xref: /freebsd/sys/arm/broadcom/bcm2835/bcm2835_dma.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
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 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/bus.h>
34 #include <sys/kernel.h>
35 #include <sys/lock.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/mutex.h>
39 #include <sys/queue.h>
40 #include <sys/resource.h>
41 #include <sys/rman.h>
42 
43 #include <dev/ofw/openfirm.h>
44 #include <dev/ofw/ofw_bus.h>
45 #include <dev/ofw/ofw_bus_subr.h>
46 
47 #include <vm/vm.h>
48 #include <vm/pmap.h>
49 #include <machine/bus.h>
50 
51 #include "bcm2835_dma.h"
52 #include "bcm2835_vcbus.h"
53 
54 #define	MAX_REG			9
55 
56 /* private flags */
57 #define	BCM_DMA_CH_USED		0x00000001
58 #define	BCM_DMA_CH_FREE		0x40000000
59 #define	BCM_DMA_CH_UNMAP	0x80000000
60 
61 /* Register Map (4.2.1.2) */
62 #define	BCM_DMA_CS(n)		(0x100*(n) + 0x00)
63 #define		CS_ACTIVE		(1 <<  0)
64 #define		CS_END			(1 <<  1)
65 #define		CS_INT			(1 <<  2)
66 #define		CS_DREQ			(1 <<  3)
67 #define		CS_ISPAUSED		(1 <<  4)
68 #define		CS_ISHELD		(1 <<  5)
69 #define		CS_ISWAIT		(1 <<  6)
70 #define		CS_ERR			(1 <<  8)
71 #define		CS_WAITWRT		(1 << 28)
72 #define		CS_DISDBG		(1 << 29)
73 #define		CS_ABORT		(1 << 30)
74 #define		CS_RESET		(1U << 31)
75 #define	BCM_DMA_CBADDR(n)	(0x100*(n) + 0x04)
76 #define	BCM_DMA_INFO(n)		(0x100*(n) + 0x08)
77 #define		INFO_INT_EN		(1 << 0)
78 #define		INFO_TDMODE		(1 << 1)
79 #define		INFO_WAIT_RESP		(1 << 3)
80 #define		INFO_D_INC		(1 << 4)
81 #define		INFO_D_WIDTH		(1 << 5)
82 #define		INFO_D_DREQ		(1 << 6)
83 #define		INFO_S_INC		(1 << 8)
84 #define		INFO_S_WIDTH		(1 << 9)
85 #define		INFO_S_DREQ		(1 << 10)
86 #define		INFO_WAITS_SHIFT	(21)
87 #define		INFO_PERMAP_SHIFT	(16)
88 #define		INFO_PERMAP_MASK	(0x1f << INFO_PERMAP_SHIFT)
89 
90 #define	BCM_DMA_SRC(n)		(0x100*(n) + 0x0C)
91 #define	BCM_DMA_DST(n)		(0x100*(n) + 0x10)
92 #define	BCM_DMA_LEN(n)		(0x100*(n) + 0x14)
93 #define	BCM_DMA_STRIDE(n)	(0x100*(n) + 0x18)
94 #define	BCM_DMA_CBNEXT(n)	(0x100*(n) + 0x1C)
95 #define	BCM_DMA_DEBUG(n)	(0x100*(n) + 0x20)
96 #define		DEBUG_ERROR_MASK	(7)
97 
98 #define	BCM_DMA_INT_STATUS	0xfe0
99 #define	BCM_DMA_ENABLE		0xff0
100 
101 /* relative offset from BCM_VC_DMA0_BASE (p.39) */
102 #define	BCM_DMA_CH(n)		(0x100*(n))
103 
104 /* channels used by GPU */
105 #define	BCM_DMA_CH_BULK		0
106 #define	BCM_DMA_CH_FAST1	2
107 #define	BCM_DMA_CH_FAST2	3
108 
109 #define	BCM_DMA_CH_GPU_MASK	((1 << BCM_DMA_CH_BULK) |	\
110 				 (1 << BCM_DMA_CH_FAST1) |	\
111 				 (1 << BCM_DMA_CH_FAST2))
112 
113 /* DMA Control Block - 256bit aligned (p.40) */
114 struct bcm_dma_cb {
115 	uint32_t info;		/* Transfer Information */
116 	uint32_t src;		/* Source Address */
117 	uint32_t dst;		/* Destination Address */
118 	uint32_t len;		/* Transfer Length */
119 	uint32_t stride;	/* 2D Mode Stride */
120 	uint32_t next;		/* Next Control Block Address */
121 	uint32_t rsvd1;		/* Reserved */
122 	uint32_t rsvd2;		/* Reserved */
123 };
124 
125 #ifdef DEBUG
126 static void bcm_dma_cb_dump(struct bcm_dma_cb *cb);
127 static void bcm_dma_reg_dump(int ch);
128 #endif
129 
130 /* DMA channel private info */
131 struct bcm_dma_ch {
132 	int			ch;
133 	uint32_t		flags;
134 	struct bcm_dma_cb *	cb;
135 	uint32_t		vc_cb;
136 	bus_dmamap_t		dma_map;
137 	void 			(*intr_func)(int, void *);
138 	void *			intr_arg;
139 };
140 
141 struct bcm_dma_softc {
142 	device_t		sc_dev;
143 	struct mtx		sc_mtx;
144 	struct resource *	sc_mem;
145 	struct resource *	sc_irq[BCM_DMA_CH_MAX];
146 	void *			sc_intrhand[BCM_DMA_CH_MAX];
147 	struct bcm_dma_ch	sc_dma_ch[BCM_DMA_CH_MAX];
148 	bus_dma_tag_t		sc_dma_tag;
149 };
150 
151 static struct bcm_dma_softc *bcm_dma_sc = NULL;
152 static uint32_t bcm_dma_channel_mask;
153 
154 static struct ofw_compat_data compat_data[] = {
155 	{"broadcom,bcm2835-dma",	1},
156 	{"brcm,bcm2835-dma",		1},
157 	{NULL,				0}
158 };
159 
160 static void
161 bcm_dmamap_cb(void *arg, bus_dma_segment_t *segs,
162 	int nseg, int err)
163 {
164         bus_addr_t *addr;
165 
166         if (err)
167                 return;
168 
169         addr = (bus_addr_t*)arg;
170         *addr = ARMC_TO_VCBUS(segs[0].ds_addr);
171 }
172 
173 static void
174 bcm_dma_reset(device_t dev, int ch)
175 {
176 	struct bcm_dma_softc *sc = device_get_softc(dev);
177 	struct bcm_dma_cb *cb;
178 	uint32_t cs;
179 	int count;
180 
181 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
182 		return;
183 
184 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch));
185 
186 	if (cs & CS_ACTIVE) {
187 		/* pause current task */
188 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), 0);
189 
190 		count = 1000;
191 		do {
192 			cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch));
193 		} while (!(cs & CS_ISPAUSED) && (count-- > 0));
194 
195 		if (!(cs & CS_ISPAUSED)) {
196 			device_printf(dev,
197 			    "Can't abort DMA transfer at channel %d\n", ch);
198 		}
199 
200 		bus_write_4(sc->sc_mem, BCM_DMA_CBNEXT(ch), 0);
201 
202 		/* Complete everything, clear interrupt */
203 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch),
204 		    CS_ABORT | CS_INT | CS_END| CS_ACTIVE);
205 	}
206 
207 	/* clear control blocks */
208 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch), 0);
209 	bus_write_4(sc->sc_mem, BCM_DMA_CBNEXT(ch), 0);
210 
211 	/* Reset control block */
212 	cb = sc->sc_dma_ch[ch].cb;
213 	bzero(cb, sizeof(*cb));
214 	cb->info = INFO_WAIT_RESP;
215 }
216 
217 static int
218 bcm_dma_init(device_t dev)
219 {
220 	struct bcm_dma_softc *sc = device_get_softc(dev);
221 	uint32_t reg;
222 	struct bcm_dma_ch *ch;
223 	void *cb_virt;
224 	vm_paddr_t cb_phys;
225 	int err;
226 	int i;
227 
228 	/*
229 	 * Only channels set in bcm_dma_channel_mask can be controlled by us.
230 	 * The others are out of our control as well as the corresponding bits
231 	 * in both BCM_DMA_ENABLE and BCM_DMA_INT_STATUS global registers. As
232 	 * these registers are RW ones, there is no safe way how to write only
233 	 * the bits which can be controlled by us.
234 	 *
235 	 * Fortunately, after reset, all channels are enabled in BCM_DMA_ENABLE
236 	 * register and all statuses are cleared in BCM_DMA_INT_STATUS one.
237 	 * Not touching these registers is a trade off between correct
238 	 * initialization which does not count on anything and not messing up
239 	 * something we have no control over.
240 	 */
241 	reg = bus_read_4(sc->sc_mem, BCM_DMA_ENABLE);
242 	if ((reg & bcm_dma_channel_mask) != bcm_dma_channel_mask)
243 		device_printf(dev, "channels are not enabled\n");
244 	reg = bus_read_4(sc->sc_mem, BCM_DMA_INT_STATUS);
245 	if ((reg & bcm_dma_channel_mask) != 0)
246 		device_printf(dev, "statuses are not cleared\n");
247 
248 	/*
249 	 * Allocate DMA chunks control blocks based on p.40 of the peripheral
250 	 * spec - control block should be 32-bit aligned.  The DMA controller
251 	 * has a full 32-bit register dedicated to this address, so we do not
252 	 * need to bother with the per-SoC peripheral restrictions.
253 	 */
254 	err = bus_dma_tag_create(bus_get_dma_tag(dev),
255 	    1, 0, BUS_SPACE_MAXADDR_32BIT,
256 	    BUS_SPACE_MAXADDR, NULL, NULL,
257 	    sizeof(struct bcm_dma_cb), 1,
258 	    sizeof(struct bcm_dma_cb),
259 	    BUS_DMA_ALLOCNOW, NULL, NULL,
260 	    &sc->sc_dma_tag);
261 
262 	if (err) {
263 		device_printf(dev, "failed allocate DMA tag\n");
264 		return (err);
265 	}
266 
267 	/* setup initial settings */
268 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
269 		ch = &sc->sc_dma_ch[i];
270 
271 		bzero(ch, sizeof(struct bcm_dma_ch));
272 		ch->ch = i;
273 		ch->flags = BCM_DMA_CH_UNMAP;
274 
275 		if ((bcm_dma_channel_mask & (1 << i)) == 0)
276 			continue;
277 
278 		err = bus_dmamem_alloc(sc->sc_dma_tag, &cb_virt,
279 		    BUS_DMA_WAITOK | BUS_DMA_COHERENT | BUS_DMA_ZERO,
280 		    &ch->dma_map);
281 		if (err) {
282 			device_printf(dev, "cannot allocate DMA memory\n");
283 			break;
284 		}
285 
286 		/*
287 		 * Least alignment for busdma-allocated stuff is cache
288 		 * line size, so just make sure nothing stupid happened
289 		 * and we got properly aligned address
290 		 */
291 		if ((uintptr_t)cb_virt & 0x1f) {
292 			device_printf(dev,
293 			    "DMA address is not 32-bytes aligned: %p\n",
294 			    (void*)cb_virt);
295 			break;
296 		}
297 
298 		err = bus_dmamap_load(sc->sc_dma_tag, ch->dma_map, cb_virt,
299 		    sizeof(struct bcm_dma_cb), bcm_dmamap_cb, &cb_phys,
300 		    BUS_DMA_WAITOK);
301 		if (err) {
302 			device_printf(dev, "cannot load DMA memory\n");
303 			break;
304 		}
305 
306 		ch->cb = cb_virt;
307 		ch->vc_cb = cb_phys;
308 		ch->flags = BCM_DMA_CH_FREE;
309 		ch->cb->info = INFO_WAIT_RESP;
310 
311 		/* reset DMA engine */
312 		bus_write_4(sc->sc_mem, BCM_DMA_CS(i), CS_RESET);
313 	}
314 
315 	return (0);
316 }
317 
318 /*
319  * Allocate DMA channel for further use, returns channel # or
320  *     BCM_DMA_CH_INVALID
321  */
322 int
323 bcm_dma_allocate(int req_ch)
324 {
325 	struct bcm_dma_softc *sc = bcm_dma_sc;
326 	int ch = BCM_DMA_CH_INVALID;
327 	int i;
328 
329 	if (sc == NULL)
330 		return (BCM_DMA_CH_INVALID);
331 
332 	if (req_ch >= BCM_DMA_CH_MAX)
333 		return (BCM_DMA_CH_INVALID);
334 
335 	/* Auto(req_ch < 0) or CH specified */
336 	mtx_lock(&sc->sc_mtx);
337 
338 	if (req_ch < 0) {
339 		for (i = 0; i < BCM_DMA_CH_MAX; i++) {
340 			if (sc->sc_dma_ch[i].flags & BCM_DMA_CH_FREE) {
341 				ch = i;
342 				sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
343 				sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
344 				break;
345 			}
346 		}
347 	} else if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
348 		ch = req_ch;
349 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
350 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
351 	}
352 
353 	mtx_unlock(&sc->sc_mtx);
354 	return (ch);
355 }
356 
357 /*
358  * Frees allocated channel. Returns 0 on success, -1 otherwise
359  */
360 int
361 bcm_dma_free(int ch)
362 {
363 	struct bcm_dma_softc *sc = bcm_dma_sc;
364 
365 	if (sc == NULL)
366 		return (-1);
367 
368 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
369 		return (-1);
370 
371 	mtx_lock(&sc->sc_mtx);
372 	if (sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED) {
373 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_FREE;
374 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_USED;
375 		sc->sc_dma_ch[ch].intr_func = NULL;
376 		sc->sc_dma_ch[ch].intr_arg = NULL;
377 
378 		/* reset DMA engine */
379 		bcm_dma_reset(sc->sc_dev, ch);
380 	}
381 
382 	mtx_unlock(&sc->sc_mtx);
383 	return (0);
384 }
385 
386 /*
387  * Assign handler function for channel interrupt
388  * Returns 0 on success, -1 otherwise
389  */
390 int
391 bcm_dma_setup_intr(int ch, void (*func)(int, void *), void *arg)
392 {
393 	struct bcm_dma_softc *sc = bcm_dma_sc;
394 	struct bcm_dma_cb *cb;
395 
396 	if (sc == NULL)
397 		return (-1);
398 
399 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
400 		return (-1);
401 
402 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
403 		return (-1);
404 
405 	sc->sc_dma_ch[ch].intr_func = func;
406 	sc->sc_dma_ch[ch].intr_arg = arg;
407 	cb = sc->sc_dma_ch[ch].cb;
408 	cb->info |= INFO_INT_EN;
409 
410 	return (0);
411 }
412 
413 /*
414  * Setup DMA source parameters
415  *     ch - channel number
416  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
417  *         source is physical memory
418  *     inc_addr - BCM_DMA_INC_ADDR if source address
419  *         should be increased after each access or
420  *         BCM_DMA_SAME_ADDR if address should remain
421  *         the same
422  *     width - size of read operation, BCM_DMA_32BIT
423  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
424  *
425  * Returns 0 on success, -1 otherwise
426  */
427 int
428 bcm_dma_setup_src(int ch, int dreq, int inc_addr, int width)
429 {
430 	struct bcm_dma_softc *sc = bcm_dma_sc;
431 	uint32_t info;
432 
433 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
434 		return (-1);
435 
436 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
437 		return (-1);
438 
439 	info = sc->sc_dma_ch[ch].cb->info;
440 	info &= ~INFO_PERMAP_MASK;
441 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
442 
443 	if (dreq)
444 		info |= INFO_S_DREQ;
445 	else
446 		info &= ~INFO_S_DREQ;
447 
448 	if (width == BCM_DMA_128BIT)
449 		info |= INFO_S_WIDTH;
450 	else
451 		info &= ~INFO_S_WIDTH;
452 
453 	if (inc_addr == BCM_DMA_INC_ADDR)
454 		info |= INFO_S_INC;
455 	else
456 		info &= ~INFO_S_INC;
457 
458 	sc->sc_dma_ch[ch].cb->info = info;
459 
460 	return (0);
461 }
462 
463 /*
464  * Setup DMA destination parameters
465  *     ch - channel number
466  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
467  *         destination is physical memory
468  *     inc_addr - BCM_DMA_INC_ADDR if source address
469  *         should be increased after each access or
470  *         BCM_DMA_SAME_ADDR if address should remain
471  *         the same
472  *     width - size of write operation, BCM_DMA_32BIT
473  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
474  *
475  * Returns 0 on success, -1 otherwise
476  */
477 int
478 bcm_dma_setup_dst(int ch, int dreq, int inc_addr, int width)
479 {
480 	struct bcm_dma_softc *sc = bcm_dma_sc;
481 	uint32_t info;
482 
483 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
484 		return (-1);
485 
486 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
487 		return (-1);
488 
489 	info = sc->sc_dma_ch[ch].cb->info;
490 	info &= ~INFO_PERMAP_MASK;
491 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
492 
493 	if (dreq)
494 		info |= INFO_D_DREQ;
495 	else
496 		info &= ~INFO_D_DREQ;
497 
498 	if (width == BCM_DMA_128BIT)
499 		info |= INFO_D_WIDTH;
500 	else
501 		info &= ~INFO_D_WIDTH;
502 
503 	if (inc_addr == BCM_DMA_INC_ADDR)
504 		info |= INFO_D_INC;
505 	else
506 		info &= ~INFO_D_INC;
507 
508 	sc->sc_dma_ch[ch].cb->info = info;
509 
510 	return (0);
511 }
512 
513 #ifdef DEBUG
514 void
515 bcm_dma_cb_dump(struct bcm_dma_cb *cb)
516 {
517 
518 	printf("DMA CB ");
519 	printf("INFO: %8.8x ", cb->info);
520 	printf("SRC: %8.8x ", cb->src);
521 	printf("DST: %8.8x ", cb->dst);
522 	printf("LEN: %8.8x ", cb->len);
523 	printf("\n");
524 	printf("STRIDE: %8.8x ", cb->stride);
525 	printf("NEXT: %8.8x ", cb->next);
526 	printf("RSVD1: %8.8x ", cb->rsvd1);
527 	printf("RSVD2: %8.8x ", cb->rsvd2);
528 	printf("\n");
529 }
530 
531 void
532 bcm_dma_reg_dump(int ch)
533 {
534 	struct bcm_dma_softc *sc = bcm_dma_sc;
535 	int i;
536 	uint32_t reg;
537 
538 	if (sc == NULL)
539 		return;
540 
541 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
542 		return;
543 
544 	printf("DMA%d: ", ch);
545 	for (i = 0; i < MAX_REG; i++) {
546 		reg = bus_read_4(sc->sc_mem, BCM_DMA_CH(ch) + i*4);
547 		printf("%8.8x ", reg);
548 	}
549 	printf("\n");
550 }
551 #endif
552 
553 /*
554  * Start DMA transaction
555  *     ch - channel number
556  *     src, dst - source and destination address in
557  *         ARM physical memory address space.
558  *     len - amount of bytes to be transferred
559  *
560  * Returns 0 on success, -1 otherwise
561  */
562 int
563 bcm_dma_start(int ch, vm_paddr_t src, vm_paddr_t dst, int len)
564 {
565 	struct bcm_dma_softc *sc = bcm_dma_sc;
566 	struct bcm_dma_cb *cb;
567 
568 	if (sc == NULL)
569 		return (-1);
570 
571 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
572 		return (-1);
573 
574 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
575 		return (-1);
576 
577 	cb = sc->sc_dma_ch[ch].cb;
578 	cb->src = ARMC_TO_VCBUS(src);
579 	cb->dst = ARMC_TO_VCBUS(dst);
580 
581 	cb->len = len;
582 
583 	bus_dmamap_sync(sc->sc_dma_tag,
584 	    sc->sc_dma_ch[ch].dma_map, BUS_DMASYNC_PREWRITE);
585 
586 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch),
587 	    sc->sc_dma_ch[ch].vc_cb);
588 	bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), CS_ACTIVE);
589 
590 #ifdef DEBUG
591 	bcm_dma_cb_dump(sc->sc_dma_ch[ch].cb);
592 	bcm_dma_reg_dump(ch);
593 #endif
594 
595 	return (0);
596 }
597 
598 /*
599  * Get length requested for DMA transaction
600  *     ch - channel number
601  *
602  * Returns size of transaction, 0 if channel is invalid
603  */
604 uint32_t
605 bcm_dma_length(int ch)
606 {
607 	struct bcm_dma_softc *sc = bcm_dma_sc;
608 	struct bcm_dma_cb *cb;
609 
610 	if (sc == NULL)
611 		return (0);
612 
613 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
614 		return (0);
615 
616 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
617 		return (0);
618 
619 	cb = sc->sc_dma_ch[ch].cb;
620 
621 	return (cb->len);
622 }
623 
624 static void
625 bcm_dma_intr(void *arg)
626 {
627 	struct bcm_dma_softc *sc = bcm_dma_sc;
628 	struct bcm_dma_ch *ch = (struct bcm_dma_ch *)arg;
629 	uint32_t cs, debug;
630 
631 	/* my interrupt? */
632 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch->ch));
633 
634 	/*
635 	 * Is it an active channel?  Our diagnostics could be better here, but
636 	 * it's not necessarily an easy task to resolve a rid/resource to an
637 	 * actual irq number.  We'd want to do this to set a flag indicating
638 	 * whether the irq is shared or not, so we know to complain.
639 	 */
640 	if (!(ch->flags & BCM_DMA_CH_USED))
641 		return;
642 
643 	/* Again, we can't complain here.  The same logic applies. */
644 	if (!(cs & (CS_INT | CS_ERR)))
645 		return;
646 
647 	if (cs & CS_ERR) {
648 		debug = bus_read_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch));
649 		device_printf(sc->sc_dev, "DMA error %d on CH%d\n",
650 			debug & DEBUG_ERROR_MASK, ch->ch);
651 		bus_write_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch),
652 		    debug & DEBUG_ERROR_MASK);
653 		bcm_dma_reset(sc->sc_dev, ch->ch);
654 	}
655 
656 	if (cs & CS_INT) {
657 		/* acknowledge interrupt */
658 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch->ch),
659 		    CS_INT | CS_END);
660 
661 		/* Prepare for possible access to len field */
662 		bus_dmamap_sync(sc->sc_dma_tag, ch->dma_map,
663 		    BUS_DMASYNC_POSTWRITE);
664 
665 		/* save callback function and argument */
666 		if (ch->intr_func)
667 			ch->intr_func(ch->ch, ch->intr_arg);
668 	}
669 }
670 
671 static int
672 bcm_dma_probe(device_t dev)
673 {
674 
675 	if (!ofw_bus_status_okay(dev))
676 		return (ENXIO);
677 
678 	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
679 		return (ENXIO);
680 
681 	device_set_desc(dev, "BCM2835 DMA Controller");
682 	return (BUS_PROBE_DEFAULT);
683 }
684 
685 static int
686 bcm_dma_attach(device_t dev)
687 {
688 	struct bcm_dma_softc *sc = device_get_softc(dev);
689 	phandle_t node;
690 	int rid, err = 0;
691 	int i;
692 
693 	sc->sc_dev = dev;
694 
695 	if (bcm_dma_sc)
696 		return (ENXIO);
697 
698 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
699 		sc->sc_irq[i] = NULL;
700 		sc->sc_intrhand[i] = NULL;
701 	}
702 
703 	/* Get DMA channel mask. */
704 	node = ofw_bus_get_node(sc->sc_dev);
705 	if (OF_getencprop(node, "brcm,dma-channel-mask", &bcm_dma_channel_mask,
706 	    sizeof(bcm_dma_channel_mask)) == -1 &&
707 	    OF_getencprop(node, "broadcom,channels", &bcm_dma_channel_mask,
708 	    sizeof(bcm_dma_channel_mask)) == -1) {
709 		device_printf(dev, "could not get channel mask property\n");
710 		return (ENXIO);
711 	}
712 
713 	/* Mask out channels used by GPU. */
714 	bcm_dma_channel_mask &= ~BCM_DMA_CH_GPU_MASK;
715 
716 	/* DMA0 - DMA14 */
717 	rid = 0;
718 	sc->sc_mem = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
719 	if (sc->sc_mem == NULL) {
720 		device_printf(dev, "could not allocate memory resource\n");
721 		return (ENXIO);
722 	}
723 
724 	/* IRQ DMA0 - DMA11 XXX NOT USE DMA12(spurious?) */
725 	for (rid = 0; rid < BCM_DMA_CH_MAX; rid++) {
726 		if ((bcm_dma_channel_mask & (1 << rid)) == 0)
727 			continue;
728 
729 		sc->sc_irq[rid] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
730 		    RF_ACTIVE | RF_SHAREABLE);
731 		if (sc->sc_irq[rid] == NULL) {
732 			device_printf(dev, "cannot allocate interrupt\n");
733 			err = ENXIO;
734 			goto fail;
735 		}
736 		if (bus_setup_intr(dev, sc->sc_irq[rid], INTR_TYPE_MISC | INTR_MPSAFE,
737 				   NULL, bcm_dma_intr, &sc->sc_dma_ch[rid],
738 				   &sc->sc_intrhand[rid])) {
739 			device_printf(dev, "cannot setup interrupt handler\n");
740 			err = ENXIO;
741 			goto fail;
742 		}
743 	}
744 
745 	mtx_init(&sc->sc_mtx, "bcmdma", "bcmdma", MTX_DEF);
746 	bcm_dma_sc = sc;
747 
748 	err = bcm_dma_init(dev);
749 	if (err)
750 		goto fail;
751 
752 	return (err);
753 
754 fail:
755 	if (sc->sc_mem)
756 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem);
757 
758 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
759 		if (sc->sc_intrhand[i])
760 			bus_teardown_intr(dev, sc->sc_irq[i], sc->sc_intrhand[i]);
761 		if (sc->sc_irq[i])
762 			bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq[i]);
763 	}
764 
765 	return (err);
766 }
767 
768 static device_method_t bcm_dma_methods[] = {
769 	DEVMETHOD(device_probe,		bcm_dma_probe),
770 	DEVMETHOD(device_attach,	bcm_dma_attach),
771 	{ 0, 0 }
772 };
773 
774 static driver_t bcm_dma_driver = {
775 	"bcm_dma",
776 	bcm_dma_methods,
777 	sizeof(struct bcm_dma_softc),
778 };
779 
780 EARLY_DRIVER_MODULE(bcm_dma, simplebus, bcm_dma_driver, 0, 0,
781     BUS_PASS_SUPPORTDEV + BUS_PASS_ORDER_MIDDLE);
782 MODULE_VERSION(bcm_dma, 1);
783