xref: /freebsd/sys/arm/broadcom/bcm2835/bcm2835_dma.c (revision 0b3105a37d7adcadcb720112fed4dc4e8040be99)
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/fdt/fdt_common.h>
44 #include <dev/ofw/openfirm.h>
45 #include <dev/ofw/ofw_bus.h>
46 #include <dev/ofw/ofw_bus_subr.h>
47 
48 #include <vm/vm.h>
49 #include <vm/pmap.h>
50 #include <machine/bus.h>
51 #include <machine/cpu.h>
52 #include <machine/cpufunc.h>
53 
54 #include "bcm2835_dma.h"
55 #include "bcm2835_vcbus.h"
56 
57 #define	MAX_REG			9
58 
59 /* private flags */
60 #define	BCM_DMA_CH_USED		0x00000001
61 #define	BCM_DMA_CH_FREE		0x40000000
62 #define	BCM_DMA_CH_UNMAP	0x80000000
63 
64 /* Register Map (4.2.1.2) */
65 #define	BCM_DMA_CS(n)		(0x100*(n) + 0x00)
66 #define		CS_ACTIVE		(1 <<  0)
67 #define		CS_END			(1 <<  1)
68 #define		CS_INT			(1 <<  2)
69 #define		CS_DREQ			(1 <<  3)
70 #define		CS_ISPAUSED		(1 <<  4)
71 #define		CS_ISHELD		(1 <<  5)
72 #define		CS_ISWAIT		(1 <<  6)
73 #define		CS_ERR			(1 <<  8)
74 #define		CS_WAITWRT		(1 << 28)
75 #define		CS_DISDBG		(1 << 29)
76 #define		CS_ABORT		(1 << 30)
77 #define		CS_RESET		(1U << 31)
78 #define	BCM_DMA_CBADDR(n)	(0x100*(n) + 0x04)
79 #define	BCM_DMA_INFO(n)		(0x100*(n) + 0x08)
80 #define		INFO_INT_EN		(1 << 0)
81 #define		INFO_TDMODE		(1 << 1)
82 #define		INFO_WAIT_RESP		(1 << 3)
83 #define		INFO_D_INC		(1 << 4)
84 #define		INFO_D_WIDTH		(1 << 5)
85 #define		INFO_D_DREQ		(1 << 6)
86 #define		INFO_S_INC		(1 << 8)
87 #define		INFO_S_WIDTH		(1 << 9)
88 #define		INFO_S_DREQ		(1 << 10)
89 #define		INFO_WAITS_SHIFT	(21)
90 #define		INFO_PERMAP_SHIFT	(16)
91 #define		INFO_PERMAP_MASK	(0x1f << INFO_PERMAP_SHIFT)
92 
93 #define	BCM_DMA_SRC(n)		(0x100*(n) + 0x0C)
94 #define	BCM_DMA_DST(n)		(0x100*(n) + 0x10)
95 #define	BCM_DMA_LEN(n)		(0x100*(n) + 0x14)
96 #define	BCM_DMA_STRIDE(n)	(0x100*(n) + 0x18)
97 #define	BCM_DMA_CBNEXT(n)	(0x100*(n) + 0x1C)
98 #define	BCM_DMA_DEBUG(n)	(0x100*(n) + 0x20)
99 #define		DEBUG_ERROR_MASK	(7)
100 
101 #define	BCM_DMA_INT_STATUS	0xfe0
102 #define	BCM_DMA_ENABLE		0xff0
103 
104 /* relative offset from BCM_VC_DMA0_BASE (p.39) */
105 #define	BCM_DMA_CH(n)		(0x100*(n))
106 
107 /* channels used by GPU */
108 #define	BCM_DMA_CH_BULK		0
109 #define	BCM_DMA_CH_FAST1	2
110 #define	BCM_DMA_CH_FAST2	3
111 
112 #define	BCM_DMA_CH_GPU_MASK	((1 << BCM_DMA_CH_BULK) |	\
113 				 (1 << BCM_DMA_CH_FAST1) |	\
114 				 (1 << BCM_DMA_CH_FAST2))
115 
116 /* DMA Control Block - 256bit aligned (p.40) */
117 struct bcm_dma_cb {
118 	uint32_t info;		/* Transfer Information */
119 	uint32_t src;		/* Source Address */
120 	uint32_t dst;		/* Destination Address */
121 	uint32_t len;		/* Transfer Length */
122 	uint32_t stride;	/* 2D Mode Stride */
123 	uint32_t next;		/* Next Control Block Address */
124 	uint32_t rsvd1;		/* Reserved */
125 	uint32_t rsvd2;		/* Reserved */
126 };
127 
128 #ifdef DEBUG
129 static void bcm_dma_cb_dump(struct bcm_dma_cb *cb);
130 static void bcm_dma_reg_dump(int ch);
131 #endif
132 
133 /* DMA channel private info */
134 struct bcm_dma_ch {
135 	int			ch;
136 	uint32_t		flags;
137 	struct bcm_dma_cb *	cb;
138 	uint32_t		vc_cb;
139 	bus_dmamap_t		dma_map;
140 	void 			(*intr_func)(int, void *);
141 	void *			intr_arg;
142 };
143 
144 struct bcm_dma_softc {
145 	device_t		sc_dev;
146 	struct mtx		sc_mtx;
147 	struct resource *	sc_mem;
148 	struct resource *	sc_irq[BCM_DMA_CH_MAX];
149 	void *			sc_intrhand[BCM_DMA_CH_MAX];
150 	struct bcm_dma_ch	sc_dma_ch[BCM_DMA_CH_MAX];
151 	bus_dma_tag_t		sc_dma_tag;
152 };
153 
154 static struct bcm_dma_softc *bcm_dma_sc = NULL;
155 static uint32_t bcm_dma_channel_mask;
156 
157 static void
158 bcm_dmamap_cb(void *arg, bus_dma_segment_t *segs,
159 	int nseg, int err)
160 {
161         bus_addr_t *addr;
162 
163         if (err)
164                 return;
165 
166         addr = (bus_addr_t*)arg;
167         *addr = PHYS_TO_VCBUS(segs[0].ds_addr);
168 }
169 
170 static void
171 bcm_dma_reset(device_t dev, int ch)
172 {
173 	struct bcm_dma_softc *sc = device_get_softc(dev);
174 	struct bcm_dma_cb *cb;
175 	uint32_t cs;
176 	int count;
177 
178 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
179 		return;
180 
181 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch));
182 
183 	if (cs & CS_ACTIVE) {
184 		/* pause current task */
185 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), 0);
186 
187 		count = 1000;
188 		do {
189 			cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch));
190 		} while (!(cs & CS_ISPAUSED) && (count-- > 0));
191 
192 		if (!(cs & CS_ISPAUSED)) {
193 			device_printf(dev,
194 			    "Can't abort DMA transfer at channel %d\n", ch);
195 		}
196 
197 		bus_write_4(sc->sc_mem, BCM_DMA_CBNEXT(ch), 0);
198 
199 		/* Complete everything, clear interrupt */
200 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch),
201 		    CS_ABORT | CS_INT | CS_END| CS_ACTIVE);
202 	}
203 
204 	/* clear control blocks */
205 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch), 0);
206 	bus_write_4(sc->sc_mem, BCM_DMA_CBNEXT(ch), 0);
207 
208 	/* Reset control block */
209 	cb = sc->sc_dma_ch[ch].cb;
210 	bzero(cb, sizeof(*cb));
211 	cb->info = INFO_WAIT_RESP;
212 }
213 
214 static int
215 bcm_dma_init(device_t dev)
216 {
217 	struct bcm_dma_softc *sc = device_get_softc(dev);
218 	uint32_t reg;
219 	struct bcm_dma_ch *ch;
220 	void *cb_virt;
221 	vm_paddr_t cb_phys;
222 	int err;
223 	int i;
224 
225 	/*
226 	 * Only channels set in bcm_dma_channel_mask can be controlled by us.
227 	 * The others are out of our control as well as the corresponding bits
228 	 * in both BCM_DMA_ENABLE and BCM_DMA_INT_STATUS global registers. As
229 	 * these registers are RW ones, there is no safe way how to write only
230 	 * the bits which can be controlled by us.
231 	 *
232 	 * Fortunately, after reset, all channels are enabled in BCM_DMA_ENABLE
233 	 * register and all statuses are cleared in BCM_DMA_INT_STATUS one.
234 	 * Not touching these registers is a trade off between correct
235 	 * initialization which does not count on anything and not messing up
236 	 * something we have no control over.
237 	 */
238 	reg = bus_read_4(sc->sc_mem, BCM_DMA_ENABLE);
239 	if ((reg & bcm_dma_channel_mask) != bcm_dma_channel_mask)
240 		device_printf(dev, "channels are not enabled\n");
241 	reg = bus_read_4(sc->sc_mem, BCM_DMA_INT_STATUS);
242 	if ((reg & bcm_dma_channel_mask) != 0)
243 		device_printf(dev, "statuses are not cleared\n");
244 
245 	/* Allocate DMA chunks control blocks */
246 	/* p.40 of spec - control block should be 32-bit aligned */
247 	err = bus_dma_tag_create(bus_get_dma_tag(dev),
248 	    1, 0, BUS_SPACE_MAXADDR_32BIT,
249 	    BUS_SPACE_MAXADDR, NULL, NULL,
250 	    sizeof(struct bcm_dma_cb), 1,
251 	    sizeof(struct bcm_dma_cb),
252 	    BUS_DMA_ALLOCNOW, NULL, NULL,
253 	    &sc->sc_dma_tag);
254 
255 	if (err) {
256 		device_printf(dev, "failed allocate DMA tag\n");
257 		return (err);
258 	}
259 
260 	/* setup initial settings */
261 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
262 		ch = &sc->sc_dma_ch[i];
263 
264 		bzero(ch, sizeof(struct bcm_dma_ch));
265 		ch->ch = i;
266 		ch->flags = BCM_DMA_CH_UNMAP;
267 
268 		if ((bcm_dma_channel_mask & (1 << i)) == 0)
269 			continue;
270 
271 		err = bus_dmamem_alloc(sc->sc_dma_tag, &cb_virt,
272 		    BUS_DMA_WAITOK | BUS_DMA_COHERENT | BUS_DMA_ZERO,
273 		    &ch->dma_map);
274 		if (err) {
275 			device_printf(dev, "cannot allocate DMA memory\n");
276 			break;
277 		}
278 
279 		/*
280 		 * Least alignment for busdma-allocated stuff is cache
281 		 * line size, so just make sure nothing stupid happend
282 		 * and we got properly aligned address
283 		 */
284 		if ((uintptr_t)cb_virt & 0x1f) {
285 			device_printf(dev,
286 			    "DMA address is not 32-bytes aligned: %p\n",
287 			    (void*)cb_virt);
288 			break;
289 		}
290 
291 		err = bus_dmamap_load(sc->sc_dma_tag, ch->dma_map, cb_virt,
292 		    sizeof(struct bcm_dma_cb), bcm_dmamap_cb, &cb_phys,
293 		    BUS_DMA_WAITOK);
294 		if (err) {
295 			device_printf(dev, "cannot load DMA memory\n");
296 			break;
297 		}
298 
299 		ch->cb = cb_virt;
300 		ch->vc_cb = cb_phys;
301 		ch->flags = BCM_DMA_CH_FREE;
302 		ch->cb->info = INFO_WAIT_RESP;
303 
304 		/* reset DMA engine */
305 		bus_write_4(sc->sc_mem, BCM_DMA_CS(i), CS_RESET);
306 	}
307 
308 	return (0);
309 }
310 
311 /*
312  * Allocate DMA channel for further use, returns channel # or
313  *     BCM_DMA_CH_INVALID
314  */
315 int
316 bcm_dma_allocate(int req_ch)
317 {
318 	struct bcm_dma_softc *sc = bcm_dma_sc;
319 	int ch = BCM_DMA_CH_INVALID;
320 	int i;
321 
322 	if (req_ch >= BCM_DMA_CH_MAX)
323 		return (BCM_DMA_CH_INVALID);
324 
325 	/* Auto(req_ch < 0) or CH specified */
326 	mtx_lock(&sc->sc_mtx);
327 
328 	if (req_ch < 0) {
329 		for (i = 0; i < BCM_DMA_CH_MAX; i++) {
330 			if (sc->sc_dma_ch[i].flags & BCM_DMA_CH_FREE) {
331 				ch = i;
332 				sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
333 				sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
334 				break;
335 			}
336 		}
337 	}
338 	else {
339 		if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
340 			ch = req_ch;
341 			sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
342 			sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
343 		}
344 	}
345 
346 	mtx_unlock(&sc->sc_mtx);
347 	return (ch);
348 }
349 
350 /*
351  * Frees allocated channel. Returns 0 on success, -1 otherwise
352  */
353 int
354 bcm_dma_free(int ch)
355 {
356 	struct bcm_dma_softc *sc = bcm_dma_sc;
357 
358 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
359 		return (-1);
360 
361 	mtx_lock(&sc->sc_mtx);
362 	if (sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED) {
363 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_FREE;
364 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_USED;
365 		sc->sc_dma_ch[ch].intr_func = NULL;
366 		sc->sc_dma_ch[ch].intr_arg = NULL;
367 
368 		/* reset DMA engine */
369 		bcm_dma_reset(sc->sc_dev, ch);
370 	}
371 
372 	mtx_unlock(&sc->sc_mtx);
373 	return (0);
374 }
375 
376 /*
377  * Assign handler function for channel interrupt
378  * Returns 0 on success, -1 otherwise
379  */
380 int
381 bcm_dma_setup_intr(int ch, void (*func)(int, void *), void *arg)
382 {
383 	struct bcm_dma_softc *sc = bcm_dma_sc;
384 	struct bcm_dma_cb *cb;
385 
386 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
387 		return (-1);
388 
389 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
390 		return (-1);
391 
392 	sc->sc_dma_ch[ch].intr_func = func;
393 	sc->sc_dma_ch[ch].intr_arg = arg;
394 	cb = sc->sc_dma_ch[ch].cb;
395 	cb->info |= INFO_INT_EN;
396 
397 	return (0);
398 }
399 
400 /*
401  * Setup DMA source parameters
402  *     ch - channel number
403  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
404  *         source is physical memory
405  *     inc_addr - BCM_DMA_INC_ADDR if source address
406  *         should be increased after each access or
407  *         BCM_DMA_SAME_ADDR if address should remain
408  *         the same
409  *     width - size of read operation, BCM_DMA_32BIT
410  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
411  *
412  * Returns 0 on success, -1 otherwise
413  */
414 int
415 bcm_dma_setup_src(int ch, int dreq, int inc_addr, int width)
416 {
417 	struct bcm_dma_softc *sc = bcm_dma_sc;
418 	uint32_t info;
419 
420 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
421 		return (-1);
422 
423 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
424 		return (-1);
425 
426 	info = sc->sc_dma_ch[ch].cb->info;
427 	info &= ~INFO_PERMAP_MASK;
428 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
429 
430 	if (dreq)
431 		info |= INFO_S_DREQ;
432 	else
433 		info &= ~INFO_S_DREQ;
434 
435 	if (width == BCM_DMA_128BIT)
436 		info |= INFO_S_WIDTH;
437 	else
438 		info &= ~INFO_S_WIDTH;
439 
440 	if (inc_addr == BCM_DMA_INC_ADDR)
441 		info |= INFO_S_INC;
442 	else
443 		info &= ~INFO_S_INC;
444 
445 	sc->sc_dma_ch[ch].cb->info = info;
446 
447 	return (0);
448 }
449 
450 /*
451  * Setup DMA destination parameters
452  *     ch - channel number
453  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
454  *         destination is physical memory
455  *     inc_addr - BCM_DMA_INC_ADDR if source address
456  *         should be increased after each access or
457  *         BCM_DMA_SAME_ADDR if address should remain
458  *         the same
459  *     width - size of write operation, BCM_DMA_32BIT
460  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
461  *
462  * Returns 0 on success, -1 otherwise
463  */
464 int
465 bcm_dma_setup_dst(int ch, int dreq, int inc_addr, int width)
466 {
467 	struct bcm_dma_softc *sc = bcm_dma_sc;
468 	uint32_t info;
469 
470 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
471 		return (-1);
472 
473 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
474 		return (-1);
475 
476 	info = sc->sc_dma_ch[ch].cb->info;
477 	info &= ~INFO_PERMAP_MASK;
478 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
479 
480 	if (dreq)
481 		info |= INFO_D_DREQ;
482 	else
483 		info &= ~INFO_D_DREQ;
484 
485 	if (width == BCM_DMA_128BIT)
486 		info |= INFO_D_WIDTH;
487 	else
488 		info &= ~INFO_D_WIDTH;
489 
490 	if (inc_addr == BCM_DMA_INC_ADDR)
491 		info |= INFO_D_INC;
492 	else
493 		info &= ~INFO_D_INC;
494 
495 	sc->sc_dma_ch[ch].cb->info = info;
496 
497 	return (0);
498 }
499 
500 #ifdef DEBUG
501 void
502 bcm_dma_cb_dump(struct bcm_dma_cb *cb)
503 {
504 
505 	printf("DMA CB ");
506 	printf("INFO: %8.8x ", cb->info);
507 	printf("SRC: %8.8x ", cb->src);
508 	printf("DST: %8.8x ", cb->dst);
509 	printf("LEN: %8.8x ", cb->len);
510 	printf("\n");
511 	printf("STRIDE: %8.8x ", cb->stride);
512 	printf("NEXT: %8.8x ", cb->next);
513 	printf("RSVD1: %8.8x ", cb->rsvd1);
514 	printf("RSVD2: %8.8x ", cb->rsvd2);
515 	printf("\n");
516 }
517 
518 void
519 bcm_dma_reg_dump(int ch)
520 {
521 	struct bcm_dma_softc *sc = bcm_dma_sc;
522 	int i;
523 	uint32_t reg;
524 
525 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
526 		return;
527 
528 	printf("DMA%d: ", ch);
529 	for (i = 0; i < MAX_REG; i++) {
530 		reg = bus_read_4(sc->sc_mem, BCM_DMA_CH(ch) + i*4);
531 		printf("%8.8x ", reg);
532 	}
533 	printf("\n");
534 }
535 #endif
536 
537 /*
538  * Start DMA transaction
539  *     ch - channel number
540  *     src, dst - source and destination address in
541  *         ARM physical memory address space.
542  *     len - amount of bytes to be transfered
543  *
544  * Returns 0 on success, -1 otherwise
545  */
546 int
547 bcm_dma_start(int ch, vm_paddr_t src, vm_paddr_t dst, int len)
548 {
549 	struct bcm_dma_softc *sc = bcm_dma_sc;
550 	struct bcm_dma_cb *cb;
551 
552 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
553 		return (-1);
554 
555 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
556 		return (-1);
557 
558 	cb = sc->sc_dma_ch[ch].cb;
559 	if (BCM2835_ARM_IS_IO(src))
560 		cb->src = IO_TO_VCBUS(src);
561 	else
562 		cb->src = PHYS_TO_VCBUS(src);
563 	if (BCM2835_ARM_IS_IO(dst))
564 		cb->dst = IO_TO_VCBUS(dst);
565 	else
566 		cb->dst = PHYS_TO_VCBUS(dst);
567 	cb->len = len;
568 
569 	bus_dmamap_sync(sc->sc_dma_tag,
570 	    sc->sc_dma_ch[ch].dma_map, BUS_DMASYNC_PREWRITE);
571 
572 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch),
573 	    sc->sc_dma_ch[ch].vc_cb);
574 	bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), CS_ACTIVE);
575 
576 #ifdef DEBUG
577 	bcm_dma_cb_dump(sc->sc_dma_ch[ch].cb);
578 	bcm_dma_reg_dump(ch);
579 #endif
580 
581 	return (0);
582 }
583 
584 /*
585  * Get length requested for DMA transaction
586  *     ch - channel number
587  *
588  * Returns size of transaction, 0 if channel is invalid
589  */
590 uint32_t
591 bcm_dma_length(int ch)
592 {
593 	struct bcm_dma_softc *sc = bcm_dma_sc;
594 	struct bcm_dma_cb *cb;
595 
596 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
597 		return (0);
598 
599 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
600 		return (0);
601 
602 	cb = sc->sc_dma_ch[ch].cb;
603 
604 	return (cb->len);
605 }
606 
607 static void
608 bcm_dma_intr(void *arg)
609 {
610 	struct bcm_dma_softc *sc = bcm_dma_sc;
611 	struct bcm_dma_ch *ch = (struct bcm_dma_ch *)arg;
612 	uint32_t cs, debug;
613 
614 	/* my interrupt? */
615 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch->ch));
616 
617 	if (!(cs & (CS_INT | CS_ERR))) {
618 		device_printf(sc->sc_dev,
619 		    "unexpected DMA intr CH=%d, CS=%x\n", ch->ch, cs);
620 		return;
621 	}
622 
623 	/* running? */
624 	if (!(ch->flags & BCM_DMA_CH_USED)) {
625 		device_printf(sc->sc_dev,
626 		    "unused DMA intr CH=%d, CS=%x\n", ch->ch, cs);
627 		return;
628 	}
629 
630 	if (cs & CS_ERR) {
631 		debug = bus_read_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch));
632 		device_printf(sc->sc_dev, "DMA error %d on CH%d\n",
633 			debug & DEBUG_ERROR_MASK, ch->ch);
634 		bus_write_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch),
635 		    debug & DEBUG_ERROR_MASK);
636 		bcm_dma_reset(sc->sc_dev, ch->ch);
637 	}
638 
639 	if (cs & CS_INT) {
640 		/* acknowledge interrupt */
641 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch->ch),
642 		    CS_INT | CS_END);
643 
644 		/* Prepare for possible access to len field */
645 		bus_dmamap_sync(sc->sc_dma_tag, ch->dma_map,
646 		    BUS_DMASYNC_POSTWRITE);
647 
648 		/* save callback function and argument */
649 		if (ch->intr_func)
650 			ch->intr_func(ch->ch, ch->intr_arg);
651 	}
652 }
653 
654 static int
655 bcm_dma_probe(device_t dev)
656 {
657 
658 	if (!ofw_bus_status_okay(dev))
659 		return (ENXIO);
660 
661 	if (!ofw_bus_is_compatible(dev, "broadcom,bcm2835-dma"))
662 		return (ENXIO);
663 
664 	device_set_desc(dev, "BCM2835 DMA Controller");
665 	return (BUS_PROBE_DEFAULT);
666 }
667 
668 static int
669 bcm_dma_attach(device_t dev)
670 {
671 	struct bcm_dma_softc *sc = device_get_softc(dev);
672 	phandle_t node;
673 	int rid, err = 0;
674 	int i;
675 
676 	sc->sc_dev = dev;
677 
678 	if (bcm_dma_sc)
679 		return (ENXIO);
680 
681 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
682 		sc->sc_irq[i] = NULL;
683 		sc->sc_intrhand[i] = NULL;
684 	}
685 
686 	/* Get DMA channel mask. */
687 	node = ofw_bus_get_node(sc->sc_dev);
688 	if (OF_getencprop(node, "brcm,dma-channel-mask", &bcm_dma_channel_mask,
689 	    sizeof(bcm_dma_channel_mask)) == -1 &&
690 	    OF_getencprop(node, "broadcom,channels", &bcm_dma_channel_mask,
691 	    sizeof(bcm_dma_channel_mask)) == -1) {
692 		device_printf(dev, "could not get channel mask property\n");
693 		return (ENXIO);
694 	}
695 
696 	/* Mask out channels used by GPU. */
697 	bcm_dma_channel_mask &= ~BCM_DMA_CH_GPU_MASK;
698 
699 	/* DMA0 - DMA14 */
700 	rid = 0;
701 	sc->sc_mem = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
702 	if (sc->sc_mem == NULL) {
703 		device_printf(dev, "could not allocate memory resource\n");
704 		return (ENXIO);
705 	}
706 
707 	/* IRQ DMA0 - DMA11 XXX NOT USE DMA12(spurious?) */
708 	for (rid = 0; rid < BCM_DMA_CH_MAX; rid++) {
709 		if ((bcm_dma_channel_mask & (1 << rid)) == 0)
710 			continue;
711 
712 		sc->sc_irq[rid] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
713 						       RF_ACTIVE);
714 		if (sc->sc_irq[rid] == NULL) {
715 			device_printf(dev, "cannot allocate interrupt\n");
716 			err = ENXIO;
717 			goto fail;
718 		}
719 		if (bus_setup_intr(dev, sc->sc_irq[rid], INTR_TYPE_MISC | INTR_MPSAFE,
720 				   NULL, bcm_dma_intr, &sc->sc_dma_ch[rid],
721 				   &sc->sc_intrhand[rid])) {
722 			device_printf(dev, "cannot setup interrupt handler\n");
723 			err = ENXIO;
724 			goto fail;
725 		}
726 	}
727 
728 	mtx_init(&sc->sc_mtx, "bcmdma", "bcmdma", MTX_DEF);
729 	bcm_dma_sc = sc;
730 
731 	err = bcm_dma_init(dev);
732 	if (err)
733 		goto fail;
734 
735 	return (err);
736 
737 fail:
738 	if (sc->sc_mem)
739 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem);
740 
741 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
742 		if (sc->sc_intrhand[i])
743 			bus_teardown_intr(dev, sc->sc_irq[i], sc->sc_intrhand[i]);
744 		if (sc->sc_irq[i])
745 			bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq[i]);
746 	}
747 
748 	return (err);
749 }
750 
751 static device_method_t bcm_dma_methods[] = {
752 	DEVMETHOD(device_probe,		bcm_dma_probe),
753 	DEVMETHOD(device_attach,	bcm_dma_attach),
754 	{ 0, 0 }
755 };
756 
757 static driver_t bcm_dma_driver = {
758 	"bcm_dma",
759 	bcm_dma_methods,
760 	sizeof(struct bcm_dma_softc),
761 };
762 
763 static devclass_t bcm_dma_devclass;
764 
765 DRIVER_MODULE(bcm_dma, simplebus, bcm_dma_driver, bcm_dma_devclass, 0, 0);
766 MODULE_VERSION(bcm_dma, 1);
767