n");
351                 goto cleanup_irq;
352         }
353         conf_printf(name, hw_config);
354         midi_devs[devc->my_dev] = kmalloc(sizeof(struct midi_operations), GFP_KERNEL);
355         if (!midi_devs[devc->my_dev]) {
356                 printk(KERN_ERR "uart401: Failed to allocate memory\n");
357                 goto cleanup_unload_mididev;
358         }
359         memcpy(midi_devs[devc->my_dev], &uart401_operations, sizeof(struct midi_operations));
360 
361         if (owner)
362                 midi_devs[devc->my_dev]->owner = owner;
363         
364         midi_devs[devc->my_dev]->devc = devc;
365         midi_devs[devc->my_dev]->converter = kmalloc(sizeof(struct synth_operations), GFP_KERNEL);
366         if (!midi_devs[devc->my_dev]->converter) {
367                 printk(KERN_WARNING "uart401: Failed to allocate memory\n");
368                 goto cleanup_midi_devs;
369         }
370         memcpy(midi_devs[devc->my_dev]->converter, &std_midi_synth, sizeof(struct synth_operations));
371         strcpy(midi_devs[devc->my_dev]->info.name, name);
372         midi_devs[devc->my_dev]->converter->id = "UART401";
373         midi_devs[devc->my_dev]->converter->midi_dev = devc->my_dev;
374 
375         if (owner)
376                 midi_devs[devc->my_dev]->converter->owner = owner;
377 
378         hw_config->slots[4] = devc->my_dev;
379         sequencer_init();
380         devc->opened = 0;
381         return 1;
382 cleanup_midi_devs:
383         kfree(midi_devs[devc->my_dev]);
384 cleanup_unload_mididev:
385         sound_unload_mididev(devc->my_dev);
386 cleanup_irq:
387         if (!devc->share_irq)
388                 free_irq(devc->irq, devc);
389 cleanup_devc:
390         kfree(devc);
391 cleanup_region:
392         release_region(hw_config->io_base, 4);
393         return 0;
394 }
395 
396 void unload_uart401(struct address_info *hw_config)
397 {
398         uart401_devc *devc;
399         int n=hw_config->slots[4];
400         
401         /* Not set up */
402         if(n==-1 || midi_devs[n]==NULL)
403                 return;
404                 
405         /* Not allocated (erm ??) */
406         
407         devc = midi_devs[hw_config->slots[4]]->devc;
408         if (devc == NULL)
409                 return;
410 
411         reset_uart401(devc);
412         release_region(hw_config->io_base, 4);
413 
414         if (!devc->share_irq)
415                 free_irq(devc->irq, devc);
416         if (devc)
417         {
418                 kfree(midi_devs[devc->my_dev]->converter);
419                 kfree(midi_devs[devc->my_dev]);
420                 kfree(devc);
421                 devc = NULL;
422         }
423         /* This kills midi_devs[x] */
424         sound_unload_mididev(hw_config->slots[4]);
425 }
426 
427 EXPORT_SYMBOL(probe_uart401);
428 EXPORT_SYMBOL(unload_uart401);
429 EXPORT_SYMBOL(uart401intr);
430 
431 static struct address_info cfg_mpu;
432 
433 static int io = -1;
434 static int irq = -1;
435 
436 module_param(io, int, 0444);
437 module_param(irq, int, 0444);
438 
439 
440 static int __init init_uart401(void)
441 {
442         cfg_mpu.irq = irq;
443         cfg_mpu.io_base = io;
444 
445         /* Can be loaded either for module use or to provide functions
446            to others */
447         if (cfg_mpu.io_base != -1 && cfg_mpu.irq != -1) {
448                 printk(KERN_INFO "MPU-401 UART driver Copyright (C) Hannu Savolainen 1993-1997");
449                 if (!probe_uart401(&cfg_mpu, THIS_MODULE))
450                         return -ENODEV;
451         }
452 
453         return 0;
454 }
455 
456 static void __exit cleanup_uart401(void)
457 {
458         if (cfg_mpu.io_base != -1 && cfg_mpu.irq != -1)
459                 unload_uart401(&cfg_mpu);
460 }
461 
462 module_init(init_uart401);
463 module_exit(cleanup_uart401);
464 
465 #ifndef MODULE
466 static int __init setup_uart401(char *str)
467 {
468         /* io, irq */
469         int ints[3];
470         
471         str = get_options(str, ARRAY_SIZE(ints), ints);
472 
473         io = ints[1];
474         irq = ints[2];
475         
476         return 1;
477 }
478 
479 __setup("uart401=", setup_uart401);
480 #endif
481 MODULE_LICENSE("GPL");
482 
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