xref: /openbmc/linux/drivers/sh/maple/maple.c (revision c6acb1e7)
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 
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 	__raw_writel(MAPLE_MAGIC, MAPLE_RESET);
98 	/* set trig type to 0 for software trigger, 1 for hardware (VBLANK) */
99 	__raw_writel(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 	__raw_writel(MAPLE_2MBPS | MAPLE_TIMEOUT(0xFFFF), MAPLE_SPEED);
109 	__raw_writel(virt_to_phys(maple_sendbuf), MAPLE_DMAADDR);
110 	__raw_writel(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 (__raw_readl(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 = kcalloc(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++ = virt_to_phys(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 	__raw_writel(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 			__flush_purge_region(maple_sendbuf + i * PAGE_SIZE,
303 					PAGE_SIZE);
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 		dev_set_name(&mdev->dev, "%d:0.port", mdev->port);
372 	} else {
373 		matched =
374 			bus_for_each_drv(&maple_bus_type, NULL, mdev,
375 				maple_check_matching_driver);
376 
377 		if (matched == 0) {
378 			/* Driver does not exist yet */
379 			dev_info(&mdev->dev, "no driver found\n");
380 			mdev->driver = &maple_unsupported_device;
381 		}
382 		dev_set_name(&mdev->dev, "%d:0%d.%lX", mdev->port,
383 			     mdev->unit, function);
384 	}
385 
386 	mdev->function = function;
387 	mdev->dev.release = &maple_release_device;
388 
389 	atomic_set(&mdev->busy, 0);
390 	error = device_register(&mdev->dev);
391 	if (error) {
392 		dev_warn(&mdev->dev, "could not register device at"
393 			" (%d, %d), with error 0x%X\n", mdev->unit,
394 			mdev->port, error);
395 		maple_free_dev(mdev);
396 		mdev = NULL;
397 		return;
398 	}
399 }
400 
401 /*
402  * if device has been registered for the given
403  * port and unit then return 1 - allows identification
404  * of which devices need to be attached or detached
405  */
406 static int check_maple_device(struct device *device, void *portptr)
407 {
408 	struct maple_device_specify *ds;
409 	struct maple_device *mdev;
410 
411 	ds = portptr;
412 	mdev = to_maple_dev(device);
413 	if (mdev->port == ds->port && mdev->unit == ds->unit)
414 		return 1;
415 	return 0;
416 }
417 
418 static int setup_maple_commands(struct device *device, void *ignored)
419 {
420 	int add;
421 	struct maple_device *mdev = to_maple_dev(device);
422 	if (mdev->interval > 0 && atomic_read(&mdev->busy) == 0 &&
423 		time_after(jiffies, mdev->when)) {
424 		/* bounce if we cannot add */
425 		add = maple_add_packet(mdev,
426 			be32_to_cpu(mdev->devinfo.function),
427 			MAPLE_COMMAND_GETCOND, 1, NULL);
428 		if (!add)
429 			mdev->when = jiffies + mdev->interval;
430 	} else {
431 		if (time_after(jiffies, maple_pnp_time))
432 			/* Ensure we don't have block reads and devinfo
433 			* calls interfering with one another - so flag the
434 			* device as busy */
435 			if (atomic_read(&mdev->busy) == 0) {
436 				atomic_set(&mdev->busy, 1);
437 				maple_add_packet(mdev, 0,
438 					MAPLE_COMMAND_DEVINFO, 0, NULL);
439 			}
440 	}
441 	return 0;
442 }
443 
444 /* VBLANK bottom half - implemented via workqueue */
445 static void maple_vblank_handler(struct work_struct *work)
446 {
447 	int x, locking;
448 	struct maple_device *mdev;
449 
450 	if (!maple_dma_done())
451 		return;
452 
453 	__raw_writel(0, MAPLE_ENABLE);
454 
455 	if (!list_empty(&maple_sentq))
456 		goto finish;
457 
458 	/*
459 	* Set up essential commands - to fetch data and
460 	* check devices are still present
461 	*/
462 	bus_for_each_dev(&maple_bus_type, NULL, NULL,
463 		setup_maple_commands);
464 
465 	if (time_after(jiffies, maple_pnp_time)) {
466 		/*
467 		* Scan the empty ports - bus is flakey and may have
468 		* mis-reported emptyness
469 		*/
470 		for (x = 0; x < MAPLE_PORTS; x++) {
471 			if (checked[x] && empty[x]) {
472 				mdev = baseunits[x];
473 				if (!mdev)
474 					break;
475 				atomic_set(&mdev->busy, 1);
476 				locking = maple_add_packet(mdev, 0,
477 					MAPLE_COMMAND_DEVINFO, 0, NULL);
478 				if (!locking)
479 					break;
480 				}
481 			}
482 
483 		maple_pnp_time = jiffies + MAPLE_PNP_INTERVAL;
484 	}
485 
486 finish:
487 	maple_send();
488 }
489 
490 /* handle devices added via hotplugs - placing them on queue for DEVINFO */
491 static void maple_map_subunits(struct maple_device *mdev, int submask)
492 {
493 	int retval, k, devcheck;
494 	struct maple_device *mdev_add;
495 	struct maple_device_specify ds;
496 
497 	ds.port = mdev->port;
498 	for (k = 0; k < 5; k++) {
499 		ds.unit = k + 1;
500 		retval =
501 		    bus_for_each_dev(&maple_bus_type, NULL, &ds,
502 				     check_maple_device);
503 		if (retval) {
504 			submask = submask >> 1;
505 			continue;
506 		}
507 		devcheck = submask & 0x01;
508 		if (devcheck) {
509 			mdev_add = maple_alloc_dev(mdev->port, k + 1);
510 			if (!mdev_add)
511 				return;
512 			atomic_set(&mdev_add->busy, 1);
513 			maple_add_packet(mdev_add, 0, MAPLE_COMMAND_DEVINFO,
514 				0, NULL);
515 			/* mark that we are checking sub devices */
516 			scanning = 1;
517 		}
518 		submask = submask >> 1;
519 	}
520 }
521 
522 /* mark a device as removed */
523 static void maple_clean_submap(struct maple_device *mdev)
524 {
525 	int killbit;
526 
527 	killbit = (mdev->unit > 0 ? (1 << (mdev->unit - 1)) & 0x1f : 0x20);
528 	killbit = ~killbit;
529 	killbit &= 0xFF;
530 	subdevice_map[mdev->port] = subdevice_map[mdev->port] & killbit;
531 }
532 
533 /* handle empty port or hotplug removal */
534 static void maple_response_none(struct maple_device *mdev)
535 {
536 	maple_clean_submap(mdev);
537 
538 	if (likely(mdev->unit != 0)) {
539 		/*
540 		* Block devices play up
541 		* and give the impression they have
542 		* been removed even when still in place or
543 		* trip the mtd layer when they have
544 		* really gone - this code traps that eventuality
545 		* and ensures we aren't overloaded with useless
546 		* error messages
547 		*/
548 		if (mdev->can_unload) {
549 			if (!mdev->can_unload(mdev)) {
550 				atomic_set(&mdev->busy, 2);
551 				wake_up(&mdev->maple_wait);
552 				return;
553 			}
554 		}
555 
556 		dev_info(&mdev->dev, "detaching device at (%d, %d)\n",
557 			mdev->port, mdev->unit);
558 		maple_detach_driver(mdev);
559 		return;
560 	} else {
561 		if (!started || !fullscan) {
562 			if (checked[mdev->port] == false) {
563 				checked[mdev->port] = true;
564 				empty[mdev->port] = true;
565 				dev_info(&mdev->dev, "no devices"
566 					" to port %d\n", mdev->port);
567 			}
568 			return;
569 		}
570 	}
571 	/* Some hardware devices generate false detach messages on unit 0 */
572 	atomic_set(&mdev->busy, 0);
573 }
574 
575 /* preprocess hotplugs or scans */
576 static void maple_response_devinfo(struct maple_device *mdev,
577 				   char *recvbuf)
578 {
579 	char submask;
580 	if (!started || (scanning == 2) || !fullscan) {
581 		if ((mdev->unit == 0) && (checked[mdev->port] == false)) {
582 			checked[mdev->port] = true;
583 			maple_attach_driver(mdev);
584 		} else {
585 			if (mdev->unit != 0)
586 				maple_attach_driver(mdev);
587 			if (mdev->unit == 0) {
588 				empty[mdev->port] = false;
589 				maple_attach_driver(mdev);
590 			}
591 		}
592 	}
593 	if (mdev->unit == 0) {
594 		submask = recvbuf[2] & 0x1F;
595 		if (submask ^ subdevice_map[mdev->port]) {
596 			maple_map_subunits(mdev, submask);
597 			subdevice_map[mdev->port] = submask;
598 		}
599 	}
600 }
601 
602 static void maple_response_fileerr(struct maple_device *mdev, void *recvbuf)
603 {
604 	if (mdev->fileerr_handler) {
605 		mdev->fileerr_handler(mdev, recvbuf);
606 		return;
607 	} else
608 		dev_warn(&mdev->dev, "device at (%d, %d) reports"
609 			"file error 0x%X\n", mdev->port, mdev->unit,
610 			((int *)recvbuf)[1]);
611 }
612 
613 static void maple_port_rescan(void)
614 {
615 	int i;
616 	struct maple_device *mdev;
617 
618 	fullscan = 1;
619 	for (i = 0; i < MAPLE_PORTS; i++) {
620 		if (checked[i] == false) {
621 			fullscan = 0;
622 			mdev = baseunits[i];
623 			maple_add_packet(mdev, 0, MAPLE_COMMAND_DEVINFO,
624 				0, NULL);
625 		}
626 	}
627 }
628 
629 /* maple dma end bottom half - implemented via workqueue */
630 static void maple_dma_handler(struct work_struct *work)
631 {
632 	struct mapleq *mq, *nmq;
633 	struct maple_device *mdev;
634 	char *recvbuf;
635 	enum maple_code code;
636 
637 	if (!maple_dma_done())
638 		return;
639 	__raw_writel(0, MAPLE_ENABLE);
640 	if (!list_empty(&maple_sentq)) {
641 		list_for_each_entry_safe(mq, nmq, &maple_sentq, list) {
642 			mdev = mq->dev;
643 			recvbuf = mq->recvbuf->buf;
644 			__flush_invalidate_region(sh_cacheop_vaddr(recvbuf),
645 					0x400);
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 		retval = -ENOMEM;
839 		goto cleanup_bothirqs;
840 	}
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 			retval = -ENOMEM;
854 			goto cleanup_cache;
855 		}
856 		baseunits[i] = mdev[i];
857 		atomic_set(&mdev[i]->busy, 1);
858 		maple_add_packet(mdev[i], 0, MAPLE_COMMAND_DEVINFO, 0, NULL);
859 		subdevice_map[i] = 0;
860 	}
861 
862 	maple_pnp_time = jiffies + HZ;
863 	/* prepare initial queue */
864 	maple_send();
865 	dev_info(&maple_bus, "bus core now registered\n");
866 
867 	return 0;
868 
869 cleanup_cache:
870 	kmem_cache_destroy(maple_queue_cache);
871 
872 cleanup_bothirqs:
873 	free_irq(HW_EVENT_VSYNC, 0);
874 
875 cleanup_irq:
876 	free_irq(HW_EVENT_MAPLE_DMA, 0);
877 
878 cleanup_dma:
879 	free_pages((unsigned long) maple_sendbuf, MAPLE_DMA_PAGES);
880 
881 cleanup_basic:
882 	driver_unregister(&maple_unsupported_device.drv);
883 
884 cleanup_bus:
885 	bus_unregister(&maple_bus_type);
886 
887 cleanup_device:
888 	device_unregister(&maple_bus);
889 
890 cleanup:
891 	printk(KERN_ERR "Maple bus registration failed\n");
892 	return retval;
893 }
894 /* Push init to later to ensure hardware gets detected */
895 fs_initcall(maple_bus_init);
896