xref: /linux/drivers/sh/maple/maple.c (revision 63870295de9adb365cd121dab94379b8cfdf986a)
1 /*
2  * Core maple bus functionality
3  *
4  *  Copyright (C) 2007, 2008 Adrian McMenamin
5  *  Copyright (C) 2001 - 2008 Paul Mundt
6  *
7  * Based on 2.4 code by:
8  *
9  *  Copyright (C) 2000-2001 YAEGASHI Takeshi
10  *  Copyright (C) 2001 M. R. Brown
11  *  Copyright (C) 2001 Paul Mundt
12  *
13  * and others.
14  *
15  * This file is subject to the terms and conditions of the GNU General Public
16  * License.  See the file "COPYING" in the main directory of this archive
17  * for more details.
18  */
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/device.h>
22 #include <linux/interrupt.h>
23 #include <linux/list.h>
24 #include <linux/io.h>
25 #include <linux/slab.h>
26 #include <linux/maple.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/delay.h>
29 #include <asm/cacheflush.h>
30 #include <asm/dma.h>
31 #include <asm/io.h>
32 #include <mach/dma.h>
33 #include <mach/sysasic.h>
34 
35 MODULE_AUTHOR("Yaegashi Takeshi, Paul Mundt, M. R. Brown, Adrian McMenamin");
36 MODULE_DESCRIPTION("Maple bus driver for Dreamcast");
37 MODULE_LICENSE("GPL v2");
38 MODULE_SUPPORTED_DEVICE("{{SEGA, Dreamcast/Maple}}");
39 
40 static void maple_dma_handler(struct work_struct *work);
41 static void maple_vblank_handler(struct work_struct *work);
42 
43 static DECLARE_WORK(maple_dma_process, maple_dma_handler);
44 static DECLARE_WORK(maple_vblank_process, maple_vblank_handler);
45 
46 static LIST_HEAD(maple_waitq);
47 static LIST_HEAD(maple_sentq);
48 
49 /* mutex to protect queue of waiting packets */
50 static DEFINE_MUTEX(maple_wlist_lock);
51 
52 static struct maple_driver maple_dummy_driver;
53 static struct device maple_bus;
54 static int subdevice_map[MAPLE_PORTS];
55 static unsigned long *maple_sendbuf, *maple_sendptr, *maple_lastptr;
56 static unsigned long maple_pnp_time;
57 static int started, scanning, fullscan;
58 static struct kmem_cache *maple_queue_cache;
59 
60 struct maple_device_specify {
61 	int port;
62 	int unit;
63 };
64 
65 static bool checked[4];
66 static struct maple_device *baseunits[4];
67 
68 /**
69  * maple_driver_register - register a maple driver
70  * @drv: maple driver to be registered.
71  *
72  * Registers the passed in @drv, while updating the bus type.
73  * Devices with matching function IDs will be automatically probed.
74  */
75 int maple_driver_register(struct maple_driver *drv)
76 {
77 	if (!drv)
78 		return -EINVAL;
79 
80 	drv->drv.bus = &maple_bus_type;
81 
82 	return driver_register(&drv->drv);
83 }
84 EXPORT_SYMBOL_GPL(maple_driver_register);
85 
86 /**
87  * maple_driver_unregister - unregister a maple driver.
88  * @drv: maple driver to unregister.
89  *
90  * Cleans up after maple_driver_register(). To be invoked in the exit
91  * path of any module drivers.
92  */
93 void maple_driver_unregister(struct maple_driver *drv)
94 {
95 	driver_unregister(&drv->drv);
96 }
97 
98 /* set hardware registers to enable next round of dma */
99 static void maplebus_dma_reset(void)
100 {
101 	ctrl_outl(MAPLE_MAGIC, MAPLE_RESET);
102 	/* set trig type to 0 for software trigger, 1 for hardware (VBLANK) */
103 	ctrl_outl(1, MAPLE_TRIGTYPE);
104 	ctrl_outl(MAPLE_2MBPS | MAPLE_TIMEOUT(50000), MAPLE_SPEED);
105 	ctrl_outl(PHYSADDR(maple_sendbuf), MAPLE_DMAADDR);
106 	ctrl_outl(1, MAPLE_ENABLE);
107 }
108 
109 /**
110  * maple_getcond_callback - setup handling MAPLE_COMMAND_GETCOND
111  * @dev: device responding
112  * @callback: handler callback
113  * @interval: interval in jiffies between callbacks
114  * @function: the function code for the device
115  */
116 void maple_getcond_callback(struct maple_device *dev,
117 			void (*callback) (struct mapleq *mq),
118 			unsigned long interval, unsigned long function)
119 {
120 	dev->callback = callback;
121 	dev->interval = interval;
122 	dev->function = cpu_to_be32(function);
123 	dev->when = jiffies;
124 }
125 EXPORT_SYMBOL_GPL(maple_getcond_callback);
126 
127 static int maple_dma_done(void)
128 {
129 	return (ctrl_inl(MAPLE_STATE) & 1) == 0;
130 }
131 
132 static void maple_release_device(struct device *dev)
133 {
134 	struct maple_device *mdev;
135 	struct mapleq *mq;
136 	if (!dev)
137 		return;
138 	mdev = to_maple_dev(dev);
139 	mq = mdev->mq;
140 	if (mq) {
141 		if (mq->recvbufdcsp)
142 			kmem_cache_free(maple_queue_cache, mq->recvbufdcsp);
143 		kfree(mq);
144 		mq = NULL;
145 	}
146 	kfree(mdev);
147 }
148 
149 /*
150  * maple_add_packet - add a single instruction to the queue
151  * @mdev - maple device
152  * @function - function on device being queried
153  * @command - maple command to add
154  * @length - length of command string (in 32 bit words)
155  * @data - remainder of command string
156  */
157 int maple_add_packet(struct maple_device *mdev, u32 function, u32 command,
158 	size_t length, void *data)
159 {
160 	int locking, ret = 0;
161 	void *sendbuf = NULL;
162 
163 	mutex_lock(&maple_wlist_lock);
164 	/* bounce if device already locked */
165 	locking = mutex_is_locked(&mdev->mq->mutex);
166 	if (locking) {
167 		ret = -EBUSY;
168 		goto out;
169 	}
170 
171 	mutex_lock(&mdev->mq->mutex);
172 
173 	if (length) {
174 		sendbuf = kmalloc(length * 4, GFP_KERNEL);
175 		if (!sendbuf) {
176 			mutex_unlock(&mdev->mq->mutex);
177 			ret = -ENOMEM;
178 			goto out;
179 		}
180 		((__be32 *)sendbuf)[0] = cpu_to_be32(function);
181 	}
182 
183 	mdev->mq->command = command;
184 	mdev->mq->length = length;
185 	if (length > 1)
186 		memcpy(sendbuf + 4, data, (length - 1) * 4);
187 	mdev->mq->sendbuf = sendbuf;
188 
189 	list_add(&mdev->mq->list, &maple_waitq);
190 out:
191 	mutex_unlock(&maple_wlist_lock);
192 	return ret;
193 }
194 EXPORT_SYMBOL_GPL(maple_add_packet);
195 
196 /*
197  * maple_add_packet_sleeps - add a single instruction to the queue
198  *  - waits for lock to be free
199  * @mdev - maple device
200  * @function - function on device being queried
201  * @command - maple command to add
202  * @length - length of command string (in 32 bit words)
203  * @data - remainder of command string
204  */
205 int maple_add_packet_sleeps(struct maple_device *mdev, u32 function,
206 	u32 command, size_t length, void *data)
207 {
208 	int locking, ret = 0;
209 	void *sendbuf = NULL;
210 
211 	locking = mutex_lock_interruptible(&mdev->mq->mutex);
212 	if (locking) {
213 		ret = -EIO;
214 		goto out;
215 	}
216 
217 	if (length) {
218 		sendbuf = kmalloc(length * 4, GFP_KERNEL);
219 		if (!sendbuf) {
220 			mutex_unlock(&mdev->mq->mutex);
221 			ret = -ENOMEM;
222 			goto out;
223 		}
224 		((__be32 *)sendbuf)[0] = cpu_to_be32(function);
225 	}
226 
227 	mdev->mq->command = command;
228 	mdev->mq->length = length;
229 	if (length > 1)
230 		memcpy(sendbuf + 4, data, (length - 1) * 4);
231 	mdev->mq->sendbuf = sendbuf;
232 
233 	mutex_lock(&maple_wlist_lock);
234 	list_add(&mdev->mq->list, &maple_waitq);
235 	mutex_unlock(&maple_wlist_lock);
236 out:
237 	return ret;
238 }
239 EXPORT_SYMBOL_GPL(maple_add_packet_sleeps);
240 
241 static struct mapleq *maple_allocq(struct maple_device *mdev)
242 {
243 	struct mapleq *mq;
244 
245 	mq = kmalloc(sizeof(*mq), GFP_KERNEL);
246 	if (!mq)
247 		goto failed_nomem;
248 
249 	mq->dev = mdev;
250 	mq->recvbufdcsp = kmem_cache_zalloc(maple_queue_cache, GFP_KERNEL);
251 	mq->recvbuf = (void *) P2SEGADDR(mq->recvbufdcsp);
252 	if (!mq->recvbuf)
253 		goto failed_p2;
254 	/*
255 	 * most devices do not need the mutex - but
256 	 * anything that injects block reads or writes
257 	 * will rely on it
258 	 */
259 	mutex_init(&mq->mutex);
260 
261 	return mq;
262 
263 failed_p2:
264 	kfree(mq);
265 failed_nomem:
266 	return NULL;
267 }
268 
269 static struct maple_device *maple_alloc_dev(int port, int unit)
270 {
271 	struct maple_device *mdev;
272 
273 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
274 	if (!mdev)
275 		return NULL;
276 
277 	mdev->port = port;
278 	mdev->unit = unit;
279 	mdev->mq = maple_allocq(mdev);
280 
281 	if (!mdev->mq) {
282 		kfree(mdev);
283 		return NULL;
284 	}
285 	mdev->dev.bus = &maple_bus_type;
286 	mdev->dev.parent = &maple_bus;
287 	return mdev;
288 }
289 
290 static void maple_free_dev(struct maple_device *mdev)
291 {
292 	if (!mdev)
293 		return;
294 	if (mdev->mq) {
295 		if (mdev->mq->recvbufdcsp)
296 			kmem_cache_free(maple_queue_cache,
297 				mdev->mq->recvbufdcsp);
298 		kfree(mdev->mq);
299 	}
300 	kfree(mdev);
301 }
302 
303 /* process the command queue into a maple command block
304  * terminating command has bit 32 of first long set to 0
305  */
306 static void maple_build_block(struct mapleq *mq)
307 {
308 	int port, unit, from, to, len;
309 	unsigned long *lsendbuf = mq->sendbuf;
310 
311 	port = mq->dev->port & 3;
312 	unit = mq->dev->unit;
313 	len = mq->length;
314 	from = port << 6;
315 	to = (port << 6) | (unit > 0 ? (1 << (unit - 1)) & 0x1f : 0x20);
316 
317 	*maple_lastptr &= 0x7fffffff;
318 	maple_lastptr = maple_sendptr;
319 
320 	*maple_sendptr++ = (port << 16) | len | 0x80000000;
321 	*maple_sendptr++ = PHYSADDR(mq->recvbuf);
322 	*maple_sendptr++ =
323 	    mq->command | (to << 8) | (from << 16) | (len << 24);
324 	while (len-- > 0)
325 		*maple_sendptr++ = *lsendbuf++;
326 }
327 
328 /* build up command queue */
329 static void maple_send(void)
330 {
331 	int i, maple_packets = 0;
332 	struct mapleq *mq, *nmq;
333 
334 	if (!list_empty(&maple_sentq))
335 		return;
336 	mutex_lock(&maple_wlist_lock);
337 	if (list_empty(&maple_waitq) || !maple_dma_done()) {
338 		mutex_unlock(&maple_wlist_lock);
339 		return;
340 	}
341 	mutex_unlock(&maple_wlist_lock);
342 	maple_lastptr = maple_sendbuf;
343 	maple_sendptr = maple_sendbuf;
344 	mutex_lock(&maple_wlist_lock);
345 	list_for_each_entry_safe(mq, nmq, &maple_waitq, list) {
346 		maple_build_block(mq);
347 		list_move(&mq->list, &maple_sentq);
348 		if (maple_packets++ > MAPLE_MAXPACKETS)
349 			break;
350 	}
351 	mutex_unlock(&maple_wlist_lock);
352 	if (maple_packets > 0) {
353 		for (i = 0; i < (1 << MAPLE_DMA_PAGES); i++)
354 			dma_cache_sync(0, maple_sendbuf + i * PAGE_SIZE,
355 				       PAGE_SIZE, DMA_BIDIRECTIONAL);
356 	}
357 }
358 
359 /* check if there is a driver registered likely to match this device */
360 static int check_matching_maple_driver(struct device_driver *driver,
361 					void *devptr)
362 {
363 	struct maple_driver *maple_drv;
364 	struct maple_device *mdev;
365 
366 	mdev = devptr;
367 	maple_drv = to_maple_driver(driver);
368 	if (mdev->devinfo.function & cpu_to_be32(maple_drv->function))
369 		return 1;
370 	return 0;
371 }
372 
373 static void maple_detach_driver(struct maple_device *mdev)
374 {
375 	if (!mdev)
376 		return;
377 	device_unregister(&mdev->dev);
378 	mdev = NULL;
379 }
380 
381 /* process initial MAPLE_COMMAND_DEVINFO for each device or port */
382 static void maple_attach_driver(struct maple_device *mdev)
383 {
384 	char *p, *recvbuf;
385 	unsigned long function;
386 	int matched, retval;
387 
388 	recvbuf = mdev->mq->recvbuf;
389 	/* copy the data as individual elements in
390 	* case of memory optimisation */
391 	memcpy(&mdev->devinfo.function, recvbuf + 4, 4);
392 	memcpy(&mdev->devinfo.function_data[0], recvbuf + 8, 12);
393 	memcpy(&mdev->devinfo.area_code, recvbuf + 20, 1);
394 	memcpy(&mdev->devinfo.connector_direction, recvbuf + 21, 1);
395 	memcpy(&mdev->devinfo.product_name[0], recvbuf + 22, 30);
396 	memcpy(&mdev->devinfo.product_licence[0], recvbuf + 52, 60);
397 	memcpy(&mdev->devinfo.standby_power, recvbuf + 112, 2);
398 	memcpy(&mdev->devinfo.max_power, recvbuf + 114, 2);
399 	memcpy(mdev->product_name, mdev->devinfo.product_name, 30);
400 	mdev->product_name[30] = '\0';
401 	memcpy(mdev->product_licence, mdev->devinfo.product_licence, 60);
402 	mdev->product_licence[60] = '\0';
403 
404 	for (p = mdev->product_name + 29; mdev->product_name <= p; p--)
405 		if (*p == ' ')
406 			*p = '\0';
407 		else
408 			break;
409 	for (p = mdev->product_licence + 59; mdev->product_licence <= p; p--)
410 		if (*p == ' ')
411 			*p = '\0';
412 		else
413 			break;
414 
415 	printk(KERN_INFO "Maple device detected: %s\n",
416 		mdev->product_name);
417 	printk(KERN_INFO "Maple device: %s\n", mdev->product_licence);
418 
419 	function = be32_to_cpu(mdev->devinfo.function);
420 
421 	if (function > 0x200) {
422 		/* Do this silently - as not a real device */
423 		function = 0;
424 		mdev->driver = &maple_dummy_driver;
425 		sprintf(mdev->dev.bus_id, "%d:0.port", mdev->port);
426 	} else {
427 		printk(KERN_INFO
428 			"Maple bus at (%d, %d): Function 0x%lX\n",
429 			mdev->port, mdev->unit, function);
430 
431 		matched =
432 			bus_for_each_drv(&maple_bus_type, NULL, mdev,
433 				check_matching_maple_driver);
434 
435 		if (matched == 0) {
436 			/* Driver does not exist yet */
437 			printk(KERN_INFO
438 				"No maple driver found.\n");
439 			mdev->driver = &maple_dummy_driver;
440 		}
441 		sprintf(mdev->dev.bus_id, "%d:0%d.%lX", mdev->port,
442 			mdev->unit, function);
443 	}
444 	mdev->function = function;
445 	mdev->dev.release = &maple_release_device;
446 	retval = device_register(&mdev->dev);
447 	if (retval) {
448 		printk(KERN_INFO
449 		"Maple bus: Attempt to register device"
450 		" (%x, %x) failed.\n",
451 		mdev->port, mdev->unit);
452 		maple_free_dev(mdev);
453 		mdev = NULL;
454 		return;
455 	}
456 }
457 
458 /*
459  * if device has been registered for the given
460  * port and unit then return 1 - allows identification
461  * of which devices need to be attached or detached
462  */
463 static int detach_maple_device(struct device *device, void *portptr)
464 {
465 	struct maple_device_specify *ds;
466 	struct maple_device *mdev;
467 
468 	ds = portptr;
469 	mdev = to_maple_dev(device);
470 	if (mdev->port == ds->port && mdev->unit == ds->unit)
471 		return 1;
472 	return 0;
473 }
474 
475 static int setup_maple_commands(struct device *device, void *ignored)
476 {
477 	int add;
478 	struct maple_device *maple_dev = to_maple_dev(device);
479 
480 	if ((maple_dev->interval > 0)
481 	    && time_after(jiffies, maple_dev->when)) {
482 		/* bounce if we cannot lock */
483 		add = maple_add_packet(maple_dev,
484 			be32_to_cpu(maple_dev->devinfo.function),
485 			MAPLE_COMMAND_GETCOND, 1, NULL);
486 		if (!add)
487 			maple_dev->when = jiffies + maple_dev->interval;
488 	} else {
489 		if (time_after(jiffies, maple_pnp_time))
490 			/* This will also bounce */
491 			maple_add_packet(maple_dev, 0,
492 				MAPLE_COMMAND_DEVINFO, 0, NULL);
493 	}
494 	return 0;
495 }
496 
497 /* VBLANK bottom half - implemented via workqueue */
498 static void maple_vblank_handler(struct work_struct *work)
499 {
500 	if (!list_empty(&maple_sentq) || !maple_dma_done())
501 		return;
502 
503 	ctrl_outl(0, MAPLE_ENABLE);
504 
505 	bus_for_each_dev(&maple_bus_type, NULL, NULL,
506 			 setup_maple_commands);
507 
508 	if (time_after(jiffies, maple_pnp_time))
509 		maple_pnp_time = jiffies + MAPLE_PNP_INTERVAL;
510 
511 	mutex_lock(&maple_wlist_lock);
512 	if (!list_empty(&maple_waitq) && list_empty(&maple_sentq)) {
513 		mutex_unlock(&maple_wlist_lock);
514 		maple_send();
515 	} else {
516 		mutex_unlock(&maple_wlist_lock);
517 	}
518 
519 	maplebus_dma_reset();
520 }
521 
522 /* handle devices added via hotplugs - placing them on queue for DEVINFO*/
523 static void maple_map_subunits(struct maple_device *mdev, int submask)
524 {
525 	int retval, k, devcheck;
526 	struct maple_device *mdev_add;
527 	struct maple_device_specify ds;
528 
529 	ds.port = mdev->port;
530 	for (k = 0; k < 5; k++) {
531 		ds.unit = k + 1;
532 		retval =
533 		    bus_for_each_dev(&maple_bus_type, NULL, &ds,
534 				     detach_maple_device);
535 		if (retval) {
536 			submask = submask >> 1;
537 			continue;
538 		}
539 		devcheck = submask & 0x01;
540 		if (devcheck) {
541 			mdev_add = maple_alloc_dev(mdev->port, k + 1);
542 			if (!mdev_add)
543 				return;
544 			maple_add_packet(mdev_add, 0, MAPLE_COMMAND_DEVINFO,
545 				0, NULL);
546 			/* mark that we are checking sub devices */
547 			scanning = 1;
548 		}
549 		submask = submask >> 1;
550 	}
551 }
552 
553 /* mark a device as removed */
554 static void maple_clean_submap(struct maple_device *mdev)
555 {
556 	int killbit;
557 
558 	killbit = (mdev->unit > 0 ? (1 << (mdev->unit - 1)) & 0x1f : 0x20);
559 	killbit = ~killbit;
560 	killbit &= 0xFF;
561 	subdevice_map[mdev->port] = subdevice_map[mdev->port] & killbit;
562 }
563 
564 /* handle empty port or hotplug removal */
565 static void maple_response_none(struct maple_device *mdev,
566 				struct mapleq *mq)
567 {
568 	if (mdev->unit != 0) {
569 		list_del(&mq->list);
570 		maple_clean_submap(mdev);
571 		printk(KERN_INFO
572 		       "Maple bus device detaching at (%d, %d)\n",
573 		       mdev->port, mdev->unit);
574 		maple_detach_driver(mdev);
575 		return;
576 	}
577 	if (!started || !fullscan) {
578 		if (checked[mdev->port] == false) {
579 			checked[mdev->port] = true;
580 			printk(KERN_INFO "No maple devices attached"
581 				" to port %d\n", mdev->port);
582 		}
583 		return;
584 	}
585 	maple_clean_submap(mdev);
586 }
587 
588 /* preprocess hotplugs or scans */
589 static void maple_response_devinfo(struct maple_device *mdev,
590 				   char *recvbuf)
591 {
592 	char submask;
593 	if (!started || (scanning == 2) || !fullscan) {
594 		if ((mdev->unit == 0) && (checked[mdev->port] == false)) {
595 			checked[mdev->port] = true;
596 			maple_attach_driver(mdev);
597 		} else {
598 			if (mdev->unit != 0)
599 				maple_attach_driver(mdev);
600 		}
601 		return;
602 	}
603 	if (mdev->unit == 0) {
604 		submask = recvbuf[2] & 0x1F;
605 		if (submask ^ subdevice_map[mdev->port]) {
606 			maple_map_subunits(mdev, submask);
607 			subdevice_map[mdev->port] = submask;
608 		}
609 	}
610 }
611 
612 static void maple_port_rescan(void)
613 {
614 	int i;
615 	struct maple_device *mdev;
616 
617 	fullscan = 1;
618 	for (i = 0; i < MAPLE_PORTS; i++) {
619 		if (checked[i] == false) {
620 			fullscan = 0;
621 			mdev = baseunits[i];
622 			/*
623 			 *  test lock in case scan has failed
624 			 *  but device is still locked
625 			 */
626 			if (mutex_is_locked(&mdev->mq->mutex))
627 				mutex_unlock(&mdev->mq->mutex);
628 			maple_add_packet(mdev, 0, MAPLE_COMMAND_DEVINFO,
629 				0, NULL);
630 		}
631 	}
632 }
633 
634 /* maple dma end bottom half - implemented via workqueue */
635 static void maple_dma_handler(struct work_struct *work)
636 {
637 	struct mapleq *mq, *nmq;
638 	struct maple_device *dev;
639 	char *recvbuf;
640 	enum maple_code code;
641 
642 	if (!maple_dma_done())
643 		return;
644 	ctrl_outl(0, MAPLE_ENABLE);
645 	if (!list_empty(&maple_sentq)) {
646 		list_for_each_entry_safe(mq, nmq, &maple_sentq, list) {
647 			recvbuf = mq->recvbuf;
648 			code = recvbuf[0];
649 			dev = mq->dev;
650 			kfree(mq->sendbuf);
651 			mutex_unlock(&mq->mutex);
652 			list_del_init(&mq->list);
653 
654 			switch (code) {
655 			case MAPLE_RESPONSE_NONE:
656 				maple_response_none(dev, mq);
657 				break;
658 
659 			case MAPLE_RESPONSE_DEVINFO:
660 				maple_response_devinfo(dev, recvbuf);
661 				break;
662 
663 			case MAPLE_RESPONSE_DATATRF:
664 				if (dev->callback)
665 					dev->callback(mq);
666 				break;
667 
668 			case MAPLE_RESPONSE_FILEERR:
669 			case MAPLE_RESPONSE_AGAIN:
670 			case MAPLE_RESPONSE_BADCMD:
671 			case MAPLE_RESPONSE_BADFUNC:
672 				printk(KERN_DEBUG
673 				       "Maple non-fatal error 0x%X\n",
674 				       code);
675 				break;
676 
677 			case MAPLE_RESPONSE_ALLINFO:
678 				printk(KERN_DEBUG
679 				       "Maple - extended device information"
680 					" not supported\n");
681 				break;
682 
683 			case MAPLE_RESPONSE_OK:
684 				break;
685 
686 			default:
687 				break;
688 			}
689 		}
690 		/* if scanning is 1 then we have subdevices to check */
691 		if (scanning == 1) {
692 			maple_send();
693 			scanning = 2;
694 		} else
695 			scanning = 0;
696 		/*check if we have actually tested all ports yet */
697 		if (!fullscan)
698 			maple_port_rescan();
699 		/* mark that we have been through the first scan */
700 		if (started == 0)
701 			started = 1;
702 	}
703 	maplebus_dma_reset();
704 }
705 
706 static irqreturn_t maplebus_dma_interrupt(int irq, void *dev_id)
707 {
708 	/* Load everything into the bottom half */
709 	schedule_work(&maple_dma_process);
710 	return IRQ_HANDLED;
711 }
712 
713 static irqreturn_t maplebus_vblank_interrupt(int irq, void *dev_id)
714 {
715 	schedule_work(&maple_vblank_process);
716 	return IRQ_HANDLED;
717 }
718 
719 static int maple_set_dma_interrupt_handler(void)
720 {
721 	return request_irq(HW_EVENT_MAPLE_DMA, maplebus_dma_interrupt,
722 		IRQF_SHARED, "maple bus DMA", &maple_dummy_driver);
723 }
724 
725 static int maple_set_vblank_interrupt_handler(void)
726 {
727 	return request_irq(HW_EVENT_VSYNC, maplebus_vblank_interrupt,
728 		IRQF_SHARED, "maple bus VBLANK", &maple_dummy_driver);
729 }
730 
731 static int maple_get_dma_buffer(void)
732 {
733 	maple_sendbuf =
734 	    (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
735 				      MAPLE_DMA_PAGES);
736 	if (!maple_sendbuf)
737 		return -ENOMEM;
738 	return 0;
739 }
740 
741 static int match_maple_bus_driver(struct device *devptr,
742 				  struct device_driver *drvptr)
743 {
744 	struct maple_driver *maple_drv = to_maple_driver(drvptr);
745 	struct maple_device *maple_dev = to_maple_dev(devptr);
746 
747 	/* Trap empty port case */
748 	if (maple_dev->devinfo.function == 0xFFFFFFFF)
749 		return 0;
750 	else if (maple_dev->devinfo.function &
751 		 cpu_to_be32(maple_drv->function))
752 		return 1;
753 	return 0;
754 }
755 
756 static int maple_bus_uevent(struct device *dev,
757 			    struct kobj_uevent_env *env)
758 {
759 	return 0;
760 }
761 
762 static void maple_bus_release(struct device *dev)
763 {
764 }
765 
766 static struct maple_driver maple_dummy_driver = {
767 	.drv = {
768 		.name = "maple_dummy_driver",
769 		.bus = &maple_bus_type,
770 	},
771 };
772 
773 struct bus_type maple_bus_type = {
774 	.name = "maple",
775 	.match = match_maple_bus_driver,
776 	.uevent = maple_bus_uevent,
777 };
778 EXPORT_SYMBOL_GPL(maple_bus_type);
779 
780 static struct device maple_bus = {
781 	.bus_id = "maple",
782 	.release = maple_bus_release,
783 };
784 
785 static int __init maple_bus_init(void)
786 {
787 	int retval, i;
788 	struct maple_device *mdev[MAPLE_PORTS];
789 	ctrl_outl(0, MAPLE_STATE);
790 
791 	retval = device_register(&maple_bus);
792 	if (retval)
793 		goto cleanup;
794 
795 	retval = bus_register(&maple_bus_type);
796 	if (retval)
797 		goto cleanup_device;
798 
799 	retval = driver_register(&maple_dummy_driver.drv);
800 	if (retval)
801 		goto cleanup_bus;
802 
803 	/* allocate memory for maple bus dma */
804 	retval = maple_get_dma_buffer();
805 	if (retval) {
806 		printk(KERN_INFO
807 		       "Maple bus: Failed to allocate Maple DMA buffers\n");
808 		goto cleanup_basic;
809 	}
810 
811 	/* set up DMA interrupt handler */
812 	retval = maple_set_dma_interrupt_handler();
813 	if (retval) {
814 		printk(KERN_INFO
815 		       "Maple bus: Failed to grab maple DMA IRQ\n");
816 		goto cleanup_dma;
817 	}
818 
819 	/* set up VBLANK interrupt handler */
820 	retval = maple_set_vblank_interrupt_handler();
821 	if (retval) {
822 		printk(KERN_INFO "Maple bus: Failed to grab VBLANK IRQ\n");
823 		goto cleanup_irq;
824 	}
825 
826 	maple_queue_cache =
827 	    kmem_cache_create("maple_queue_cache", 0x400, 0,
828 			      SLAB_POISON|SLAB_HWCACHE_ALIGN, NULL);
829 
830 	if (!maple_queue_cache)
831 		goto cleanup_bothirqs;
832 
833 	INIT_LIST_HEAD(&maple_waitq);
834 	INIT_LIST_HEAD(&maple_sentq);
835 
836 	/* setup maple ports */
837 	for (i = 0; i < MAPLE_PORTS; i++) {
838 		checked[i] = false;
839 		mdev[i] = maple_alloc_dev(i, 0);
840 		baseunits[i] = mdev[i];
841 		if (!mdev[i]) {
842 			while (i-- > 0)
843 				maple_free_dev(mdev[i]);
844 			goto cleanup_cache;
845 		}
846 		maple_add_packet(mdev[i], 0, MAPLE_COMMAND_DEVINFO, 0, NULL);
847 		subdevice_map[i] = 0;
848 	}
849 
850 	/* setup maplebus hardware */
851 	maplebus_dma_reset();
852 	/* initial detection */
853 	maple_send();
854 	maple_pnp_time = jiffies;
855 	printk(KERN_INFO "Maple bus core now registered.\n");
856 
857 	return 0;
858 
859 cleanup_cache:
860 	kmem_cache_destroy(maple_queue_cache);
861 
862 cleanup_bothirqs:
863 	free_irq(HW_EVENT_VSYNC, 0);
864 
865 cleanup_irq:
866 	free_irq(HW_EVENT_MAPLE_DMA, 0);
867 
868 cleanup_dma:
869 	free_pages((unsigned long) maple_sendbuf, MAPLE_DMA_PAGES);
870 
871 cleanup_basic:
872 	driver_unregister(&maple_dummy_driver.drv);
873 
874 cleanup_bus:
875 	bus_unregister(&maple_bus_type);
876 
877 cleanup_device:
878 	device_unregister(&maple_bus);
879 
880 cleanup:
881 	printk(KERN_INFO "Maple bus registration failed\n");
882 	return retval;
883 }
884 /* Push init to later to ensure hardware gets detected */
885 fs_initcall(maple_bus_init);
886