xref: /freebsd/sys/arm/broadcom/bcm2835/bcm2835_sdhci.c (revision 64de80195bba295c961a4cdf96dbe0e4979bdf2a)
1 /*-
2  * Copyright (c) 2012 Oleksandr Tymoshenko <gonzo@freebsd.org>
3  * All rights reserved.
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 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
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/rman.h>
39 #include <sys/sysctl.h>
40 #include <sys/taskqueue.h>
41 
42 #include <machine/bus.h>
43 
44 #include <dev/fdt/fdt_common.h>
45 #include <dev/ofw/ofw_bus.h>
46 #include <dev/ofw/ofw_bus_subr.h>
47 
48 #include <dev/mmc/bridge.h>
49 #include <dev/mmc/mmcreg.h>
50 #include <dev/mmc/mmcbrvar.h>
51 
52 #include <dev/sdhci/sdhci.h>
53 #include "sdhci_if.h"
54 
55 #include "bcm2835_dma.h"
56 #include "bcm2835_vcbus.h"
57 
58 #define	BCM2835_DEFAULT_SDHCI_FREQ	50
59 
60 #define	BCM_SDHCI_BUFFER_SIZE		512
61 #define	NUM_DMA_SEGS			2
62 
63 #ifdef DEBUG
64 #define dprintf(fmt, args...) do { printf("%s(): ", __func__);   \
65     printf(fmt,##args); } while (0)
66 #else
67 #define dprintf(fmt, args...)
68 #endif
69 
70 static int bcm2835_sdhci_hs = 1;
71 static int bcm2835_sdhci_pio_mode = 0;
72 
73 TUNABLE_INT("hw.bcm2835.sdhci.hs", &bcm2835_sdhci_hs);
74 TUNABLE_INT("hw.bcm2835.sdhci.pio_mode", &bcm2835_sdhci_pio_mode);
75 
76 struct bcm_sdhci_softc {
77 	device_t		sc_dev;
78 	struct mtx		sc_mtx;
79 	struct resource *	sc_mem_res;
80 	struct resource *	sc_irq_res;
81 	bus_space_tag_t		sc_bst;
82 	bus_space_handle_t	sc_bsh;
83 	void *			sc_intrhand;
84 	struct mmc_request *	sc_req;
85 	struct mmc_data *	sc_data;
86 	uint32_t		sc_flags;
87 #define	LPC_SD_FLAGS_IGNORECRC		(1 << 0)
88 	int			sc_xfer_direction;
89 #define	DIRECTION_READ		0
90 #define	DIRECTION_WRITE		1
91 	int			sc_xfer_done;
92 	int			sc_bus_busy;
93 	struct sdhci_slot	sc_slot;
94 	int			sc_dma_inuse;
95 	int			sc_dma_ch;
96 	bus_dma_tag_t		sc_dma_tag;
97 	bus_dmamap_t		sc_dma_map;
98 	vm_paddr_t		sc_sdhci_buffer_phys;
99 	uint32_t		cmd_and_mode;
100 	bus_addr_t		dmamap_seg_addrs[NUM_DMA_SEGS];
101 	bus_size_t		dmamap_seg_sizes[NUM_DMA_SEGS];
102 	int			dmamap_seg_count;
103 	int			dmamap_seg_index;
104 	int			dmamap_status;
105 };
106 
107 static int bcm_sdhci_probe(device_t);
108 static int bcm_sdhci_attach(device_t);
109 static int bcm_sdhci_detach(device_t);
110 static void bcm_sdhci_intr(void *);
111 
112 static int bcm_sdhci_get_ro(device_t, device_t);
113 static void bcm_sdhci_dma_intr(int ch, void *arg);
114 
115 #define	bcm_sdhci_lock(_sc)						\
116     mtx_lock(&_sc->sc_mtx);
117 #define	bcm_sdhci_unlock(_sc)						\
118     mtx_unlock(&_sc->sc_mtx);
119 
120 static void
121 bcm_sdhci_dmacb(void *arg, bus_dma_segment_t *segs, int nseg, int err)
122 {
123 	struct bcm_sdhci_softc *sc = arg;
124 	int i;
125 
126 	sc->dmamap_status = err;
127 	sc->dmamap_seg_count = nseg;
128 
129 	/* Note nseg is guaranteed to be zero if err is non-zero. */
130 	for (i = 0; i < nseg; i++) {
131 		sc->dmamap_seg_addrs[i] = segs[i].ds_addr;
132 		sc->dmamap_seg_sizes[i] = segs[i].ds_len;
133 	}
134 }
135 
136 static int
137 bcm_sdhci_probe(device_t dev)
138 {
139 
140 	if (!ofw_bus_status_okay(dev))
141 		return (ENXIO);
142 
143 	if (!ofw_bus_is_compatible(dev, "broadcom,bcm2835-sdhci"))
144 		return (ENXIO);
145 
146 	device_set_desc(dev, "Broadcom 2708 SDHCI controller");
147 	return (BUS_PROBE_DEFAULT);
148 }
149 
150 static int
151 bcm_sdhci_attach(device_t dev)
152 {
153 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
154 	int rid, err;
155 	phandle_t node;
156 	pcell_t cell;
157 	int default_freq;
158 
159 	sc->sc_dev = dev;
160 	sc->sc_req = NULL;
161 	err = 0;
162 
163 	default_freq = BCM2835_DEFAULT_SDHCI_FREQ;
164 	node = ofw_bus_get_node(sc->sc_dev);
165 	if ((OF_getprop(node, "clock-frequency", &cell, sizeof(cell))) > 0)
166 		default_freq = (int)fdt32_to_cpu(cell)/1000000;
167 
168 	dprintf("SDHCI frequency: %dMHz\n", default_freq);
169 
170 	mtx_init(&sc->sc_mtx, "bcm sdhci", "sdhci", MTX_DEF);
171 
172 	rid = 0;
173 	sc->sc_mem_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
174 	    RF_ACTIVE);
175 	if (!sc->sc_mem_res) {
176 		device_printf(dev, "cannot allocate memory window\n");
177 		err = ENXIO;
178 		goto fail;
179 	}
180 
181 	sc->sc_bst = rman_get_bustag(sc->sc_mem_res);
182 	sc->sc_bsh = rman_get_bushandle(sc->sc_mem_res);
183 
184 	rid = 0;
185 	sc->sc_irq_res = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
186 	    RF_ACTIVE);
187 	if (!sc->sc_irq_res) {
188 		device_printf(dev, "cannot allocate interrupt\n");
189 		err = ENXIO;
190 		goto fail;
191 	}
192 
193 	if (bus_setup_intr(dev, sc->sc_irq_res, INTR_TYPE_BIO | INTR_MPSAFE,
194 	    NULL, bcm_sdhci_intr, sc, &sc->sc_intrhand)) {
195 		device_printf(dev, "cannot setup interrupt handler\n");
196 		err = ENXIO;
197 		goto fail;
198 	}
199 
200 	if (!bcm2835_sdhci_pio_mode)
201 		sc->sc_slot.opt = SDHCI_PLATFORM_TRANSFER;
202 
203 	sc->sc_slot.caps = SDHCI_CAN_VDD_330 | SDHCI_CAN_VDD_180;
204 	if (bcm2835_sdhci_hs)
205 		sc->sc_slot.caps |= SDHCI_CAN_DO_HISPD;
206 	sc->sc_slot.caps |= (default_freq << SDHCI_CLOCK_BASE_SHIFT);
207 	sc->sc_slot.quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK
208 		| SDHCI_QUIRK_BROKEN_TIMEOUT_VAL
209 		| SDHCI_QUIRK_DONT_SET_HISPD_BIT
210 		| SDHCI_QUIRK_MISSING_CAPS;
211 
212 	sdhci_init_slot(dev, &sc->sc_slot, 0);
213 
214 	sc->sc_dma_ch = bcm_dma_allocate(BCM_DMA_CH_FAST1);
215 	if (sc->sc_dma_ch == BCM_DMA_CH_INVALID)
216 		sc->sc_dma_ch = bcm_dma_allocate(BCM_DMA_CH_FAST2);
217 	if (sc->sc_dma_ch == BCM_DMA_CH_INVALID)
218 		sc->sc_dma_ch = bcm_dma_allocate(BCM_DMA_CH_ANY);
219 	if (sc->sc_dma_ch == BCM_DMA_CH_INVALID)
220 		goto fail;
221 
222 	bcm_dma_setup_intr(sc->sc_dma_ch, bcm_sdhci_dma_intr, sc);
223 
224 	/* Allocate bus_dma resources. */
225 	err = bus_dma_tag_create(bus_get_dma_tag(dev),
226 	    1, 0, BUS_SPACE_MAXADDR_32BIT,
227 	    BUS_SPACE_MAXADDR, NULL, NULL,
228 	    BCM_SDHCI_BUFFER_SIZE, NUM_DMA_SEGS, BCM_SDHCI_BUFFER_SIZE,
229 	    BUS_DMA_ALLOCNOW, NULL, NULL,
230 	    &sc->sc_dma_tag);
231 
232 	if (err) {
233 		device_printf(dev, "failed allocate DMA tag");
234 		goto fail;
235 	}
236 
237 	err = bus_dmamap_create(sc->sc_dma_tag, 0, &sc->sc_dma_map);
238 	if (err) {
239 		device_printf(dev, "bus_dmamap_create failed\n");
240 		goto fail;
241 	}
242 
243 	sc->sc_sdhci_buffer_phys = BUS_SPACE_PHYSADDR(sc->sc_mem_res,
244 	    SDHCI_BUFFER);
245 
246 	bus_generic_probe(dev);
247 	bus_generic_attach(dev);
248 
249 	sdhci_start_slot(&sc->sc_slot);
250 
251 	return (0);
252 
253 fail:
254 	if (sc->sc_intrhand)
255 		bus_teardown_intr(dev, sc->sc_irq_res, sc->sc_intrhand);
256 	if (sc->sc_irq_res)
257 		bus_release_resource(dev, SYS_RES_IRQ, 0, sc->sc_irq_res);
258 	if (sc->sc_mem_res)
259 		bus_release_resource(dev, SYS_RES_MEMORY, 0, sc->sc_mem_res);
260 	mtx_destroy(&sc->sc_mtx);
261 
262 	return (err);
263 }
264 
265 static int
266 bcm_sdhci_detach(device_t dev)
267 {
268 
269 	return (EBUSY);
270 }
271 
272 static void
273 bcm_sdhci_intr(void *arg)
274 {
275 	struct bcm_sdhci_softc *sc = arg;
276 
277 	sdhci_generic_intr(&sc->sc_slot);
278 }
279 
280 static int
281 bcm_sdhci_get_ro(device_t bus, device_t child)
282 {
283 
284 	return (0);
285 }
286 
287 static inline uint32_t
288 RD4(struct bcm_sdhci_softc *sc, bus_size_t off)
289 {
290 	uint32_t val = bus_space_read_4(sc->sc_bst, sc->sc_bsh, off);
291 	return val;
292 }
293 
294 static inline void
295 WR4(struct bcm_sdhci_softc *sc, bus_size_t off, uint32_t val)
296 {
297 
298 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, off, val);
299 	/*
300 	 * The Arasan HC has a bug where it may lose the content of
301 	 * consecutive writes to registers that are within two SD-card
302 	 * clock cycles of each other (a clock domain crossing problem).
303 	 */
304 	if (sc->sc_slot.clock > 0)
305 		DELAY(((2 * 1000000) / sc->sc_slot.clock) + 1);
306 }
307 
308 static uint8_t
309 bcm_sdhci_read_1(device_t dev, struct sdhci_slot *slot, bus_size_t off)
310 {
311 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
312 	uint32_t val = RD4(sc, off & ~3);
313 
314 	return ((val >> (off & 3)*8) & 0xff);
315 }
316 
317 static uint16_t
318 bcm_sdhci_read_2(device_t dev, struct sdhci_slot *slot, bus_size_t off)
319 {
320 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
321 	uint32_t val = RD4(sc, off & ~3);
322 
323 	/*
324 	 * Standard 32-bit handling of command and transfer mode.
325 	 */
326 	if (off == SDHCI_TRANSFER_MODE) {
327 		return (sc->cmd_and_mode >> 16);
328 	} else if (off == SDHCI_COMMAND_FLAGS) {
329 		return (sc->cmd_and_mode & 0x0000ffff);
330 	}
331 	return ((val >> (off & 3)*8) & 0xffff);
332 }
333 
334 static uint32_t
335 bcm_sdhci_read_4(device_t dev, struct sdhci_slot *slot, bus_size_t off)
336 {
337 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
338 
339 	return RD4(sc, off);
340 }
341 
342 static void
343 bcm_sdhci_read_multi_4(device_t dev, struct sdhci_slot *slot, bus_size_t off,
344     uint32_t *data, bus_size_t count)
345 {
346 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
347 
348 	bus_space_read_multi_4(sc->sc_bst, sc->sc_bsh, off, data, count);
349 }
350 
351 static void
352 bcm_sdhci_write_1(device_t dev, struct sdhci_slot *slot, bus_size_t off, uint8_t val)
353 {
354 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
355 	uint32_t val32 = RD4(sc, off & ~3);
356 	val32 &= ~(0xff << (off & 3)*8);
357 	val32 |= (val << (off & 3)*8);
358 	WR4(sc, off & ~3, val32);
359 }
360 
361 static void
362 bcm_sdhci_write_2(device_t dev, struct sdhci_slot *slot, bus_size_t off, uint16_t val)
363 {
364 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
365 	uint32_t val32;
366 	if (off == SDHCI_COMMAND_FLAGS)
367 		val32 = sc->cmd_and_mode;
368 	else
369 		val32 = RD4(sc, off & ~3);
370 	val32 &= ~(0xffff << (off & 3)*8);
371 	val32 |= (val << (off & 3)*8);
372 	if (off == SDHCI_TRANSFER_MODE)
373 		sc->cmd_and_mode = val32;
374 	else {
375 		WR4(sc, off & ~3, val32);
376 		if (off == SDHCI_COMMAND_FLAGS)
377 			sc->cmd_and_mode = val32;
378 	}
379 }
380 
381 static void
382 bcm_sdhci_write_4(device_t dev, struct sdhci_slot *slot, bus_size_t off, uint32_t val)
383 {
384 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
385 	WR4(sc, off, val);
386 }
387 
388 static void
389 bcm_sdhci_write_multi_4(device_t dev, struct sdhci_slot *slot, bus_size_t off,
390     uint32_t *data, bus_size_t count)
391 {
392 	struct bcm_sdhci_softc *sc = device_get_softc(dev);
393 
394 	bus_space_write_multi_4(sc->sc_bst, sc->sc_bsh, off, data, count);
395 }
396 
397 static void
398 bcm_sdhci_start_dma_seg(struct bcm_sdhci_softc *sc)
399 {
400 	struct sdhci_slot *slot;
401 	vm_paddr_t pdst, psrc;
402 	int err, idx, len, sync_op;
403 
404 	slot = &sc->sc_slot;
405 	idx = sc->dmamap_seg_index++;
406 	len = sc->dmamap_seg_sizes[idx];
407 	slot->offset += len;
408 
409 	if (slot->curcmd->data->flags & MMC_DATA_READ) {
410 		bcm_dma_setup_src(sc->sc_dma_ch, BCM_DMA_DREQ_EMMC,
411 		    BCM_DMA_SAME_ADDR, BCM_DMA_32BIT);
412 		bcm_dma_setup_dst(sc->sc_dma_ch, BCM_DMA_DREQ_NONE,
413 		    BCM_DMA_INC_ADDR,
414 		    (len & 0xf) ? BCM_DMA_32BIT : BCM_DMA_128BIT);
415 		psrc = sc->sc_sdhci_buffer_phys;
416 		pdst = sc->dmamap_seg_addrs[idx];
417 		sync_op = BUS_DMASYNC_PREREAD;
418 	} else {
419 		bcm_dma_setup_src(sc->sc_dma_ch, BCM_DMA_DREQ_NONE,
420 		    BCM_DMA_INC_ADDR,
421 		    (len & 0xf) ? BCM_DMA_32BIT : BCM_DMA_128BIT);
422 		bcm_dma_setup_dst(sc->sc_dma_ch, BCM_DMA_DREQ_EMMC,
423 		    BCM_DMA_SAME_ADDR, BCM_DMA_32BIT);
424 		psrc = sc->dmamap_seg_addrs[idx];
425 		pdst = sc->sc_sdhci_buffer_phys;
426 		sync_op = BUS_DMASYNC_PREWRITE;
427 	}
428 
429 	/*
430 	 * When starting a new DMA operation do the busdma sync operation, and
431 	 * disable SDCHI data interrrupts because we'll be driven by DMA
432 	 * interrupts (or SDHCI error interrupts) until the IO is done.
433 	 */
434 	if (idx == 0) {
435 		bus_dmamap_sync(sc->sc_dma_tag, sc->sc_dma_map, sync_op);
436 		slot->intmask &= ~(SDHCI_INT_DATA_AVAIL |
437 		    SDHCI_INT_SPACE_AVAIL | SDHCI_INT_DATA_END);
438 		bcm_sdhci_write_4(sc->sc_dev, &sc->sc_slot, SDHCI_SIGNAL_ENABLE,
439 		    slot->intmask);
440 	}
441 
442 	/*
443 	 * Start the DMA transfer.  Only programming errors (like failing to
444 	 * allocate a channel) cause a non-zero return from bcm_dma_start().
445 	 */
446 	err = bcm_dma_start(sc->sc_dma_ch, psrc, pdst, len);
447 	KASSERT((err == 0), ("bcm2835_sdhci: failed DMA start"));
448 }
449 
450 static void
451 bcm_sdhci_dma_intr(int ch, void *arg)
452 {
453 	struct bcm_sdhci_softc *sc = (struct bcm_sdhci_softc *)arg;
454 	struct sdhci_slot *slot = &sc->sc_slot;
455 	uint32_t reg, mask;
456 	int left, sync_op;
457 
458 	mtx_lock(&slot->mtx);
459 
460 	/*
461 	 * If there are more segments for the current dma, start the next one.
462 	 * Otherwise unload the dma map and decide what to do next based on the
463 	 * status of the sdhci controller and whether there's more data left.
464 	 */
465 	if (sc->dmamap_seg_index < sc->dmamap_seg_count) {
466 		bcm_sdhci_start_dma_seg(sc);
467 		mtx_unlock(&slot->mtx);
468 		return;
469 	}
470 
471 	if (slot->curcmd->data->flags & MMC_DATA_READ) {
472 		sync_op = BUS_DMASYNC_POSTREAD;
473 		mask = SDHCI_INT_DATA_AVAIL;
474 	} else {
475 		sync_op = BUS_DMASYNC_POSTWRITE;
476 		mask = SDHCI_INT_SPACE_AVAIL;
477 	}
478 	bus_dmamap_sync(sc->sc_dma_tag, sc->sc_dma_map, sync_op);
479 	bus_dmamap_unload(sc->sc_dma_tag, sc->sc_dma_map);
480 
481 	sc->dmamap_seg_count = 0;
482 	sc->dmamap_seg_index = 0;
483 
484 	left = min(BCM_SDHCI_BUFFER_SIZE,
485 	    slot->curcmd->data->len - slot->offset);
486 
487 	/* DATA END? */
488 	reg = bcm_sdhci_read_4(slot->bus, slot, SDHCI_INT_STATUS);
489 
490 	if (reg & SDHCI_INT_DATA_END) {
491 		/* ACK for all outstanding interrupts */
492 		bcm_sdhci_write_4(slot->bus, slot, SDHCI_INT_STATUS, reg);
493 
494 		/* enable INT */
495 		slot->intmask |= SDHCI_INT_DATA_AVAIL | SDHCI_INT_SPACE_AVAIL
496 		    | SDHCI_INT_DATA_END;
497 		bcm_sdhci_write_4(slot->bus, slot, SDHCI_SIGNAL_ENABLE,
498 		    slot->intmask);
499 
500 		/* finish this data */
501 		sdhci_finish_data(slot);
502 	}
503 	else {
504 		/* already available? */
505 		if (reg & mask) {
506 
507 			/* ACK for DATA_AVAIL or SPACE_AVAIL */
508 			bcm_sdhci_write_4(slot->bus, slot,
509 			    SDHCI_INT_STATUS, mask);
510 
511 			/* continue next DMA transfer */
512 			if (bus_dmamap_load(sc->sc_dma_tag, sc->sc_dma_map,
513 			    (uint8_t *)slot->curcmd->data->data +
514 			    slot->offset, left, bcm_sdhci_dmacb, sc,
515 			    BUS_DMA_NOWAIT) != 0 || sc->dmamap_status != 0) {
516 				slot->curcmd->error = MMC_ERR_NO_MEMORY;
517 				sdhci_finish_data(slot);
518 			} else {
519 				bcm_sdhci_start_dma_seg(sc);
520 			}
521 		} else {
522 			/* wait for next data by INT */
523 
524 			/* enable INT */
525 			slot->intmask |= SDHCI_INT_DATA_AVAIL |
526 			    SDHCI_INT_SPACE_AVAIL | SDHCI_INT_DATA_END;
527 			bcm_sdhci_write_4(slot->bus, slot, SDHCI_SIGNAL_ENABLE,
528 			    slot->intmask);
529 		}
530 	}
531 
532 	mtx_unlock(&slot->mtx);
533 }
534 
535 static void
536 bcm_sdhci_read_dma(device_t dev, struct sdhci_slot *slot)
537 {
538 	struct bcm_sdhci_softc *sc = device_get_softc(slot->bus);
539 	size_t left;
540 
541 	if (sc->dmamap_seg_count != 0) {
542 		device_printf(sc->sc_dev, "DMA in use\n");
543 		return;
544 	}
545 
546 	left = min(BCM_SDHCI_BUFFER_SIZE,
547 	    slot->curcmd->data->len - slot->offset);
548 
549 	KASSERT((left & 3) == 0,
550 	    ("%s: len = %d, not word-aligned", __func__, left));
551 
552 	if (bus_dmamap_load(sc->sc_dma_tag, sc->sc_dma_map,
553 	    (uint8_t *)slot->curcmd->data->data + slot->offset, left,
554 	    bcm_sdhci_dmacb, sc, BUS_DMA_NOWAIT) != 0 ||
555 	    sc->dmamap_status != 0) {
556 		slot->curcmd->error = MMC_ERR_NO_MEMORY;
557 		return;
558 	}
559 
560 	/* DMA start */
561 	bcm_sdhci_start_dma_seg(sc);
562 }
563 
564 static void
565 bcm_sdhci_write_dma(device_t dev, struct sdhci_slot *slot)
566 {
567 	struct bcm_sdhci_softc *sc = device_get_softc(slot->bus);
568 	size_t left;
569 
570 	if (sc->dmamap_seg_count != 0) {
571 		device_printf(sc->sc_dev, "DMA in use\n");
572 		return;
573 	}
574 
575 	left = min(BCM_SDHCI_BUFFER_SIZE,
576 	    slot->curcmd->data->len - slot->offset);
577 
578 	KASSERT((left & 3) == 0,
579 	    ("%s: len = %d, not word-aligned", __func__, left));
580 
581 	if (bus_dmamap_load(sc->sc_dma_tag, sc->sc_dma_map,
582 	    (uint8_t *)slot->curcmd->data->data + slot->offset, left,
583 	    bcm_sdhci_dmacb, sc, BUS_DMA_NOWAIT) != 0 ||
584 	    sc->dmamap_status != 0) {
585 		slot->curcmd->error = MMC_ERR_NO_MEMORY;
586 		return;
587 	}
588 
589 	/* DMA start */
590 	bcm_sdhci_start_dma_seg(sc);
591 }
592 
593 static int
594 bcm_sdhci_will_handle_transfer(device_t dev, struct sdhci_slot *slot)
595 {
596 	size_t left;
597 
598 	/*
599 	 * Do not use DMA for transfers less than block size or with a length
600 	 * that is not a multiple of four.
601 	 */
602 	left = min(BCM_DMA_BLOCK_SIZE,
603 	    slot->curcmd->data->len - slot->offset);
604 	if (left < BCM_DMA_BLOCK_SIZE)
605 		return (0);
606 	if (left & 0x03)
607 		return (0);
608 
609 	return (1);
610 }
611 
612 static void
613 bcm_sdhci_start_transfer(device_t dev, struct sdhci_slot *slot,
614     uint32_t *intmask)
615 {
616 
617 	/* DMA transfer FIFO 1KB */
618 	if (slot->curcmd->data->flags & MMC_DATA_READ)
619 		bcm_sdhci_read_dma(dev, slot);
620 	else
621 		bcm_sdhci_write_dma(dev, slot);
622 }
623 
624 static void
625 bcm_sdhci_finish_transfer(device_t dev, struct sdhci_slot *slot)
626 {
627 
628 	sdhci_finish_data(slot);
629 }
630 
631 static device_method_t bcm_sdhci_methods[] = {
632 	/* Device interface */
633 	DEVMETHOD(device_probe,		bcm_sdhci_probe),
634 	DEVMETHOD(device_attach,	bcm_sdhci_attach),
635 	DEVMETHOD(device_detach,	bcm_sdhci_detach),
636 
637 	/* Bus interface */
638 	DEVMETHOD(bus_read_ivar,	sdhci_generic_read_ivar),
639 	DEVMETHOD(bus_write_ivar,	sdhci_generic_write_ivar),
640 	DEVMETHOD(bus_print_child,	bus_generic_print_child),
641 
642 	/* MMC bridge interface */
643 	DEVMETHOD(mmcbr_update_ios,	sdhci_generic_update_ios),
644 	DEVMETHOD(mmcbr_request,	sdhci_generic_request),
645 	DEVMETHOD(mmcbr_get_ro,		bcm_sdhci_get_ro),
646 	DEVMETHOD(mmcbr_acquire_host,	sdhci_generic_acquire_host),
647 	DEVMETHOD(mmcbr_release_host,	sdhci_generic_release_host),
648 
649 	/* Platform transfer methods */
650 	DEVMETHOD(sdhci_platform_will_handle,		bcm_sdhci_will_handle_transfer),
651 	DEVMETHOD(sdhci_platform_start_transfer,	bcm_sdhci_start_transfer),
652 	DEVMETHOD(sdhci_platform_finish_transfer,	bcm_sdhci_finish_transfer),
653 	/* SDHCI registers accessors */
654 	DEVMETHOD(sdhci_read_1,		bcm_sdhci_read_1),
655 	DEVMETHOD(sdhci_read_2,		bcm_sdhci_read_2),
656 	DEVMETHOD(sdhci_read_4,		bcm_sdhci_read_4),
657 	DEVMETHOD(sdhci_read_multi_4,	bcm_sdhci_read_multi_4),
658 	DEVMETHOD(sdhci_write_1,	bcm_sdhci_write_1),
659 	DEVMETHOD(sdhci_write_2,	bcm_sdhci_write_2),
660 	DEVMETHOD(sdhci_write_4,	bcm_sdhci_write_4),
661 	DEVMETHOD(sdhci_write_multi_4,	bcm_sdhci_write_multi_4),
662 
663 	{ 0, 0 }
664 };
665 
666 static devclass_t bcm_sdhci_devclass;
667 
668 static driver_t bcm_sdhci_driver = {
669 	"sdhci_bcm",
670 	bcm_sdhci_methods,
671 	sizeof(struct bcm_sdhci_softc),
672 };
673 
674 DRIVER_MODULE(sdhci_bcm, simplebus, bcm_sdhci_driver, bcm_sdhci_devclass, 0, 0);
675 MODULE_DEPEND(sdhci_bcm, sdhci, 1, 1, 1);
676