xref: /openbmc/linux/drivers/video/fbdev/pxa3xx-gcu.c (revision 465191d6)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  pxa3xx-gcu.c - Linux kernel module for PXA3xx graphics controllers
4  *
5  *  This driver needs a DirectFB counterpart in user space, communication
6  *  is handled via mmap()ed memory areas and an ioctl.
7  *
8  *  Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
9  *  Copyright (c) 2009 Janine Kropp <nin@directfb.org>
10  *  Copyright (c) 2009 Denis Oliver Kropp <dok@directfb.org>
11  */
12 
13 /*
14  * WARNING: This controller is attached to System Bus 2 of the PXA which
15  * needs its arbiter to be enabled explicitly (CKENB & 1<<9).
16  * There is currently no way to do this from Linux, so you need to teach
17  * your bootloader for now.
18  */
19 
20 #include <linux/module.h>
21 #include <linux/platform_device.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/miscdevice.h>
24 #include <linux/interrupt.h>
25 #include <linux/spinlock.h>
26 #include <linux/uaccess.h>
27 #include <linux/ioctl.h>
28 #include <linux/delay.h>
29 #include <linux/sched.h>
30 #include <linux/slab.h>
31 #include <linux/clk.h>
32 #include <linux/fs.h>
33 #include <linux/io.h>
34 #include <linux/of.h>
35 
36 #include "pxa3xx-gcu.h"
37 
38 #define DRV_NAME	"pxa3xx-gcu"
39 
40 #define REG_GCCR	0x00
41 #define GCCR_SYNC_CLR	(1 << 9)
42 #define GCCR_BP_RST	(1 << 8)
43 #define GCCR_ABORT	(1 << 6)
44 #define GCCR_STOP	(1 << 4)
45 
46 #define REG_GCISCR	0x04
47 #define REG_GCIECR	0x08
48 #define REG_GCRBBR	0x20
49 #define REG_GCRBLR	0x24
50 #define REG_GCRBHR	0x28
51 #define REG_GCRBTR	0x2C
52 #define REG_GCRBEXHR	0x30
53 
54 #define IE_EOB		(1 << 0)
55 #define IE_EEOB		(1 << 5)
56 #define IE_ALL		0xff
57 
58 #define SHARED_SIZE	PAGE_ALIGN(sizeof(struct pxa3xx_gcu_shared))
59 
60 /* #define PXA3XX_GCU_DEBUG */
61 /* #define PXA3XX_GCU_DEBUG_TIMER */
62 
63 #ifdef PXA3XX_GCU_DEBUG
64 #define QDUMP(msg)					\
65 	do {						\
66 		QPRINT(priv, KERN_DEBUG, msg);		\
67 	} while (0)
68 #else
69 #define QDUMP(msg)	do {} while (0)
70 #endif
71 
72 #define QERROR(msg)					\
73 	do {						\
74 		QPRINT(priv, KERN_ERR, msg);		\
75 	} while (0)
76 
77 struct pxa3xx_gcu_batch {
78 	struct pxa3xx_gcu_batch *next;
79 	u32			*ptr;
80 	dma_addr_t		 phys;
81 	unsigned long		 length;
82 };
83 
84 struct pxa3xx_gcu_priv {
85 	struct device		 *dev;
86 	void __iomem		 *mmio_base;
87 	struct clk		 *clk;
88 	struct pxa3xx_gcu_shared *shared;
89 	dma_addr_t		  shared_phys;
90 	struct resource		 *resource_mem;
91 	struct miscdevice	  misc_dev;
92 	wait_queue_head_t	  wait_idle;
93 	wait_queue_head_t	  wait_free;
94 	spinlock_t		  spinlock;
95 	struct timespec64	  base_time;
96 
97 	struct pxa3xx_gcu_batch *free;
98 	struct pxa3xx_gcu_batch *ready;
99 	struct pxa3xx_gcu_batch *ready_last;
100 	struct pxa3xx_gcu_batch *running;
101 };
102 
103 static inline unsigned long
104 gc_readl(struct pxa3xx_gcu_priv *priv, unsigned int off)
105 {
106 	return __raw_readl(priv->mmio_base + off);
107 }
108 
109 static inline void
110 gc_writel(struct pxa3xx_gcu_priv *priv, unsigned int off, unsigned long val)
111 {
112 	__raw_writel(val, priv->mmio_base + off);
113 }
114 
115 #define QPRINT(priv, level, msg)					\
116 	do {								\
117 		struct timespec64 ts;					\
118 		struct pxa3xx_gcu_shared *shared = priv->shared;	\
119 		u32 base = gc_readl(priv, REG_GCRBBR);			\
120 									\
121 		ktime_get_ts64(&ts);					\
122 		ts = timespec64_sub(ts, priv->base_time);		\
123 									\
124 		printk(level "%lld.%03ld.%03ld - %-17s: %-21s (%s, "	\
125 			"STATUS "					\
126 			"0x%02lx, B 0x%08lx [%ld], E %5ld, H %5ld, "	\
127 			"T %5ld)\n",					\
128 			(s64)(ts.tv_sec),				\
129 			ts.tv_nsec / NSEC_PER_MSEC,			\
130 			(ts.tv_nsec % NSEC_PER_MSEC) / USEC_PER_MSEC,	\
131 			__func__, msg,					\
132 			shared->hw_running ? "running" : "   idle",	\
133 			gc_readl(priv, REG_GCISCR),			\
134 			gc_readl(priv, REG_GCRBBR),			\
135 			gc_readl(priv, REG_GCRBLR),			\
136 			(gc_readl(priv, REG_GCRBEXHR) - base) / 4,	\
137 			(gc_readl(priv, REG_GCRBHR) - base) / 4,	\
138 			(gc_readl(priv, REG_GCRBTR) - base) / 4);	\
139 	} while (0)
140 
141 static void
142 pxa3xx_gcu_reset(struct pxa3xx_gcu_priv *priv)
143 {
144 	QDUMP("RESET");
145 
146 	/* disable interrupts */
147 	gc_writel(priv, REG_GCIECR, 0);
148 
149 	/* reset hardware */
150 	gc_writel(priv, REG_GCCR, GCCR_ABORT);
151 	gc_writel(priv, REG_GCCR, 0);
152 
153 	memset(priv->shared, 0, SHARED_SIZE);
154 	priv->shared->buffer_phys = priv->shared_phys;
155 	priv->shared->magic = PXA3XX_GCU_SHARED_MAGIC;
156 
157 	ktime_get_ts64(&priv->base_time);
158 
159 	/* set up the ring buffer pointers */
160 	gc_writel(priv, REG_GCRBLR, 0);
161 	gc_writel(priv, REG_GCRBBR, priv->shared_phys);
162 	gc_writel(priv, REG_GCRBTR, priv->shared_phys);
163 
164 	/* enable all IRQs except EOB */
165 	gc_writel(priv, REG_GCIECR, IE_ALL & ~IE_EOB);
166 }
167 
168 static void
169 dump_whole_state(struct pxa3xx_gcu_priv *priv)
170 {
171 	struct pxa3xx_gcu_shared *sh = priv->shared;
172 	u32 base = gc_readl(priv, REG_GCRBBR);
173 
174 	QDUMP("DUMP");
175 
176 	printk(KERN_DEBUG "== PXA3XX-GCU DUMP ==\n"
177 		"%s, STATUS 0x%02lx, B 0x%08lx [%ld], E %5ld, H %5ld, T %5ld\n",
178 		sh->hw_running ? "running" : "idle   ",
179 		gc_readl(priv, REG_GCISCR),
180 		gc_readl(priv, REG_GCRBBR),
181 		gc_readl(priv, REG_GCRBLR),
182 		(gc_readl(priv, REG_GCRBEXHR) - base) / 4,
183 		(gc_readl(priv, REG_GCRBHR) - base) / 4,
184 		(gc_readl(priv, REG_GCRBTR) - base) / 4);
185 }
186 
187 static void
188 flush_running(struct pxa3xx_gcu_priv *priv)
189 {
190 	struct pxa3xx_gcu_batch *running = priv->running;
191 	struct pxa3xx_gcu_batch *next;
192 
193 	while (running) {
194 		next = running->next;
195 		running->next = priv->free;
196 		priv->free = running;
197 		running = next;
198 	}
199 
200 	priv->running = NULL;
201 }
202 
203 static void
204 run_ready(struct pxa3xx_gcu_priv *priv)
205 {
206 	unsigned int num = 0;
207 	struct pxa3xx_gcu_shared *shared = priv->shared;
208 	struct pxa3xx_gcu_batch	*ready = priv->ready;
209 
210 	QDUMP("Start");
211 
212 	BUG_ON(!ready);
213 
214 	shared->buffer[num++] = 0x05000000;
215 
216 	while (ready) {
217 		shared->buffer[num++] = 0x00000001;
218 		shared->buffer[num++] = ready->phys;
219 		ready = ready->next;
220 	}
221 
222 	shared->buffer[num++] = 0x05000000;
223 	priv->running = priv->ready;
224 	priv->ready = priv->ready_last = NULL;
225 	gc_writel(priv, REG_GCRBLR, 0);
226 	shared->hw_running = 1;
227 
228 	/* ring base address */
229 	gc_writel(priv, REG_GCRBBR, shared->buffer_phys);
230 
231 	/* ring tail address */
232 	gc_writel(priv, REG_GCRBTR, shared->buffer_phys + num * 4);
233 
234 	/* ring length */
235 	gc_writel(priv, REG_GCRBLR, ((num + 63) & ~63) * 4);
236 }
237 
238 static irqreturn_t
239 pxa3xx_gcu_handle_irq(int irq, void *ctx)
240 {
241 	struct pxa3xx_gcu_priv *priv = ctx;
242 	struct pxa3xx_gcu_shared *shared = priv->shared;
243 	u32 status = gc_readl(priv, REG_GCISCR) & IE_ALL;
244 
245 	QDUMP("-Interrupt");
246 
247 	if (!status)
248 		return IRQ_NONE;
249 
250 	spin_lock(&priv->spinlock);
251 	shared->num_interrupts++;
252 
253 	if (status & IE_EEOB) {
254 		QDUMP(" [EEOB]");
255 
256 		flush_running(priv);
257 		wake_up_all(&priv->wait_free);
258 
259 		if (priv->ready) {
260 			run_ready(priv);
261 		} else {
262 			/* There is no more data prepared by the userspace.
263 			 * Set hw_running = 0 and wait for the next userspace
264 			 * kick-off */
265 			shared->num_idle++;
266 			shared->hw_running = 0;
267 
268 			QDUMP(" '-> Idle.");
269 
270 			/* set ring buffer length to zero */
271 			gc_writel(priv, REG_GCRBLR, 0);
272 
273 			wake_up_all(&priv->wait_idle);
274 		}
275 
276 		shared->num_done++;
277 	} else {
278 		QERROR(" [???]");
279 		dump_whole_state(priv);
280 	}
281 
282 	/* Clear the interrupt */
283 	gc_writel(priv, REG_GCISCR, status);
284 	spin_unlock(&priv->spinlock);
285 
286 	return IRQ_HANDLED;
287 }
288 
289 static int
290 pxa3xx_gcu_wait_idle(struct pxa3xx_gcu_priv *priv)
291 {
292 	int ret = 0;
293 
294 	QDUMP("Waiting for idle...");
295 
296 	/* Does not need to be atomic. There's a lock in user space,
297 	 * but anyhow, this is just for statistics. */
298 	priv->shared->num_wait_idle++;
299 
300 	while (priv->shared->hw_running) {
301 		int num = priv->shared->num_interrupts;
302 		u32 rbexhr = gc_readl(priv, REG_GCRBEXHR);
303 
304 		ret = wait_event_interruptible_timeout(priv->wait_idle,
305 					!priv->shared->hw_running, HZ*4);
306 
307 		if (ret != 0)
308 			break;
309 
310 		if (gc_readl(priv, REG_GCRBEXHR) == rbexhr &&
311 		    priv->shared->num_interrupts == num) {
312 			QERROR("TIMEOUT");
313 			ret = -ETIMEDOUT;
314 			break;
315 		}
316 	}
317 
318 	QDUMP("done");
319 
320 	return ret;
321 }
322 
323 static int
324 pxa3xx_gcu_wait_free(struct pxa3xx_gcu_priv *priv)
325 {
326 	int ret = 0;
327 
328 	QDUMP("Waiting for free...");
329 
330 	/* Does not need to be atomic. There's a lock in user space,
331 	 * but anyhow, this is just for statistics. */
332 	priv->shared->num_wait_free++;
333 
334 	while (!priv->free) {
335 		u32 rbexhr = gc_readl(priv, REG_GCRBEXHR);
336 
337 		ret = wait_event_interruptible_timeout(priv->wait_free,
338 						       priv->free, HZ*4);
339 
340 		if (ret < 0)
341 			break;
342 
343 		if (ret > 0)
344 			continue;
345 
346 		if (gc_readl(priv, REG_GCRBEXHR) == rbexhr) {
347 			QERROR("TIMEOUT");
348 			ret = -ETIMEDOUT;
349 			break;
350 		}
351 	}
352 
353 	QDUMP("done");
354 
355 	return ret;
356 }
357 
358 /* Misc device layer */
359 
360 static inline struct pxa3xx_gcu_priv *to_pxa3xx_gcu_priv(struct file *file)
361 {
362 	struct miscdevice *dev = file->private_data;
363 	return container_of(dev, struct pxa3xx_gcu_priv, misc_dev);
364 }
365 
366 /*
367  * provide an empty .open callback, so the core sets file->private_data
368  * for us.
369  */
370 static int pxa3xx_gcu_open(struct inode *inode, struct file *file)
371 {
372 	return 0;
373 }
374 
375 static ssize_t
376 pxa3xx_gcu_write(struct file *file, const char *buff,
377 		 size_t count, loff_t *offp)
378 {
379 	int ret;
380 	unsigned long flags;
381 	struct pxa3xx_gcu_batch	*buffer;
382 	struct pxa3xx_gcu_priv *priv = to_pxa3xx_gcu_priv(file);
383 
384 	int words = count / 4;
385 
386 	/* Does not need to be atomic. There's a lock in user space,
387 	 * but anyhow, this is just for statistics. */
388 	priv->shared->num_writes++;
389 	priv->shared->num_words += words;
390 
391 	/* Last word reserved for batch buffer end command */
392 	if (words >= PXA3XX_GCU_BATCH_WORDS)
393 		return -E2BIG;
394 
395 	/* Wait for a free buffer */
396 	if (!priv->free) {
397 		ret = pxa3xx_gcu_wait_free(priv);
398 		if (ret < 0)
399 			return ret;
400 	}
401 
402 	/*
403 	 * Get buffer from free list
404 	 */
405 	spin_lock_irqsave(&priv->spinlock, flags);
406 	buffer = priv->free;
407 	priv->free = buffer->next;
408 	spin_unlock_irqrestore(&priv->spinlock, flags);
409 
410 
411 	/* Copy data from user into buffer */
412 	ret = copy_from_user(buffer->ptr, buff, words * 4);
413 	if (ret) {
414 		spin_lock_irqsave(&priv->spinlock, flags);
415 		buffer->next = priv->free;
416 		priv->free = buffer;
417 		spin_unlock_irqrestore(&priv->spinlock, flags);
418 		return -EFAULT;
419 	}
420 
421 	buffer->length = words;
422 
423 	/* Append batch buffer end command */
424 	buffer->ptr[words] = 0x01000000;
425 
426 	/*
427 	 * Add buffer to ready list
428 	 */
429 	spin_lock_irqsave(&priv->spinlock, flags);
430 
431 	buffer->next = NULL;
432 
433 	if (priv->ready) {
434 		BUG_ON(priv->ready_last == NULL);
435 
436 		priv->ready_last->next = buffer;
437 	} else
438 		priv->ready = buffer;
439 
440 	priv->ready_last = buffer;
441 
442 	if (!priv->shared->hw_running)
443 		run_ready(priv);
444 
445 	spin_unlock_irqrestore(&priv->spinlock, flags);
446 
447 	return words * 4;
448 }
449 
450 
451 static long
452 pxa3xx_gcu_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
453 {
454 	unsigned long flags;
455 	struct pxa3xx_gcu_priv *priv = to_pxa3xx_gcu_priv(file);
456 
457 	switch (cmd) {
458 	case PXA3XX_GCU_IOCTL_RESET:
459 		spin_lock_irqsave(&priv->spinlock, flags);
460 		pxa3xx_gcu_reset(priv);
461 		spin_unlock_irqrestore(&priv->spinlock, flags);
462 		return 0;
463 
464 	case PXA3XX_GCU_IOCTL_WAIT_IDLE:
465 		return pxa3xx_gcu_wait_idle(priv);
466 	}
467 
468 	return -ENOSYS;
469 }
470 
471 static int
472 pxa3xx_gcu_mmap(struct file *file, struct vm_area_struct *vma)
473 {
474 	unsigned int size = vma->vm_end - vma->vm_start;
475 	struct pxa3xx_gcu_priv *priv = to_pxa3xx_gcu_priv(file);
476 
477 	switch (vma->vm_pgoff) {
478 	case 0:
479 		/* hand out the shared data area */
480 		if (size != SHARED_SIZE)
481 			return -EINVAL;
482 
483 		return dma_mmap_coherent(priv->dev, vma,
484 			priv->shared, priv->shared_phys, size);
485 
486 	case SHARED_SIZE >> PAGE_SHIFT:
487 		/* hand out the MMIO base for direct register access
488 		 * from userspace */
489 		if (size != resource_size(priv->resource_mem))
490 			return -EINVAL;
491 
492 		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
493 
494 		return io_remap_pfn_range(vma, vma->vm_start,
495 				priv->resource_mem->start >> PAGE_SHIFT,
496 				size, vma->vm_page_prot);
497 	}
498 
499 	return -EINVAL;
500 }
501 
502 
503 #ifdef PXA3XX_GCU_DEBUG_TIMER
504 static struct timer_list pxa3xx_gcu_debug_timer;
505 static struct pxa3xx_gcu_priv *debug_timer_priv;
506 
507 static void pxa3xx_gcu_debug_timedout(struct timer_list *unused)
508 {
509 	struct pxa3xx_gcu_priv *priv = debug_timer_priv;
510 
511 	QERROR("Timer DUMP");
512 
513 	mod_timer(&pxa3xx_gcu_debug_timer, jiffies + 5 * HZ);
514 }
515 
516 static void pxa3xx_gcu_init_debug_timer(struct pxa3xx_gcu_priv *priv)
517 {
518 	/* init the timer structure */
519 	debug_timer_priv = priv;
520 	timer_setup(&pxa3xx_gcu_debug_timer, pxa3xx_gcu_debug_timedout, 0);
521 	pxa3xx_gcu_debug_timedout(NULL);
522 }
523 #else
524 static inline void pxa3xx_gcu_init_debug_timer(struct pxa3xx_gcu_priv *priv) {}
525 #endif
526 
527 static int
528 pxa3xx_gcu_add_buffer(struct device *dev,
529 		      struct pxa3xx_gcu_priv *priv)
530 {
531 	struct pxa3xx_gcu_batch *buffer;
532 
533 	buffer = kzalloc(sizeof(struct pxa3xx_gcu_batch), GFP_KERNEL);
534 	if (!buffer)
535 		return -ENOMEM;
536 
537 	buffer->ptr = dma_alloc_coherent(dev, PXA3XX_GCU_BATCH_WORDS * 4,
538 					 &buffer->phys, GFP_KERNEL);
539 	if (!buffer->ptr) {
540 		kfree(buffer);
541 		return -ENOMEM;
542 	}
543 
544 	buffer->next = priv->free;
545 	priv->free = buffer;
546 
547 	return 0;
548 }
549 
550 static void
551 pxa3xx_gcu_free_buffers(struct device *dev,
552 			struct pxa3xx_gcu_priv *priv)
553 {
554 	struct pxa3xx_gcu_batch *next, *buffer = priv->free;
555 
556 	while (buffer) {
557 		next = buffer->next;
558 
559 		dma_free_coherent(dev, PXA3XX_GCU_BATCH_WORDS * 4,
560 				  buffer->ptr, buffer->phys);
561 
562 		kfree(buffer);
563 		buffer = next;
564 	}
565 
566 	priv->free = NULL;
567 }
568 
569 static const struct file_operations pxa3xx_gcu_miscdev_fops = {
570 	.owner =		THIS_MODULE,
571 	.open =			pxa3xx_gcu_open,
572 	.write =		pxa3xx_gcu_write,
573 	.unlocked_ioctl =	pxa3xx_gcu_ioctl,
574 	.mmap =			pxa3xx_gcu_mmap,
575 };
576 
577 static int pxa3xx_gcu_probe(struct platform_device *pdev)
578 {
579 	int i, ret, irq;
580 	struct resource *r;
581 	struct pxa3xx_gcu_priv *priv;
582 	struct device *dev = &pdev->dev;
583 
584 	priv = devm_kzalloc(dev, sizeof(struct pxa3xx_gcu_priv), GFP_KERNEL);
585 	if (!priv)
586 		return -ENOMEM;
587 
588 	init_waitqueue_head(&priv->wait_idle);
589 	init_waitqueue_head(&priv->wait_free);
590 	spin_lock_init(&priv->spinlock);
591 
592 	/* we allocate the misc device structure as part of our own allocation,
593 	 * so we can get a pointer to our priv structure later on with
594 	 * container_of(). This isn't really necessary as we have a fixed minor
595 	 * number anyway, but this is to avoid statics. */
596 
597 	priv->misc_dev.minor	= PXA3XX_GCU_MINOR,
598 	priv->misc_dev.name	= DRV_NAME,
599 	priv->misc_dev.fops	= &pxa3xx_gcu_miscdev_fops;
600 
601 	/* handle IO resources */
602 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
603 	priv->mmio_base = devm_ioremap_resource(dev, r);
604 	if (IS_ERR(priv->mmio_base))
605 		return PTR_ERR(priv->mmio_base);
606 
607 	/* enable the clock */
608 	priv->clk = devm_clk_get(dev, NULL);
609 	if (IS_ERR(priv->clk))
610 		return dev_err_probe(dev, PTR_ERR(priv->clk), "failed to get clock\n");
611 
612 	/* request the IRQ */
613 	irq = platform_get_irq(pdev, 0);
614 	if (irq < 0)
615 		return irq;
616 
617 	ret = devm_request_irq(dev, irq, pxa3xx_gcu_handle_irq,
618 			       0, DRV_NAME, priv);
619 	if (ret < 0) {
620 		dev_err(dev, "request_irq failed\n");
621 		return ret;
622 	}
623 
624 	/* allocate dma memory */
625 	priv->shared = dma_alloc_coherent(dev, SHARED_SIZE,
626 					  &priv->shared_phys, GFP_KERNEL);
627 	if (!priv->shared) {
628 		dev_err(dev, "failed to allocate DMA memory\n");
629 		return -ENOMEM;
630 	}
631 
632 	/* register misc device */
633 	ret = misc_register(&priv->misc_dev);
634 	if (ret < 0) {
635 		dev_err(dev, "misc_register() for minor %d failed\n",
636 			PXA3XX_GCU_MINOR);
637 		goto err_free_dma;
638 	}
639 
640 	ret = clk_prepare_enable(priv->clk);
641 	if (ret < 0) {
642 		dev_err(dev, "failed to enable clock\n");
643 		goto err_misc_deregister;
644 	}
645 
646 	for (i = 0; i < 8; i++) {
647 		ret = pxa3xx_gcu_add_buffer(dev, priv);
648 		if (ret) {
649 			pxa3xx_gcu_free_buffers(dev, priv);
650 			dev_err(dev, "failed to allocate DMA memory\n");
651 			goto err_disable_clk;
652 		}
653 	}
654 
655 	platform_set_drvdata(pdev, priv);
656 	priv->resource_mem = r;
657 	priv->dev = dev;
658 	pxa3xx_gcu_reset(priv);
659 	pxa3xx_gcu_init_debug_timer(priv);
660 
661 	dev_info(dev, "registered @0x%p, DMA 0x%p (%d bytes), IRQ %d\n",
662 			(void *) r->start, (void *) priv->shared_phys,
663 			SHARED_SIZE, irq);
664 	return 0;
665 
666 err_disable_clk:
667 	clk_disable_unprepare(priv->clk);
668 
669 err_misc_deregister:
670 	misc_deregister(&priv->misc_dev);
671 
672 err_free_dma:
673 	dma_free_coherent(dev, SHARED_SIZE,
674 			  priv->shared, priv->shared_phys);
675 
676 	return ret;
677 }
678 
679 static int pxa3xx_gcu_remove(struct platform_device *pdev)
680 {
681 	struct pxa3xx_gcu_priv *priv = platform_get_drvdata(pdev);
682 	struct device *dev = &pdev->dev;
683 
684 	pxa3xx_gcu_wait_idle(priv);
685 	misc_deregister(&priv->misc_dev);
686 	dma_free_coherent(dev, SHARED_SIZE, priv->shared, priv->shared_phys);
687 	clk_disable_unprepare(priv->clk);
688 	pxa3xx_gcu_free_buffers(dev, priv);
689 
690 	return 0;
691 }
692 
693 #ifdef CONFIG_OF
694 static const struct of_device_id pxa3xx_gcu_of_match[] = {
695 	{ .compatible = "marvell,pxa300-gcu", },
696 	{ }
697 };
698 MODULE_DEVICE_TABLE(of, pxa3xx_gcu_of_match);
699 #endif
700 
701 static struct platform_driver pxa3xx_gcu_driver = {
702 	.probe	  = pxa3xx_gcu_probe,
703 	.remove	 = pxa3xx_gcu_remove,
704 	.driver	 = {
705 		.name   = DRV_NAME,
706 		.of_match_table = of_match_ptr(pxa3xx_gcu_of_match),
707 	},
708 };
709 
710 module_platform_driver(pxa3xx_gcu_driver);
711 
712 MODULE_DESCRIPTION("PXA3xx graphics controller unit driver");
713 MODULE_LICENSE("GPL");
714 MODULE_ALIAS_MISCDEV(PXA3XX_GCU_MINOR);
715 MODULE_AUTHOR("Janine Kropp <nin@directfb.org>, "
716 		"Denis Oliver Kropp <dok@directfb.org>, "
717 		"Daniel Mack <daniel@caiaq.de>");
718