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      1 /*	$NetBSD: ld_sdmmc.c,v 1.45 2025/04/13 02:34:03 rin Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2008 KIYOHARA Takashi
      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 ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     18  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     19  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
     20  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     22  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     24  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
     25  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  *
     28  */
     29 
     30 #include <sys/cdefs.h>
     31 __KERNEL_RCSID(0, "$NetBSD: ld_sdmmc.c,v 1.45 2025/04/13 02:34:03 rin Exp $");
     32 
     33 #ifdef _KERNEL_OPT
     34 #include "opt_sdmmc.h"
     35 #endif
     36 
     37 #include <sys/param.h>
     38 #include <sys/types.h>
     39 
     40 #include <sys/buf.h>
     41 #include <sys/bufq.h>
     42 #include <sys/bus.h>
     43 #include <sys/device.h>
     44 #include <sys/disk.h>
     45 #include <sys/disklabel.h>
     46 #include <sys/dkio.h>
     47 #include <sys/endian.h>
     48 #include <sys/kernel.h>
     49 #include <sys/kmem.h>
     50 #include <sys/kthread.h>
     51 #include <sys/module.h>
     52 #include <sys/syslog.h>
     53 #include <sys/systm.h>
     54 
     55 #include <dev/ldvar.h>
     56 
     57 #include <dev/sdmmc/sdmmcvar.h>
     58 
     59 #include "ioconf.h"
     60 
     61 #ifdef LD_SDMMC_DEBUG
     62 #define DPRINTF(s)	printf s
     63 #else
     64 #define DPRINTF(s)	__nothing
     65 #endif
     66 
     67 #define	LD_SDMMC_IORETRIES	5	/* number of retries before giving up */
     68 #define	RECOVERYTIME		hz/2	/* time to wait before retrying a cmd */
     69 
     70 #define	LD_SDMMC_MAXQUEUECNT	4	/* number of queued bio requests */
     71 #define	LD_SDMMC_MAXTASKCNT	8	/* number of tasks in task pool */
     72 
     73 struct ld_sdmmc_softc;
     74 
     75 struct ld_sdmmc_task {
     76 	struct sdmmc_task task;
     77 	struct ld_sdmmc_softc *task_sc;
     78 
     79 	struct buf *task_bp;
     80 	int task_retries; /* number of xfer retry */
     81 	struct callout task_restart_ch;
     82 
     83 	bool task_poll;
     84 	int *task_errorp;
     85 
     86 	TAILQ_ENTRY(ld_sdmmc_task) task_entry;
     87 };
     88 
     89 struct ld_sdmmc_softc {
     90 	struct ld_softc sc_ld;
     91 	int sc_hwunit;
     92 	char *sc_typename;
     93 	struct sdmmc_function *sc_sf;
     94 
     95 	kmutex_t sc_lock;
     96 	kcondvar_t sc_cv;
     97 	TAILQ_HEAD(, ld_sdmmc_task) sc_freeq;
     98 	TAILQ_HEAD(, ld_sdmmc_task) sc_xferq;
     99 	unsigned sc_busy;
    100 	bool sc_dying;
    101 
    102 	struct evcnt sc_ev_discard;	/* discard counter */
    103 	struct evcnt sc_ev_discarderr;	/* discard error counter */
    104 	struct evcnt sc_ev_discardbusy;	/* discard busy counter */
    105 	struct evcnt sc_ev_cachesyncbusy; /* cache sync busy counter */
    106 
    107 	struct ld_sdmmc_task sc_task[LD_SDMMC_MAXTASKCNT];
    108 };
    109 
    110 static int ld_sdmmc_match(device_t, cfdata_t, void *);
    111 static void ld_sdmmc_attach(device_t, device_t, void *);
    112 static int ld_sdmmc_detach(device_t, int);
    113 
    114 static int ld_sdmmc_dump(struct ld_softc *, void *, daddr_t, int);
    115 static int ld_sdmmc_start(struct ld_softc *, struct buf *);
    116 static void ld_sdmmc_restart(void *);
    117 static int ld_sdmmc_discard(struct ld_softc *, struct buf *);
    118 static int ld_sdmmc_ioctl(struct ld_softc *, u_long, void *, int32_t, bool);
    119 
    120 static void ld_sdmmc_doattach(void *);
    121 static void ld_sdmmc_dobio(void *);
    122 static void ld_sdmmc_dodiscard(void *);
    123 
    124 CFATTACH_DECL_NEW(ld_sdmmc, sizeof(struct ld_sdmmc_softc),
    125     ld_sdmmc_match, ld_sdmmc_attach, ld_sdmmc_detach, NULL);
    126 
    127 static struct ld_sdmmc_task *
    128 ld_sdmmc_task_get(struct ld_sdmmc_softc *sc)
    129 {
    130 	struct ld_sdmmc_task *task;
    131 
    132 	KASSERT(mutex_owned(&sc->sc_lock));
    133 
    134 	if (sc->sc_dying || (task = TAILQ_FIRST(&sc->sc_freeq)) == NULL)
    135 		return NULL;
    136 	TAILQ_REMOVE(&sc->sc_freeq, task, task_entry);
    137 	TAILQ_INSERT_TAIL(&sc->sc_xferq, task, task_entry);
    138 	KASSERT(task->task_bp == NULL);
    139 	KASSERT(task->task_errorp == NULL);
    140 
    141 	return task;
    142 }
    143 
    144 static void
    145 ld_sdmmc_task_put(struct ld_sdmmc_softc *sc, struct ld_sdmmc_task *task)
    146 {
    147 
    148 	KASSERT(mutex_owned(&sc->sc_lock));
    149 
    150 	TAILQ_REMOVE(&sc->sc_xferq, task, task_entry);
    151 	TAILQ_INSERT_TAIL(&sc->sc_freeq, task, task_entry);
    152 	task->task_bp = NULL;
    153 	task->task_errorp = NULL;
    154 }
    155 
    156 static void
    157 ld_sdmmc_task_cancel(struct ld_sdmmc_softc *sc, struct ld_sdmmc_task *task)
    158 {
    159 	struct buf *bp;
    160 	int *errorp;
    161 
    162 	KASSERT(mutex_owned(&sc->sc_lock));
    163 	KASSERT(sc->sc_dying);
    164 
    165 	/*
    166 	 * Either the callout or the task may be pending, but not both.
    167 	 * First, determine whether the callout is pending.
    168 	 */
    169 	if (callout_pending(&task->task_restart_ch) ||
    170 	    callout_invoking(&task->task_restart_ch)) {
    171 		/*
    172 		 * The callout either is pending, or just started but
    173 		 * is waiting for us to release the lock.  At this
    174 		 * point, it will notice sc->sc_dying and give up, so
    175 		 * just wait for it to complete and then we will
    176 		 * release everything.
    177 		 */
    178 		callout_halt(&task->task_restart_ch, &sc->sc_lock);
    179 	} else {
    180 		/*
    181 		 * If the callout is running, it has just scheduled, so
    182 		 * after we wait for the callout to finish running, the
    183 		 * task is either pending or running.  If the task is
    184 		 * already running, it will notice sc->sc_dying and
    185 		 * give up; otherwise we have to release everything.
    186 		 */
    187 		callout_halt(&task->task_restart_ch, &sc->sc_lock);
    188 		if (!sdmmc_del_task(sc->sc_sf->sc, &task->task, &sc->sc_lock))
    189 			return; /* task already started, let it clean up */
    190 	}
    191 
    192 	/*
    193 	 * It is our responsibility to clean up.  Move it from xferq
    194 	 * back to freeq and make sure to notify anyone waiting that
    195 	 * it's finished.
    196 	 */
    197 	bp = task->task_bp;
    198 	errorp = task->task_errorp;
    199 	ld_sdmmc_task_put(sc, task);
    200 
    201 	/*
    202 	 * If the task was for an asynchronous I/O xfer, fail the I/O
    203 	 * xfer, with the softc lock dropped since this is a callback
    204 	 * into arbitrary other subsystems.
    205 	 */
    206 	if (bp) {
    207 		mutex_exit(&sc->sc_lock);
    208 		/*
    209 		 * XXX We assume that the same sequence works for bio
    210 		 * and discard -- that lddiscardend is just the same as
    211 		 * setting bp->b_resid = bp->b_bcount in the event of
    212 		 * error and then calling lddone.
    213 		 */
    214 		bp->b_error = ENXIO;
    215 		bp->b_resid = bp->b_bcount;
    216 		lddone(&sc->sc_ld, bp);
    217 		mutex_enter(&sc->sc_lock);
    218 	}
    219 
    220 	/*
    221 	 * If the task was for a synchronous operation (cachesync),
    222 	 * then just set the error indicator and wake up the waiter.
    223 	 */
    224 	if (errorp) {
    225 		*errorp = ENXIO;
    226 		cv_broadcast(&sc->sc_cv);
    227 	}
    228 }
    229 
    230 /* ARGSUSED */
    231 static int
    232 ld_sdmmc_match(device_t parent, cfdata_t match, void *aux)
    233 {
    234 	struct sdmmc_softc *sdmsc = device_private(parent);
    235 
    236 	if (ISSET(sdmsc->sc_flags, SMF_MEM_MODE))
    237 		return 1;
    238 	return 0;
    239 }
    240 
    241 /* ARGSUSED */
    242 static void
    243 ld_sdmmc_attach(device_t parent, device_t self, void *aux)
    244 {
    245 	struct ld_sdmmc_softc *sc = device_private(self);
    246 	struct sdmmc_attach_args *sa = aux;
    247 	struct ld_softc *ld = &sc->sc_ld;
    248 	struct ld_sdmmc_task *task;
    249 	struct lwp *lwp;
    250 	const char *cardtype;
    251 	int i;
    252 
    253 	ld->sc_dv = self;
    254 
    255 	aprint_normal(": <0x%02x:0x%04x:%s:0x%02x:0x%08x:0x%03x>\n",
    256 	    sa->sf->cid.mid, sa->sf->cid.oid, sa->sf->cid.pnm,
    257 	    sa->sf->cid.rev, sa->sf->cid.psn, sa->sf->cid.mdt);
    258 	aprint_naive("\n");
    259 
    260 	if (ISSET(sa->sf->sc->sc_flags, SMF_SD_MODE)) {
    261 		cardtype = "SD card";
    262 	} else {
    263 		cardtype = "MMC";
    264 	}
    265 	sc->sc_typename = kmem_asprintf("%s 0x%02x:0x%04x:%s",
    266 	    cardtype, sa->sf->cid.mid, sa->sf->cid.oid, sa->sf->cid.pnm);
    267 
    268 	evcnt_attach_dynamic(&sc->sc_ev_discard, EVCNT_TYPE_MISC,
    269 	    NULL, device_xname(self), "sdmmc discard count");
    270 	evcnt_attach_dynamic(&sc->sc_ev_discarderr, EVCNT_TYPE_MISC,
    271 	    NULL, device_xname(self), "sdmmc discard errors");
    272 	evcnt_attach_dynamic(&sc->sc_ev_discardbusy, EVCNT_TYPE_MISC,
    273 	    NULL, device_xname(self), "sdmmc discard busy");
    274 
    275 	mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_SDMMC);
    276 	cv_init(&sc->sc_cv, "ldsdmmc");
    277 	TAILQ_INIT(&sc->sc_freeq);
    278 	TAILQ_INIT(&sc->sc_xferq);
    279 	sc->sc_dying = false;
    280 
    281 	const int ntask = __arraycount(sc->sc_task);
    282 	for (i = 0; i < ntask; i++) {
    283 		task = &sc->sc_task[i];
    284 		task->task_sc = sc;
    285 		callout_init(&task->task_restart_ch, CALLOUT_MPSAFE);
    286 		TAILQ_INSERT_TAIL(&sc->sc_freeq, task, task_entry);
    287 	}
    288 
    289 	sc->sc_hwunit = 0;	/* always 0? */
    290 	sc->sc_sf = sa->sf;
    291 
    292 	ld->sc_flags = LDF_ENABLED | LDF_MPSAFE;
    293 	ld->sc_secperunit = sc->sc_sf->csd.capacity;
    294 	ld->sc_secsize = SDMMC_SECTOR_SIZE;
    295 	ld->sc_maxxfer = MAXPHYS;
    296 	ld->sc_maxqueuecnt = LD_SDMMC_MAXQUEUECNT;
    297 	ld->sc_dump = ld_sdmmc_dump;
    298 	ld->sc_start = ld_sdmmc_start;
    299 	ld->sc_discard = ld_sdmmc_discard;
    300 	ld->sc_ioctl = ld_sdmmc_ioctl;
    301 	ld->sc_typename = sc->sc_typename;
    302 
    303 	/*
    304 	 * Defer attachment of ld + disk subsystem to a thread.
    305 	 *
    306 	 * This is necessary because wedge autodiscover needs to
    307 	 * open and call into the ld driver, which could deadlock
    308 	 * when the sdmmc driver isn't ready in early bootstrap.
    309 	 *
    310 	 * Don't mark thread as MPSAFE to keep aprint output sane.
    311 	 */
    312 	config_pending_incr(self);
    313 	if (kthread_create(PRI_NONE, 0, NULL,
    314 	    ld_sdmmc_doattach, sc, &lwp, "%sattach", device_xname(self))) {
    315 		aprint_error_dev(self, "couldn't create thread\n");
    316 	}
    317 }
    318 
    319 static void
    320 ld_sdmmc_doattach(void *arg)
    321 {
    322 	struct ld_sdmmc_softc *sc = (struct ld_sdmmc_softc *)arg;
    323 	struct ld_softc *ld = &sc->sc_ld;
    324 	struct sdmmc_softc *ssc = device_private(device_parent(ld->sc_dv));
    325 	const u_int emmc_cache_size = sc->sc_sf->ext_csd.cache_size;
    326 	const bool sd_cache = sc->sc_sf->ssr.cache;
    327 	char buf[sizeof("9999 KB")];
    328 
    329 	ldattach(ld, BUFQ_DISK_DEFAULT_STRAT);
    330 	aprint_normal_dev(ld->sc_dv, "%d-bit width,", sc->sc_sf->width);
    331 	if (ssc->sc_transfer_mode != NULL)
    332 		aprint_normal(" %s,", ssc->sc_transfer_mode);
    333 	if (emmc_cache_size > 0) {
    334 		format_bytes(buf, sizeof(buf), emmc_cache_size);
    335 		aprint_normal(" %s cache%s,", buf,
    336 		    ISSET(sc->sc_sf->flags, SFF_CACHE_ENABLED) ? "" :
    337 		    " (disabled)");
    338 	} else if (sd_cache) {
    339 		aprint_normal(" Cache%s,",
    340 		    ISSET(sc->sc_sf->flags, SFF_CACHE_ENABLED) ? "" :
    341 		    " (disabled)");
    342 	}
    343 	if ((ssc->sc_busclk / 1000) != 0)
    344 		aprint_normal(" %u.%03u MHz\n",
    345 		    ssc->sc_busclk / 1000, ssc->sc_busclk % 1000);
    346 	else
    347 		aprint_normal(" %u KHz\n", ssc->sc_busclk % 1000);
    348 	config_pending_decr(ld->sc_dv);
    349 	kthread_exit(0);
    350 }
    351 
    352 static int
    353 ld_sdmmc_detach(device_t dev, int flags)
    354 {
    355 	struct ld_sdmmc_softc *sc = device_private(dev);
    356 	struct ld_softc *ld = &sc->sc_ld;
    357 	struct ld_sdmmc_task *task;
    358 	int error, i;
    359 
    360 	/*
    361 	 * Block new xfers, or fail if the disk is still open and the
    362 	 * detach isn't forced.  After this point, we are committed to
    363 	 * detaching.
    364 	 */
    365 	error = ldbegindetach(ld, flags);
    366 	if (error)
    367 		return error;
    368 
    369 	/*
    370 	 * Abort all pending tasks, and wait for all pending waiters to
    371 	 * notice that we're gone.
    372 	 */
    373 	mutex_enter(&sc->sc_lock);
    374 	sc->sc_dying = true;
    375 	while ((task = TAILQ_FIRST(&sc->sc_xferq)) != NULL)
    376 		ld_sdmmc_task_cancel(sc, task);
    377 	while (sc->sc_busy)
    378 		cv_wait(&sc->sc_cv, &sc->sc_lock);
    379 	mutex_exit(&sc->sc_lock);
    380 
    381 	/* Done!  Destroy the disk.  */
    382 	ldenddetach(ld);
    383 
    384 	KASSERT(TAILQ_EMPTY(&sc->sc_xferq));
    385 
    386 	for (i = 0; i < __arraycount(sc->sc_task); i++)
    387 		callout_destroy(&sc->sc_task[i].task_restart_ch);
    388 
    389 	cv_destroy(&sc->sc_cv);
    390 	mutex_destroy(&sc->sc_lock);
    391 
    392 	evcnt_detach(&sc->sc_ev_discard);
    393 	evcnt_detach(&sc->sc_ev_discarderr);
    394 	evcnt_detach(&sc->sc_ev_discardbusy);
    395 	kmem_free(sc->sc_typename, strlen(sc->sc_typename) + 1);
    396 
    397 	return 0;
    398 }
    399 
    400 static int
    401 ld_sdmmc_start(struct ld_softc *ld, struct buf *bp)
    402 {
    403 	struct ld_sdmmc_softc *sc = device_private(ld->sc_dv);
    404 	struct ld_sdmmc_task *task;
    405 	int error;
    406 
    407 	mutex_enter(&sc->sc_lock);
    408 	if ((task = ld_sdmmc_task_get(sc)) == NULL) {
    409 		error = EAGAIN;
    410 		goto out;
    411 	}
    412 
    413 	task->task_bp = bp;
    414 	task->task_retries = 0;
    415 	sdmmc_init_task(&task->task, ld_sdmmc_dobio, task);
    416 
    417 	sdmmc_add_task(sc->sc_sf->sc, &task->task);
    418 
    419 	/* Success!  The xfer is now queued.  */
    420 	error = 0;
    421 
    422 out:	mutex_exit(&sc->sc_lock);
    423 	return error;
    424 }
    425 
    426 static void
    427 ld_sdmmc_restart(void *arg)
    428 {
    429 	struct ld_sdmmc_task *task = (struct ld_sdmmc_task *)arg;
    430 	struct ld_sdmmc_softc *sc = task->task_sc;
    431 	struct buf *bp = task->task_bp;
    432 
    433 	bp->b_resid = bp->b_bcount;
    434 
    435 	mutex_enter(&sc->sc_lock);
    436 	callout_ack(&task->task_restart_ch);
    437 	if (!sc->sc_dying)
    438 		sdmmc_add_task(sc->sc_sf->sc, &task->task);
    439 	mutex_exit(&sc->sc_lock);
    440 }
    441 
    442 static void
    443 ld_sdmmc_dobio(void *arg)
    444 {
    445 	struct ld_sdmmc_task *task = (struct ld_sdmmc_task *)arg;
    446 	struct ld_sdmmc_softc *sc = task->task_sc;
    447 	struct buf *bp = task->task_bp;
    448 	int error;
    449 
    450 	/*
    451 	 * I/O operation
    452 	 */
    453 	DPRINTF(("%s: I/O operation (dir=%s, blkno=0x%jx, bcnt=0x%x)\n",
    454 	    device_xname(sc->sc_ld.sc_dv), bp->b_flags & B_READ ? "IN" : "OUT",
    455 	    bp->b_rawblkno, bp->b_bcount));
    456 
    457 	/* is everything done in terms of blocks? */
    458 	if (bp->b_rawblkno >= sc->sc_sf->csd.capacity) {
    459 		/* trying to read or write past end of device */
    460 		aprint_error_dev(sc->sc_ld.sc_dv,
    461 		    "blkno 0x%" PRIu64 " exceeds capacity %d\n",
    462 		    bp->b_rawblkno, sc->sc_sf->csd.capacity);
    463 		bp->b_error = EINVAL;
    464 		bp->b_resid = bp->b_bcount;
    465 
    466 		goto done;
    467 	}
    468 
    469 	if (bp->b_flags & B_READ)
    470 		error = sdmmc_mem_read_block(sc->sc_sf, bp->b_rawblkno,
    471 		    bp->b_data, bp->b_bcount);
    472 	else
    473 		error = sdmmc_mem_write_block(sc->sc_sf, bp->b_rawblkno,
    474 		    bp->b_data, bp->b_bcount);
    475 	if (error) {
    476 		if (task->task_retries < LD_SDMMC_IORETRIES) {
    477 			struct dk_softc *dksc = &sc->sc_ld.sc_dksc;
    478 			struct cfdriver *cd = device_cfdriver(dksc->sc_dev);
    479 
    480 			diskerr(bp, cd->cd_name, "error", LOG_PRINTF, 0,
    481 				dksc->sc_dkdev.dk_label);
    482 			printf(", retrying\n");
    483 			task->task_retries++;
    484 			mutex_enter(&sc->sc_lock);
    485 			if (sc->sc_dying) {
    486 				bp->b_resid = bp->b_bcount;
    487 				bp->b_error = error;
    488 				goto done_locked;
    489 			} else {
    490 				callout_reset(&task->task_restart_ch,
    491 				    RECOVERYTIME, ld_sdmmc_restart, task);
    492 			}
    493 			mutex_exit(&sc->sc_lock);
    494 			return;
    495 		}
    496 		bp->b_error = error;
    497 		bp->b_resid = bp->b_bcount;
    498 	} else {
    499 		bp->b_resid = 0;
    500 	}
    501 
    502 done:
    503 	/* Dissociate the task from the I/O xfer and release it.  */
    504 	mutex_enter(&sc->sc_lock);
    505 done_locked:
    506 	ld_sdmmc_task_put(sc, task);
    507 	mutex_exit(&sc->sc_lock);
    508 
    509 	lddone(&sc->sc_ld, bp);
    510 }
    511 
    512 static int
    513 ld_sdmmc_dump(struct ld_softc *ld, void *data, daddr_t blkno, int blkcnt)
    514 {
    515 	struct ld_sdmmc_softc *sc = device_private(ld->sc_dv);
    516 
    517 	if (blkno + blkcnt - 1 >= sc->sc_sf->csd.capacity)
    518 		return EIO;
    519 
    520 	return sdmmc_mem_write_block(sc->sc_sf, blkno, data,
    521 	    blkcnt * ld->sc_secsize);
    522 }
    523 
    524 static void
    525 ld_sdmmc_dodiscard(void *arg)
    526 {
    527 	struct ld_sdmmc_task *task = arg;
    528 	struct ld_sdmmc_softc *sc = task->task_sc;
    529 	struct buf *bp = task->task_bp;
    530 	uint32_t sblkno, nblks;
    531 	int error;
    532 
    533 	/* first and last block to erase */
    534 	sblkno = bp->b_rawblkno;
    535 	nblks  = howmany(bp->b_bcount, sc->sc_ld.sc_secsize);
    536 
    537 	/* An error from discard is non-fatal */
    538 	error = sdmmc_mem_discard(sc->sc_sf, sblkno, sblkno + nblks - 1);
    539 
    540 	/* Count error or success and release the task.  */
    541 	mutex_enter(&sc->sc_lock);
    542 	if (error)
    543 		sc->sc_ev_discarderr.ev_count++;
    544 	else
    545 		sc->sc_ev_discard.ev_count++;
    546 	ld_sdmmc_task_put(sc, task);
    547 	mutex_exit(&sc->sc_lock);
    548 
    549 	/* Record the error and notify the xfer of completion.  */
    550 	if (error)
    551 		bp->b_error = error;
    552 	lddiscardend(&sc->sc_ld, bp);
    553 }
    554 
    555 static int
    556 ld_sdmmc_discard(struct ld_softc *ld, struct buf *bp)
    557 {
    558 	struct ld_sdmmc_softc *sc = device_private(ld->sc_dv);
    559 	struct ld_sdmmc_task *task;
    560 	int error;
    561 
    562 	mutex_enter(&sc->sc_lock);
    563 
    564 	/* Acquire a free task, or drop the request altogether.  */
    565 	if ((task = ld_sdmmc_task_get(sc)) == NULL) {
    566 		sc->sc_ev_discardbusy.ev_count++;
    567 		error = EBUSY;
    568 		goto out;
    569 	}
    570 
    571 	/* Set up the task and schedule it.  */
    572 	task->task_bp = bp;
    573 	sdmmc_init_task(&task->task, ld_sdmmc_dodiscard, task);
    574 
    575 	sdmmc_add_task(sc->sc_sf->sc, &task->task);
    576 
    577 	/* Success!  The request is queued.  */
    578 	error = 0;
    579 
    580 out:	mutex_exit(&sc->sc_lock);
    581 	return error;
    582 }
    583 
    584 static void
    585 ld_sdmmc_docachesync(void *arg)
    586 {
    587 	struct ld_sdmmc_task *task = arg;
    588 	struct ld_sdmmc_softc *sc = task->task_sc;
    589 	int error;
    590 
    591 	/* Flush the cache.  */
    592 	error = sdmmc_mem_flush_cache(sc->sc_sf, task->task_poll);
    593 
    594 	mutex_enter(&sc->sc_lock);
    595 
    596 	/* Notify the other thread that we're done; pass on the error.  */
    597 	*task->task_errorp = error;
    598 	cv_broadcast(&sc->sc_cv);
    599 
    600 	/* Release the task.  */
    601 	ld_sdmmc_task_put(sc, task);
    602 
    603 	mutex_exit(&sc->sc_lock);
    604 }
    605 
    606 static int
    607 ld_sdmmc_cachesync(struct ld_softc *ld, bool poll)
    608 {
    609 	struct ld_sdmmc_softc *sc = device_private(ld->sc_dv);
    610 	struct sdmmc_softc *sdmmc = device_private(device_parent(ld->sc_dv));
    611 	struct ld_sdmmc_task *task;
    612 	int error = -1;
    613 
    614 	/*
    615 	 * If we come here through the sdmmc discovery task, we can't
    616 	 * wait for a new task because the new task can't even begin
    617 	 * until the sdmmc discovery task has completed.
    618 	 *
    619 	 * XXX This is wrong, because there may already be queued I/O
    620 	 * tasks ahead of us.  Fixing this properly requires doing
    621 	 * discovery in a separate thread.  But this should avoid the
    622 	 * deadlock of PR kern/57870 (https://gnats.NetBSD.org/57870)
    623 	 * until we do split that up.
    624 	 */
    625 	if (curlwp == sdmmc->sc_tskq_lwp)
    626 		return sdmmc_mem_flush_cache(sc->sc_sf, poll);
    627 
    628 	mutex_enter(&sc->sc_lock);
    629 
    630 	/* Acquire a free task, or fail with EBUSY.  */
    631 	if ((task = ld_sdmmc_task_get(sc)) == NULL) {
    632 		sc->sc_ev_cachesyncbusy.ev_count++;
    633 		error = EBUSY;
    634 		goto out;
    635 	}
    636 
    637 	/* Set up the task and schedule it.  */
    638 	task->task_poll = poll;
    639 	task->task_errorp = &error;
    640 	sdmmc_init_task(&task->task, ld_sdmmc_docachesync, task);
    641 
    642 	sdmmc_add_task(sc->sc_sf->sc, &task->task);
    643 
    644 	/*
    645 	 * Wait for the task to complete.  If the device is yanked,
    646 	 * detach will notify us.  Keep the busy count up until we're
    647 	 * done waiting so that the softc doesn't go away until we're
    648 	 * done.
    649 	 */
    650 	sc->sc_busy++;
    651 	KASSERT(sc->sc_busy <= LD_SDMMC_MAXTASKCNT);
    652 	while (error == -1)
    653 		cv_wait(&sc->sc_cv, &sc->sc_lock);
    654 	if (--sc->sc_busy == 0)
    655 		cv_broadcast(&sc->sc_cv);
    656 
    657 out:	mutex_exit(&sc->sc_lock);
    658 	return error;
    659 }
    660 
    661 static int
    662 ld_sdmmc_ioctl(struct ld_softc *ld, u_long cmd, void *addr, int32_t flag,
    663     bool poll)
    664 {
    665 
    666 	switch (cmd) {
    667 	case DIOCCACHESYNC:
    668 		return ld_sdmmc_cachesync(ld, poll);
    669 	default:
    670 		return EPASSTHROUGH;
    671 	}
    672 }
    673 
    674 MODULE(MODULE_CLASS_DRIVER, ld_sdmmc, "ld");
    675 
    676 #ifdef _MODULE
    677 /*
    678  * XXX Don't allow ioconf.c to redefine the "struct cfdriver ld_cd"
    679  * XXX it will be defined in the common-code module
    680  */
    681 #undef  CFDRIVER_DECL
    682 #define CFDRIVER_DECL(name, class, attr)
    683 #include "ioconf.c"
    684 #endif
    685 
    686 static int
    687 ld_sdmmc_modcmd(modcmd_t cmd, void *opaque)
    688 {
    689 #ifdef _MODULE
    690 	/*
    691 	 * We ignore the cfdriver_vec[] that ioconf provides, since
    692 	 * the cfdrivers are attached already.
    693 	 */
    694 	static struct cfdriver * const no_cfdriver_vec[] = { NULL };
    695 #endif
    696 	int error = 0;
    697 
    698 #ifdef _MODULE
    699 	switch (cmd) {
    700 	case MODULE_CMD_INIT:
    701 		error = config_init_component(no_cfdriver_vec,
    702 		    cfattach_ioconf_ld_sdmmc, cfdata_ioconf_ld_sdmmc);
    703 		break;
    704 	case MODULE_CMD_FINI:
    705 		error = config_fini_component(no_cfdriver_vec,
    706 		    cfattach_ioconf_ld_sdmmc, cfdata_ioconf_ld_sdmmc);
    707 		break;
    708 	default:
    709 		error = ENOTTY;
    710 		break;
    711 	}
    712 #endif
    713 
    714 	return error;
    715 }
    716