xref: /freebsd/sys/dev/mmc/mmc.c (revision 94942af266ac119ede0ca836f9aa5a5ac0582938)
1 /*-
2  * Copyright (c) 2006 Bernd Walter.  All rights reserved.
3  * Copyright (c) 2006 M. Warner Losh.  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 ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/kernel.h>
32 #include <sys/malloc.h>
33 #include <sys/lock.h>
34 #include <sys/module.h>
35 #include <sys/mutex.h>
36 #include <sys/bus.h>
37 
38 #include <dev/mmc/mmcreg.h>
39 #include <dev/mmc/mmcbrvar.h>
40 #include <dev/mmc/mmcvar.h>
41 #include "mmcbr_if.h"
42 #include "mmcbus_if.h"
43 
44 struct mmc_softc {
45 	device_t dev;
46 	struct mtx sc_mtx;
47 	struct intr_config_hook config_intrhook;
48 	device_t owner;
49 	uint32_t last_rca;
50 };
51 
52 /*
53  * Per-card data
54  */
55 struct mmc_ivars {
56 	uint32_t raw_cid[4];	/* Raw bits of the CID */
57 	uint32_t raw_csd[4];	/* Raw bits of the CSD */
58 	uint16_t rca;
59 	enum mmc_card_mode mode;
60 	struct mmc_cid cid;	/* cid decoded */
61 	struct mmc_csd csd;	/* csd decoded */
62 };
63 
64 #define CMD_RETRIES	3
65 
66 /* bus entry points */
67 static int mmc_probe(device_t dev);
68 static int mmc_attach(device_t dev);
69 static int mmc_detach(device_t dev);
70 
71 #define MMC_LOCK(_sc)		mtx_lock(&(_sc)->sc_mtx)
72 #define	MMC_UNLOCK(_sc)		mtx_unlock(&(_sc)->sc_mtx)
73 #define MMC_LOCK_INIT(_sc) \
74 	mtx_init(&_sc->sc_mtx, device_get_nameunit(_sc->dev), \
75 	    "mmc", MTX_DEF)
76 #define MMC_LOCK_DESTROY(_sc)	mtx_destroy(&_sc->sc_mtx);
77 #define MMC_ASSERT_LOCKED(_sc)	mtx_assert(&_sc->sc_mtx, MA_OWNED);
78 #define MMC_ASSERT_UNLOCKED(_sc) mtx_assert(&_sc->sc_mtx, MA_NOTOWNED);
79 
80 static void mmc_delayed_attach(void *);
81 static int mmc_wait_for_cmd(struct mmc_softc *sc, struct mmc_command *cmd,
82     int retries);
83 static int mmc_wait_for_command(struct mmc_softc *sc, uint32_t opcode,
84     uint32_t arg, uint32_t flags, uint32_t *resp, int retries);
85 
86 static void
87 mmc_ms_delay(int ms)
88 {
89 	DELAY(1000 * ms);	/* XXX BAD */
90 }
91 
92 static int
93 mmc_probe(device_t dev)
94 {
95 
96 	device_set_desc(dev, "mmc/sd bus");
97 	return (0);
98 }
99 
100 static int
101 mmc_attach(device_t dev)
102 {
103 	struct mmc_softc *sc;
104 
105 	sc = device_get_softc(dev);
106 	sc->dev = dev;
107 	MMC_LOCK_INIT(sc);
108 
109 	/* We'll probe and attach our children later, but before / mount */
110 	sc->config_intrhook.ich_func = mmc_delayed_attach;
111 	sc->config_intrhook.ich_arg = sc;
112 	if (config_intrhook_establish(&sc->config_intrhook) != 0)
113 		device_printf(dev, "config_intrhook_establish failed\n");
114 	return (0);
115 }
116 
117 static int
118 mmc_detach(device_t dev)
119 {
120 	struct mmc_softc *sc = device_get_softc(dev);
121 	device_t *kids;
122 	int i, nkid;
123 
124 	/* kill children [ph33r].  -sorbo */
125 	if (device_get_children(sc->dev, &kids, &nkid) != 0)
126 		return 0;
127 	for (i = 0; i < nkid; i++) {
128 		device_t kid = kids[i];
129 		void *ivar = device_get_ivars(kid);
130 
131 		device_detach(kid);
132 		device_delete_child(sc->dev, kid);
133 		free(ivar, M_DEVBUF);
134 	}
135 	free(kids, M_TEMP);
136 
137 	MMC_LOCK_DESTROY(sc);
138 
139 	return 0;
140 }
141 
142 static int
143 mmc_acquire_bus(device_t busdev, device_t dev)
144 {
145 	struct mmc_softc *sc;
146 	int err;
147 	int rca;
148 
149 	err = MMCBR_ACQUIRE_HOST(device_get_parent(busdev), dev);
150 	if (err)
151 		return (err);
152 	sc = device_get_softc(busdev);
153 	MMC_LOCK(sc);
154 	if (sc->owner)
155 		panic("mmc: host bridge didn't seralize us.");
156 	sc->owner = dev;
157 	MMC_UNLOCK(sc);
158 
159 	if (busdev != dev) {
160 		// Keep track of the last rca that we've selected.  If
161 		// we're asked to do it again, don't.  We never unselect
162 		// unless the bus code itself wants the mmc bus.
163 		rca = mmc_get_rca(dev);
164 		if (sc->last_rca != rca) {
165 			mmc_wait_for_command(sc, MMC_SELECT_CARD, rca << 16,
166 			    MMC_RSP_R1 | MMC_CMD_AC, NULL, CMD_RETRIES);
167 			sc->last_rca = rca;
168 		}
169 		// XXX should set bus width here?
170 	} else {
171 		// If there's a card selected, stand down.
172 		if (sc->last_rca != 0) {
173 			mmc_wait_for_command(sc, MMC_SELECT_CARD, 0,
174 			    MMC_RSP_R1 | MMC_CMD_AC, NULL, CMD_RETRIES);
175 			sc->last_rca = 0;
176 		}
177 		// XXX should set bus width here?
178 	}
179 
180 	return (0);
181 }
182 
183 static int
184 mmc_release_bus(device_t busdev, device_t dev)
185 {
186 	struct mmc_softc *sc;
187 	int err;
188 
189 	sc = device_get_softc(busdev);
190 
191 	MMC_LOCK(sc);
192 	if (!sc->owner)
193 		panic("mmc: releasing unowned bus.");
194 	if (sc->owner != dev)
195 		panic("mmc: you don't own the bus.  game over.");
196 	MMC_UNLOCK(sc);
197 	err = MMCBR_RELEASE_HOST(device_get_parent(busdev), dev);
198 	if (err)
199 		return (err);
200 	MMC_LOCK(sc);
201 	sc->owner = NULL;
202 	MMC_UNLOCK(sc);
203 	return (0);
204 }
205 
206 static void
207 mmc_rescan_cards(struct mmc_softc *sc)
208 {
209 	/* XXX: Look at the children and see if they respond to status */
210 }
211 
212 static uint32_t
213 mmc_select_vdd(struct mmc_softc *sc, uint32_t ocr)
214 {
215     // XXX
216 	return ocr;
217 }
218 
219 static int
220 mmc_highest_voltage(uint32_t ocr)
221 {
222 	int i;
223 
224 	for (i = 30; i >= 0; i--)
225 		if (ocr & (1 << i))
226 			return i;
227 	return (-1);
228 }
229 
230 static void
231 mmc_wakeup(struct mmc_request *req)
232 {
233 	struct mmc_softc *sc;
234 
235 //	printf("Wakeup for req %p done_data %p\n", req, req->done_data);
236 	sc = (struct mmc_softc *)req->done_data;
237 	MMC_LOCK(sc);
238 	req->flags |= MMC_REQ_DONE;
239 	wakeup(req);
240 	MMC_UNLOCK(sc);
241 }
242 
243 static int
244 mmc_wait_for_req(struct mmc_softc *sc, struct mmc_request *req)
245 {
246 	int err;
247 
248 	req->done = mmc_wakeup;
249 	req->done_data = sc;
250 //	printf("Submitting request %p sc %p\n", req, sc);
251 	MMCBR_REQUEST(device_get_parent(sc->dev), sc->dev, req);
252 	MMC_LOCK(sc);
253 	do {
254 		err = msleep(req, &sc->sc_mtx, PZERO | PCATCH, "mmcreq",
255 		    hz / 10);
256 	} while (!(req->flags & MMC_REQ_DONE) && err == EAGAIN);
257 //	printf("Request %p done with error %d\n", req, err);
258 	MMC_UNLOCK(sc);
259 	return (err);
260 }
261 
262 static int
263 mmc_wait_for_request(device_t brdev, device_t reqdev, struct mmc_request *req)
264 {
265 	struct mmc_softc *sc = device_get_softc(brdev);
266 
267 	return mmc_wait_for_req(sc, req);
268 }
269 
270 static int
271 mmc_wait_for_cmd(struct mmc_softc *sc, struct mmc_command *cmd, int retries)
272 {
273 	struct mmc_request mreq;
274 
275 	memset(&mreq, 0, sizeof(mreq));
276 	memset(cmd->resp, 0, sizeof(cmd->resp));
277 	cmd->retries = retries;
278 	cmd->data = NULL;
279 	mreq.cmd = cmd;
280 //	printf("CMD: %x ARG %x\n", cmd->opcode, cmd->arg);
281 	mmc_wait_for_req(sc, &mreq);
282 	return (cmd->error);
283 }
284 
285 static int
286 mmc_wait_for_app_cmd(struct mmc_softc *sc, uint32_t rca,
287     struct mmc_command *cmd, int retries)
288 {
289 	struct mmc_command appcmd;
290 	int err = MMC_ERR_NONE, i;
291 
292 	for (i = 0; i <= retries; i++) {
293 		appcmd.opcode = MMC_APP_CMD;
294 		appcmd.arg = rca << 16;
295 		appcmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
296 		mmc_wait_for_cmd(sc, &appcmd, 0);
297 		err = appcmd.error;
298 		if (err != MMC_ERR_NONE)
299 			continue;
300 		if (!(appcmd.resp[0] & R1_APP_CMD))
301 			return MMC_ERR_FAILED;
302 		mmc_wait_for_cmd(sc, cmd, 0);
303 		err = cmd->error;
304 		if (err == MMC_ERR_NONE)
305 			break;
306 	}
307 	return (err);
308 }
309 
310 static int
311 mmc_wait_for_command(struct mmc_softc *sc, uint32_t opcode,
312     uint32_t arg, uint32_t flags, uint32_t *resp, int retries)
313 {
314 	struct mmc_command cmd;
315 	int err;
316 
317 	memset(&cmd, 0, sizeof(cmd));
318 	cmd.opcode = opcode;
319 	cmd.arg = arg;
320 	cmd.flags = flags;
321 	err = mmc_wait_for_cmd(sc, &cmd, retries);
322 	if (err)
323 		return (err);
324 	if (cmd.error)
325 		return (cmd.error);
326 	if (resp) {
327 		if (flags & MMC_RSP_136)
328 			memcpy(resp, cmd.resp, 4 * sizeof(uint32_t));
329 		else
330 			*resp = cmd.resp[0];
331 	}
332 	return (0);
333 }
334 
335 static void
336 mmc_idle_cards(struct mmc_softc *sc)
337 {
338 	device_t dev;
339 	struct mmc_command cmd;
340 
341 	dev = sc->dev;
342 	mmcbr_set_chip_select(dev, cs_high);
343 	mmcbr_update_ios(dev);
344 	mmc_ms_delay(1);
345 
346 	memset(&cmd, 0, sizeof(cmd));
347 	cmd.opcode = MMC_GO_IDLE_STATE;
348 	cmd.arg = 0;
349 	cmd.flags = MMC_RSP_NONE | MMC_CMD_BC;
350 	mmc_wait_for_cmd(sc, &cmd, 0);
351 	mmc_ms_delay(1);
352 
353 	mmcbr_set_chip_select(dev, cs_dontcare);
354 	mmcbr_update_ios(dev);
355 	mmc_ms_delay(1);
356 }
357 
358 static int
359 mmc_send_app_op_cond(struct mmc_softc *sc, uint32_t ocr, uint32_t *rocr)
360 {
361 	struct mmc_command cmd;
362 	int err = MMC_ERR_NONE, i;
363 
364 	memset(&cmd, 0, sizeof(cmd));
365 	cmd.opcode = ACMD_SD_SEND_OP_COND;
366 	cmd.arg = ocr;
367 	cmd.flags = MMC_RSP_R3 | MMC_CMD_BCR;
368 
369 	for (i = 0; i < 10; i++) {
370 		err = mmc_wait_for_app_cmd(sc, 0, &cmd, CMD_RETRIES);
371 		if (err != MMC_ERR_NONE)
372 			break;
373 		if ((cmd.resp[0] & MMC_OCR_CARD_BUSY) || ocr == 0)
374 			break;
375 		err = MMC_ERR_TIMEOUT;
376 		mmc_ms_delay(10);
377 	}
378 	if (rocr && err == MMC_ERR_NONE)
379 		*rocr = cmd.resp[0];
380 	return err;
381 }
382 
383 static int
384 mmc_send_op_cond(struct mmc_softc *sc, uint32_t ocr, uint32_t *rocr)
385 {
386 	struct mmc_command cmd;
387 	int err = MMC_ERR_NONE, i;
388 
389 	memset(&cmd, 0, sizeof(cmd));
390 	cmd.opcode = MMC_SEND_OP_COND;
391 	cmd.arg = ocr;
392 	cmd.flags = MMC_RSP_R3 | MMC_CMD_BCR;
393 
394 	for (i = 0; i < 100; i++) {
395 		err = mmc_wait_for_cmd(sc, &cmd, CMD_RETRIES);
396 		if (err != MMC_ERR_NONE)
397 			break;
398 		if ((cmd.resp[0] & MMC_OCR_CARD_BUSY) || ocr == 0)
399 			break;
400 		err = MMC_ERR_TIMEOUT;
401 		mmc_ms_delay(10);
402 	}
403 	if (rocr && err == MMC_ERR_NONE)
404 		*rocr = cmd.resp[0];
405 	return err;
406 }
407 
408 static void
409 mmc_power_up(struct mmc_softc *sc)
410 {
411 	device_t dev;
412 
413 	dev = sc->dev;
414 	mmcbr_set_vdd(dev, mmc_highest_voltage(mmcbr_get_host_ocr(dev)));
415 	mmcbr_set_bus_mode(dev, opendrain);
416 	mmcbr_set_chip_select(dev, cs_dontcare);
417 	mmcbr_set_bus_width(dev, bus_width_1);
418 	mmcbr_set_power_mode(dev, power_up);
419 	mmcbr_set_clock(dev, 0);
420 	mmcbr_update_ios(dev);
421 	mmc_ms_delay(1);
422 
423 	mmcbr_set_clock(dev, mmcbr_get_f_min(sc->dev));
424 	mmcbr_set_power_mode(dev, power_on);
425 	mmcbr_update_ios(dev);
426 	mmc_ms_delay(2);
427 }
428 
429 // I wonder if the following is endian safe.
430 static uint32_t
431 mmc_get_bits(uint32_t *bits, int start, int size)
432 {
433 	const int i = 3 - (start / 32);
434 	const int shift = start & 31;
435 	uint32_t retval = bits[i] >> shift;
436 	if (size + shift > 32)
437 		retval |= bits[i - 1] << (32 - shift);
438 	return retval & ((1 << size) - 1);
439 }
440 
441 static void
442 mmc_decode_cid(int is_sd, uint32_t *raw_cid, struct mmc_cid *cid)
443 {
444 	int i;
445 
446 	memset(cid, 0, sizeof(*cid));
447 	if (is_sd) {
448 		/* There's no version info, so we take it on faith */
449 		cid->mid = mmc_get_bits(raw_cid, 120, 8);
450 		cid->oid = mmc_get_bits(raw_cid, 104, 16);
451 		for (i = 0; i < 5; i++)
452 			cid->pnm[i] = mmc_get_bits(raw_cid, 96 - i * 8, 8);
453 		cid->prv = mmc_get_bits(raw_cid, 56, 8);
454 		cid->psn = mmc_get_bits(raw_cid, 24, 32);
455 		cid->mdt_year = mmc_get_bits(raw_cid, 12, 8) + 2001;
456 		cid->mdt_month = mmc_get_bits(raw_cid, 8, 4);
457 	} else {
458 		// XXX write me
459 		panic("write mmc cid decoder");
460 	}
461 }
462 
463 static const int exp[8] = {
464 	1, 10, 100, 1000, 10000, 100000, 1000000, 10000000
465 };
466 static const int mant[16] = {
467 	10, 12, 13, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 70, 80
468 };
469 static const int cur_min[8] = {
470 	500, 1000, 5000, 10000, 25000, 35000, 60000, 100000
471 };
472 static const int cur_max[8] = {
473 	1000, 5000, 10000, 25000, 35000, 45000, 800000, 200000
474 };
475 
476 static void
477 mmc_decode_csd(int is_sd, uint32_t *raw_csd, struct mmc_csd *csd)
478 {
479 	int v;
480 	int m;
481 	int e;
482 
483 	memset(csd, 0, sizeof(*csd));
484 	if (is_sd) {
485 		csd->csd_structure = v = mmc_get_bits(raw_csd, 126, 2);
486 		if (v == 0) {
487 			m = mmc_get_bits(raw_csd, 115, 4);
488 			e = mmc_get_bits(raw_csd, 112, 3);
489 			csd->tacc = exp[e] * mant[m] + 9 / 10;
490 			csd->nsac = mmc_get_bits(raw_csd, 104, 8) * 100;
491 			m = mmc_get_bits(raw_csd, 99, 4);
492 			e = mmc_get_bits(raw_csd, 96, 3);
493 			csd->tran_speed = exp[e] * 10000 * mant[m];
494 			csd->ccc = mmc_get_bits(raw_csd, 84, 12);
495 			csd->read_bl_len = 1 << mmc_get_bits(raw_csd, 80, 4);
496 			csd->read_bl_partial = mmc_get_bits(raw_csd, 79, 1);
497 			csd->write_blk_misalign = mmc_get_bits(raw_csd, 78, 1);
498 			csd->read_blk_misalign = mmc_get_bits(raw_csd, 77, 1);
499 			csd->dsr_imp = mmc_get_bits(raw_csd, 76, 1);
500 			csd->vdd_r_curr_min = cur_min[mmc_get_bits(raw_csd, 59, 3)];
501 			csd->vdd_r_curr_max = cur_max[mmc_get_bits(raw_csd, 56, 3)];
502 			csd->vdd_w_curr_min = cur_min[mmc_get_bits(raw_csd, 53, 3)];
503 			csd->vdd_w_curr_max = cur_max[mmc_get_bits(raw_csd, 50, 3)];
504 			m = mmc_get_bits(raw_csd, 62, 12);
505 			e = mmc_get_bits(raw_csd, 47, 3);
506 			csd->capacity = ((1 + m) << (e + 2)) * csd->read_bl_len;
507 			csd->erase_blk_en = mmc_get_bits(raw_csd, 46, 1);
508 			csd->sector_size = mmc_get_bits(raw_csd, 39, 7);
509 			csd->wp_grp_size = mmc_get_bits(raw_csd, 32, 7);
510 			csd->wp_grp_enable = mmc_get_bits(raw_csd, 31, 1);
511 			csd->r2w_factor = 1 << mmc_get_bits(raw_csd, 26, 3);
512 			csd->write_bl_len = 1 << mmc_get_bits(raw_csd, 22, 4);
513 			csd->write_bl_partial = mmc_get_bits(raw_csd, 21, 1);
514 		} else if (v == 1) {
515 			panic("Write SDHC CSD parser");
516 		} else
517 			panic("unknown SD CSD version");
518 	} else {
519 		panic("Write a MMC CSD parser");
520 	}
521 }
522 
523 static int
524 mmc_all_send_cid(struct mmc_softc *sc, uint32_t *rawcid)
525 {
526 	struct mmc_command cmd;
527 	int err;
528 
529 	cmd.opcode = MMC_ALL_SEND_CID;
530 	cmd.arg = 0;
531 	cmd.flags = MMC_RSP_R2 | MMC_CMD_BCR;
532 	err = mmc_wait_for_cmd(sc, &cmd, 0);
533 	memcpy(rawcid, cmd.resp, 4 * sizeof(uint32_t));
534 	return (err);
535 }
536 
537 static int
538 mmc_send_csd(struct mmc_softc *sc, uint16_t rca, uint32_t *rawcid)
539 {
540 	struct mmc_command cmd;
541 	int err;
542 
543 	cmd.opcode = MMC_SEND_CSD;
544 	cmd.arg = rca << 16;
545 	cmd.flags = MMC_RSP_R2 | MMC_CMD_BCR;
546 	err = mmc_wait_for_cmd(sc, &cmd, 0);
547 	memcpy(rawcid, cmd.resp, 4 * sizeof(uint32_t));
548 	return (err);
549 }
550 
551 static int
552 mmc_send_relative_addr(struct mmc_softc *sc, uint32_t *resp)
553 {
554 	struct mmc_command cmd;
555 	int err;
556 
557 	cmd.opcode = SD_SEND_RELATIVE_ADDR;
558 	cmd.arg = 0;
559 	cmd.flags = MMC_RSP_R6 | MMC_CMD_BCR;
560 	err = mmc_wait_for_cmd(sc, &cmd, 0);
561 	*resp = cmd.resp[0];
562 	return (err);
563 }
564 
565 static void
566 mmc_discover_cards(struct mmc_softc *sc)
567 {
568 	struct mmc_ivars *ivar;
569 	int err;
570 	uint32_t resp;
571 	device_t child;
572 
573 	while (1) {
574 		ivar = malloc(sizeof(struct mmc_ivars), M_DEVBUF, M_WAITOK);
575 		if (!ivar)
576 			return;
577 		err = mmc_all_send_cid(sc, ivar->raw_cid);
578 		if (err == MMC_ERR_TIMEOUT)
579 			break;
580 		if (err != MMC_ERR_NONE) {
581 			printf("Error reading CID %d\n", err);
582 			break;
583 		}
584 		if (mmcbr_get_mode(sc->dev) == mode_sd) {
585 			ivar->mode = mode_sd;
586 			mmc_decode_cid(1, ivar->raw_cid, &ivar->cid);
587 			mmc_send_relative_addr(sc, &resp);
588 			ivar->rca = resp >> 16;
589 			// RO check
590 			mmc_send_csd(sc, ivar->rca, ivar->raw_csd);
591 			mmc_decode_csd(1, ivar->raw_csd, &ivar->csd);
592 			printf("SD CARD: %lld bytes\n", (long long)
593 			    ivar->csd.capacity);
594 			child = device_add_child(sc->dev, NULL, -1);
595 			device_set_ivars(child, ivar);
596 			return;
597 		}
598 		panic("Write MMC card code here");
599 	}
600 	free(ivar, M_DEVBUF);
601 }
602 
603 static void
604 mmc_go_discovery(struct mmc_softc *sc)
605 {
606 	uint32_t ocr;
607 	device_t dev;
608 
609 	dev = sc->dev;
610 	if (mmcbr_get_power_mode(dev) != power_on) {
611 		// First, try SD modes
612 		mmcbr_set_mode(dev, mode_sd);
613 		mmc_power_up(sc);
614 		mmcbr_set_bus_mode(dev, pushpull);
615 		mmc_idle_cards(sc);
616 		if (mmc_send_app_op_cond(sc, 0, &ocr) != MMC_ERR_NONE) {
617 			// Failed, try MMC
618 			mmcbr_set_mode(dev, mode_mmc);
619 			if (mmc_send_op_cond(sc, 0, &ocr) != MMC_ERR_NONE)
620 				return;	// Failed both, punt! XXX power down?
621 		}
622 		mmcbr_set_ocr(dev, mmc_select_vdd(sc, ocr));
623 		if (mmcbr_get_ocr(dev) != 0)
624 			mmc_idle_cards(sc);
625 	} else {
626 		mmcbr_set_bus_mode(dev, opendrain);
627 		mmcbr_set_clock(dev, mmcbr_get_f_min(dev));
628 		mmcbr_update_ios(dev);
629 		// XXX recompute vdd based on new cards?
630 	}
631 	/*
632 	 * Make sure that we have a mutually agreeable voltage to at least
633 	 * one card on the bus.
634 	 */
635 	if (mmcbr_get_ocr(dev) == 0)
636 		return;
637 	/*
638 	 * Reselect the cards after we've idled them above.
639 	 */
640 	if (mmcbr_get_mode(dev) == mode_sd)
641 		mmc_send_app_op_cond(sc, mmcbr_get_ocr(dev), NULL);
642 	else
643 		mmc_send_op_cond(sc, mmcbr_get_ocr(dev), NULL);
644 	mmc_discover_cards(sc);
645 
646 	mmcbr_set_bus_mode(dev, pushpull);
647 	mmcbr_update_ios(dev);
648 	bus_generic_attach(dev);
649 //	mmc_update_children_sysctl(dev);
650 }
651 
652 static int
653 mmc_calculate_clock(struct mmc_softc *sc)
654 {
655 	int max_dtr = 0;
656 	int nkid, i, f_min, f_max;
657 	device_t *kids;
658 
659 	f_min = mmcbr_get_f_min(sc->dev);
660 	f_max = mmcbr_get_f_max(sc->dev);
661 	max_dtr = f_max;
662 	if (device_get_children(sc->dev, &kids, &nkid) != 0)
663 		panic("can't get children");
664 	for (i = 0; i < nkid; i++)
665 		if (mmc_get_tran_speed(kids[i]) < max_dtr)
666 			max_dtr = mmc_get_tran_speed(kids[i]);
667 	free(kids, M_TEMP);
668 	device_printf(sc->dev, "setting transfer rate to %d.%03dMHz\n",
669 	    max_dtr / 1000000, (max_dtr / 1000) % 1000);
670 	return max_dtr;
671 }
672 
673 static void
674 mmc_scan(struct mmc_softc *sc)
675 {
676 	device_t dev;
677 
678 	dev = sc->dev;
679 	mmc_acquire_bus(dev, dev);
680 
681 	if (mmcbr_get_power_mode(dev) == power_on)
682 		mmc_rescan_cards(sc);
683 	mmc_go_discovery(sc);
684 	mmcbr_set_clock(dev, mmc_calculate_clock(sc));
685 	mmcbr_update_ios(dev);
686 
687 	mmc_release_bus(dev, dev);
688 	// XXX probe/attach/detach children?
689 }
690 
691 static int
692 mmc_read_ivar(device_t bus, device_t child, int which, u_char *result)
693 {
694 	struct mmc_ivars *ivar = device_get_ivars(child);
695 
696 	switch (which) {
697 	default:
698 		return (EINVAL);
699 	case MMC_IVAR_DSR_IMP:
700 		*(int *)result = ivar->csd.dsr_imp;
701 		break;
702 	case MMC_IVAR_MEDIA_SIZE:
703 		*(int *)result = ivar->csd.capacity;
704 		break;
705 	case MMC_IVAR_RCA:
706 		*(int *)result = ivar->rca;
707 		break;
708 	case MMC_IVAR_SECTOR_SIZE:
709 		*(int *)result = 512;
710 		break;
711 	case MMC_IVAR_TRAN_SPEED:
712 		*(int *)result = ivar->csd.tran_speed;
713 		break;
714 	}
715 	return (0);
716 }
717 
718 static int
719 mmc_write_ivar(device_t bus, device_t child, int which, uintptr_t value)
720 {
721 	// None are writable ATM
722 	switch (which) {
723 	default:
724 		return (EINVAL);
725 	}
726 	return (0);
727 }
728 
729 
730 static void
731 mmc_delayed_attach(void *xsc)
732 {
733 	struct mmc_softc *sc = xsc;
734 
735 	mmc_scan(sc);
736 	config_intrhook_disestablish(&sc->config_intrhook);
737 }
738 
739 static device_method_t mmc_methods[] = {
740 	/* device_if */
741 	DEVMETHOD(device_probe, mmc_probe),
742 	DEVMETHOD(device_attach, mmc_attach),
743 	DEVMETHOD(device_detach, mmc_detach),
744 
745 	/* Bus interface */
746 	DEVMETHOD(bus_read_ivar, mmc_read_ivar),
747 	DEVMETHOD(bus_write_ivar, mmc_write_ivar),
748 
749 	/* MMC Bus interface */
750 	DEVMETHOD(mmcbus_wait_for_request, mmc_wait_for_request),
751 	DEVMETHOD(mmcbus_acquire_bus, mmc_acquire_bus),
752 	DEVMETHOD(mmcbus_release_bus, mmc_release_bus),
753 
754 	{0, 0},
755 };
756 
757 static driver_t mmc_driver = {
758 	"mmc",
759 	mmc_methods,
760 	sizeof(struct mmc_softc),
761 };
762 static devclass_t mmc_devclass;
763 
764 
765 DRIVER_MODULE(mmc, at91_mci, mmc_driver, mmc_devclass, 0, 0);
766 DRIVER_MODULE(mmc, sdh, mmc_driver, mmc_devclass, 0, 0);
767