xref: /openbmc/linux/drivers/sh/maple/maple.c (revision b9b77222)
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 <linux/module.h>
24 #include <asm/cacheflush.h>
25 #include <asm/dma.h>
26 #include <asm/io.h>
27 #include <mach/dma.h>
28 #include <mach/sysasic.h>
29 
30 MODULE_AUTHOR("Adrian McMenamin <adrian@mcmen.demon.co.uk>");
31 MODULE_DESCRIPTION("Maple bus driver for Dreamcast");
32 MODULE_LICENSE("GPL v2");
33 MODULE_SUPPORTED_DEVICE("{{SEGA, Dreamcast/Maple}}");
34 
35 static void maple_dma_handler(struct work_struct *work);
36 static void maple_vblank_handler(struct work_struct *work);
37 
38 static DECLARE_WORK(maple_dma_process, maple_dma_handler);
39 static DECLARE_WORK(maple_vblank_process, maple_vblank_handler);
40 
41 static LIST_HEAD(maple_waitq);
42 static LIST_HEAD(maple_sentq);
43 
44 /* mutex to protect queue of waiting packets */
45 static DEFINE_MUTEX(maple_wlist_lock);
46 
47 static struct maple_driver maple_unsupported_device;
48 static struct device maple_bus;
49 static int subdevice_map[MAPLE_PORTS];
50 static unsigned long *maple_sendbuf, *maple_sendptr, *maple_lastptr;
51 static unsigned long maple_pnp_time;
52 static int started, scanning, fullscan;
53 static struct kmem_cache *maple_queue_cache;
54 
55 struct maple_device_specify {
56 	int port;
57 	int unit;
58 };
59 
60 static bool checked[MAPLE_PORTS];
61 static bool empty[MAPLE_PORTS];
62 static struct maple_device *baseunits[MAPLE_PORTS];
63 
64 /**
65  * maple_driver_register - register a maple driver
66  * @drv: maple driver to be registered.
67  *
68  * Registers the passed in @drv, while updating the bus type.
69  * Devices with matching function IDs will be automatically probed.
70  */
71 int maple_driver_register(struct maple_driver *drv)
72 {
73 	if (!drv)
74 		return -EINVAL;
75 
76 	drv->drv.bus = &maple_bus_type;
77 
78 	return driver_register(&drv->drv);
79 }
80 EXPORT_SYMBOL_GPL(maple_driver_register);
81 
82 /**
83  * maple_driver_unregister - unregister a maple driver.
84  * @drv: maple driver to unregister.
85  *
86  * Cleans up after maple_driver_register(). To be invoked in the exit
87  * path of any module drivers.
88  */
89 void maple_driver_unregister(struct maple_driver *drv)
90 {
91 	driver_unregister(&drv->drv);
92 }
93 EXPORT_SYMBOL_GPL(maple_driver_unregister);
94 
95 /* set hardware registers to enable next round of dma */
96 static void maple_dma_reset(void)
97 {
98 	__raw_writel(MAPLE_MAGIC, MAPLE_RESET);
99 	/* set trig type to 0 for software trigger, 1 for hardware (VBLANK) */
100 	__raw_writel(1, MAPLE_TRIGTYPE);
101 	/*
102 	* Maple system register
103 	* bits 31 - 16	timeout in units of 20nsec
104 	* bit 12	hard trigger - set 0 to keep responding to VBLANK
105 	* bits 9 - 8	set 00 for 2 Mbps, 01 for 1 Mbps
106 	* bits 3 - 0	delay (in 1.3ms) between VBLANK and start of DMA
107 	* max delay is 11
108 	*/
109 	__raw_writel(MAPLE_2MBPS | MAPLE_TIMEOUT(0xFFFF), MAPLE_SPEED);
110 	__raw_writel(virt_to_phys(maple_sendbuf), MAPLE_DMAADDR);
111 	__raw_writel(1, MAPLE_ENABLE);
112 }
113 
114 /**
115  * maple_getcond_callback - setup handling MAPLE_COMMAND_GETCOND
116  * @dev: device responding
117  * @callback: handler callback
118  * @interval: interval in jiffies between callbacks
119  * @function: the function code for the device
120  */
121 void maple_getcond_callback(struct maple_device *dev,
122 			void (*callback) (struct mapleq *mq),
123 			unsigned long interval, unsigned long function)
124 {
125 	dev->callback = callback;
126 	dev->interval = interval;
127 	dev->function = cpu_to_be32(function);
128 	dev->when = jiffies;
129 }
130 EXPORT_SYMBOL_GPL(maple_getcond_callback);
131 
132 static int maple_dma_done(void)
133 {
134 	return (__raw_readl(MAPLE_STATE) & 1) == 0;
135 }
136 
137 static void maple_release_device(struct device *dev)
138 {
139 	struct maple_device *mdev;
140 	struct mapleq *mq;
141 
142 	mdev = to_maple_dev(dev);
143 	mq = mdev->mq;
144 	kmem_cache_free(maple_queue_cache, mq->recvbuf);
145 	kfree(mq);
146 	kfree(mdev);
147 }
148 
149 /**
150  * maple_add_packet - add a single instruction to the maple bus 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 ret = 0;
161 	void *sendbuf = NULL;
162 
163 	if (length) {
164 		sendbuf = kcalloc(length, 4, GFP_KERNEL);
165 		if (!sendbuf) {
166 			ret = -ENOMEM;
167 			goto out;
168 		}
169 		((__be32 *)sendbuf)[0] = cpu_to_be32(function);
170 	}
171 
172 	mdev->mq->command = command;
173 	mdev->mq->length = length;
174 	if (length > 1)
175 		memcpy(sendbuf + 4, data, (length - 1) * 4);
176 	mdev->mq->sendbuf = sendbuf;
177 
178 	mutex_lock(&maple_wlist_lock);
179 	list_add_tail(&mdev->mq->list, &maple_waitq);
180 	mutex_unlock(&maple_wlist_lock);
181 out:
182 	return ret;
183 }
184 EXPORT_SYMBOL_GPL(maple_add_packet);
185 
186 static struct mapleq *maple_allocq(struct maple_device *mdev)
187 {
188 	struct mapleq *mq;
189 
190 	mq = kzalloc(sizeof(*mq), GFP_KERNEL);
191 	if (!mq)
192 		goto failed_nomem;
193 
194 	INIT_LIST_HEAD(&mq->list);
195 	mq->dev = mdev;
196 	mq->recvbuf = kmem_cache_zalloc(maple_queue_cache, GFP_KERNEL);
197 	if (!mq->recvbuf)
198 		goto failed_p2;
199 	mq->recvbuf->buf = &((mq->recvbuf->bufx)[0]);
200 
201 	return mq;
202 
203 failed_p2:
204 	kfree(mq);
205 failed_nomem:
206 	dev_err(&mdev->dev, "could not allocate memory for device (%d, %d)\n",
207 		mdev->port, mdev->unit);
208 	return NULL;
209 }
210 
211 static struct maple_device *maple_alloc_dev(int port, int unit)
212 {
213 	struct maple_device *mdev;
214 
215 	/* zero this out to avoid kobj subsystem
216 	* thinking it has already been registered */
217 
218 	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
219 	if (!mdev)
220 		return NULL;
221 
222 	mdev->port = port;
223 	mdev->unit = unit;
224 
225 	mdev->mq = maple_allocq(mdev);
226 
227 	if (!mdev->mq) {
228 		kfree(mdev);
229 		return NULL;
230 	}
231 	mdev->dev.bus = &maple_bus_type;
232 	mdev->dev.parent = &maple_bus;
233 	init_waitqueue_head(&mdev->maple_wait);
234 	return mdev;
235 }
236 
237 static void maple_free_dev(struct maple_device *mdev)
238 {
239 	kmem_cache_free(maple_queue_cache, mdev->mq->recvbuf);
240 	kfree(mdev->mq);
241 	kfree(mdev);
242 }
243 
244 /* process the command queue into a maple command block
245  * terminating command has bit 32 of first long set to 0
246  */
247 static void maple_build_block(struct mapleq *mq)
248 {
249 	int port, unit, from, to, len;
250 	unsigned long *lsendbuf = mq->sendbuf;
251 
252 	port = mq->dev->port & 3;
253 	unit = mq->dev->unit;
254 	len = mq->length;
255 	from = port << 6;
256 	to = (port << 6) | (unit > 0 ? (1 << (unit - 1)) & 0x1f : 0x20);
257 
258 	*maple_lastptr &= 0x7fffffff;
259 	maple_lastptr = maple_sendptr;
260 
261 	*maple_sendptr++ = (port << 16) | len | 0x80000000;
262 	*maple_sendptr++ = virt_to_phys(mq->recvbuf->buf);
263 	*maple_sendptr++ =
264 	    mq->command | (to << 8) | (from << 16) | (len << 24);
265 	while (len-- > 0)
266 		*maple_sendptr++ = *lsendbuf++;
267 }
268 
269 /* build up command queue */
270 static void maple_send(void)
271 {
272 	int i, maple_packets = 0;
273 	struct mapleq *mq, *nmq;
274 
275 	if (!maple_dma_done())
276 		return;
277 
278 	/* disable DMA */
279 	__raw_writel(0, MAPLE_ENABLE);
280 
281 	if (!list_empty(&maple_sentq))
282 		goto finish;
283 
284 	mutex_lock(&maple_wlist_lock);
285 	if (list_empty(&maple_waitq)) {
286 		mutex_unlock(&maple_wlist_lock);
287 		goto finish;
288 	}
289 
290 	maple_lastptr = maple_sendbuf;
291 	maple_sendptr = maple_sendbuf;
292 
293 	list_for_each_entry_safe(mq, nmq, &maple_waitq, list) {
294 		maple_build_block(mq);
295 		list_del_init(&mq->list);
296 		list_add_tail(&mq->list, &maple_sentq);
297 		if (maple_packets++ > MAPLE_MAXPACKETS)
298 			break;
299 	}
300 	mutex_unlock(&maple_wlist_lock);
301 	if (maple_packets > 0) {
302 		for (i = 0; i < (1 << MAPLE_DMA_PAGES); i++)
303 			sh_sync_dma_for_device(maple_sendbuf + i * PAGE_SIZE,
304 				       PAGE_SIZE, DMA_BIDIRECTIONAL);
305 	}
306 
307 finish:
308 	maple_dma_reset();
309 }
310 
311 /* check if there is a driver registered likely to match this device */
312 static int maple_check_matching_driver(struct device_driver *driver,
313 					void *devptr)
314 {
315 	struct maple_driver *maple_drv;
316 	struct maple_device *mdev;
317 
318 	mdev = devptr;
319 	maple_drv = to_maple_driver(driver);
320 	if (mdev->devinfo.function & cpu_to_be32(maple_drv->function))
321 		return 1;
322 	return 0;
323 }
324 
325 static void maple_detach_driver(struct maple_device *mdev)
326 {
327 	device_unregister(&mdev->dev);
328 }
329 
330 /* process initial MAPLE_COMMAND_DEVINFO for each device or port */
331 static void maple_attach_driver(struct maple_device *mdev)
332 {
333 	char *p, *recvbuf;
334 	unsigned long function;
335 	int matched, error;
336 
337 	recvbuf = mdev->mq->recvbuf->buf;
338 	/* copy the data as individual elements in
339 	* case of memory optimisation */
340 	memcpy(&mdev->devinfo.function, recvbuf + 4, 4);
341 	memcpy(&mdev->devinfo.function_data[0], recvbuf + 8, 12);
342 	memcpy(&mdev->devinfo.area_code, recvbuf + 20, 1);
343 	memcpy(&mdev->devinfo.connector_direction, recvbuf + 21, 1);
344 	memcpy(&mdev->devinfo.product_name[0], recvbuf + 22, 30);
345 	memcpy(&mdev->devinfo.standby_power, recvbuf + 112, 2);
346 	memcpy(&mdev->devinfo.max_power, recvbuf + 114, 2);
347 	memcpy(mdev->product_name, mdev->devinfo.product_name, 30);
348 	mdev->product_name[30] = '\0';
349 	memcpy(mdev->product_licence, mdev->devinfo.product_licence, 60);
350 	mdev->product_licence[60] = '\0';
351 
352 	for (p = mdev->product_name + 29; mdev->product_name <= p; p--)
353 		if (*p == ' ')
354 			*p = '\0';
355 		else
356 			break;
357 	for (p = mdev->product_licence + 59; mdev->product_licence <= p; p--)
358 		if (*p == ' ')
359 			*p = '\0';
360 		else
361 			break;
362 
363 	function = be32_to_cpu(mdev->devinfo.function);
364 
365 	dev_info(&mdev->dev, "detected %s: function 0x%lX: at (%d, %d)\n",
366 		mdev->product_name, function, mdev->port, mdev->unit);
367 
368 	if (function > 0x200) {
369 		/* Do this silently - as not a real device */
370 		function = 0;
371 		mdev->driver = &maple_unsupported_device;
372 		dev_set_name(&mdev->dev, "%d:0.port", mdev->port);
373 	} else {
374 		matched =
375 			bus_for_each_drv(&maple_bus_type, NULL, mdev,
376 				maple_check_matching_driver);
377 
378 		if (matched == 0) {
379 			/* Driver does not exist yet */
380 			dev_info(&mdev->dev, "no driver found\n");
381 			mdev->driver = &maple_unsupported_device;
382 		}
383 		dev_set_name(&mdev->dev, "%d:0%d.%lX", mdev->port,
384 			     mdev->unit, function);
385 	}
386 
387 	mdev->function = function;
388 	mdev->dev.release = &maple_release_device;
389 
390 	atomic_set(&mdev->busy, 0);
391 	error = device_register(&mdev->dev);
392 	if (error) {
393 		dev_warn(&mdev->dev, "could not register device at"
394 			" (%d, %d), with error 0x%X\n", mdev->unit,
395 			mdev->port, error);
396 		maple_free_dev(mdev);
397 		mdev = NULL;
398 		return;
399 	}
400 }
401 
402 /*
403  * if device has been registered for the given
404  * port and unit then return 1 - allows identification
405  * of which devices need to be attached or detached
406  */
407 static int check_maple_device(struct device *device, void *portptr)
408 {
409 	struct maple_device_specify *ds;
410 	struct maple_device *mdev;
411 
412 	ds = portptr;
413 	mdev = to_maple_dev(device);
414 	if (mdev->port == ds->port && mdev->unit == ds->unit)
415 		return 1;
416 	return 0;
417 }
418 
419 static int setup_maple_commands(struct device *device, void *ignored)
420 {
421 	int add;
422 	struct maple_device *mdev = to_maple_dev(device);
423 	if (mdev->interval > 0 && atomic_read(&mdev->busy) == 0 &&
424 		time_after(jiffies, mdev->when)) {
425 		/* bounce if we cannot add */
426 		add = maple_add_packet(mdev,
427 			be32_to_cpu(mdev->devinfo.function),
428 			MAPLE_COMMAND_GETCOND, 1, NULL);
429 		if (!add)
430 			mdev->when = jiffies + mdev->interval;
431 	} else {
432 		if (time_after(jiffies, maple_pnp_time))
433 			/* Ensure we don't have block reads and devinfo
434 			* calls interfering with one another - so flag the
435 			* device as busy */
436 			if (atomic_read(&mdev->busy) == 0) {
437 				atomic_set(&mdev->busy, 1);
438 				maple_add_packet(mdev, 0,
439 					MAPLE_COMMAND_DEVINFO, 0, NULL);
440 			}
441 	}
442 	return 0;
443 }
444 
445 /* VBLANK bottom half - implemented via workqueue */
446 static void maple_vblank_handler(struct work_struct *work)
447 {
448 	int x, locking;
449 	struct maple_device *mdev;
450 
451 	if (!maple_dma_done())
452 		return;
453 
454 	__raw_writel(0, MAPLE_ENABLE);
455 
456 	if (!list_empty(&maple_sentq))
457 		goto finish;
458 
459 	/*
460 	* Set up essential commands - to fetch data and
461 	* check devices are still present
462 	*/
463 	bus_for_each_dev(&maple_bus_type, NULL, NULL,
464 		setup_maple_commands);
465 
466 	if (time_after(jiffies, maple_pnp_time)) {
467 		/*
468 		* Scan the empty ports - bus is flakey and may have
469 		* mis-reported emptyness
470 		*/
471 		for (x = 0; x < MAPLE_PORTS; x++) {
472 			if (checked[x] && empty[x]) {
473 				mdev = baseunits[x];
474 				if (!mdev)
475 					break;
476 				atomic_set(&mdev->busy, 1);
477 				locking = maple_add_packet(mdev, 0,
478 					MAPLE_COMMAND_DEVINFO, 0, NULL);
479 				if (!locking)
480 					break;
481 				}
482 			}
483 
484 		maple_pnp_time = jiffies + MAPLE_PNP_INTERVAL;
485 	}
486 
487 finish:
488 	maple_send();
489 }
490 
491 /* handle devices added via hotplugs - placing them on queue for DEVINFO */
492 static void maple_map_subunits(struct maple_device *mdev, int submask)
493 {
494 	int retval, k, devcheck;
495 	struct maple_device *mdev_add;
496 	struct maple_device_specify ds;
497 
498 	ds.port = mdev->port;
499 	for (k = 0; k < 5; k++) {
500 		ds.unit = k + 1;
501 		retval =
502 		    bus_for_each_dev(&maple_bus_type, NULL, &ds,
503 				     check_maple_device);
504 		if (retval) {
505 			submask = submask >> 1;
506 			continue;
507 		}
508 		devcheck = submask & 0x01;
509 		if (devcheck) {
510 			mdev_add = maple_alloc_dev(mdev->port, k + 1);
511 			if (!mdev_add)
512 				return;
513 			atomic_set(&mdev_add->busy, 1);
514 			maple_add_packet(mdev_add, 0, MAPLE_COMMAND_DEVINFO,
515 				0, NULL);
516 			/* mark that we are checking sub devices */
517 			scanning = 1;
518 		}
519 		submask = submask >> 1;
520 	}
521 }
522 
523 /* mark a device as removed */
524 static void maple_clean_submap(struct maple_device *mdev)
525 {
526 	int killbit;
527 
528 	killbit = (mdev->unit > 0 ? (1 << (mdev->unit - 1)) & 0x1f : 0x20);
529 	killbit = ~killbit;
530 	killbit &= 0xFF;
531 	subdevice_map[mdev->port] = subdevice_map[mdev->port] & killbit;
532 }
533 
534 /* handle empty port or hotplug removal */
535 static void maple_response_none(struct maple_device *mdev)
536 {
537 	maple_clean_submap(mdev);
538 
539 	if (likely(mdev->unit != 0)) {
540 		/*
541 		* Block devices play up
542 		* and give the impression they have
543 		* been removed even when still in place or
544 		* trip the mtd layer when they have
545 		* really gone - this code traps that eventuality
546 		* and ensures we aren't overloaded with useless
547 		* error messages
548 		*/
549 		if (mdev->can_unload) {
550 			if (!mdev->can_unload(mdev)) {
551 				atomic_set(&mdev->busy, 2);
552 				wake_up(&mdev->maple_wait);
553 				return;
554 			}
555 		}
556 
557 		dev_info(&mdev->dev, "detaching device at (%d, %d)\n",
558 			mdev->port, mdev->unit);
559 		maple_detach_driver(mdev);
560 		return;
561 	} else {
562 		if (!started || !fullscan) {
563 			if (checked[mdev->port] == false) {
564 				checked[mdev->port] = true;
565 				empty[mdev->port] = true;
566 				dev_info(&mdev->dev, "no devices"
567 					" to port %d\n", mdev->port);
568 			}
569 			return;
570 		}
571 	}
572 	/* Some hardware devices generate false detach messages on unit 0 */
573 	atomic_set(&mdev->busy, 0);
574 }
575 
576 /* preprocess hotplugs or scans */
577 static void maple_response_devinfo(struct maple_device *mdev,
578 				   char *recvbuf)
579 {
580 	char submask;
581 	if (!started || (scanning == 2) || !fullscan) {
582 		if ((mdev->unit == 0) && (checked[mdev->port] == false)) {
583 			checked[mdev->port] = true;
584 			maple_attach_driver(mdev);
585 		} else {
586 			if (mdev->unit != 0)
587 				maple_attach_driver(mdev);
588 			if (mdev->unit == 0) {
589 				empty[mdev->port] = false;
590 				maple_attach_driver(mdev);
591 			}
592 		}
593 	}
594 	if (mdev->unit == 0) {
595 		submask = recvbuf[2] & 0x1F;
596 		if (submask ^ subdevice_map[mdev->port]) {
597 			maple_map_subunits(mdev, submask);
598 			subdevice_map[mdev->port] = submask;
599 		}
600 	}
601 }
602 
603 static void maple_response_fileerr(struct maple_device *mdev, void *recvbuf)
604 {
605 	if (mdev->fileerr_handler) {
606 		mdev->fileerr_handler(mdev, recvbuf);
607 		return;
608 	} else
609 		dev_warn(&mdev->dev, "device at (%d, %d) reports"
610 			"file error 0x%X\n", mdev->port, mdev->unit,
611 			((int *)recvbuf)[1]);
612 }
613 
614 static void maple_port_rescan(void)
615 {
616 	int i;
617 	struct maple_device *mdev;
618 
619 	fullscan = 1;
620 	for (i = 0; i < MAPLE_PORTS; i++) {
621 		if (checked[i] == false) {
622 			fullscan = 0;
623 			mdev = baseunits[i];
624 			maple_add_packet(mdev, 0, MAPLE_COMMAND_DEVINFO,
625 				0, NULL);
626 		}
627 	}
628 }
629 
630 /* maple dma end bottom half - implemented via workqueue */
631 static void maple_dma_handler(struct work_struct *work)
632 {
633 	struct mapleq *mq, *nmq;
634 	struct maple_device *mdev;
635 	char *recvbuf;
636 	enum maple_code code;
637 
638 	if (!maple_dma_done())
639 		return;
640 	__raw_writel(0, MAPLE_ENABLE);
641 	if (!list_empty(&maple_sentq)) {
642 		list_for_each_entry_safe(mq, nmq, &maple_sentq, list) {
643 			mdev = mq->dev;
644 			recvbuf = mq->recvbuf->buf;
645 			sh_sync_dma_for_device(recvbuf, 0x400, DMA_FROM_DEVICE);
646 			code = recvbuf[0];
647 			kfree(mq->sendbuf);
648 			list_del_init(&mq->list);
649 			switch (code) {
650 			case MAPLE_RESPONSE_NONE:
651 				maple_response_none(mdev);
652 				break;
653 
654 			case MAPLE_RESPONSE_DEVINFO:
655 				maple_response_devinfo(mdev, recvbuf);
656 				atomic_set(&mdev->busy, 0);
657 				break;
658 
659 			case MAPLE_RESPONSE_DATATRF:
660 				if (mdev->callback)
661 					mdev->callback(mq);
662 				atomic_set(&mdev->busy, 0);
663 				wake_up(&mdev->maple_wait);
664 				break;
665 
666 			case MAPLE_RESPONSE_FILEERR:
667 				maple_response_fileerr(mdev, recvbuf);
668 				atomic_set(&mdev->busy, 0);
669 				wake_up(&mdev->maple_wait);
670 				break;
671 
672 			case MAPLE_RESPONSE_AGAIN:
673 			case MAPLE_RESPONSE_BADCMD:
674 			case MAPLE_RESPONSE_BADFUNC:
675 				dev_warn(&mdev->dev, "non-fatal error"
676 					" 0x%X at (%d, %d)\n", code,
677 					mdev->port, mdev->unit);
678 				atomic_set(&mdev->busy, 0);
679 				break;
680 
681 			case MAPLE_RESPONSE_ALLINFO:
682 				dev_notice(&mdev->dev, "extended"
683 				" device information request for (%d, %d)"
684 				" but call is not supported\n", mdev->port,
685 				mdev->unit);
686 				atomic_set(&mdev->busy, 0);
687 				break;
688 
689 			case MAPLE_RESPONSE_OK:
690 				atomic_set(&mdev->busy, 0);
691 				wake_up(&mdev->maple_wait);
692 				break;
693 
694 			default:
695 				break;
696 			}
697 		}
698 		/* if scanning is 1 then we have subdevices to check */
699 		if (scanning == 1) {
700 			maple_send();
701 			scanning = 2;
702 		} else
703 			scanning = 0;
704 		/*check if we have actually tested all ports yet */
705 		if (!fullscan)
706 			maple_port_rescan();
707 		/* mark that we have been through the first scan */
708 		started = 1;
709 	}
710 	maple_send();
711 }
712 
713 static irqreturn_t maple_dma_interrupt(int irq, void *dev_id)
714 {
715 	/* Load everything into the bottom half */
716 	schedule_work(&maple_dma_process);
717 	return IRQ_HANDLED;
718 }
719 
720 static irqreturn_t maple_vblank_interrupt(int irq, void *dev_id)
721 {
722 	schedule_work(&maple_vblank_process);
723 	return IRQ_HANDLED;
724 }
725 
726 static int maple_set_dma_interrupt_handler(void)
727 {
728 	return request_irq(HW_EVENT_MAPLE_DMA, maple_dma_interrupt,
729 		IRQF_SHARED, "maple bus DMA", &maple_unsupported_device);
730 }
731 
732 static int maple_set_vblank_interrupt_handler(void)
733 {
734 	return request_irq(HW_EVENT_VSYNC, maple_vblank_interrupt,
735 		IRQF_SHARED, "maple bus VBLANK", &maple_unsupported_device);
736 }
737 
738 static int maple_get_dma_buffer(void)
739 {
740 	maple_sendbuf =
741 	    (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO,
742 				      MAPLE_DMA_PAGES);
743 	if (!maple_sendbuf)
744 		return -ENOMEM;
745 	return 0;
746 }
747 
748 static int maple_match_bus_driver(struct device *devptr,
749 				  struct device_driver *drvptr)
750 {
751 	struct maple_driver *maple_drv = to_maple_driver(drvptr);
752 	struct maple_device *maple_dev = to_maple_dev(devptr);
753 
754 	/* Trap empty port case */
755 	if (maple_dev->devinfo.function == 0xFFFFFFFF)
756 		return 0;
757 	else if (maple_dev->devinfo.function &
758 		 cpu_to_be32(maple_drv->function))
759 		return 1;
760 	return 0;
761 }
762 
763 static int maple_bus_uevent(struct device *dev,
764 			    struct kobj_uevent_env *env)
765 {
766 	return 0;
767 }
768 
769 static void maple_bus_release(struct device *dev)
770 {
771 }
772 
773 static struct maple_driver maple_unsupported_device = {
774 	.drv = {
775 		.name = "maple_unsupported_device",
776 		.bus = &maple_bus_type,
777 	},
778 };
779 /*
780  * maple_bus_type - core maple bus structure
781  */
782 struct bus_type maple_bus_type = {
783 	.name = "maple",
784 	.match = maple_match_bus_driver,
785 	.uevent = maple_bus_uevent,
786 };
787 EXPORT_SYMBOL_GPL(maple_bus_type);
788 
789 static struct device maple_bus = {
790 	.init_name = "maple",
791 	.release = maple_bus_release,
792 };
793 
794 static int __init maple_bus_init(void)
795 {
796 	int retval, i;
797 	struct maple_device *mdev[MAPLE_PORTS];
798 
799 	__raw_writel(0, MAPLE_ENABLE);
800 
801 	retval = device_register(&maple_bus);
802 	if (retval)
803 		goto cleanup;
804 
805 	retval = bus_register(&maple_bus_type);
806 	if (retval)
807 		goto cleanup_device;
808 
809 	retval = driver_register(&maple_unsupported_device.drv);
810 	if (retval)
811 		goto cleanup_bus;
812 
813 	/* allocate memory for maple bus dma */
814 	retval = maple_get_dma_buffer();
815 	if (retval) {
816 		dev_err(&maple_bus, "failed to allocate DMA buffers\n");
817 		goto cleanup_basic;
818 	}
819 
820 	/* set up DMA interrupt handler */
821 	retval = maple_set_dma_interrupt_handler();
822 	if (retval) {
823 		dev_err(&maple_bus, "bus failed to grab maple "
824 			"DMA IRQ\n");
825 		goto cleanup_dma;
826 	}
827 
828 	/* set up VBLANK interrupt handler */
829 	retval = maple_set_vblank_interrupt_handler();
830 	if (retval) {
831 		dev_err(&maple_bus, "bus failed to grab VBLANK IRQ\n");
832 		goto cleanup_irq;
833 	}
834 
835 	maple_queue_cache = KMEM_CACHE(maple_buffer, SLAB_HWCACHE_ALIGN);
836 
837 	if (!maple_queue_cache)
838 		goto cleanup_bothirqs;
839 
840 	INIT_LIST_HEAD(&maple_waitq);
841 	INIT_LIST_HEAD(&maple_sentq);
842 
843 	/* setup maple ports */
844 	for (i = 0; i < MAPLE_PORTS; i++) {
845 		checked[i] = false;
846 		empty[i] = false;
847 		mdev[i] = maple_alloc_dev(i, 0);
848 		if (!mdev[i]) {
849 			while (i-- > 0)
850 				maple_free_dev(mdev[i]);
851 			goto cleanup_cache;
852 		}
853 		baseunits[i] = mdev[i];
854 		atomic_set(&mdev[i]->busy, 1);
855 		maple_add_packet(mdev[i], 0, MAPLE_COMMAND_DEVINFO, 0, NULL);
856 		subdevice_map[i] = 0;
857 	}
858 
859 	maple_pnp_time = jiffies + HZ;
860 	/* prepare initial queue */
861 	maple_send();
862 	dev_info(&maple_bus, "bus core now registered\n");
863 
864 	return 0;
865 
866 cleanup_cache:
867 	kmem_cache_destroy(maple_queue_cache);
868 
869 cleanup_bothirqs:
870 	free_irq(HW_EVENT_VSYNC, 0);
871 
872 cleanup_irq:
873 	free_irq(HW_EVENT_MAPLE_DMA, 0);
874 
875 cleanup_dma:
876 	free_pages((unsigned long) maple_sendbuf, MAPLE_DMA_PAGES);
877 
878 cleanup_basic:
879 	driver_unregister(&maple_unsupported_device.drv);
880 
881 cleanup_bus:
882 	bus_unregister(&maple_bus_type);
883 
884 cleanup_device:
885 	device_unregister(&maple_bus);
886 
887 cleanup:
888 	printk(KERN_ERR "Maple bus registration failed\n");
889 	return retval;
890 }
891 /* Push init to later to ensure hardware gets detected */
892 fs_initcall(maple_bus_init);
893