xref: /freebsd/sys/arm/broadcom/bcm2835/bcm2835_dma.c (revision b9f654b163bce26de79705e77b872427c9f2afa1)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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 = PHYS_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 	/* Allocate DMA chunks control blocks */
251 	/* p.40 of spec - control block should be 32-bit aligned */
252 	err = bus_dma_tag_create(bus_get_dma_tag(dev),
253 	    1, 0, BUS_SPACE_MAXADDR_32BIT,
254 	    BUS_SPACE_MAXADDR, NULL, NULL,
255 	    sizeof(struct bcm_dma_cb), 1,
256 	    sizeof(struct bcm_dma_cb),
257 	    BUS_DMA_ALLOCNOW, NULL, NULL,
258 	    &sc->sc_dma_tag);
259 
260 	if (err) {
261 		device_printf(dev, "failed allocate DMA tag\n");
262 		return (err);
263 	}
264 
265 	/* setup initial settings */
266 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
267 		ch = &sc->sc_dma_ch[i];
268 
269 		bzero(ch, sizeof(struct bcm_dma_ch));
270 		ch->ch = i;
271 		ch->flags = BCM_DMA_CH_UNMAP;
272 
273 		if ((bcm_dma_channel_mask & (1 << i)) == 0)
274 			continue;
275 
276 		err = bus_dmamem_alloc(sc->sc_dma_tag, &cb_virt,
277 		    BUS_DMA_WAITOK | BUS_DMA_COHERENT | BUS_DMA_ZERO,
278 		    &ch->dma_map);
279 		if (err) {
280 			device_printf(dev, "cannot allocate DMA memory\n");
281 			break;
282 		}
283 
284 		/*
285 		 * Least alignment for busdma-allocated stuff is cache
286 		 * line size, so just make sure nothing stupid happened
287 		 * and we got properly aligned address
288 		 */
289 		if ((uintptr_t)cb_virt & 0x1f) {
290 			device_printf(dev,
291 			    "DMA address is not 32-bytes aligned: %p\n",
292 			    (void*)cb_virt);
293 			break;
294 		}
295 
296 		err = bus_dmamap_load(sc->sc_dma_tag, ch->dma_map, cb_virt,
297 		    sizeof(struct bcm_dma_cb), bcm_dmamap_cb, &cb_phys,
298 		    BUS_DMA_WAITOK);
299 		if (err) {
300 			device_printf(dev, "cannot load DMA memory\n");
301 			break;
302 		}
303 
304 		ch->cb = cb_virt;
305 		ch->vc_cb = cb_phys;
306 		ch->flags = BCM_DMA_CH_FREE;
307 		ch->cb->info = INFO_WAIT_RESP;
308 
309 		/* reset DMA engine */
310 		bus_write_4(sc->sc_mem, BCM_DMA_CS(i), CS_RESET);
311 	}
312 
313 	return (0);
314 }
315 
316 /*
317  * Allocate DMA channel for further use, returns channel # or
318  *     BCM_DMA_CH_INVALID
319  */
320 int
321 bcm_dma_allocate(int req_ch)
322 {
323 	struct bcm_dma_softc *sc = bcm_dma_sc;
324 	int ch = BCM_DMA_CH_INVALID;
325 	int i;
326 
327 	if (req_ch >= BCM_DMA_CH_MAX)
328 		return (BCM_DMA_CH_INVALID);
329 
330 	/* Auto(req_ch < 0) or CH specified */
331 	mtx_lock(&sc->sc_mtx);
332 
333 	if (req_ch < 0) {
334 		for (i = 0; i < BCM_DMA_CH_MAX; i++) {
335 			if (sc->sc_dma_ch[i].flags & BCM_DMA_CH_FREE) {
336 				ch = i;
337 				sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
338 				sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
339 				break;
340 			}
341 		}
342 	}
343 	else {
344 		if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
345 			ch = req_ch;
346 			sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
347 			sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
348 		}
349 	}
350 
351 	mtx_unlock(&sc->sc_mtx);
352 	return (ch);
353 }
354 
355 /*
356  * Frees allocated channel. Returns 0 on success, -1 otherwise
357  */
358 int
359 bcm_dma_free(int ch)
360 {
361 	struct bcm_dma_softc *sc = bcm_dma_sc;
362 
363 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
364 		return (-1);
365 
366 	mtx_lock(&sc->sc_mtx);
367 	if (sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED) {
368 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_FREE;
369 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_USED;
370 		sc->sc_dma_ch[ch].intr_func = NULL;
371 		sc->sc_dma_ch[ch].intr_arg = NULL;
372 
373 		/* reset DMA engine */
374 		bcm_dma_reset(sc->sc_dev, ch);
375 	}
376 
377 	mtx_unlock(&sc->sc_mtx);
378 	return (0);
379 }
380 
381 /*
382  * Assign handler function for channel interrupt
383  * Returns 0 on success, -1 otherwise
384  */
385 int
386 bcm_dma_setup_intr(int ch, void (*func)(int, void *), void *arg)
387 {
388 	struct bcm_dma_softc *sc = bcm_dma_sc;
389 	struct bcm_dma_cb *cb;
390 
391 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
392 		return (-1);
393 
394 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
395 		return (-1);
396 
397 	sc->sc_dma_ch[ch].intr_func = func;
398 	sc->sc_dma_ch[ch].intr_arg = arg;
399 	cb = sc->sc_dma_ch[ch].cb;
400 	cb->info |= INFO_INT_EN;
401 
402 	return (0);
403 }
404 
405 /*
406  * Setup DMA source parameters
407  *     ch - channel number
408  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
409  *         source is physical memory
410  *     inc_addr - BCM_DMA_INC_ADDR if source address
411  *         should be increased after each access or
412  *         BCM_DMA_SAME_ADDR if address should remain
413  *         the same
414  *     width - size of read operation, BCM_DMA_32BIT
415  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
416  *
417  * Returns 0 on success, -1 otherwise
418  */
419 int
420 bcm_dma_setup_src(int ch, int dreq, int inc_addr, int width)
421 {
422 	struct bcm_dma_softc *sc = bcm_dma_sc;
423 	uint32_t info;
424 
425 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
426 		return (-1);
427 
428 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
429 		return (-1);
430 
431 	info = sc->sc_dma_ch[ch].cb->info;
432 	info &= ~INFO_PERMAP_MASK;
433 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
434 
435 	if (dreq)
436 		info |= INFO_S_DREQ;
437 	else
438 		info &= ~INFO_S_DREQ;
439 
440 	if (width == BCM_DMA_128BIT)
441 		info |= INFO_S_WIDTH;
442 	else
443 		info &= ~INFO_S_WIDTH;
444 
445 	if (inc_addr == BCM_DMA_INC_ADDR)
446 		info |= INFO_S_INC;
447 	else
448 		info &= ~INFO_S_INC;
449 
450 	sc->sc_dma_ch[ch].cb->info = info;
451 
452 	return (0);
453 }
454 
455 /*
456  * Setup DMA destination parameters
457  *     ch - channel number
458  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
459  *         destination is physical memory
460  *     inc_addr - BCM_DMA_INC_ADDR if source address
461  *         should be increased after each access or
462  *         BCM_DMA_SAME_ADDR if address should remain
463  *         the same
464  *     width - size of write operation, BCM_DMA_32BIT
465  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
466  *
467  * Returns 0 on success, -1 otherwise
468  */
469 int
470 bcm_dma_setup_dst(int ch, int dreq, int inc_addr, int width)
471 {
472 	struct bcm_dma_softc *sc = bcm_dma_sc;
473 	uint32_t info;
474 
475 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
476 		return (-1);
477 
478 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
479 		return (-1);
480 
481 	info = sc->sc_dma_ch[ch].cb->info;
482 	info &= ~INFO_PERMAP_MASK;
483 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
484 
485 	if (dreq)
486 		info |= INFO_D_DREQ;
487 	else
488 		info &= ~INFO_D_DREQ;
489 
490 	if (width == BCM_DMA_128BIT)
491 		info |= INFO_D_WIDTH;
492 	else
493 		info &= ~INFO_D_WIDTH;
494 
495 	if (inc_addr == BCM_DMA_INC_ADDR)
496 		info |= INFO_D_INC;
497 	else
498 		info &= ~INFO_D_INC;
499 
500 	sc->sc_dma_ch[ch].cb->info = info;
501 
502 	return (0);
503 }
504 
505 #ifdef DEBUG
506 void
507 bcm_dma_cb_dump(struct bcm_dma_cb *cb)
508 {
509 
510 	printf("DMA CB ");
511 	printf("INFO: %8.8x ", cb->info);
512 	printf("SRC: %8.8x ", cb->src);
513 	printf("DST: %8.8x ", cb->dst);
514 	printf("LEN: %8.8x ", cb->len);
515 	printf("\n");
516 	printf("STRIDE: %8.8x ", cb->stride);
517 	printf("NEXT: %8.8x ", cb->next);
518 	printf("RSVD1: %8.8x ", cb->rsvd1);
519 	printf("RSVD2: %8.8x ", cb->rsvd2);
520 	printf("\n");
521 }
522 
523 void
524 bcm_dma_reg_dump(int ch)
525 {
526 	struct bcm_dma_softc *sc = bcm_dma_sc;
527 	int i;
528 	uint32_t reg;
529 
530 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
531 		return;
532 
533 	printf("DMA%d: ", ch);
534 	for (i = 0; i < MAX_REG; i++) {
535 		reg = bus_read_4(sc->sc_mem, BCM_DMA_CH(ch) + i*4);
536 		printf("%8.8x ", reg);
537 	}
538 	printf("\n");
539 }
540 #endif
541 
542 /*
543  * Start DMA transaction
544  *     ch - channel number
545  *     src, dst - source and destination address in
546  *         ARM physical memory address space.
547  *     len - amount of bytes to be transferred
548  *
549  * Returns 0 on success, -1 otherwise
550  */
551 int
552 bcm_dma_start(int ch, vm_paddr_t src, vm_paddr_t dst, int len)
553 {
554 	struct bcm_dma_softc *sc = bcm_dma_sc;
555 	struct bcm_dma_cb *cb;
556 
557 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
558 		return (-1);
559 
560 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
561 		return (-1);
562 
563 	cb = sc->sc_dma_ch[ch].cb;
564 	if (BCM2835_ARM_IS_IO(src))
565 		cb->src = IO_TO_VCBUS(src);
566 	else
567 		cb->src = PHYS_TO_VCBUS(src);
568 	if (BCM2835_ARM_IS_IO(dst))
569 		cb->dst = IO_TO_VCBUS(dst);
570 	else
571 		cb->dst = PHYS_TO_VCBUS(dst);
572 	cb->len = len;
573 
574 	bus_dmamap_sync(sc->sc_dma_tag,
575 	    sc->sc_dma_ch[ch].dma_map, BUS_DMASYNC_PREWRITE);
576 
577 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch),
578 	    sc->sc_dma_ch[ch].vc_cb);
579 	bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), CS_ACTIVE);
580 
581 #ifdef DEBUG
582 	bcm_dma_cb_dump(sc->sc_dma_ch[ch].cb);
583 	bcm_dma_reg_dump(ch);
584 #endif
585 
586 	return (0);
587 }
588 
589 /*
590  * Get length requested for DMA transaction
591  *     ch - channel number
592  *
593  * Returns size of transaction, 0 if channel is invalid
594  */
595 uint32_t
596 bcm_dma_length(int ch)
597 {
598 	struct bcm_dma_softc *sc = bcm_dma_sc;
599 	struct bcm_dma_cb *cb;
600 
601 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
602 		return (0);
603 
604 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
605 		return (0);
606 
607 	cb = sc->sc_dma_ch[ch].cb;
608 
609 	return (cb->len);
610 }
611 
612 static void
613 bcm_dma_intr(void *arg)
614 {
615 	struct bcm_dma_softc *sc = bcm_dma_sc;
616 	struct bcm_dma_ch *ch = (struct bcm_dma_ch *)arg;
617 	uint32_t cs, debug;
618 
619 	/* my interrupt? */
620 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch->ch));
621 
622 	if (!(cs & (CS_INT | CS_ERR))) {
623 		device_printf(sc->sc_dev,
624 		    "unexpected DMA intr CH=%d, CS=%x\n", ch->ch, cs);
625 		return;
626 	}
627 
628 	/* running? */
629 	if (!(ch->flags & BCM_DMA_CH_USED)) {
630 		device_printf(sc->sc_dev,
631 		    "unused DMA intr CH=%d, CS=%x\n", ch->ch, cs);
632 		return;
633 	}
634 
635 	if (cs & CS_ERR) {
636 		debug = bus_read_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch));
637 		device_printf(sc->sc_dev, "DMA error %d on CH%d\n",
638 			debug & DEBUG_ERROR_MASK, ch->ch);
639 		bus_write_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch),
640 		    debug & DEBUG_ERROR_MASK);
641 		bcm_dma_reset(sc->sc_dev, ch->ch);
642 	}
643 
644 	if (cs & CS_INT) {
645 		/* acknowledge interrupt */
646 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch->ch),
647 		    CS_INT | CS_END);
648 
649 		/* Prepare for possible access to len field */
650 		bus_dmamap_sync(sc->sc_dma_tag, ch->dma_map,
651 		    BUS_DMASYNC_POSTWRITE);
652 
653 		/* save callback function and argument */
654 		if (ch->intr_func)
655 			ch->intr_func(ch->ch, ch->intr_arg);
656 	}
657 }
658 
659 static int
660 bcm_dma_probe(device_t dev)
661 {
662 
663 	if (!ofw_bus_status_okay(dev))
664 		return (ENXIO);
665 
666 	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
667 		return (ENXIO);
668 
669 	device_set_desc(dev, "BCM2835 DMA Controller");
670 	return (BUS_PROBE_DEFAULT);
671 }
672 
673 static int
674 bcm_dma_attach(device_t dev)
675 {
676 	struct bcm_dma_softc *sc = device_get_softc(dev);
677 	phandle_t node;
678 	int rid, err = 0;
679 	int i;
680 
681 	sc->sc_dev = dev;
682 
683 	if (bcm_dma_sc)
684 		return (ENXIO);
685 
686 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
687 		sc->sc_irq[i] = NULL;
688 		sc->sc_intrhand[i] = NULL;
689 	}
690 
691 	/* Get DMA channel mask. */
692 	node = ofw_bus_get_node(sc->sc_dev);
693 	if (OF_getencprop(node, "brcm,dma-channel-mask", &bcm_dma_channel_mask,
694 	    sizeof(bcm_dma_channel_mask)) == -1 &&
695 	    OF_getencprop(node, "broadcom,channels", &bcm_dma_channel_mask,
696 	    sizeof(bcm_dma_channel_mask)) == -1) {
697 		device_printf(dev, "could not get channel mask property\n");
698 		return (ENXIO);
699 	}
700 
701 	/* Mask out channels used by GPU. */
702 	bcm_dma_channel_mask &= ~BCM_DMA_CH_GPU_MASK;
703 
704 	/* DMA0 - DMA14 */
705 	rid = 0;
706 	sc->sc_mem = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
707 	if (sc->sc_mem == NULL) {
708 		device_printf(dev, "could not allocate memory resource\n");
709 		return (ENXIO);
710 	}
711 
712 	/* IRQ DMA0 - DMA11 XXX NOT USE DMA12(spurious?) */
713 	for (rid = 0; rid < BCM_DMA_CH_MAX; rid++) {
714 		if ((bcm_dma_channel_mask & (1 << rid)) == 0)
715 			continue;
716 
717 		sc->sc_irq[rid] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
718 						       RF_ACTIVE);
719 		if (sc->sc_irq[rid] == NULL) {
720 			device_printf(dev, "cannot allocate interrupt\n");
721 			err = ENXIO;
722 			goto fail;
723 		}
724 		if (bus_setup_intr(dev, sc->sc_irq[rid], INTR_TYPE_MISC | INTR_MPSAFE,
725 				   NULL, bcm_dma_intr, &sc->sc_dma_ch[rid],
726 				   &sc->sc_intrhand[rid])) {
727 			device_printf(dev, "cannot setup interrupt handler\n");
728 			err = ENXIO;
729 			goto fail;
730 		}
731 	}
732 
733 	mtx_init(&sc->sc_mtx, "bcmdma", "bcmdma", MTX_DEF);
734 	bcm_dma_sc = sc;
735 
736 	err = bcm_dma_init(dev);
737 	if (err)
738 		goto fail;
739 
740 	return (err);
741 
742 fail:
743 	if (sc->sc_mem)
744 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem);
745 
746 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
747 		if (sc->sc_intrhand[i])
748 			bus_teardown_intr(dev, sc->sc_irq[i], sc->sc_intrhand[i]);
749 		if (sc->sc_irq[i])
750 			bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq[i]);
751 	}
752 
753 	return (err);
754 }
755 
756 static device_method_t bcm_dma_methods[] = {
757 	DEVMETHOD(device_probe,		bcm_dma_probe),
758 	DEVMETHOD(device_attach,	bcm_dma_attach),
759 	{ 0, 0 }
760 };
761 
762 static driver_t bcm_dma_driver = {
763 	"bcm_dma",
764 	bcm_dma_methods,
765 	sizeof(struct bcm_dma_softc),
766 };
767 
768 static devclass_t bcm_dma_devclass;
769 
770 DRIVER_MODULE(bcm_dma, simplebus, bcm_dma_driver, bcm_dma_devclass, 0, 0);
771 MODULE_VERSION(bcm_dma, 1);
772