1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
5  * All rights reserved.
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 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/bus.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/malloc.h>
38 #include <sys/module.h>
39 #include <sys/mutex.h>
40 #include <sys/rman.h>
41 #include <sys/sysctl.h>
42 #include <sys/taskqueue.h>
43 
44 #include <machine/bus.h>
45 
46 #include <dev/ofw/ofw_bus.h>
47 #include <dev/ofw/ofw_bus_subr.h>
48 
49 #include <dev/mmc/bridge.h>
50 #include <dev/mmc/mmcreg.h>
51 
52 #include <dev/sdhci/sdhci.h>
53 
54 #include "mmcbr_if.h"
55 #include "sdhci_if.h"
56 
57 #include "opt_mmccam.h"
58 
59 #include "bcm2835_dma.h"
60 #include <arm/broadcom/bcm2835/bcm2835_mbox_prop.h>
61 #include "bcm2835_vcbus.h"
62 
63 #define	BCM2835_DEFAULT_SDHCI_FREQ	50
64 
65 #define	BCM_SDHCI_BUFFER_SIZE		512
66 #define	NUM_DMA_SEGS			2
67 
68 #ifdef DEBUG
69 #define dprintf(fmt, args...) do { printf("%s(): ", __func__);   \
70     printf(fmt,##args); } while (0)
71 #else
72 #define dprintf(fmt, args...)
73 #endif
74 
75 static int bcm2835_sdhci_hs = 1;
76 static int bcm2835_sdhci_pio_mode = 0;
77 
78 static struct ofw_compat_data compat_data[] = {
79 	{"broadcom,bcm2835-sdhci",	1},
80 	{"brcm,bcm2835-sdhci",		1},
81 	{"brcm,bcm2835-mmc",		1},
82 	{NULL,				0}
83 };
84 
85 TUNABLE_INT("hw.bcm2835.sdhci.hs", &bcm2835_sdhci_hs);
86 TUNABLE_INT("hw.bcm2835.sdhci.pio_mode", &bcm2835_sdhci_pio_mode);
87 
88 struct bcm_sdhci_softc {
89 	device_t		sc_dev;
90 	struct resource *	sc_mem_res;
91 	struct resource *	sc_irq_res;
92 	bus_space_tag_t		sc_bst;
93 	bus_space_handle_t	sc_bsh;
94 	void *			sc_intrhand;
95 	struct mmc_request *	sc_req;
96 	struct sdhci_slot	sc_slot;
97 	int			sc_dma_ch;
98 	bus_dma_tag_t		sc_dma_tag;
99 	bus_dmamap_t		sc_dma_map;
100 	vm_paddr_t		sc_sdhci_buffer_phys;
101 	uint32_t		cmd_and_mode;
102 	bus_addr_t		dmamap_seg_addrs[NUM_DMA_SEGS];
103 	bus_size_t		dmamap_seg_sizes[NUM_DMA_SEGS];
104 	int			dmamap_seg_count;
105 	int			dmamap_seg_index;
106 	int			dmamap_status;
107 };
108 
109 static int bcm_sdhci_probe(device_t);
110 static int bcm_sdhci_attach(device_t);
111 static int bcm_sdhci_detach(device_t);
112 static void bcm_sdhci_intr(void *);
113 
114 static int bcm_sdhci_get_ro(device_t, device_t);
115 static void bcm_sdhci_dma_intr(int ch, void *arg);
116 
117 static void
118 bcm_sdhci_dmacb(void *arg, bus_dma_segment_t *segs, int nseg, int err)
119 {
120 	struct bcm_sdhci_softc *sc = arg;
121 	int i;
122 
123 	sc->dmamap_status = err;
124 	sc->dmamap_seg_count = nseg;
125 
126 	/* Note nseg is guaranteed to be zero if err is non-zero. */
127 	for (i = 0; i < nseg; i++) {
128 		sc->dmamap_seg_addrs[i] = segs[i].ds_addr;
129 		sc->dmamap_seg_sizes[i] = segs[i].ds_len;
130 	}
131 }
132 
133 static int
134 bcm_sdhci_probe(device_t dev)
135 {
136 
137 	if (!ofw_bus_status_okay(dev))
138 		return (ENXIO);
139 
140 	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
141 		return (ENXIO);
142 
143 	device_set_desc(dev, "Broadcom 2708 SDHCI controller");
144 
145 	return (BUS_PROBE_DEFAULT);
146 }
147 
148 static int
149 bcm_sdhci_attach(device_t dev)
150 {
151 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
152 	int rid, err;
153 	phandle_t node;
154 	pcell_t cell;
155 	u_int default_freq;
156 
157 	sc->sc_dev = dev;
158 	sc->sc_req = NULL;
159 
160 	err = bcm2835_mbox_set_power_state(BCM2835_MBOX_POWER_ID_EMMC,
161 	    TRUE);
162 	if (err != 0) {
163 		if (bootverbose)
164 			device_printf(dev, "Unable to enable the power\n");
165 		return (err);
166 	}
167 
168 	default_freq = 0;
169 	err = bcm2835_mbox_get_clock_rate(BCM2835_MBOX_CLOCK_ID_EMMC,
170 	    &default_freq);
171 	if (err == 0) {
172 		/* Convert to MHz */
173 		default_freq /= 1000000;
174 	}
175 	if (default_freq == 0) {
176 		node = ofw_bus_get_node(sc->sc_dev);
177 		if ((OF_getencprop(node, "clock-frequency", &cell,
178 		    sizeof(cell))) > 0)
179 			default_freq = cell / 1000000;
180 	}
181 	if (default_freq == 0)
182 		default_freq = BCM2835_DEFAULT_SDHCI_FREQ;
183 
184 	if (bootverbose)
185 		device_printf(dev, "SDHCI frequency: %dMHz\n", default_freq);
186 
187 	rid = 0;
188 	sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
189 	    RF_ACTIVE);
190 	if (!sc->sc_mem_res) {
191 		device_printf(dev, "cannot allocate memory window\n");
192 		err = ENXIO;
193 		goto fail;
194 	}
195 
196 	sc->sc_bst = rman_get_bustag(sc->sc_mem_res);
197 	sc->sc_bsh = rman_get_bushandle(sc->sc_mem_res);
198 
199 	rid = 0;
200 	sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
201 	    RF_ACTIVE);
202 	if (!sc->sc_irq_res) {
203 		device_printf(dev, "cannot allocate interrupt\n");
204 		err = ENXIO;
205 		goto fail;
206 	}
207 
208 	if (bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_BIO | INTR_MPSAFE,
209 	    NULL, bcm_sdhci_intr, sc, &sc->sc_intrhand)) {
210 		device_printf(dev, "cannot setup interrupt handler\n");
211 		err = ENXIO;
212 		goto fail;
213 	}
214 
215 	if (!bcm2835_sdhci_pio_mode)
216 		sc->sc_slot.opt = SDHCI_PLATFORM_TRANSFER;
217 
218 	sc->sc_slot.caps = SDHCI_CAN_VDD_330 | SDHCI_CAN_VDD_180;
219 	if (bcm2835_sdhci_hs)
220 		sc->sc_slot.caps |= SDHCI_CAN_DO_HISPD;
221 	sc->sc_slot.caps |= (default_freq << SDHCI_CLOCK_BASE_SHIFT);
222 	sc->sc_slot.quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK
223 		| SDHCI_QUIRK_BROKEN_TIMEOUT_VAL
224 		| SDHCI_QUIRK_DONT_SET_HISPD_BIT
225 		| SDHCI_QUIRK_MISSING_CAPS;
226 
227 	sdhci_init_slot(dev, &sc->sc_slot, 0);
228 
229 	sc->sc_dma_ch = bcm_dma_allocate(BCM_DMA_CH_ANY);
230 	if (sc->sc_dma_ch == BCM_DMA_CH_INVALID)
231 		goto fail;
232 
233 	bcm_dma_setup_intr(sc->sc_dma_ch, bcm_sdhci_dma_intr, sc);
234 
235 	/* Allocate bus_dma resources. */
236 	err = bus_dma_tag_create(bus_get_dma_tag(dev),
237 	    1, 0, BUS_SPACE_MAXADDR_32BIT,
238 	    BUS_SPACE_MAXADDR, NULL, NULL,
239 	    BCM_SDHCI_BUFFER_SIZE, NUM_DMA_SEGS, BCM_SDHCI_BUFFER_SIZE,
240 	    BUS_DMA_ALLOCNOW, NULL, NULL,
241 	    &sc->sc_dma_tag);
242 
243 	if (err) {
244 		device_printf(dev, "failed allocate DMA tag");
245 		goto fail;
246 	}
247 
248 	err = bus_dmamap_create(sc->sc_dma_tag, 0, &sc->sc_dma_map);
249 	if (err) {
250 		device_printf(dev, "bus_dmamap_create failed\n");
251 		goto fail;
252 	}
253 
254 	/* FIXME: Fix along with other BUS_SPACE_PHYSADDR instances */
255 	sc->sc_sdhci_buffer_phys = rman_get_start(sc->sc_mem_res) +
256 	    SDHCI_BUFFER;
257 
258 	bus_generic_probe(dev);
259 	bus_generic_attach(dev);
260 
261 	sdhci_start_slot(&sc->sc_slot);
262 
263 	return (0);
264 
265 fail:
266 	if (sc->sc_intrhand)
267 		bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intrhand);
268 	if (sc->sc_irq_res)
269 		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
270 	if (sc->sc_mem_res)
271 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
272 
273 	return (err);
274 }
275 
276 static int
277 bcm_sdhci_detach(device_t dev)
278 {
279 
280 	return (EBUSY);
281 }
282 
283 static void
284 bcm_sdhci_intr(void *arg)
285 {
286 	struct bcm_sdhci_softc *sc = arg;
287 
288 	sdhci_generic_intr(&sc->sc_slot);
289 }
290 
291 static int
292 bcm_sdhci_get_ro(device_t bus, device_t child)
293 {
294 
295 	return (0);
296 }
297 
298 static inline uint32_t
299 RD4(struct bcm_sdhci_softc *sc, bus_size_t off)
300 {
301 	uint32_t val = bus_space_read_4(sc->sc_bst, sc->sc_bsh, off);
302 	return val;
303 }
304 
305 static inline void
306 WR4(struct bcm_sdhci_softc *sc, bus_size_t off, uint32_t val)
307 {
308 
309 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, off, val);
310 	/*
311 	 * The Arasan HC has a bug where it may lose the content of
312 	 * consecutive writes to registers that are within two SD-card
313 	 * clock cycles of each other (a clock domain crossing problem).
314 	 */
315 	if (sc->sc_slot.clock > 0)
316 		DELAY(((2 * 1000000) / sc->sc_slot.clock) + 1);
317 }
318 
319 static uint8_t
320 bcm_sdhci_read_1(device_t dev, struct sdhci_slot *slot, bus_size_t off)
321 {
322 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
323 	uint32_t val = RD4(sc, off & ~3);
324 
325 	return ((val >> (off & 3)*8) & 0xff);
326 }
327 
328 static uint16_t
329 bcm_sdhci_read_2(device_t dev, struct sdhci_slot *slot, bus_size_t off)
330 {
331 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
332 	uint32_t val = RD4(sc, off & ~3);
333 
334 	/*
335 	 * Standard 32-bit handling of command and transfer mode.
336 	 */
337 	if (off == SDHCI_TRANSFER_MODE) {
338 		return (sc->cmd_and_mode >> 16);
339 	} else if (off == SDHCI_COMMAND_FLAGS) {
340 		return (sc->cmd_and_mode & 0x0000ffff);
341 	}
342 	return ((val >> (off & 3)*8) & 0xffff);
343 }
344 
345 static uint32_t
346 bcm_sdhci_read_4(device_t dev, struct sdhci_slot *slot, bus_size_t off)
347 {
348 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
349 
350 	return RD4(sc, off);
351 }
352 
353 static void
354 bcm_sdhci_read_multi_4(device_t dev, struct sdhci_slot *slot, bus_size_t off,
355     uint32_t *data, bus_size_t count)
356 {
357 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
358 
359 	bus_space_read_multi_4(sc->sc_bst, sc->sc_bsh, off, data, count);
360 }
361 
362 static void
363 bcm_sdhci_write_1(device_t dev, struct sdhci_slot *slot, bus_size_t off, uint8_t val)
364 {
365 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
366 	uint32_t val32 = RD4(sc, off & ~3);
367 	val32 &= ~(0xff << (off & 3)*8);
368 	val32 |= (val << (off & 3)*8);
369 	WR4(sc, off & ~3, val32);
370 }
371 
372 static void
373 bcm_sdhci_write_2(device_t dev, struct sdhci_slot *slot, bus_size_t off, uint16_t val)
374 {
375 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
376 	uint32_t val32;
377 	if (off == SDHCI_COMMAND_FLAGS)
378 		val32 = sc->cmd_and_mode;
379 	else
380 		val32 = RD4(sc, off & ~3);
381 	val32 &= ~(0xffff << (off & 3)*8);
382 	val32 |= (val << (off & 3)*8);
383 	if (off == SDHCI_TRANSFER_MODE)
384 		sc->cmd_and_mode = val32;
385 	else {
386 		WR4(sc, off & ~3, val32);
387 		if (off == SDHCI_COMMAND_FLAGS)
388 			sc->cmd_and_mode = val32;
389 	}
390 }
391 
392 static void
393 bcm_sdhci_write_4(device_t dev, struct sdhci_slot *slot, bus_size_t off, uint32_t val)
394 {
395 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
396 	WR4(sc, off, val);
397 }
398 
399 static void
400 bcm_sdhci_write_multi_4(device_t dev, struct sdhci_slot *slot, bus_size_t off,
401     uint32_t *data, bus_size_t count)
402 {
403 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
404 
405 	bus_space_write_multi_4(sc->sc_bst, sc->sc_bsh, off, data, count);
406 }
407 
408 static void
409 bcm_sdhci_start_dma_seg(struct bcm_sdhci_softc *sc)
410 {
411 	struct sdhci_slot *slot;
412 	vm_paddr_t pdst, psrc;
413 	int err, idx, len, sync_op;
414 
415 	slot = &sc->sc_slot;
416 	idx = sc->dmamap_seg_index++;
417 	len = sc->dmamap_seg_sizes[idx];
418 	slot->offset += len;
419 
420 	if (slot->curcmd->data->flags & MMC_DATA_READ) {
421 		bcm_dma_setup_src(sc->sc_dma_ch, BCM_DMA_DREQ_EMMC,
422 		    BCM_DMA_SAME_ADDR, BCM_DMA_32BIT);
423 		bcm_dma_setup_dst(sc->sc_dma_ch, BCM_DMA_DREQ_NONE,
424 		    BCM_DMA_INC_ADDR,
425 		    (len & 0xf) ? BCM_DMA_32BIT : BCM_DMA_128BIT);
426 		psrc = sc->sc_sdhci_buffer_phys;
427 		pdst = sc->dmamap_seg_addrs[idx];
428 		sync_op = BUS_DMASYNC_PREREAD;
429 	} else {
430 		bcm_dma_setup_src(sc->sc_dma_ch, BCM_DMA_DREQ_NONE,
431 		    BCM_DMA_INC_ADDR,
432 		    (len & 0xf) ? BCM_DMA_32BIT : BCM_DMA_128BIT);
433 		bcm_dma_setup_dst(sc->sc_dma_ch, BCM_DMA_DREQ_EMMC,
434 		    BCM_DMA_SAME_ADDR, BCM_DMA_32BIT);
435 		psrc = sc->dmamap_seg_addrs[idx];
436 		pdst = sc->sc_sdhci_buffer_phys;
437 		sync_op = BUS_DMASYNC_PREWRITE;
438 	}
439 
440 	/*
441 	 * When starting a new DMA operation do the busdma sync operation, and
442 	 * disable SDCHI data interrrupts because we'll be driven by DMA
443 	 * interrupts (or SDHCI error interrupts) until the IO is done.
444 	 */
445 	if (idx == 0) {
446 		bus_dmamap_sync(sc->sc_dma_tag, sc->sc_dma_map, sync_op);
447 		slot->intmask &= ~(SDHCI_INT_DATA_AVAIL |
448 		    SDHCI_INT_SPACE_AVAIL | SDHCI_INT_DATA_END);
449 		bcm_sdhci_write_4(sc->sc_dev, &sc->sc_slot, SDHCI_SIGNAL_ENABLE,
450 		    slot->intmask);
451 	}
452 
453 	/*
454 	 * Start the DMA transfer.  Only programming errors (like failing to
455 	 * allocate a channel) cause a non-zero return from bcm_dma_start().
456 	 */
457 	err = bcm_dma_start(sc->sc_dma_ch, psrc, pdst, len);
458 	KASSERT((err == 0), ("bcm2835_sdhci: failed DMA start"));
459 }
460 
461 static void
462 bcm_sdhci_dma_intr(int ch, void *arg)
463 {
464 	struct bcm_sdhci_softc *sc = (struct bcm_sdhci_softc *)arg;
465 	struct sdhci_slot *slot = &sc->sc_slot;
466 	uint32_t reg, mask;
467 	int left, sync_op;
468 
469 	mtx_lock(&slot->mtx);
470 
471 	/*
472 	 * If there are more segments for the current dma, start the next one.
473 	 * Otherwise unload the dma map and decide what to do next based on the
474 	 * status of the sdhci controller and whether there's more data left.
475 	 */
476 	if (sc->dmamap_seg_index < sc->dmamap_seg_count) {
477 		bcm_sdhci_start_dma_seg(sc);
478 		mtx_unlock(&slot->mtx);
479 		return;
480 	}
481 
482 	if (slot->curcmd->data->flags & MMC_DATA_READ) {
483 		sync_op = BUS_DMASYNC_POSTREAD;
484 		mask = SDHCI_INT_DATA_AVAIL;
485 	} else {
486 		sync_op = BUS_DMASYNC_POSTWRITE;
487 		mask = SDHCI_INT_SPACE_AVAIL;
488 	}
489 	bus_dmamap_sync(sc->sc_dma_tag, sc->sc_dma_map, sync_op);
490 	bus_dmamap_unload(sc->sc_dma_tag, sc->sc_dma_map);
491 
492 	sc->dmamap_seg_count = 0;
493 	sc->dmamap_seg_index = 0;
494 
495 	left = min(BCM_SDHCI_BUFFER_SIZE,
496 	    slot->curcmd->data->len - slot->offset);
497 
498 	/* DATA END? */
499 	reg = bcm_sdhci_read_4(slot->bus, slot, SDHCI_INT_STATUS);
500 
501 	if (reg & SDHCI_INT_DATA_END) {
502 		/* ACK for all outstanding interrupts */
503 		bcm_sdhci_write_4(slot->bus, slot, SDHCI_INT_STATUS, reg);
504 
505 		/* enable INT */
506 		slot->intmask |= SDHCI_INT_DATA_AVAIL | SDHCI_INT_SPACE_AVAIL
507 		    | SDHCI_INT_DATA_END;
508 		bcm_sdhci_write_4(slot->bus, slot, SDHCI_SIGNAL_ENABLE,
509 		    slot->intmask);
510 
511 		/* finish this data */
512 		sdhci_finish_data(slot);
513 	}
514 	else {
515 		/* already available? */
516 		if (reg & mask) {
517 
518 			/* ACK for DATA_AVAIL or SPACE_AVAIL */
519 			bcm_sdhci_write_4(slot->bus, slot,
520 			    SDHCI_INT_STATUS, mask);
521 
522 			/* continue next DMA transfer */
523 			if (bus_dmamap_load(sc->sc_dma_tag, sc->sc_dma_map,
524 			    (uint8_t *)slot->curcmd->data->data +
525 			    slot->offset, left, bcm_sdhci_dmacb, sc,
526 			    BUS_DMA_NOWAIT) != 0 || sc->dmamap_status != 0) {
527 				slot->curcmd->error = MMC_ERR_NO_MEMORY;
528 				sdhci_finish_data(slot);
529 			} else {
530 				bcm_sdhci_start_dma_seg(sc);
531 			}
532 		} else {
533 			/* wait for next data by INT */
534 
535 			/* enable INT */
536 			slot->intmask |= SDHCI_INT_DATA_AVAIL |
537 			    SDHCI_INT_SPACE_AVAIL | SDHCI_INT_DATA_END;
538 			bcm_sdhci_write_4(slot->bus, slot, SDHCI_SIGNAL_ENABLE,
539 			    slot->intmask);
540 		}
541 	}
542 
543 	mtx_unlock(&slot->mtx);
544 }
545 
546 static void
547 bcm_sdhci_read_dma(device_t dev, struct sdhci_slot *slot)
548 {
549 	struct bcm_sdhci_softc *sc = device_get_softc(slot->bus);
550 	size_t left;
551 
552 	if (sc->dmamap_seg_count != 0) {
553 		device_printf(sc->sc_dev, "DMA in use\n");
554 		return;
555 	}
556 
557 	left = min(BCM_SDHCI_BUFFER_SIZE,
558 	    slot->curcmd->data->len - slot->offset);
559 
560 	KASSERT((left & 3) == 0,
561 	    ("%s: len = %zu, not word-aligned", __func__, left));
562 
563 	if (bus_dmamap_load(sc->sc_dma_tag, sc->sc_dma_map,
564 	    (uint8_t *)slot->curcmd->data->data + slot->offset, left,
565 	    bcm_sdhci_dmacb, sc, BUS_DMA_NOWAIT) != 0 ||
566 	    sc->dmamap_status != 0) {
567 		slot->curcmd->error = MMC_ERR_NO_MEMORY;
568 		return;
569 	}
570 
571 	/* DMA start */
572 	bcm_sdhci_start_dma_seg(sc);
573 }
574 
575 static void
576 bcm_sdhci_write_dma(device_t dev, struct sdhci_slot *slot)
577 {
578 	struct bcm_sdhci_softc *sc = device_get_softc(slot->bus);
579 	size_t left;
580 
581 	if (sc->dmamap_seg_count != 0) {
582 		device_printf(sc->sc_dev, "DMA in use\n");
583 		return;
584 	}
585 
586 	left = min(BCM_SDHCI_BUFFER_SIZE,
587 	    slot->curcmd->data->len - slot->offset);
588 
589 	KASSERT((left & 3) == 0,
590 	    ("%s: len = %zu, not word-aligned", __func__, left));
591 
592 	if (bus_dmamap_load(sc->sc_dma_tag, sc->sc_dma_map,
593 	    (uint8_t *)slot->curcmd->data->data + slot->offset, left,
594 	    bcm_sdhci_dmacb, sc, BUS_DMA_NOWAIT) != 0 ||
595 	    sc->dmamap_status != 0) {
596 		slot->curcmd->error = MMC_ERR_NO_MEMORY;
597 		return;
598 	}
599 
600 	/* DMA start */
601 	bcm_sdhci_start_dma_seg(sc);
602 }
603 
604 static int
605 bcm_sdhci_will_handle_transfer(device_t dev, struct sdhci_slot *slot)
606 {
607 	size_t left;
608 
609 	/*
610 	 * Do not use DMA for transfers less than block size or with a length
611 	 * that is not a multiple of four.
612 	 */
613 	left = min(BCM_DMA_BLOCK_SIZE,
614 	    slot->curcmd->data->len - slot->offset);
615 	if (left < BCM_DMA_BLOCK_SIZE)
616 		return (0);
617 	if (left & 0x03)
618 		return (0);
619 
620 	return (1);
621 }
622 
623 static void
624 bcm_sdhci_start_transfer(device_t dev, struct sdhci_slot *slot,
625     uint32_t *intmask)
626 {
627 
628 	/* DMA transfer FIFO 1KB */
629 	if (slot->curcmd->data->flags & MMC_DATA_READ)
630 		bcm_sdhci_read_dma(dev, slot);
631 	else
632 		bcm_sdhci_write_dma(dev, slot);
633 }
634 
635 static void
636 bcm_sdhci_finish_transfer(device_t dev, struct sdhci_slot *slot)
637 {
638 
639 	sdhci_finish_data(slot);
640 }
641 
642 static device_method_t bcm_sdhci_methods[] = {
643 	/* Device interface */
644 	DEVMETHOD(device_probe,		bcm_sdhci_probe),
645 	DEVMETHOD(device_attach,	bcm_sdhci_attach),
646 	DEVMETHOD(device_detach,	bcm_sdhci_detach),
647 
648 	/* Bus interface */
649 	DEVMETHOD(bus_read_ivar,	sdhci_generic_read_ivar),
650 	DEVMETHOD(bus_write_ivar,	sdhci_generic_write_ivar),
651 
652 	/* MMC bridge interface */
653 	DEVMETHOD(mmcbr_update_ios,	sdhci_generic_update_ios),
654 	DEVMETHOD(mmcbr_request,	sdhci_generic_request),
655 	DEVMETHOD(mmcbr_get_ro,		bcm_sdhci_get_ro),
656 	DEVMETHOD(mmcbr_acquire_host,	sdhci_generic_acquire_host),
657 	DEVMETHOD(mmcbr_release_host,	sdhci_generic_release_host),
658 
659 	/* Platform transfer methods */
660 	DEVMETHOD(sdhci_platform_will_handle,		bcm_sdhci_will_handle_transfer),
661 	DEVMETHOD(sdhci_platform_start_transfer,	bcm_sdhci_start_transfer),
662 	DEVMETHOD(sdhci_platform_finish_transfer,	bcm_sdhci_finish_transfer),
663 	/* SDHCI registers accessors */
664 	DEVMETHOD(sdhci_read_1,		bcm_sdhci_read_1),
665 	DEVMETHOD(sdhci_read_2,		bcm_sdhci_read_2),
666 	DEVMETHOD(sdhci_read_4,		bcm_sdhci_read_4),
667 	DEVMETHOD(sdhci_read_multi_4,	bcm_sdhci_read_multi_4),
668 	DEVMETHOD(sdhci_write_1,	bcm_sdhci_write_1),
669 	DEVMETHOD(sdhci_write_2,	bcm_sdhci_write_2),
670 	DEVMETHOD(sdhci_write_4,	bcm_sdhci_write_4),
671 	DEVMETHOD(sdhci_write_multi_4,	bcm_sdhci_write_multi_4),
672 
673 	DEVMETHOD_END
674 };
675 
676 static devclass_t bcm_sdhci_devclass;
677 
678 static driver_t bcm_sdhci_driver = {
679 	"sdhci_bcm",
680 	bcm_sdhci_methods,
681 	sizeof(struct bcm_sdhci_softc),
682 };
683 
684 DRIVER_MODULE(sdhci_bcm, simplebus, bcm_sdhci_driver, bcm_sdhci_devclass,
685     NULL, NULL);
686 MODULE_DEPEND(sdhci_bcm, sdhci, 1, 1, 1);
687 #ifndef MMCCAM
688 MMC_DECLARE_BRIDGE(sdhci_bcm);
689 #endif
690