xref: /freebsd/sys/arm/broadcom/bcm2835/bcm2835_dma.c (revision 193d9e768ba63fcfb187cfd17f461f7d41345048)
1 /*
2  * Copyright (c) 2013 Daisuke Aoyama <aoyama@peach.ne.jp>
3  * Copyright (c) 2013 Oleksandr Tymoshenko <gonzo@bluezbox.com>
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
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 = PHYS_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 	/* Allocate DMA chunks control blocks */
249 	/* p.40 of spec - control block should be 32-bit aligned */
250 	err = bus_dma_tag_create(bus_get_dma_tag(dev),
251 	    1, 0, BUS_SPACE_MAXADDR_32BIT,
252 	    BUS_SPACE_MAXADDR, NULL, NULL,
253 	    sizeof(struct bcm_dma_cb), 1,
254 	    sizeof(struct bcm_dma_cb),
255 	    BUS_DMA_ALLOCNOW, NULL, NULL,
256 	    &sc->sc_dma_tag);
257 
258 	if (err) {
259 		device_printf(dev, "failed allocate DMA tag\n");
260 		return (err);
261 	}
262 
263 	/* setup initial settings */
264 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
265 		ch = &sc->sc_dma_ch[i];
266 
267 		bzero(ch, sizeof(struct bcm_dma_ch));
268 		ch->ch = i;
269 		ch->flags = BCM_DMA_CH_UNMAP;
270 
271 		if ((bcm_dma_channel_mask & (1 << i)) == 0)
272 			continue;
273 
274 		err = bus_dmamem_alloc(sc->sc_dma_tag, &cb_virt,
275 		    BUS_DMA_WAITOK | BUS_DMA_COHERENT | BUS_DMA_ZERO,
276 		    &ch->dma_map);
277 		if (err) {
278 			device_printf(dev, "cannot allocate DMA memory\n");
279 			break;
280 		}
281 
282 		/*
283 		 * Least alignment for busdma-allocated stuff is cache
284 		 * line size, so just make sure nothing stupid happened
285 		 * and we got properly aligned address
286 		 */
287 		if ((uintptr_t)cb_virt & 0x1f) {
288 			device_printf(dev,
289 			    "DMA address is not 32-bytes aligned: %p\n",
290 			    (void*)cb_virt);
291 			break;
292 		}
293 
294 		err = bus_dmamap_load(sc->sc_dma_tag, ch->dma_map, cb_virt,
295 		    sizeof(struct bcm_dma_cb), bcm_dmamap_cb, &cb_phys,
296 		    BUS_DMA_WAITOK);
297 		if (err) {
298 			device_printf(dev, "cannot load DMA memory\n");
299 			break;
300 		}
301 
302 		ch->cb = cb_virt;
303 		ch->vc_cb = cb_phys;
304 		ch->flags = BCM_DMA_CH_FREE;
305 		ch->cb->info = INFO_WAIT_RESP;
306 
307 		/* reset DMA engine */
308 		bus_write_4(sc->sc_mem, BCM_DMA_CS(i), CS_RESET);
309 	}
310 
311 	return (0);
312 }
313 
314 /*
315  * Allocate DMA channel for further use, returns channel # or
316  *     BCM_DMA_CH_INVALID
317  */
318 int
319 bcm_dma_allocate(int req_ch)
320 {
321 	struct bcm_dma_softc *sc = bcm_dma_sc;
322 	int ch = BCM_DMA_CH_INVALID;
323 	int i;
324 
325 	if (req_ch >= BCM_DMA_CH_MAX)
326 		return (BCM_DMA_CH_INVALID);
327 
328 	/* Auto(req_ch < 0) or CH specified */
329 	mtx_lock(&sc->sc_mtx);
330 
331 	if (req_ch < 0) {
332 		for (i = 0; i < BCM_DMA_CH_MAX; i++) {
333 			if (sc->sc_dma_ch[i].flags & BCM_DMA_CH_FREE) {
334 				ch = i;
335 				sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
336 				sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
337 				break;
338 			}
339 		}
340 	}
341 	else {
342 		if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
343 			ch = req_ch;
344 			sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
345 			sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
346 		}
347 	}
348 
349 	mtx_unlock(&sc->sc_mtx);
350 	return (ch);
351 }
352 
353 /*
354  * Frees allocated channel. Returns 0 on success, -1 otherwise
355  */
356 int
357 bcm_dma_free(int ch)
358 {
359 	struct bcm_dma_softc *sc = bcm_dma_sc;
360 
361 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
362 		return (-1);
363 
364 	mtx_lock(&sc->sc_mtx);
365 	if (sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED) {
366 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_FREE;
367 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_USED;
368 		sc->sc_dma_ch[ch].intr_func = NULL;
369 		sc->sc_dma_ch[ch].intr_arg = NULL;
370 
371 		/* reset DMA engine */
372 		bcm_dma_reset(sc->sc_dev, ch);
373 	}
374 
375 	mtx_unlock(&sc->sc_mtx);
376 	return (0);
377 }
378 
379 /*
380  * Assign handler function for channel interrupt
381  * Returns 0 on success, -1 otherwise
382  */
383 int
384 bcm_dma_setup_intr(int ch, void (*func)(int, void *), void *arg)
385 {
386 	struct bcm_dma_softc *sc = bcm_dma_sc;
387 	struct bcm_dma_cb *cb;
388 
389 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
390 		return (-1);
391 
392 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
393 		return (-1);
394 
395 	sc->sc_dma_ch[ch].intr_func = func;
396 	sc->sc_dma_ch[ch].intr_arg = arg;
397 	cb = sc->sc_dma_ch[ch].cb;
398 	cb->info |= INFO_INT_EN;
399 
400 	return (0);
401 }
402 
403 /*
404  * Setup DMA source parameters
405  *     ch - channel number
406  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
407  *         source is physical memory
408  *     inc_addr - BCM_DMA_INC_ADDR if source address
409  *         should be increased after each access or
410  *         BCM_DMA_SAME_ADDR if address should remain
411  *         the same
412  *     width - size of read operation, BCM_DMA_32BIT
413  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
414  *
415  * Returns 0 on success, -1 otherwise
416  */
417 int
418 bcm_dma_setup_src(int ch, int dreq, int inc_addr, int width)
419 {
420 	struct bcm_dma_softc *sc = bcm_dma_sc;
421 	uint32_t info;
422 
423 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
424 		return (-1);
425 
426 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
427 		return (-1);
428 
429 	info = sc->sc_dma_ch[ch].cb->info;
430 	info &= ~INFO_PERMAP_MASK;
431 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
432 
433 	if (dreq)
434 		info |= INFO_S_DREQ;
435 	else
436 		info &= ~INFO_S_DREQ;
437 
438 	if (width == BCM_DMA_128BIT)
439 		info |= INFO_S_WIDTH;
440 	else
441 		info &= ~INFO_S_WIDTH;
442 
443 	if (inc_addr == BCM_DMA_INC_ADDR)
444 		info |= INFO_S_INC;
445 	else
446 		info &= ~INFO_S_INC;
447 
448 	sc->sc_dma_ch[ch].cb->info = info;
449 
450 	return (0);
451 }
452 
453 /*
454  * Setup DMA destination parameters
455  *     ch - channel number
456  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
457  *         destination is physical memory
458  *     inc_addr - BCM_DMA_INC_ADDR if source address
459  *         should be increased after each access or
460  *         BCM_DMA_SAME_ADDR if address should remain
461  *         the same
462  *     width - size of write operation, BCM_DMA_32BIT
463  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
464  *
465  * Returns 0 on success, -1 otherwise
466  */
467 int
468 bcm_dma_setup_dst(int ch, int dreq, int inc_addr, int width)
469 {
470 	struct bcm_dma_softc *sc = bcm_dma_sc;
471 	uint32_t info;
472 
473 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
474 		return (-1);
475 
476 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
477 		return (-1);
478 
479 	info = sc->sc_dma_ch[ch].cb->info;
480 	info &= ~INFO_PERMAP_MASK;
481 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
482 
483 	if (dreq)
484 		info |= INFO_D_DREQ;
485 	else
486 		info &= ~INFO_D_DREQ;
487 
488 	if (width == BCM_DMA_128BIT)
489 		info |= INFO_D_WIDTH;
490 	else
491 		info &= ~INFO_D_WIDTH;
492 
493 	if (inc_addr == BCM_DMA_INC_ADDR)
494 		info |= INFO_D_INC;
495 	else
496 		info &= ~INFO_D_INC;
497 
498 	sc->sc_dma_ch[ch].cb->info = info;
499 
500 	return (0);
501 }
502 
503 #ifdef DEBUG
504 void
505 bcm_dma_cb_dump(struct bcm_dma_cb *cb)
506 {
507 
508 	printf("DMA CB ");
509 	printf("INFO: %8.8x ", cb->info);
510 	printf("SRC: %8.8x ", cb->src);
511 	printf("DST: %8.8x ", cb->dst);
512 	printf("LEN: %8.8x ", cb->len);
513 	printf("\n");
514 	printf("STRIDE: %8.8x ", cb->stride);
515 	printf("NEXT: %8.8x ", cb->next);
516 	printf("RSVD1: %8.8x ", cb->rsvd1);
517 	printf("RSVD2: %8.8x ", cb->rsvd2);
518 	printf("\n");
519 }
520 
521 void
522 bcm_dma_reg_dump(int ch)
523 {
524 	struct bcm_dma_softc *sc = bcm_dma_sc;
525 	int i;
526 	uint32_t reg;
527 
528 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
529 		return;
530 
531 	printf("DMA%d: ", ch);
532 	for (i = 0; i < MAX_REG; i++) {
533 		reg = bus_read_4(sc->sc_mem, BCM_DMA_CH(ch) + i*4);
534 		printf("%8.8x ", reg);
535 	}
536 	printf("\n");
537 }
538 #endif
539 
540 /*
541  * Start DMA transaction
542  *     ch - channel number
543  *     src, dst - source and destination address in
544  *         ARM physical memory address space.
545  *     len - amount of bytes to be transferred
546  *
547  * Returns 0 on success, -1 otherwise
548  */
549 int
550 bcm_dma_start(int ch, vm_paddr_t src, vm_paddr_t dst, int len)
551 {
552 	struct bcm_dma_softc *sc = bcm_dma_sc;
553 	struct bcm_dma_cb *cb;
554 
555 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
556 		return (-1);
557 
558 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
559 		return (-1);
560 
561 	cb = sc->sc_dma_ch[ch].cb;
562 	if (BCM2835_ARM_IS_IO(src))
563 		cb->src = IO_TO_VCBUS(src);
564 	else
565 		cb->src = PHYS_TO_VCBUS(src);
566 	if (BCM2835_ARM_IS_IO(dst))
567 		cb->dst = IO_TO_VCBUS(dst);
568 	else
569 		cb->dst = PHYS_TO_VCBUS(dst);
570 	cb->len = len;
571 
572 	bus_dmamap_sync(sc->sc_dma_tag,
573 	    sc->sc_dma_ch[ch].dma_map, BUS_DMASYNC_PREWRITE);
574 
575 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch),
576 	    sc->sc_dma_ch[ch].vc_cb);
577 	bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), CS_ACTIVE);
578 
579 #ifdef DEBUG
580 	bcm_dma_cb_dump(sc->sc_dma_ch[ch].cb);
581 	bcm_dma_reg_dump(ch);
582 #endif
583 
584 	return (0);
585 }
586 
587 /*
588  * Get length requested for DMA transaction
589  *     ch - channel number
590  *
591  * Returns size of transaction, 0 if channel is invalid
592  */
593 uint32_t
594 bcm_dma_length(int ch)
595 {
596 	struct bcm_dma_softc *sc = bcm_dma_sc;
597 	struct bcm_dma_cb *cb;
598 
599 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
600 		return (0);
601 
602 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
603 		return (0);
604 
605 	cb = sc->sc_dma_ch[ch].cb;
606 
607 	return (cb->len);
608 }
609 
610 static void
611 bcm_dma_intr(void *arg)
612 {
613 	struct bcm_dma_softc *sc = bcm_dma_sc;
614 	struct bcm_dma_ch *ch = (struct bcm_dma_ch *)arg;
615 	uint32_t cs, debug;
616 
617 	/* my interrupt? */
618 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch->ch));
619 
620 	if (!(cs & (CS_INT | CS_ERR))) {
621 		device_printf(sc->sc_dev,
622 		    "unexpected DMA intr CH=%d, CS=%x\n", ch->ch, cs);
623 		return;
624 	}
625 
626 	/* running? */
627 	if (!(ch->flags & BCM_DMA_CH_USED)) {
628 		device_printf(sc->sc_dev,
629 		    "unused DMA intr CH=%d, CS=%x\n", ch->ch, cs);
630 		return;
631 	}
632 
633 	if (cs & CS_ERR) {
634 		debug = bus_read_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch));
635 		device_printf(sc->sc_dev, "DMA error %d on CH%d\n",
636 			debug & DEBUG_ERROR_MASK, ch->ch);
637 		bus_write_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch),
638 		    debug & DEBUG_ERROR_MASK);
639 		bcm_dma_reset(sc->sc_dev, ch->ch);
640 	}
641 
642 	if (cs & CS_INT) {
643 		/* acknowledge interrupt */
644 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch->ch),
645 		    CS_INT | CS_END);
646 
647 		/* Prepare for possible access to len field */
648 		bus_dmamap_sync(sc->sc_dma_tag, ch->dma_map,
649 		    BUS_DMASYNC_POSTWRITE);
650 
651 		/* save callback function and argument */
652 		if (ch->intr_func)
653 			ch->intr_func(ch->ch, ch->intr_arg);
654 	}
655 }
656 
657 static int
658 bcm_dma_probe(device_t dev)
659 {
660 
661 	if (!ofw_bus_status_okay(dev))
662 		return (ENXIO);
663 
664 	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
665 		return (ENXIO);
666 
667 	device_set_desc(dev, "BCM2835 DMA Controller");
668 	return (BUS_PROBE_DEFAULT);
669 }
670 
671 static int
672 bcm_dma_attach(device_t dev)
673 {
674 	struct bcm_dma_softc *sc = device_get_softc(dev);
675 	phandle_t node;
676 	int rid, err = 0;
677 	int i;
678 
679 	sc->sc_dev = dev;
680 
681 	if (bcm_dma_sc)
682 		return (ENXIO);
683 
684 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
685 		sc->sc_irq[i] = NULL;
686 		sc->sc_intrhand[i] = NULL;
687 	}
688 
689 	/* Get DMA channel mask. */
690 	node = ofw_bus_get_node(sc->sc_dev);
691 	if (OF_getencprop(node, "brcm,dma-channel-mask", &bcm_dma_channel_mask,
692 	    sizeof(bcm_dma_channel_mask)) == -1 &&
693 	    OF_getencprop(node, "broadcom,channels", &bcm_dma_channel_mask,
694 	    sizeof(bcm_dma_channel_mask)) == -1) {
695 		device_printf(dev, "could not get channel mask property\n");
696 		return (ENXIO);
697 	}
698 
699 	/* Mask out channels used by GPU. */
700 	bcm_dma_channel_mask &= ~BCM_DMA_CH_GPU_MASK;
701 
702 	/* DMA0 - DMA14 */
703 	rid = 0;
704 	sc->sc_mem = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
705 	if (sc->sc_mem == NULL) {
706 		device_printf(dev, "could not allocate memory resource\n");
707 		return (ENXIO);
708 	}
709 
710 	/* IRQ DMA0 - DMA11 XXX NOT USE DMA12(spurious?) */
711 	for (rid = 0; rid < BCM_DMA_CH_MAX; rid++) {
712 		if ((bcm_dma_channel_mask & (1 << rid)) == 0)
713 			continue;
714 
715 		sc->sc_irq[rid] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
716 						       RF_ACTIVE);
717 		if (sc->sc_irq[rid] == NULL) {
718 			device_printf(dev, "cannot allocate interrupt\n");
719 			err = ENXIO;
720 			goto fail;
721 		}
722 		if (bus_setup_intr(dev, sc->sc_irq[rid], INTR_TYPE_MISC | INTR_MPSAFE,
723 				   NULL, bcm_dma_intr, &sc->sc_dma_ch[rid],
724 				   &sc->sc_intrhand[rid])) {
725 			device_printf(dev, "cannot setup interrupt handler\n");
726 			err = ENXIO;
727 			goto fail;
728 		}
729 	}
730 
731 	mtx_init(&sc->sc_mtx, "bcmdma", "bcmdma", MTX_DEF);
732 	bcm_dma_sc = sc;
733 
734 	err = bcm_dma_init(dev);
735 	if (err)
736 		goto fail;
737 
738 	return (err);
739 
740 fail:
741 	if (sc->sc_mem)
742 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem);
743 
744 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
745 		if (sc->sc_intrhand[i])
746 			bus_teardown_intr(dev, sc->sc_irq[i], sc->sc_intrhand[i]);
747 		if (sc->sc_irq[i])
748 			bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq[i]);
749 	}
750 
751 	return (err);
752 }
753 
754 static device_method_t bcm_dma_methods[] = {
755 	DEVMETHOD(device_probe,		bcm_dma_probe),
756 	DEVMETHOD(device_attach,	bcm_dma_attach),
757 	{ 0, 0 }
758 };
759 
760 static driver_t bcm_dma_driver = {
761 	"bcm_dma",
762 	bcm_dma_methods,
763 	sizeof(struct bcm_dma_softc),
764 };
765 
766 static devclass_t bcm_dma_devclass;
767 
768 DRIVER_MODULE(bcm_dma, simplebus, bcm_dma_driver, bcm_dma_devclass, 0, 0);
769 MODULE_VERSION(bcm_dma, 1);
770