xref: /freebsd/sys/arm/broadcom/bcm2835/bcm2835_dma.c (revision 3494f7c0)
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/param.h>
31 #include <sys/systm.h>
32 #include <sys/bus.h>
33 #include <sys/kernel.h>
34 #include <sys/lock.h>
35 #include <sys/malloc.h>
36 #include <sys/module.h>
37 #include <sys/mutex.h>
38 #include <sys/queue.h>
39 #include <sys/resource.h>
40 #include <sys/rman.h>
41 
42 #include <dev/ofw/openfirm.h>
43 #include <dev/ofw/ofw_bus.h>
44 #include <dev/ofw/ofw_bus_subr.h>
45 
46 #include <vm/vm.h>
47 #include <vm/pmap.h>
48 #include <machine/bus.h>
49 
50 #include "bcm2835_dma.h"
51 #include "bcm2835_vcbus.h"
52 
53 #define	MAX_REG			9
54 
55 /* private flags */
56 #define	BCM_DMA_CH_USED		0x00000001
57 #define	BCM_DMA_CH_FREE		0x40000000
58 #define	BCM_DMA_CH_UNMAP	0x80000000
59 
60 /* Register Map (4.2.1.2) */
61 #define	BCM_DMA_CS(n)		(0x100*(n) + 0x00)
62 #define		CS_ACTIVE		(1 <<  0)
63 #define		CS_END			(1 <<  1)
64 #define		CS_INT			(1 <<  2)
65 #define		CS_DREQ			(1 <<  3)
66 #define		CS_ISPAUSED		(1 <<  4)
67 #define		CS_ISHELD		(1 <<  5)
68 #define		CS_ISWAIT		(1 <<  6)
69 #define		CS_ERR			(1 <<  8)
70 #define		CS_WAITWRT		(1 << 28)
71 #define		CS_DISDBG		(1 << 29)
72 #define		CS_ABORT		(1 << 30)
73 #define		CS_RESET		(1U << 31)
74 #define	BCM_DMA_CBADDR(n)	(0x100*(n) + 0x04)
75 #define	BCM_DMA_INFO(n)		(0x100*(n) + 0x08)
76 #define		INFO_INT_EN		(1 << 0)
77 #define		INFO_TDMODE		(1 << 1)
78 #define		INFO_WAIT_RESP		(1 << 3)
79 #define		INFO_D_INC		(1 << 4)
80 #define		INFO_D_WIDTH		(1 << 5)
81 #define		INFO_D_DREQ		(1 << 6)
82 #define		INFO_S_INC		(1 << 8)
83 #define		INFO_S_WIDTH		(1 << 9)
84 #define		INFO_S_DREQ		(1 << 10)
85 #define		INFO_WAITS_SHIFT	(21)
86 #define		INFO_PERMAP_SHIFT	(16)
87 #define		INFO_PERMAP_MASK	(0x1f << INFO_PERMAP_SHIFT)
88 
89 #define	BCM_DMA_SRC(n)		(0x100*(n) + 0x0C)
90 #define	BCM_DMA_DST(n)		(0x100*(n) + 0x10)
91 #define	BCM_DMA_LEN(n)		(0x100*(n) + 0x14)
92 #define	BCM_DMA_STRIDE(n)	(0x100*(n) + 0x18)
93 #define	BCM_DMA_CBNEXT(n)	(0x100*(n) + 0x1C)
94 #define	BCM_DMA_DEBUG(n)	(0x100*(n) + 0x20)
95 #define		DEBUG_ERROR_MASK	(7)
96 
97 #define	BCM_DMA_INT_STATUS	0xfe0
98 #define	BCM_DMA_ENABLE		0xff0
99 
100 /* relative offset from BCM_VC_DMA0_BASE (p.39) */
101 #define	BCM_DMA_CH(n)		(0x100*(n))
102 
103 /* channels used by GPU */
104 #define	BCM_DMA_CH_BULK		0
105 #define	BCM_DMA_CH_FAST1	2
106 #define	BCM_DMA_CH_FAST2	3
107 
108 #define	BCM_DMA_CH_GPU_MASK	((1 << BCM_DMA_CH_BULK) |	\
109 				 (1 << BCM_DMA_CH_FAST1) |	\
110 				 (1 << BCM_DMA_CH_FAST2))
111 
112 /* DMA Control Block - 256bit aligned (p.40) */
113 struct bcm_dma_cb {
114 	uint32_t info;		/* Transfer Information */
115 	uint32_t src;		/* Source Address */
116 	uint32_t dst;		/* Destination Address */
117 	uint32_t len;		/* Transfer Length */
118 	uint32_t stride;	/* 2D Mode Stride */
119 	uint32_t next;		/* Next Control Block Address */
120 	uint32_t rsvd1;		/* Reserved */
121 	uint32_t rsvd2;		/* Reserved */
122 };
123 
124 #ifdef DEBUG
125 static void bcm_dma_cb_dump(struct bcm_dma_cb *cb);
126 static void bcm_dma_reg_dump(int ch);
127 #endif
128 
129 /* DMA channel private info */
130 struct bcm_dma_ch {
131 	int			ch;
132 	uint32_t		flags;
133 	struct bcm_dma_cb *	cb;
134 	uint32_t		vc_cb;
135 	bus_dmamap_t		dma_map;
136 	void 			(*intr_func)(int, void *);
137 	void *			intr_arg;
138 };
139 
140 struct bcm_dma_softc {
141 	device_t		sc_dev;
142 	struct mtx		sc_mtx;
143 	struct resource *	sc_mem;
144 	struct resource *	sc_irq[BCM_DMA_CH_MAX];
145 	void *			sc_intrhand[BCM_DMA_CH_MAX];
146 	struct bcm_dma_ch	sc_dma_ch[BCM_DMA_CH_MAX];
147 	bus_dma_tag_t		sc_dma_tag;
148 };
149 
150 static struct bcm_dma_softc *bcm_dma_sc = NULL;
151 static uint32_t bcm_dma_channel_mask;
152 
153 static struct ofw_compat_data compat_data[] = {
154 	{"broadcom,bcm2835-dma",	1},
155 	{"brcm,bcm2835-dma",		1},
156 	{NULL,				0}
157 };
158 
159 static void
160 bcm_dmamap_cb(void *arg, bus_dma_segment_t *segs,
161 	int nseg, int err)
162 {
163         bus_addr_t *addr;
164 
165         if (err)
166                 return;
167 
168         addr = (bus_addr_t*)arg;
169         *addr = ARMC_TO_VCBUS(segs[0].ds_addr);
170 }
171 
172 static void
173 bcm_dma_reset(device_t dev, int ch)
174 {
175 	struct bcm_dma_softc *sc = device_get_softc(dev);
176 	struct bcm_dma_cb *cb;
177 	uint32_t cs;
178 	int count;
179 
180 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
181 		return;
182 
183 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch));
184 
185 	if (cs & CS_ACTIVE) {
186 		/* pause current task */
187 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), 0);
188 
189 		count = 1000;
190 		do {
191 			cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch));
192 		} while (!(cs & CS_ISPAUSED) && (count-- > 0));
193 
194 		if (!(cs & CS_ISPAUSED)) {
195 			device_printf(dev,
196 			    "Can't abort DMA transfer at channel %d\n", ch);
197 		}
198 
199 		bus_write_4(sc->sc_mem, BCM_DMA_CBNEXT(ch), 0);
200 
201 		/* Complete everything, clear interrupt */
202 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch),
203 		    CS_ABORT | CS_INT | CS_END| CS_ACTIVE);
204 	}
205 
206 	/* clear control blocks */
207 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch), 0);
208 	bus_write_4(sc->sc_mem, BCM_DMA_CBNEXT(ch), 0);
209 
210 	/* Reset control block */
211 	cb = sc->sc_dma_ch[ch].cb;
212 	bzero(cb, sizeof(*cb));
213 	cb->info = INFO_WAIT_RESP;
214 }
215 
216 static int
217 bcm_dma_init(device_t dev)
218 {
219 	struct bcm_dma_softc *sc = device_get_softc(dev);
220 	uint32_t reg;
221 	struct bcm_dma_ch *ch;
222 	void *cb_virt;
223 	vm_paddr_t cb_phys;
224 	int err;
225 	int i;
226 
227 	/*
228 	 * Only channels set in bcm_dma_channel_mask can be controlled by us.
229 	 * The others are out of our control as well as the corresponding bits
230 	 * in both BCM_DMA_ENABLE and BCM_DMA_INT_STATUS global registers. As
231 	 * these registers are RW ones, there is no safe way how to write only
232 	 * the bits which can be controlled by us.
233 	 *
234 	 * Fortunately, after reset, all channels are enabled in BCM_DMA_ENABLE
235 	 * register and all statuses are cleared in BCM_DMA_INT_STATUS one.
236 	 * Not touching these registers is a trade off between correct
237 	 * initialization which does not count on anything and not messing up
238 	 * something we have no control over.
239 	 */
240 	reg = bus_read_4(sc->sc_mem, BCM_DMA_ENABLE);
241 	if ((reg & bcm_dma_channel_mask) != bcm_dma_channel_mask)
242 		device_printf(dev, "channels are not enabled\n");
243 	reg = bus_read_4(sc->sc_mem, BCM_DMA_INT_STATUS);
244 	if ((reg & bcm_dma_channel_mask) != 0)
245 		device_printf(dev, "statuses are not cleared\n");
246 
247 	/*
248 	 * Allocate DMA chunks control blocks based on p.40 of the peripheral
249 	 * spec - control block should be 32-bit aligned.  The DMA controller
250 	 * has a full 32-bit register dedicated to this address, so we do not
251 	 * need to bother with the per-SoC peripheral restrictions.
252 	 */
253 	err = bus_dma_tag_create(bus_get_dma_tag(dev),
254 	    1, 0, BUS_SPACE_MAXADDR_32BIT,
255 	    BUS_SPACE_MAXADDR, NULL, NULL,
256 	    sizeof(struct bcm_dma_cb), 1,
257 	    sizeof(struct bcm_dma_cb),
258 	    BUS_DMA_ALLOCNOW, NULL, NULL,
259 	    &sc->sc_dma_tag);
260 
261 	if (err) {
262 		device_printf(dev, "failed allocate DMA tag\n");
263 		return (err);
264 	}
265 
266 	/* setup initial settings */
267 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
268 		ch = &sc->sc_dma_ch[i];
269 
270 		bzero(ch, sizeof(struct bcm_dma_ch));
271 		ch->ch = i;
272 		ch->flags = BCM_DMA_CH_UNMAP;
273 
274 		if ((bcm_dma_channel_mask & (1 << i)) == 0)
275 			continue;
276 
277 		err = bus_dmamem_alloc(sc->sc_dma_tag, &cb_virt,
278 		    BUS_DMA_WAITOK | BUS_DMA_COHERENT | BUS_DMA_ZERO,
279 		    &ch->dma_map);
280 		if (err) {
281 			device_printf(dev, "cannot allocate DMA memory\n");
282 			break;
283 		}
284 
285 		/*
286 		 * Least alignment for busdma-allocated stuff is cache
287 		 * line size, so just make sure nothing stupid happened
288 		 * and we got properly aligned address
289 		 */
290 		if ((uintptr_t)cb_virt & 0x1f) {
291 			device_printf(dev,
292 			    "DMA address is not 32-bytes aligned: %p\n",
293 			    (void*)cb_virt);
294 			break;
295 		}
296 
297 		err = bus_dmamap_load(sc->sc_dma_tag, ch->dma_map, cb_virt,
298 		    sizeof(struct bcm_dma_cb), bcm_dmamap_cb, &cb_phys,
299 		    BUS_DMA_WAITOK);
300 		if (err) {
301 			device_printf(dev, "cannot load DMA memory\n");
302 			break;
303 		}
304 
305 		ch->cb = cb_virt;
306 		ch->vc_cb = cb_phys;
307 		ch->flags = BCM_DMA_CH_FREE;
308 		ch->cb->info = INFO_WAIT_RESP;
309 
310 		/* reset DMA engine */
311 		bus_write_4(sc->sc_mem, BCM_DMA_CS(i), CS_RESET);
312 	}
313 
314 	return (0);
315 }
316 
317 /*
318  * Allocate DMA channel for further use, returns channel # or
319  *     BCM_DMA_CH_INVALID
320  */
321 int
322 bcm_dma_allocate(int req_ch)
323 {
324 	struct bcm_dma_softc *sc = bcm_dma_sc;
325 	int ch = BCM_DMA_CH_INVALID;
326 	int i;
327 
328 	if (sc == NULL)
329 		return (BCM_DMA_CH_INVALID);
330 
331 	if (req_ch >= BCM_DMA_CH_MAX)
332 		return (BCM_DMA_CH_INVALID);
333 
334 	/* Auto(req_ch < 0) or CH specified */
335 	mtx_lock(&sc->sc_mtx);
336 
337 	if (req_ch < 0) {
338 		for (i = 0; i < BCM_DMA_CH_MAX; i++) {
339 			if (sc->sc_dma_ch[i].flags & BCM_DMA_CH_FREE) {
340 				ch = i;
341 				sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
342 				sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
343 				break;
344 			}
345 		}
346 	} else if (sc->sc_dma_ch[req_ch].flags & BCM_DMA_CH_FREE) {
347 		ch = req_ch;
348 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_FREE;
349 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_USED;
350 	}
351 
352 	mtx_unlock(&sc->sc_mtx);
353 	return (ch);
354 }
355 
356 /*
357  * Frees allocated channel. Returns 0 on success, -1 otherwise
358  */
359 int
360 bcm_dma_free(int ch)
361 {
362 	struct bcm_dma_softc *sc = bcm_dma_sc;
363 
364 	if (sc == NULL)
365 		return (-1);
366 
367 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
368 		return (-1);
369 
370 	mtx_lock(&sc->sc_mtx);
371 	if (sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED) {
372 		sc->sc_dma_ch[ch].flags |= BCM_DMA_CH_FREE;
373 		sc->sc_dma_ch[ch].flags &= ~BCM_DMA_CH_USED;
374 		sc->sc_dma_ch[ch].intr_func = NULL;
375 		sc->sc_dma_ch[ch].intr_arg = NULL;
376 
377 		/* reset DMA engine */
378 		bcm_dma_reset(sc->sc_dev, ch);
379 	}
380 
381 	mtx_unlock(&sc->sc_mtx);
382 	return (0);
383 }
384 
385 /*
386  * Assign handler function for channel interrupt
387  * Returns 0 on success, -1 otherwise
388  */
389 int
390 bcm_dma_setup_intr(int ch, void (*func)(int, void *), void *arg)
391 {
392 	struct bcm_dma_softc *sc = bcm_dma_sc;
393 	struct bcm_dma_cb *cb;
394 
395 	if (sc == NULL)
396 		return (-1);
397 
398 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
399 		return (-1);
400 
401 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
402 		return (-1);
403 
404 	sc->sc_dma_ch[ch].intr_func = func;
405 	sc->sc_dma_ch[ch].intr_arg = arg;
406 	cb = sc->sc_dma_ch[ch].cb;
407 	cb->info |= INFO_INT_EN;
408 
409 	return (0);
410 }
411 
412 /*
413  * Setup DMA source parameters
414  *     ch - channel number
415  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
416  *         source is physical memory
417  *     inc_addr - BCM_DMA_INC_ADDR if source address
418  *         should be increased after each access or
419  *         BCM_DMA_SAME_ADDR if address should remain
420  *         the same
421  *     width - size of read operation, BCM_DMA_32BIT
422  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
423  *
424  * Returns 0 on success, -1 otherwise
425  */
426 int
427 bcm_dma_setup_src(int ch, int dreq, int inc_addr, int width)
428 {
429 	struct bcm_dma_softc *sc = bcm_dma_sc;
430 	uint32_t info;
431 
432 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
433 		return (-1);
434 
435 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
436 		return (-1);
437 
438 	info = sc->sc_dma_ch[ch].cb->info;
439 	info &= ~INFO_PERMAP_MASK;
440 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
441 
442 	if (dreq)
443 		info |= INFO_S_DREQ;
444 	else
445 		info &= ~INFO_S_DREQ;
446 
447 	if (width == BCM_DMA_128BIT)
448 		info |= INFO_S_WIDTH;
449 	else
450 		info &= ~INFO_S_WIDTH;
451 
452 	if (inc_addr == BCM_DMA_INC_ADDR)
453 		info |= INFO_S_INC;
454 	else
455 		info &= ~INFO_S_INC;
456 
457 	sc->sc_dma_ch[ch].cb->info = info;
458 
459 	return (0);
460 }
461 
462 /*
463  * Setup DMA destination parameters
464  *     ch - channel number
465  *     dreq - hardware DREQ # or BCM_DMA_DREQ_NONE if
466  *         destination is physical memory
467  *     inc_addr - BCM_DMA_INC_ADDR if source address
468  *         should be increased after each access or
469  *         BCM_DMA_SAME_ADDR if address should remain
470  *         the same
471  *     width - size of write operation, BCM_DMA_32BIT
472  *         for 32bit bursts, BCM_DMA_128BIT for 128 bits
473  *
474  * Returns 0 on success, -1 otherwise
475  */
476 int
477 bcm_dma_setup_dst(int ch, int dreq, int inc_addr, int width)
478 {
479 	struct bcm_dma_softc *sc = bcm_dma_sc;
480 	uint32_t info;
481 
482 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
483 		return (-1);
484 
485 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
486 		return (-1);
487 
488 	info = sc->sc_dma_ch[ch].cb->info;
489 	info &= ~INFO_PERMAP_MASK;
490 	info |= (dreq << INFO_PERMAP_SHIFT) & INFO_PERMAP_MASK;
491 
492 	if (dreq)
493 		info |= INFO_D_DREQ;
494 	else
495 		info &= ~INFO_D_DREQ;
496 
497 	if (width == BCM_DMA_128BIT)
498 		info |= INFO_D_WIDTH;
499 	else
500 		info &= ~INFO_D_WIDTH;
501 
502 	if (inc_addr == BCM_DMA_INC_ADDR)
503 		info |= INFO_D_INC;
504 	else
505 		info &= ~INFO_D_INC;
506 
507 	sc->sc_dma_ch[ch].cb->info = info;
508 
509 	return (0);
510 }
511 
512 #ifdef DEBUG
513 void
514 bcm_dma_cb_dump(struct bcm_dma_cb *cb)
515 {
516 
517 	printf("DMA CB ");
518 	printf("INFO: %8.8x ", cb->info);
519 	printf("SRC: %8.8x ", cb->src);
520 	printf("DST: %8.8x ", cb->dst);
521 	printf("LEN: %8.8x ", cb->len);
522 	printf("\n");
523 	printf("STRIDE: %8.8x ", cb->stride);
524 	printf("NEXT: %8.8x ", cb->next);
525 	printf("RSVD1: %8.8x ", cb->rsvd1);
526 	printf("RSVD2: %8.8x ", cb->rsvd2);
527 	printf("\n");
528 }
529 
530 void
531 bcm_dma_reg_dump(int ch)
532 {
533 	struct bcm_dma_softc *sc = bcm_dma_sc;
534 	int i;
535 	uint32_t reg;
536 
537 	if (sc == NULL)
538 		return;
539 
540 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
541 		return;
542 
543 	printf("DMA%d: ", ch);
544 	for (i = 0; i < MAX_REG; i++) {
545 		reg = bus_read_4(sc->sc_mem, BCM_DMA_CH(ch) + i*4);
546 		printf("%8.8x ", reg);
547 	}
548 	printf("\n");
549 }
550 #endif
551 
552 /*
553  * Start DMA transaction
554  *     ch - channel number
555  *     src, dst - source and destination address in
556  *         ARM physical memory address space.
557  *     len - amount of bytes to be transferred
558  *
559  * Returns 0 on success, -1 otherwise
560  */
561 int
562 bcm_dma_start(int ch, vm_paddr_t src, vm_paddr_t dst, int len)
563 {
564 	struct bcm_dma_softc *sc = bcm_dma_sc;
565 	struct bcm_dma_cb *cb;
566 
567 	if (sc == NULL)
568 		return (-1);
569 
570 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
571 		return (-1);
572 
573 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
574 		return (-1);
575 
576 	cb = sc->sc_dma_ch[ch].cb;
577 	cb->src = ARMC_TO_VCBUS(src);
578 	cb->dst = ARMC_TO_VCBUS(dst);
579 
580 	cb->len = len;
581 
582 	bus_dmamap_sync(sc->sc_dma_tag,
583 	    sc->sc_dma_ch[ch].dma_map, BUS_DMASYNC_PREWRITE);
584 
585 	bus_write_4(sc->sc_mem, BCM_DMA_CBADDR(ch),
586 	    sc->sc_dma_ch[ch].vc_cb);
587 	bus_write_4(sc->sc_mem, BCM_DMA_CS(ch), CS_ACTIVE);
588 
589 #ifdef DEBUG
590 	bcm_dma_cb_dump(sc->sc_dma_ch[ch].cb);
591 	bcm_dma_reg_dump(ch);
592 #endif
593 
594 	return (0);
595 }
596 
597 /*
598  * Get length requested for DMA transaction
599  *     ch - channel number
600  *
601  * Returns size of transaction, 0 if channel is invalid
602  */
603 uint32_t
604 bcm_dma_length(int ch)
605 {
606 	struct bcm_dma_softc *sc = bcm_dma_sc;
607 	struct bcm_dma_cb *cb;
608 
609 	if (sc == NULL)
610 		return (0);
611 
612 	if (ch < 0 || ch >= BCM_DMA_CH_MAX)
613 		return (0);
614 
615 	if (!(sc->sc_dma_ch[ch].flags & BCM_DMA_CH_USED))
616 		return (0);
617 
618 	cb = sc->sc_dma_ch[ch].cb;
619 
620 	return (cb->len);
621 }
622 
623 static void
624 bcm_dma_intr(void *arg)
625 {
626 	struct bcm_dma_softc *sc = bcm_dma_sc;
627 	struct bcm_dma_ch *ch = (struct bcm_dma_ch *)arg;
628 	uint32_t cs, debug;
629 
630 	/* my interrupt? */
631 	cs = bus_read_4(sc->sc_mem, BCM_DMA_CS(ch->ch));
632 
633 	/*
634 	 * Is it an active channel?  Our diagnostics could be better here, but
635 	 * it's not necessarily an easy task to resolve a rid/resource to an
636 	 * actual irq number.  We'd want to do this to set a flag indicating
637 	 * whether the irq is shared or not, so we know to complain.
638 	 */
639 	if (!(ch->flags & BCM_DMA_CH_USED))
640 		return;
641 
642 	/* Again, we can't complain here.  The same logic applies. */
643 	if (!(cs & (CS_INT | CS_ERR)))
644 		return;
645 
646 	if (cs & CS_ERR) {
647 		debug = bus_read_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch));
648 		device_printf(sc->sc_dev, "DMA error %d on CH%d\n",
649 			debug & DEBUG_ERROR_MASK, ch->ch);
650 		bus_write_4(sc->sc_mem, BCM_DMA_DEBUG(ch->ch),
651 		    debug & DEBUG_ERROR_MASK);
652 		bcm_dma_reset(sc->sc_dev, ch->ch);
653 	}
654 
655 	if (cs & CS_INT) {
656 		/* acknowledge interrupt */
657 		bus_write_4(sc->sc_mem, BCM_DMA_CS(ch->ch),
658 		    CS_INT | CS_END);
659 
660 		/* Prepare for possible access to len field */
661 		bus_dmamap_sync(sc->sc_dma_tag, ch->dma_map,
662 		    BUS_DMASYNC_POSTWRITE);
663 
664 		/* save callback function and argument */
665 		if (ch->intr_func)
666 			ch->intr_func(ch->ch, ch->intr_arg);
667 	}
668 }
669 
670 static int
671 bcm_dma_probe(device_t dev)
672 {
673 
674 	if (!ofw_bus_status_okay(dev))
675 		return (ENXIO);
676 
677 	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
678 		return (ENXIO);
679 
680 	device_set_desc(dev, "BCM2835 DMA Controller");
681 	return (BUS_PROBE_DEFAULT);
682 }
683 
684 static int
685 bcm_dma_attach(device_t dev)
686 {
687 	struct bcm_dma_softc *sc = device_get_softc(dev);
688 	phandle_t node;
689 	int rid, err = 0;
690 	int i;
691 
692 	sc->sc_dev = dev;
693 
694 	if (bcm_dma_sc)
695 		return (ENXIO);
696 
697 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
698 		sc->sc_irq[i] = NULL;
699 		sc->sc_intrhand[i] = NULL;
700 	}
701 
702 	/* Get DMA channel mask. */
703 	node = ofw_bus_get_node(sc->sc_dev);
704 	if (OF_getencprop(node, "brcm,dma-channel-mask", &bcm_dma_channel_mask,
705 	    sizeof(bcm_dma_channel_mask)) == -1 &&
706 	    OF_getencprop(node, "broadcom,channels", &bcm_dma_channel_mask,
707 	    sizeof(bcm_dma_channel_mask)) == -1) {
708 		device_printf(dev, "could not get channel mask property\n");
709 		return (ENXIO);
710 	}
711 
712 	/* Mask out channels used by GPU. */
713 	bcm_dma_channel_mask &= ~BCM_DMA_CH_GPU_MASK;
714 
715 	/* DMA0 - DMA14 */
716 	rid = 0;
717 	sc->sc_mem = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
718 	if (sc->sc_mem == NULL) {
719 		device_printf(dev, "could not allocate memory resource\n");
720 		return (ENXIO);
721 	}
722 
723 	/* IRQ DMA0 - DMA11 XXX NOT USE DMA12(spurious?) */
724 	for (rid = 0; rid < BCM_DMA_CH_MAX; rid++) {
725 		if ((bcm_dma_channel_mask & (1 << rid)) == 0)
726 			continue;
727 
728 		sc->sc_irq[rid] = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
729 		    RF_ACTIVE | RF_SHAREABLE);
730 		if (sc->sc_irq[rid] == NULL) {
731 			device_printf(dev, "cannot allocate interrupt\n");
732 			err = ENXIO;
733 			goto fail;
734 		}
735 		if (bus_setup_intr(dev, sc->sc_irq[rid], INTR_TYPE_MISC | INTR_MPSAFE,
736 				   NULL, bcm_dma_intr, &sc->sc_dma_ch[rid],
737 				   &sc->sc_intrhand[rid])) {
738 			device_printf(dev, "cannot setup interrupt handler\n");
739 			err = ENXIO;
740 			goto fail;
741 		}
742 	}
743 
744 	mtx_init(&sc->sc_mtx, "bcmdma", "bcmdma", MTX_DEF);
745 	bcm_dma_sc = sc;
746 
747 	err = bcm_dma_init(dev);
748 	if (err)
749 		goto fail;
750 
751 	return (err);
752 
753 fail:
754 	if (sc->sc_mem)
755 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem);
756 
757 	for (i = 0; i < BCM_DMA_CH_MAX; i++) {
758 		if (sc->sc_intrhand[i])
759 			bus_teardown_intr(dev, sc->sc_irq[i], sc->sc_intrhand[i]);
760 		if (sc->sc_irq[i])
761 			bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq[i]);
762 	}
763 
764 	return (err);
765 }
766 
767 static device_method_t bcm_dma_methods[] = {
768 	DEVMETHOD(device_probe,		bcm_dma_probe),
769 	DEVMETHOD(device_attach,	bcm_dma_attach),
770 	{ 0, 0 }
771 };
772 
773 static driver_t bcm_dma_driver = {
774 	"bcm_dma",
775 	bcm_dma_methods,
776 	sizeof(struct bcm_dma_softc),
777 };
778 
779 EARLY_DRIVER_MODULE(bcm_dma, simplebus, bcm_dma_driver, 0, 0,
780     BUS_PASS_SUPPORTDEV + BUS_PASS_ORDER_MIDDLE);
781 MODULE_VERSION(bcm_dma, 1);
782