xref: /linux/drivers/sh/maple/maple.c (revision b233b28eac0cc37d07c2d007ea08c86c778c5af4)
1 /*
2  * Core maple bus functionality
3  *
4  *  Copyright (C) 2007 - 2009 Adrian McMenamin
5  *  Copyright (C) 2001 - 2008 Paul Mundt
6  *  Copyright (C) 2000 - 2001 YAEGASHI Takeshi
7  *  Copyright (C) 2001 M. R. Brown
8  *
9  * This file is subject to the terms and conditions of the GNU General Public
10  * License.  See the file "COPYING" in the main directory of this archive
11  * for more details.
12  */
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/device.h>
16 #include <linux/interrupt.h>
17 #include <linux/list.h>
18 #include <linux/io.h>
19 #include <linux/slab.h>
20 #include <linux/maple.h>
21 #include <linux/dma-mapping.h>
22 #include <linux/delay.h>
23 #include <asm/cacheflush.h>
24 #include <asm/dma.h>
25 #include <asm/io.h>
26 #include <mach/dma.h>
27 #include <mach/sysasic.h>
28 
29 MODULE_AUTHOR("Adrian McMenamin <adrian@mcmen.demon.co.uk>");
30 MODULE_DESCRIPTION("Maple bus driver for Dreamcast");
31 MODULE_LICENSE("GPL v2");
32 MODULE_SUPPORTED_DEVICE("{{SEGA, Dreamcast/Maple}}");
33 
34 static void maple_dma_handler(struct work_struct *work);
35 static void maple_vblank_handler(struct work_struct *work);
36 
37 static DECLARE_WORK(maple_dma_process, maple_dma_handler);
38 static DECLARE_WORK(maple_vblank_process, maple_vblank_handler);
39 
40 static LIST_HEAD(maple_waitq);
41 static LIST_HEAD(maple_sentq);
42 
43 /* mutex to protect queue of waiting packets */
44 static DEFINE_MUTEX(maple_wlist_lock);
45 
46 static struct maple_driver maple_unsupported_device;
47 static struct device maple_bus;
48 static int subdevice_map[MAPLE_PORTS];
49 static unsigned long *maple_sendbuf, *maple_sendptr, *maple_lastptr;
50 static unsigned long maple_pnp_time;
51 static int started, scanning, fullscan;
52 static struct kmem_cache *maple_queue_cache;
53 
54 struct maple_device_specify {
55 	int port;
56 	int unit;
57 };
58 
59 static bool checked[MAPLE_PORTS];
60 static bool empty[MAPLE_PORTS];
61 static struct maple_device *baseunits[MAPLE_PORTS];
62 
63 /**
64  * maple_driver_register - register a maple driver
65  * @drv: maple driver to be registered.
66  *
67  * Registers the passed in @drv, while updating the bus type.
68  * Devices with matching function IDs will be automatically probed.
69  */
70 int maple_driver_register(struct maple_driver *drv)
71 {
72 	if (!drv)
73 		return -EINVAL;
74 
75 	drv->drv.bus = &maple_bus_type;
76 
77 	return driver_register(&drv->drv);
78 }
79 EXPORT_SYMBOL_GPL(maple_driver_register);
80 
81 /**
82  * maple_driver_unregister - unregister a maple driver.
83  * @drv: maple driver to unregister.
84  *
85  * Cleans up after maple_driver_register(). To be invoked in the exit
86  * path of any module drivers.
87  */
88 void maple_driver_unregister(struct maple_driver *drv)
89 {
90 	driver_unregister(&drv->drv);
91 }
92 EXPORT_SYMBOL_GPL(maple_driver_unregister);
93 
94 /* set hardware registers to enable next round of dma */
95 static void maple_dma_reset(void)
96 {
97 	ctrl_outl(MAPLE_MAGIC, MAPLE_RESET);
98 	/* set trig type to 0 for software trigger, 1 for hardware (VBLANK) */
99 	ctrl_outl(1, MAPLE_TRIGTYPE);
100 	/*
101 	* Maple system register
102 	* bits 31 - 16	timeout in units of 20nsec
103 	* bit 12	hard trigger - set 0 to keep responding to VBLANK
104 	* bits 9 - 8	set 00 for 2 Mbps, 01 for 1 Mbps
105 	* bits 3 - 0	delay (in 1.3ms) between VBLANK and start of DMA
106 	* max delay is 11
107 	*/
108 	ctrl_outl(MAPLE_2MBPS | MAPLE_TIMEOUT(0xFFFF), MAPLE_SPEED);
109 	ctrl_outl(PHYSADDR(maple_sendbuf), MAPLE_DMAADDR);
110 	ctrl_outl(1, MAPLE_ENABLE);
111 }
112 
113 /**
114  * maple_getcond_callback - setup handling MAPLE_COMMAND_GETCOND
115  * @dev: device responding
116  * @callback: handler callback
117  * @interval: interval in jiffies between callbacks
118  * @function: the function code for the device
119  */
120 void maple_getcond_callback(struct maple_device *dev,
121 			void (*callback) (struct mapleq *mq),
122 			unsigned long interval, unsigned long function)
123 {
124 	dev->callback = callback;
125 	dev->interval = interval;
126 	dev->function = cpu_to_be32(function);
127 	dev->when = jiffies;
128 }
129 EXPORT_SYMBOL_GPL(maple_getcond_callback);
130 
131 static int maple_dma_done(void)
132 {
133 	return (ctrl_inl(MAPLE_STATE) & 1) == 0;
134 }
135 
136 static void maple_release_device(struct device *dev)
137 {
138 	struct maple_device *mdev;
139 	struct mapleq *mq;
140 
141 	mdev = to_maple_dev(dev);
142 	mq = mdev->mq;
143 	kmem_cache_free(maple_queue_cache, mq->recvbuf);
144 	kfree(mq);
145 	kfree(mdev);
146 }
147 
148 /**
149  * maple_add_packet - add a single instruction to the maple bus queue
150  * @mdev: maple device
151  * @function: function on device being queried
152  * @command: maple command to add
153  * @length: length of command string (in 32 bit words)
154  * @data: remainder of command string
155  */
156 int maple_add_packet(struct maple_device *mdev, u32 function, u32 command,
157 	size_t length, void *data)
158 {
159 	int ret = 0;
160 	void *sendbuf = NULL;
161 
162 	if (length) {
163 		sendbuf = kzalloc(length * 4, GFP_KERNEL);
164 		if (!sendbuf) {
165 			ret = -ENOMEM;
166 			goto out;
167 		}
168 		((__be32 *)sendbuf)[0] = cpu_to_be32(function);
169 	}
170 
171 	mdev->mq->command = command;
172 	mdev->mq->length = length;
173 	if (length > 1)
174 		memcpy(sendbuf + 4, data, (length - 1) * 4);
175 	mdev->mq->sendbuf = sendbuf;
176 
177 	mutex_lock(&maple_wlist_lock);
178 	list_add_tail(&mdev->mq->list, &maple_waitq);
179 	mutex_unlock(&maple_wlist_lock);
180 out:
181 	return ret;
182 }
183 EXPORT_SYMBOL_GPL(maple_add_packet);
184 
185 static struct mapleq *maple_allocq(struct maple_device *mdev)
186 {
187 	struct mapleq *mq;
188 
189 	mq = kzalloc(sizeof(*mq), GFP_KERNEL);
190 	if (!mq)
191 		goto failed_nomem;
192 
193 	INIT_LIST_HEAD(&mq->list);
194 	mq->dev = mdev;
195 	mq->recvbuf = kmem_cache_zalloc(maple_queue_cache, GFP_KERNEL);
196 	if (!mq->recvbuf)
197 		goto failed_p2;
198 	mq->recvbuf->buf = &((mq->recvbuf->bufx)[0]);
199 
200 	return mq;
201 
202 failed_p2:
203 	kfree(mq);
204 failed_nomem:
205 	dev_err(&mdev->dev, "could not allocate memory for device (%d, %d)\n",
206 		mdev->port, mdev->unit);
207 	return NULL;
208 }
209 
210 static struct maple_device *maple_alloc_dev(int port, int unit)
211 {
212 	struct maple_device *mdev;
213 
214 	/* zero this out to avoid kobj subsystem
215 	* thinking it has already been registered */
216 
217 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
218 	if (!mdev)
219 		return NULL;
220 
221 	mdev->port = port;
222 	mdev->unit = unit;
223 
224 	mdev->mq = maple_allocq(mdev);
225 
226 	if (!mdev->mq) {
227 		kfree(mdev);
228 		return NULL;
229 	}
230 	mdev->dev.bus = &maple_bus_type;
231 	mdev->dev.parent = &maple_bus;
232 	init_waitqueue_head(&mdev->maple_wait);
233 	return mdev;
234 }
235 
236 static void maple_free_dev(struct maple_device *mdev)
237 {
238 	kmem_cache_free(maple_queue_cache, mdev->mq->recvbuf);
239 	kfree(mdev->mq);
240 	kfree(mdev);
241 }
242 
243 /* process the command queue into a maple command block
244  * terminating command has bit 32 of first long set to 0
245  */
246 static void maple_build_block(struct mapleq *mq)
247 {
248 	int port, unit, from, to, len;
249 	unsigned long *lsendbuf = mq->sendbuf;
250 
251 	port = mq->dev->port & 3;
252 	unit = mq->dev->unit;
253 	len = mq->length;
254 	from = port << 6;
255 	to = (port << 6) | (unit > 0 ? (1 << (unit - 1)) & 0x1f : 0x20);
256 
257 	*maple_lastptr &= 0x7fffffff;
258 	maple_lastptr = maple_sendptr;
259 
260 	*maple_sendptr++ = (port << 16) | len | 0x80000000;
261 	*maple_sendptr++ = PHYSADDR(mq->recvbuf->buf);
262 	*maple_sendptr++ =
263 	    mq->command | (to << 8) | (from << 16) | (len << 24);
264 	while (len-- > 0)
265 		*maple_sendptr++ = *lsendbuf++;
266 }
267 
268 /* build up command queue */
269 static void maple_send(void)
270 {
271 	int i, maple_packets = 0;
272 	struct mapleq *mq, *nmq;
273 
274 	if (!maple_dma_done())
275 		return;
276 
277 	/* disable DMA */
278 	ctrl_outl(0, MAPLE_ENABLE);
279 
280 	if (!list_empty(&maple_sentq))
281 		goto finish;
282 
283 	mutex_lock(&maple_wlist_lock);
284 	if (list_empty(&maple_waitq)) {
285 		mutex_unlock(&maple_wlist_lock);
286 		goto finish;
287 	}
288 
289 	maple_lastptr = maple_sendbuf;
290 	maple_sendptr = maple_sendbuf;
291 
292 	list_for_each_entry_safe(mq, nmq, &maple_waitq, list) {
293 		maple_build_block(mq);
294 		list_del_init(&mq->list);
295 		list_add_tail(&mq->list, &maple_sentq);
296 		if (maple_packets++ > MAPLE_MAXPACKETS)
297 			break;
298 	}
299 	mutex_unlock(&maple_wlist_lock);
300 	if (maple_packets > 0) {
301 		for (i = 0; i < (1 << MAPLE_DMA_PAGES); i++)
302 			dma_cache_sync(0, maple_sendbuf + i * PAGE_SIZE,
303 				       PAGE_SIZE, DMA_BIDIRECTIONAL);
304 	}
305 
306 finish:
307 	maple_dma_reset();
308 }
309 
310 /* check if there is a driver registered likely to match this device */
311 static int maple_check_matching_driver(struct device_driver *driver,
312 					void *devptr)
313 {
314 	struct maple_driver *maple_drv;
315 	struct maple_device *mdev;
316 
317 	mdev = devptr;
318 	maple_drv = to_maple_driver(driver);
319 	if (mdev->devinfo.function & cpu_to_be32(maple_drv->function))
320 		return 1;
321 	return 0;
322 }
323 
324 static void maple_detach_driver(struct maple_device *mdev)
325 {
326 	device_unregister(&mdev->dev);
327 }
328 
329 /* process initial MAPLE_COMMAND_DEVINFO for each device or port */
330 static void maple_attach_driver(struct maple_device *mdev)
331 {
332 	char *p, *recvbuf;
333 	unsigned long function;
334 	int matched, error;
335 
336 	recvbuf = mdev->mq->recvbuf->buf;
337 	/* copy the data as individual elements in
338 	* case of memory optimisation */
339 	memcpy(&mdev->devinfo.function, recvbuf + 4, 4);
340 	memcpy(&mdev->devinfo.function_data[0], recvbuf + 8, 12);
341 	memcpy(&mdev->devinfo.area_code, recvbuf + 20, 1);
342 	memcpy(&mdev->devinfo.connector_direction, recvbuf + 21, 1);
343 	memcpy(&mdev->devinfo.product_name[0], recvbuf + 22, 30);
344 	memcpy(&mdev->devinfo.standby_power, recvbuf + 112, 2);
345 	memcpy(&mdev->devinfo.max_power, recvbuf + 114, 2);
346 	memcpy(mdev->product_name, mdev->devinfo.product_name, 30);
347 	mdev->product_name[30] = '\0';
348 	memcpy(mdev->product_licence, mdev->devinfo.product_licence, 60);
349 	mdev->product_licence[60] = '\0';
350 
351 	for (p = mdev->product_name + 29; mdev->product_name <= p; p--)
352 		if (*p == ' ')
353 			*p = '\0';
354 		else
355 			break;
356 	for (p = mdev->product_licence + 59; mdev->product_licence <= p; p--)
357 		if (*p == ' ')
358 			*p = '\0';
359 		else
360 			break;
361 
362 	function = be32_to_cpu(mdev->devinfo.function);
363 
364 	dev_info(&mdev->dev, "detected %s: function 0x%lX: at (%d, %d)\n",
365 		mdev->product_name, function, mdev->port, mdev->unit);
366 
367 	if (function > 0x200) {
368 		/* Do this silently - as not a real device */
369 		function = 0;
370 		mdev->driver = &maple_unsupported_device;
371 		sprintf(mdev->dev.bus_id, "%d:0.port", mdev->port);
372 
373 	} else {
374 
375 		matched =
376 			bus_for_each_drv(&maple_bus_type, NULL, mdev,
377 				maple_check_matching_driver);
378 
379 		if (matched == 0) {
380 			/* Driver does not exist yet */
381 			dev_info(&mdev->dev, "no driver found\n");
382 			mdev->driver = &maple_unsupported_device;
383 		}
384 		sprintf(mdev->dev.bus_id, "%d:0%d.%lX", mdev->port,
385 			mdev->unit, function);
386 	}
387 
388 	mdev->function = function;
389 	mdev->dev.release = &maple_release_device;
390 
391 	atomic_set(&mdev->busy, 0);
392 	error = device_register(&mdev->dev);
393 	if (error) {
394 		dev_warn(&mdev->dev, "could not register device at"
395 			" (%d, %d), with error 0x%X\n", mdev->unit,
396 			mdev->port, error);
397 		maple_free_dev(mdev);
398 		mdev = NULL;
399 		return;
400 	}
401 }
402 
403 /*
404  * if device has been registered for the given
405  * port and unit then return 1 - allows identification
406  * of which devices need to be attached or detached
407  */
408 static int check_maple_device(struct device *device, void *portptr)
409 {
410 	struct maple_device_specify *ds;
411 	struct maple_device *mdev;
412 
413 	ds = portptr;
414 	mdev = to_maple_dev(device);
415 	if (mdev->port == ds->port && mdev->unit == ds->unit)
416 		return 1;
417 	return 0;
418 }
419 
420 static int setup_maple_commands(struct device *device, void *ignored)
421 {
422 	int add;
423 	struct maple_device *mdev = to_maple_dev(device);
424 	if (mdev->interval > 0 && atomic_read(&mdev->busy) == 0 &&
425 		time_after(jiffies, mdev->when)) {
426 		/* bounce if we cannot add */
427 		add = maple_add_packet(mdev,
428 			be32_to_cpu(mdev->devinfo.function),
429 			MAPLE_COMMAND_GETCOND, 1, NULL);
430 		if (!add)
431 			mdev->when = jiffies + mdev->interval;
432 	} else {
433 		if (time_after(jiffies, maple_pnp_time))
434 			/* Ensure we don't have block reads and devinfo
435 			* calls interfering with one another - so flag the
436 			* device as busy */
437 			if (atomic_read(&mdev->busy) == 0) {
438 				atomic_set(&mdev->busy, 1);
439 				maple_add_packet(mdev, 0,
440 					MAPLE_COMMAND_DEVINFO, 0, NULL);
441 			}
442 	}
443 	return 0;
444 }
445 
446 /* VBLANK bottom half - implemented via workqueue */
447 static void maple_vblank_handler(struct work_struct *work)
448 {
449 	int x, locking;
450 	struct maple_device *mdev;
451 
452 	if (!maple_dma_done())
453 		return;
454 
455 	ctrl_outl(0, MAPLE_ENABLE);
456 
457 	if (!list_empty(&maple_sentq))
458 		goto finish;
459 
460 	/*
461 	* Set up essential commands - to fetch data and
462 	* check devices are still present
463 	*/
464 	bus_for_each_dev(&maple_bus_type, NULL, NULL,
465 		setup_maple_commands);
466 
467 	if (time_after(jiffies, maple_pnp_time)) {
468 		/*
469 		* Scan the empty ports - bus is flakey and may have
470 		* mis-reported emptyness
471 		*/
472 		for (x = 0; x < MAPLE_PORTS; x++) {
473 			if (checked[x] && empty[x]) {
474 				mdev = baseunits[x];
475 				if (!mdev)
476 					break;
477 				atomic_set(&mdev->busy, 1);
478 				locking = maple_add_packet(mdev, 0,
479 					MAPLE_COMMAND_DEVINFO, 0, NULL);
480 				if (!locking)
481 					break;
482 				}
483 			}
484 
485 		maple_pnp_time = jiffies + MAPLE_PNP_INTERVAL;
486 	}
487 
488 finish:
489 	maple_send();
490 }
491 
492 /* handle devices added via hotplugs - placing them on queue for DEVINFO */
493 static void maple_map_subunits(struct maple_device *mdev, int submask)
494 {
495 	int retval, k, devcheck;
496 	struct maple_device *mdev_add;
497 	struct maple_device_specify ds;
498 
499 	ds.port = mdev->port;
500 	for (k = 0; k < 5; k++) {
501 		ds.unit = k + 1;
502 		retval =
503 		    bus_for_each_dev(&maple_bus_type, NULL, &ds,
504 				     check_maple_device);
505 		if (retval) {
506 			submask = submask >> 1;
507 			continue;
508 		}
509 		devcheck = submask & 0x01;
510 		if (devcheck) {
511 			mdev_add = maple_alloc_dev(mdev->port, k + 1);
512 			if (!mdev_add)
513 				return;
514 			atomic_set(&mdev_add->busy, 1);
515 			maple_add_packet(mdev_add, 0, MAPLE_COMMAND_DEVINFO,
516 				0, NULL);
517 			/* mark that we are checking sub devices */
518 			scanning = 1;
519 		}
520 		submask = submask >> 1;
521 	}
522 }
523 
524 /* mark a device as removed */
525 static void maple_clean_submap(struct maple_device *mdev)
526 {
527 	int killbit;
528 
529 	killbit = (mdev->unit > 0 ? (1 << (mdev->unit - 1)) & 0x1f : 0x20);
530 	killbit = ~killbit;
531 	killbit &= 0xFF;
532 	subdevice_map[mdev->port] = subdevice_map[mdev->port] & killbit;
533 }
534 
535 /* handle empty port or hotplug removal */
536 static void maple_response_none(struct maple_device *mdev)
537 {
538 	maple_clean_submap(mdev);
539 
540 	if (likely(mdev->unit != 0)) {
541 		/*
542 		* Block devices play up
543 		* and give the impression they have
544 		* been removed even when still in place or
545 		* trip the mtd layer when they have
546 		* really gone - this code traps that eventuality
547 		* and ensures we aren't overloaded with useless
548 		* error messages
549 		*/
550 		if (mdev->can_unload) {
551 			if (!mdev->can_unload(mdev)) {
552 				atomic_set(&mdev->busy, 2);
553 				wake_up(&mdev->maple_wait);
554 				return;
555 			}
556 		}
557 
558 		dev_info(&mdev->dev, "detaching device at (%d, %d)\n",
559 			mdev->port, mdev->unit);
560 		maple_detach_driver(mdev);
561 		return;
562 	} else {
563 		if (!started || !fullscan) {
564 			if (checked[mdev->port] == false) {
565 				checked[mdev->port] = true;
566 				empty[mdev->port] = true;
567 				dev_info(&mdev->dev, "no devices"
568 					" to port %d\n", mdev->port);
569 			}
570 			return;
571 		}
572 	}
573 	/* Some hardware devices generate false detach messages on unit 0 */
574 	atomic_set(&mdev->busy, 0);
575 }
576 
577 /* preprocess hotplugs or scans */
578 static void maple_response_devinfo(struct maple_device *mdev,
579 				   char *recvbuf)
580 {
581 	char submask;
582 	if (!started || (scanning == 2) || !fullscan) {
583 		if ((mdev->unit == 0) && (checked[mdev->port] == false)) {
584 			checked[mdev->port] = true;
585 			maple_attach_driver(mdev);
586 		} else {
587 			if (mdev->unit != 0)
588 				maple_attach_driver(mdev);
589 			if (mdev->unit == 0) {
590 				empty[mdev->port] = false;
591 				maple_attach_driver(mdev);
592 			}
593 		}
594 	}
595 	if (mdev->unit == 0) {
596 		submask = recvbuf[2] & 0x1F;
597 		if (submask ^ subdevice_map[mdev->port]) {
598 			maple_map_subunits(mdev, submask);
599 			subdevice_map[mdev->port] = submask;
600 		}
601 	}
602 }
603 
604 static void maple_response_fileerr(struct maple_device *mdev, void *recvbuf)
605 {
606 	if (mdev->fileerr_handler) {
607 		mdev->fileerr_handler(mdev, recvbuf);
608 		return;
609 	} else
610 		dev_warn(&mdev->dev, "device at (%d, %d) reports"
611 			"file error 0x%X\n", mdev->port, mdev->unit,
612 			((int *)recvbuf)[1]);
613 }
614 
615 static void maple_port_rescan(void)
616 {
617 	int i;
618 	struct maple_device *mdev;
619 
620 	fullscan = 1;
621 	for (i = 0; i < MAPLE_PORTS; i++) {
622 		if (checked[i] == false) {
623 			fullscan = 0;
624 			mdev = baseunits[i];
625 			maple_add_packet(mdev, 0, MAPLE_COMMAND_DEVINFO,
626 				0, NULL);
627 		}
628 	}
629 }
630 
631 /* maple dma end bottom half - implemented via workqueue */
632 static void maple_dma_handler(struct work_struct *work)
633 {
634 	struct mapleq *mq, *nmq;
635 	struct maple_device *mdev;
636 	char *recvbuf;
637 	enum maple_code code;
638 
639 	if (!maple_dma_done())
640 		return;
641 	ctrl_outl(0, MAPLE_ENABLE);
642 	if (!list_empty(&maple_sentq)) {
643 		list_for_each_entry_safe(mq, nmq, &maple_sentq, list) {
644 			mdev = mq->dev;
645 			recvbuf = mq->recvbuf->buf;
646 			dma_cache_sync(&mdev->dev, recvbuf, 0x400,
647 				DMA_FROM_DEVICE);
648 			code = recvbuf[0];
649 			kfree(mq->sendbuf);
650 			list_del_init(&mq->list);
651 			switch (code) {
652 			case MAPLE_RESPONSE_NONE:
653 				maple_response_none(mdev);
654 				break;
655 
656 			case MAPLE_RESPONSE_DEVINFO:
657 				maple_response_devinfo(mdev, recvbuf);
658 				atomic_set(&mdev->busy, 0);
659 				break;
660 
661 			case MAPLE_RESPONSE_DATATRF:
662 				if (mdev->callback)
663 					mdev->callback(mq);
664 				atomic_set(&mdev->busy, 0);
665 				wake_up(&mdev->maple_wait);
666 				break;
667 
668 			case MAPLE_RESPONSE_FILEERR:
669 				maple_response_fileerr(mdev, recvbuf);
670 				atomic_set(&mdev->busy, 0);
671 				wake_up(&mdev->maple_wait);
672 				break;
673 
674 			case MAPLE_RESPONSE_AGAIN:
675 			case MAPLE_RESPONSE_BADCMD:
676 			case MAPLE_RESPONSE_BADFUNC:
677 				dev_warn(&mdev->dev, "non-fatal error"
678 					" 0x%X at (%d, %d)\n", code,
679 					mdev->port, mdev->unit);
680 				atomic_set(&mdev->busy, 0);
681 				break;
682 
683 			case MAPLE_RESPONSE_ALLINFO:
684 				dev_notice(&mdev->dev, "extended"
685 				" device information request for (%d, %d)"
686 				" but call is not supported\n", mdev->port,
687 				mdev->unit);
688 				atomic_set(&mdev->busy, 0);
689 				break;
690 
691 			case MAPLE_RESPONSE_OK:
692 				atomic_set(&mdev->busy, 0);
693 				wake_up(&mdev->maple_wait);
694 				break;
695 
696 			default:
697 				break;
698 			}
699 		}
700 		/* if scanning is 1 then we have subdevices to check */
701 		if (scanning == 1) {
702 			maple_send();
703 			scanning = 2;
704 		} else
705 			scanning = 0;
706 		/*check if we have actually tested all ports yet */
707 		if (!fullscan)
708 			maple_port_rescan();
709 		/* mark that we have been through the first scan */
710 		started = 1;
711 	}
712 	maple_send();
713 }
714 
715 static irqreturn_t maple_dma_interrupt(int irq, void *dev_id)
716 {
717 	/* Load everything into the bottom half */
718 	schedule_work(&maple_dma_process);
719 	return IRQ_HANDLED;
720 }
721 
722 static irqreturn_t maple_vblank_interrupt(int irq, void *dev_id)
723 {
724 	schedule_work(&maple_vblank_process);
725 	return IRQ_HANDLED;
726 }
727 
728 static int maple_set_dma_interrupt_handler(void)
729 {
730 	return request_irq(HW_EVENT_MAPLE_DMA, maple_dma_interrupt,
731 		IRQF_SHARED, "maple bus DMA", &maple_unsupported_device);
732 }
733 
734 static int maple_set_vblank_interrupt_handler(void)
735 {
736 	return request_irq(HW_EVENT_VSYNC, maple_vblank_interrupt,
737 		IRQF_SHARED, "maple bus VBLANK", &maple_unsupported_device);
738 }
739 
740 static int maple_get_dma_buffer(void)
741 {
742 	maple_sendbuf =
743 	    (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
744 				      MAPLE_DMA_PAGES);
745 	if (!maple_sendbuf)
746 		return -ENOMEM;
747 	return 0;
748 }
749 
750 static int maple_match_bus_driver(struct device *devptr,
751 				  struct device_driver *drvptr)
752 {
753 	struct maple_driver *maple_drv = to_maple_driver(drvptr);
754 	struct maple_device *maple_dev = to_maple_dev(devptr);
755 
756 	/* Trap empty port case */
757 	if (maple_dev->devinfo.function == 0xFFFFFFFF)
758 		return 0;
759 	else if (maple_dev->devinfo.function &
760 		 cpu_to_be32(maple_drv->function))
761 		return 1;
762 	return 0;
763 }
764 
765 static int maple_bus_uevent(struct device *dev,
766 			    struct kobj_uevent_env *env)
767 {
768 	return 0;
769 }
770 
771 static void maple_bus_release(struct device *dev)
772 {
773 }
774 
775 static struct maple_driver maple_unsupported_device = {
776 	.drv = {
777 		.name = "maple_unsupported_device",
778 		.bus = &maple_bus_type,
779 	},
780 };
781 /**
782  * maple_bus_type - core maple bus structure
783  */
784 struct bus_type maple_bus_type = {
785 	.name = "maple",
786 	.match = maple_match_bus_driver,
787 	.uevent = maple_bus_uevent,
788 };
789 EXPORT_SYMBOL_GPL(maple_bus_type);
790 
791 static struct device maple_bus = {
792 	.bus_id = "maple",
793 	.release = maple_bus_release,
794 };
795 
796 static int __init maple_bus_init(void)
797 {
798 	int retval, i;
799 	struct maple_device *mdev[MAPLE_PORTS];
800 
801 	ctrl_outl(0, MAPLE_ENABLE);
802 
803 	retval = device_register(&maple_bus);
804 	if (retval)
805 		goto cleanup;
806 
807 	retval = bus_register(&maple_bus_type);
808 	if (retval)
809 		goto cleanup_device;
810 
811 	retval = driver_register(&maple_unsupported_device.drv);
812 	if (retval)
813 		goto cleanup_bus;
814 
815 	/* allocate memory for maple bus dma */
816 	retval = maple_get_dma_buffer();
817 	if (retval) {
818 		dev_err(&maple_bus, "failed to allocate DMA buffers\n");
819 		goto cleanup_basic;
820 	}
821 
822 	/* set up DMA interrupt handler */
823 	retval = maple_set_dma_interrupt_handler();
824 	if (retval) {
825 		dev_err(&maple_bus, "bus failed to grab maple "
826 			"DMA IRQ\n");
827 		goto cleanup_dma;
828 	}
829 
830 	/* set up VBLANK interrupt handler */
831 	retval = maple_set_vblank_interrupt_handler();
832 	if (retval) {
833 		dev_err(&maple_bus, "bus failed to grab VBLANK IRQ\n");
834 		goto cleanup_irq;
835 	}
836 
837 	maple_queue_cache = KMEM_CACHE(maple_buffer, SLAB_HWCACHE_ALIGN);
838 
839 	if (!maple_queue_cache)
840 		goto cleanup_bothirqs;
841 
842 	INIT_LIST_HEAD(&maple_waitq);
843 	INIT_LIST_HEAD(&maple_sentq);
844 
845 	/* setup maple ports */
846 	for (i = 0; i < MAPLE_PORTS; i++) {
847 		checked[i] = false;
848 		empty[i] = false;
849 		mdev[i] = maple_alloc_dev(i, 0);
850 		if (!mdev[i]) {
851 			while (i-- > 0)
852 				maple_free_dev(mdev[i]);
853 			goto cleanup_cache;
854 		}
855 		baseunits[i] = mdev[i];
856 		atomic_set(&mdev[i]->busy, 1);
857 		maple_add_packet(mdev[i], 0, MAPLE_COMMAND_DEVINFO, 0, NULL);
858 		subdevice_map[i] = 0;
859 	}
860 
861 	maple_pnp_time = jiffies + HZ;
862 	/* prepare initial queue */
863 	maple_send();
864 	dev_info(&maple_bus, "bus core now registered\n");
865 
866 	return 0;
867 
868 cleanup_cache:
869 	kmem_cache_destroy(maple_queue_cache);
870 
871 cleanup_bothirqs:
872 	free_irq(HW_EVENT_VSYNC, 0);
873 
874 cleanup_irq:
875 	free_irq(HW_EVENT_MAPLE_DMA, 0);
876 
877 cleanup_dma:
878 	free_pages((unsigned long) maple_sendbuf, MAPLE_DMA_PAGES);
879 
880 cleanup_basic:
881 	driver_unregister(&maple_unsupported_device.drv);
882 
883 cleanup_bus:
884 	bus_unregister(&maple_bus_type);
885 
886 cleanup_device:
887 	device_unregister(&maple_bus);
888 
889 cleanup:
890 	printk(KERN_ERR "Maple bus registration failed\n");
891 	return retval;
892 }
893 /* Push init to later to ensure hardware gets detected */
894 fs_initcall(maple_bus_init);
895