xref: /freebsd/sys/arm/broadcom/bcm2835/bcm2835_dma.c (revision 7ef62cebc2f965b0f640263e179276928885e33d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2013 Daisuke Aoyama <aoyama@peach.ne.jp>
5  * Copyright (c) 2013 Oleksandr Tymoshenko <gonzo@bluezbox.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  */
29 
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/bus.h>
36 #include <sys/kernel.h>
37 #include <sys/lock.h>
38 #include <sys/malloc.h>
39 #include <sys/module.h>
40 #include <sys/mutex.h>
41 #include <sys/queue.h>
42 #include <sys/resource.h>
43 #include <sys/rman.h>
44 
45 #include <dev/ofw/openfirm.h>
46 #include <dev/ofw/ofw_bus.h>
47 #include <dev/ofw/ofw_bus_subr.h>
48 
49 #include <vm/vm.h>
50 #include <vm/pmap.h>
51 #include <machine/bus.h>
52 
53 #include "bcm2835_dma.h"
54 #include "bcm2835_vcbus.h"
55 
56 #define	MAX_REG			9
57 
58 /* private flags */
59 #define	BCM_DMA_CH_USED		0x00000001
60 #define	BCM_DMA_CH_FREE		0x40000000
61 #define	BCM_DMA_CH_UNMAP	0x80000000
62 
63 /* Register Map (4.2.1.2) */
64 #define	BCM_DMA_CS(n)		(0x100*(n) + 0x00)
65 #define		CS_ACTIVE		(1 <<  0)
66 #define		CS_END			(1 <<  1)
67 #define		CS_INT			(1 <<  2)
68 #define		CS_DREQ			(1 <<  3)
69 #define		CS_ISPAUSED		(1 <<  4)
70 #define		CS_ISHELD		(1 <<  5)
71 #define		CS_ISWAIT		(1 <<  6)
72 #define		CS_ERR			(1 <<  8)
73 #define		CS_WAITWRT		(1 << 28)
74 #define		CS_DISDBG		(1 << 29)
75 #define		CS_ABORT		(1 << 30)
76 #define		CS_RESET		(1U << 31)
77 #define	BCM_DMA_CBADDR(n)	(0x100*(n) + 0x04)
78 #define	BCM_DMA_INFO(n)		(0x100*(n) + 0x08)
79 #define		INFO_INT_EN		(1 << 0)
80 #define		INFO_TDMODE		(1 << 1)
81 #define		INFO_WAIT_RESP		(1 << 3)
82 #define		INFO_D_INC		(1 << 4)
83 #define		INFO_D_WIDTH		(1 << 5)
84 #define		INFO_D_DREQ		(1 << 6)
85 #define		INFO_S_INC		(1 << 8)
86 #define		INFO_S_WIDTH		(1 << 9)
87 #define		INFO_S_DREQ		(1 << 10)
88 #define		INFO_WAITS_SHIFT	(21)
89 #define		INFO_PERMAP_SHIFT	(16)
90 #define		INFO_PERMAP_MASK	(0x1f << INFO_PERMAP_SHIFT)
91 
92 #define	BCM_DMA_SRC(n)		(0x100*(n) + 0x0C)
93 #define	BCM_DMA_DST(n)		(0x100*(n) + 0x10)
94 #define	BCM_DMA_LEN(n)		(0x100*(n) + 0x14)
95 #define	BCM_DMA_STRIDE(n)	(0x100*(n) + 0x18)
96 #define	BCM_DMA_CBNEXT(n)	(0x100*(n) + 0x1C)
97 #define	BCM_DMA_DEBUG(n)	(0x100*(n) + 0x20)
98 #define		DEBUG_ERROR_MASK	(7)
99 
100 #define	BCM_DMA_INT_STATUS	0xfe0
101 #define	BCM_DMA_ENABLE		0xff0
102 
103 /* relative offset from BCM_VC_DMA0_BASE (p.39) */
104 #define	BCM_DMA_CH(n)		(0x100*(n))
105 
106 /* channels used by GPU */
107 #define	BCM_DMA_CH_BULK		0
108 #define	BCM_DMA_CH_FAST1	2
109 #define	BCM_DMA_CH_FAST2	3
110 
111 #define	BCM_DMA_CH_GPU_MASK	((1 << BCM_DMA_CH_BULK) |	\
112 				 (1 << BCM_DMA_CH_FAST1) |	\
113 				 (1 << BCM_DMA_CH_FAST2))
114 
115 /* DMA Control Block - 256bit aligned (p.40) */
116 struct bcm_dma_cb {
117 	uint32_t info;		/* Transfer Information */
118 	uint32_t src;		/* Source Address */
119 	uint32_t dst;		/* Destination Address */
120 	uint32_t len;		/* Transfer Length */
121 	uint32_t stride;	/* 2D Mode Stride */
122 	uint32_t next;		/* Next Control Block Address */
123 	uint32_t rsvd1;		/* Reserved */
124 	uint32_t rsvd2;		/* Reserved */
125 };
126 
127 #ifdef DEBUG
128 static void bcm_dma_cb_dump(struct bcm_dma_cb *cb);
129 static void bcm_dma_reg_dump(int ch);
130 #endif
131 
132 /* DMA channel private info */
133 struct bcm_dma_ch {
134 	int			ch;
135 	uint32_t		flags;
136 	struct bcm_dma_cb *	cb;
137 	uint32_t		vc_cb;
138 	bus_dmamap_t		dma_map;
139 	void 			(*intr_func)(int, void *);
140 	void *			intr_arg;
141 };
142 
143 struct bcm_dma_softc {
144 	device_t		sc_dev;
145 	struct mtx		sc_mtx;
146 	struct resource *	sc_mem;
147 	struct resource *	sc_irq[BCM_DMA_CH_MAX];
148 	void *			sc_intrhand[BCM_DMA_CH_MAX];
149 	struct bcm_dma_ch	sc_dma_ch[BCM_DMA_CH_MAX];
150 	bus_dma_tag_t		sc_dma_tag;
151 };
152 
153 static struct bcm_dma_softc *bcm_dma_sc = NULL;
154 static uint32_t bcm_dma_channel_mask;
155 
156 static struct ofw_compat_data compat_data[] = {
157 	{"broadcom,bcm2835-dma",	1},
158 	{"brcm,bcm2835-dma",		1},
159 	{NULL,				0}
160 };
161 
162 static void
163 bcm_dmamap_cb(void *arg, bus_dma_segment_t *segs,
164 	int nseg, int err)
165 {
166         bus_addr_t *addr;
167 
168         if (err)
169                 return;
170 
171         addr = (bus_addr_t*)arg;
172         *addr = ARMC_TO_VCBUS(segs[0].ds_addr);
173 }
174 
175 static void
176 bcm_dma_reset(device_t dev, int ch)
177 {
178 	struct bcm_dma_softc *sc = device_get_softc(dev);
179 	struct bcm_dma_cb *cb;
180 	uint32_t cs;
181 	int count;
182 
183 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
184 		return;
185 
186 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch));
187 
188 	if (cs & CS_ACTIVE) {
189 		/* pause current task */
190 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), 0);
191 
192 		count = 1000;
193 		do {
194 			cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch));
195 		} while (!(cs & CS_ISPAUSED) && (count-- > 0));
196 
197 		if (!(cs & CS_ISPAUSED)) {
198 			device_printf(dev,
199 			    "Can't abort DMA transfer at channel %d\n", ch);
200 		}
201 
202 		bus_write_4(sc->sc_mem, BCM_DMA_CBNEXT(ch), 0);
203 
204 		/* Complete everything, clear interrupt */
205 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch),
206 		    CS_ABORT | CS_INT | CS_END| CS_ACTIVE);
207 	}
208 
209 	/* clear control blocks */
210 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch), 0);
211 	bus_write_4(sc->sc_mem, BCM_DMA_CBNEXT(ch), 0);
212 
213 	/* Reset control block */
214 	cb = sc->sc_dma_ch[ch].cb;
215 	bzero(cb, sizeof(*cb));
216 	cb->info = INFO_WAIT_RESP;
217 }
218 
219 static int
220 bcm_dma_init(device_t dev)
221 {
222 	struct bcm_dma_softc *sc = device_get_softc(dev);
223 	uint32_t reg;
224 	struct bcm_dma_ch *ch;
225 	void *cb_virt;
226 	vm_paddr_t cb_phys;
227 	int err;
228 	int i;
229 
230 	/*
231 	 * Only channels set in bcm_dma_channel_mask can be controlled by us.
232 	 * The others are out of our control as well as the corresponding bits
233 	 * in both BCM_DMA_ENABLE and BCM_DMA_INT_STATUS global registers. As
234 	 * these registers are RW ones, there is no safe way how to write only
235 	 * the bits which can be controlled by us.
236 	 *
237 	 * Fortunately, after reset, all channels are enabled in BCM_DMA_ENABLE
238 	 * register and all statuses are cleared in BCM_DMA_INT_STATUS one.
239 	 * Not touching these registers is a trade off between correct
240 	 * initialization which does not count on anything and not messing up
241 	 * something we have no control over.
242 	 */
243 	reg = bus_read_4(sc->sc_mem, BCM_DMA_ENABLE);
244 	if ((reg & bcm_dma_channel_mask) != bcm_dma_channel_mask)
245 		device_printf(dev, "channels are not enabled\n");
246 	reg = bus_read_4(sc->sc_mem, BCM_DMA_INT_STATUS);
247 	if ((reg & bcm_dma_channel_mask) != 0)
248 		device_printf(dev, "statuses are not cleared\n");
249 
250 	/*
251 	 * Allocate DMA chunks control blocks based on p.40 of the peripheral
252 	 * spec - control block should be 32-bit aligned.  The DMA controller
253 	 * has a full 32-bit register dedicated to this address, so we do not
254 	 * need to bother with the per-SoC peripheral restrictions.
255 	 */
256 	err = bus_dma_tag_create(bus_get_dma_tag(dev),
257 	    1, 0, BUS_SPACE_MAXADDR_32BIT,
258 	    BUS_SPACE_MAXADDR, NULL, NULL,
259 	    sizeof(struct bcm_dma_cb), 1,
260 	    sizeof(struct bcm_dma_cb),
261 	    BUS_DMA_ALLOCNOW, NULL, NULL,
262 	    &sc->sc_dma_tag);
263 
264 	if (err) {
265 		device_printf(dev, "failed allocate DMA tag\n");
266 		return (err);
267 	}
268 
269 	/* setup initial settings */
270 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
271 		ch = &sc->sc_dma_ch[i];
272 
273 		bzero(ch, sizeof(struct bcm_dma_ch));
274 		ch->ch = i;
275 		ch->flags = BCM_DMA_CH_UNMAP;
276 
277 		if ((bcm_dma_channel_mask & (1 << i)) == 0)
278 			continue;
279 
280 		err = bus_dmamem_alloc(sc->sc_dma_tag, &cb_virt,
281 		    BUS_DMA_WAITOK | BUS_DMA_COHERENT | BUS_DMA_ZERO,
282 		    &ch->dma_map);
283 		if (err) {
284 			device_printf(dev, "cannot allocate DMA memory\n");
285 			break;
286 		}
287 
288 		/*
289 		 * Least alignment for busdma-allocated stuff is cache
290 		 * line size, so just make sure nothing stupid happened
291 		 * and we got properly aligned address
292 		 */
293 		if ((uintptr_t)cb_virt & 0x1f) {
294 			device_printf(dev,
295 			    "DMA address is not 32-bytes aligned: %p\n",
296 			    (void*)cb_virt);
297 			break;
298 		}
299 
300 		err = bus_dmamap_load(sc->sc_dma_tag, ch->dma_map, cb_virt,
301 		    sizeof(struct bcm_dma_cb), bcm_dmamap_cb, &cb_phys,
302 		    BUS_DMA_WAITOK);
303 		if (err) {
304 			device_printf(dev, "cannot load DMA memory\n");
305 			break;
306 		}
307 
308 		ch->cb = cb_virt;
309 		ch->vc_cb = cb_phys;
310 		ch->flags = BCM_DMA_CH_FREE;
311 		ch->cb->info = INFO_WAIT_RESP;
312 
313 		/* reset DMA engine */
314 		bus_write_4(sc->sc_mem, BCM_DMA_CS(i), CS_RESET);
315 	}
316 
317 	return (0);
318 }
319 
320 /*
321  * Allocate DMA channel for further use, returns channel # or
322  *     BCM_DMA_CH_INVALID
323  */
324 int
325 bcm_dma_allocate(int req_ch)
326 {
327 	struct bcm_dma_softc *sc = bcm_dma_sc;
328 	int ch = BCM_DMA_CH_INVALID;
329 	int i;
330 
331 	if (sc == NULL)
332 		return (BCM_DMA_CH_INVALID);
333 
334 	if (req_ch >= BCM_DMA_CH_MAX)
335 		return (BCM_DMA_CH_INVALID);
336 
337 	/* Auto(req_ch < 0) or CH specified */
338 	mtx_lock(&sc->sc_mtx);
339 
340 	if (req_ch < 0) {
341 		for (i = 0; i < BCM_DMA_CH_MAX; i++) {
342 			if (sc->sc_dma_ch[i].flags & BCM_DMA_CH_FREE) {
343 				ch = i;
344 				sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
345 				sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
346 				break;
347 			}
348 		}
349 	} else if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
350 		ch = req_ch;
351 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
352 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
353 	}
354 
355 	mtx_unlock(&sc->sc_mtx);
356 	return (ch);
357 }
358 
359 /*
360  * Frees allocated channel. Returns 0 on success, -1 otherwise
361  */
362 int
363 bcm_dma_free(int ch)
364 {
365 	struct bcm_dma_softc *sc = bcm_dma_sc;
366 
367 	if (sc == NULL)
368 		return (-1);
369 
370 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
371 		return (-1);
372 
373 	mtx_lock(&sc->sc_mtx);
374 	if (sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED) {
375 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_FREE;
376 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_USED;
377 		sc->sc_dma_ch[ch].intr_func = NULL;
378 		sc->sc_dma_ch[ch].intr_arg = NULL;
379 
380 		/* reset DMA engine */
381 		bcm_dma_reset(sc->sc_dev, ch);
382 	}
383 
384 	mtx_unlock(&sc->sc_mtx);
385 	return (0);
386 }
387 
388 /*
389  * Assign handler function for channel interrupt
390  * Returns 0 on success, -1 otherwise
391  */
392 int
393 bcm_dma_setup_intr(int ch, void (*func)(int, void *), void *arg)
394 {
395 	struct bcm_dma_softc *sc = bcm_dma_sc;
396 	struct bcm_dma_cb *cb;
397 
398 	if (sc == NULL)
399 		return (-1);
400 
401 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
402 		return (-1);
403 
404 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
405 		return (-1);
406 
407 	sc->sc_dma_ch[ch].intr_func = func;
408 	sc->sc_dma_ch[ch].intr_arg = arg;
409 	cb = sc->sc_dma_ch[ch].cb;
410 	cb->info |= INFO_INT_EN;
411 
412 	return (0);
413 }
414 
415 /*
416  * Setup DMA source parameters
417  *     ch - channel number
418  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
419  *         source is physical memory
420  *     inc_addr - BCM_DMA_INC_ADDR if source address
421  *         should be increased after each access or
422  *         BCM_DMA_SAME_ADDR if address should remain
423  *         the same
424  *     width - size of read operation, BCM_DMA_32BIT
425  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
426  *
427  * Returns 0 on success, -1 otherwise
428  */
429 int
430 bcm_dma_setup_src(int ch, int dreq, int inc_addr, int width)
431 {
432 	struct bcm_dma_softc *sc = bcm_dma_sc;
433 	uint32_t info;
434 
435 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
436 		return (-1);
437 
438 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
439 		return (-1);
440 
441 	info = sc->sc_dma_ch[ch].cb->info;
442 	info &= ~INFO_PERMAP_MASK;
443 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
444 
445 	if (dreq)
446 		info |= INFO_S_DREQ;
447 	else
448 		info &= ~INFO_S_DREQ;
449 
450 	if (width == BCM_DMA_128BIT)
451 		info |= INFO_S_WIDTH;
452 	else
453 		info &= ~INFO_S_WIDTH;
454 
455 	if (inc_addr == BCM_DMA_INC_ADDR)
456 		info |= INFO_S_INC;
457 	else
458 		info &= ~INFO_S_INC;
459 
460 	sc->sc_dma_ch[ch].cb->info = info;
461 
462 	return (0);
463 }
464 
465 /*
466  * Setup DMA destination parameters
467  *     ch - channel number
468  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
469  *         destination is physical memory
470  *     inc_addr - BCM_DMA_INC_ADDR if source address
471  *         should be increased after each access or
472  *         BCM_DMA_SAME_ADDR if address should remain
473  *         the same
474  *     width - size of write operation, BCM_DMA_32BIT
475  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
476  *
477  * Returns 0 on success, -1 otherwise
478  */
479 int
480 bcm_dma_setup_dst(int ch, int dreq, int inc_addr, int width)
481 {
482 	struct bcm_dma_softc *sc = bcm_dma_sc;
483 	uint32_t info;
484 
485 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
486 		return (-1);
487 
488 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
489 		return (-1);
490 
491 	info = sc->sc_dma_ch[ch].cb->info;
492 	info &= ~INFO_PERMAP_MASK;
493 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
494 
495 	if (dreq)
496 		info |= INFO_D_DREQ;
497 	else
498 		info &= ~INFO_D_DREQ;
499 
500 	if (width == BCM_DMA_128BIT)
501 		info |= INFO_D_WIDTH;
502 	else
503 		info &= ~INFO_D_WIDTH;
504 
505 	if (inc_addr == BCM_DMA_INC_ADDR)
506 		info |= INFO_D_INC;
507 	else
508 		info &= ~INFO_D_INC;
509 
510 	sc->sc_dma_ch[ch].cb->info = info;
511 
512 	return (0);
513 }
514 
515 #ifdef DEBUG
516 void
517 bcm_dma_cb_dump(struct bcm_dma_cb *cb)
518 {
519 
520 	printf("DMA CB ");
521 	printf("INFO: %8.8x ", cb->info);
522 	printf("SRC: %8.8x ", cb->src);
523 	printf("DST: %8.8x ", cb->dst);
524 	printf("LEN: %8.8x ", cb->len);
525 	printf("\n");
526 	printf("STRIDE: %8.8x ", cb->stride);
527 	printf("NEXT: %8.8x ", cb->next);
528 	printf("RSVD1: %8.8x ", cb->rsvd1);
529 	printf("RSVD2: %8.8x ", cb->rsvd2);
530 	printf("\n");
531 }
532 
533 void
534 bcm_dma_reg_dump(int ch)
535 {
536 	struct bcm_dma_softc *sc = bcm_dma_sc;
537 	int i;
538 	uint32_t reg;
539 
540 	if (sc == NULL)
541 		return;
542 
543 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
544 		return;
545 
546 	printf("DMA%d: ", ch);
547 	for (i = 0; i < MAX_REG; i++) {
548 		reg = bus_read_4(sc->sc_mem, BCM_DMA_CH(ch) + i*4);
549 		printf("%8.8x ", reg);
550 	}
551 	printf("\n");
552 }
553 #endif
554 
555 /*
556  * Start DMA transaction
557  *     ch - channel number
558  *     src, dst - source and destination address in
559  *         ARM physical memory address space.
560  *     len - amount of bytes to be transferred
561  *
562  * Returns 0 on success, -1 otherwise
563  */
564 int
565 bcm_dma_start(int ch, vm_paddr_t src, vm_paddr_t dst, int len)
566 {
567 	struct bcm_dma_softc *sc = bcm_dma_sc;
568 	struct bcm_dma_cb *cb;
569 
570 	if (sc == NULL)
571 		return (-1);
572 
573 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
574 		return (-1);
575 
576 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
577 		return (-1);
578 
579 	cb = sc->sc_dma_ch[ch].cb;
580 	cb->src = ARMC_TO_VCBUS(src);
581 	cb->dst = ARMC_TO_VCBUS(dst);
582 
583 	cb->len = len;
584 
585 	bus_dmamap_sync(sc->sc_dma_tag,
586 	    sc->sc_dma_ch[ch].dma_map, BUS_DMASYNC_PREWRITE);
587 
588 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch),
589 	    sc->sc_dma_ch[ch].vc_cb);
590 	bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), CS_ACTIVE);
591 
592 #ifdef DEBUG
593 	bcm_dma_cb_dump(sc->sc_dma_ch[ch].cb);
594 	bcm_dma_reg_dump(ch);
595 #endif
596 
597 	return (0);
598 }
599 
600 /*
601  * Get length requested for DMA transaction
602  *     ch - channel number
603  *
604  * Returns size of transaction, 0 if channel is invalid
605  */
606 uint32_t
607 bcm_dma_length(int ch)
608 {
609 	struct bcm_dma_softc *sc = bcm_dma_sc;
610 	struct bcm_dma_cb *cb;
611 
612 	if (sc == NULL)
613 		return (0);
614 
615 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
616 		return (0);
617 
618 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
619 		return (0);
620 
621 	cb = sc->sc_dma_ch[ch].cb;
622 
623 	return (cb->len);
624 }
625 
626 static void
627 bcm_dma_intr(void *arg)
628 {
629 	struct bcm_dma_softc *sc = bcm_dma_sc;
630 	struct bcm_dma_ch *ch = (struct bcm_dma_ch *)arg;
631 	uint32_t cs, debug;
632 
633 	/* my interrupt? */
634 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch->ch));
635 
636 	/*
637 	 * Is it an active channel?  Our diagnostics could be better here, but
638 	 * it's not necessarily an easy task to resolve a rid/resource to an
639 	 * actual irq number.  We'd want to do this to set a flag indicating
640 	 * whether the irq is shared or not, so we know to complain.
641 	 */
642 	if (!(ch->flags & BCM_DMA_CH_USED))
643 		return;
644 
645 	/* Again, we can't complain here.  The same logic applies. */
646 	if (!(cs & (CS_INT | CS_ERR)))
647 		return;
648 
649 	if (cs & CS_ERR) {
650 		debug = bus_read_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch));
651 		device_printf(sc->sc_dev, "DMA error %d on CH%d\n",
652 			debug & DEBUG_ERROR_MASK, ch->ch);
653 		bus_write_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch),
654 		    debug & DEBUG_ERROR_MASK);
655 		bcm_dma_reset(sc->sc_dev, ch->ch);
656 	}
657 
658 	if (cs & CS_INT) {
659 		/* acknowledge interrupt */
660 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch->ch),
661 		    CS_INT | CS_END);
662 
663 		/* Prepare for possible access to len field */
664 		bus_dmamap_sync(sc->sc_dma_tag, ch->dma_map,
665 		    BUS_DMASYNC_POSTWRITE);
666 
667 		/* save callback function and argument */
668 		if (ch->intr_func)
669 			ch->intr_func(ch->ch, ch->intr_arg);
670 	}
671 }
672 
673 static int
674 bcm_dma_probe(device_t dev)
675 {
676 
677 	if (!ofw_bus_status_okay(dev))
678 		return (ENXIO);
679 
680 	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
681 		return (ENXIO);
682 
683 	device_set_desc(dev, "BCM2835 DMA Controller");
684 	return (BUS_PROBE_DEFAULT);
685 }
686 
687 static int
688 bcm_dma_attach(device_t dev)
689 {
690 	struct bcm_dma_softc *sc = device_get_softc(dev);
691 	phandle_t node;
692 	int rid, err = 0;
693 	int i;
694 
695 	sc->sc_dev = dev;
696 
697 	if (bcm_dma_sc)
698 		return (ENXIO);
699 
700 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
701 		sc->sc_irq[i] = NULL;
702 		sc->sc_intrhand[i] = NULL;
703 	}
704 
705 	/* Get DMA channel mask. */
706 	node = ofw_bus_get_node(sc->sc_dev);
707 	if (OF_getencprop(node, "brcm,dma-channel-mask", &bcm_dma_channel_mask,
708 	    sizeof(bcm_dma_channel_mask)) == -1 &&
709 	    OF_getencprop(node, "broadcom,channels", &bcm_dma_channel_mask,
710 	    sizeof(bcm_dma_channel_mask)) == -1) {
711 		device_printf(dev, "could not get channel mask property\n");
712 		return (ENXIO);
713 	}
714 
715 	/* Mask out channels used by GPU. */
716 	bcm_dma_channel_mask &= ~BCM_DMA_CH_GPU_MASK;
717 
718 	/* DMA0 - DMA14 */
719 	rid = 0;
720 	sc->sc_mem = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
721 	if (sc->sc_mem == NULL) {
722 		device_printf(dev, "could not allocate memory resource\n");
723 		return (ENXIO);
724 	}
725 
726 	/* IRQ DMA0 - DMA11 XXX NOT USE DMA12(spurious?) */
727 	for (rid = 0; rid < BCM_DMA_CH_MAX; rid++) {
728 		if ((bcm_dma_channel_mask & (1 << rid)) == 0)
729 			continue;
730 
731 		sc->sc_irq[rid] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
732 		    RF_ACTIVE | RF_SHAREABLE);
733 		if (sc->sc_irq[rid] == NULL) {
734 			device_printf(dev, "cannot allocate interrupt\n");
735 			err = ENXIO;
736 			goto fail;
737 		}
738 		if (bus_setup_intr(dev, sc->sc_irq[rid], INTR_TYPE_MISC | INTR_MPSAFE,
739 				   NULL, bcm_dma_intr, &sc->sc_dma_ch[rid],
740 				   &sc->sc_intrhand[rid])) {
741 			device_printf(dev, "cannot setup interrupt handler\n");
742 			err = ENXIO;
743 			goto fail;
744 		}
745 	}
746 
747 	mtx_init(&sc->sc_mtx, "bcmdma", "bcmdma", MTX_DEF);
748 	bcm_dma_sc = sc;
749 
750 	err = bcm_dma_init(dev);
751 	if (err)
752 		goto fail;
753 
754 	return (err);
755 
756 fail:
757 	if (sc->sc_mem)
758 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem);
759 
760 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
761 		if (sc->sc_intrhand[i])
762 			bus_teardown_intr(dev, sc->sc_irq[i], sc->sc_intrhand[i]);
763 		if (sc->sc_irq[i])
764 			bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq[i]);
765 	}
766 
767 	return (err);
768 }
769 
770 static device_method_t bcm_dma_methods[] = {
771 	DEVMETHOD(device_probe,		bcm_dma_probe),
772 	DEVMETHOD(device_attach,	bcm_dma_attach),
773 	{ 0, 0 }
774 };
775 
776 static driver_t bcm_dma_driver = {
777 	"bcm_dma",
778 	bcm_dma_methods,
779 	sizeof(struct bcm_dma_softc),
780 };
781 
782 EARLY_DRIVER_MODULE(bcm_dma, simplebus, bcm_dma_driver, 0, 0,
783     BUS_PASS_SUPPORTDEV + BUS_PASS_ORDER_MIDDLE);
784 MODULE_VERSION(bcm_dma, 1);
785