The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/dev/altera/sdcard/altera_sdcard.c

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    1 /*-
    2  * Copyright (c) 2012 Robert N. M. Watson
    3  * All rights reserved.
    4  *
    5  * This software was developed by SRI International and the University of
    6  * Cambridge Computer Laboratory under DARPA/AFRL contract (FA8750-10-C-0237)
    7  * ("CTSRD"), as part of the DARPA CRASH research programme.
    8  *
    9  * Redistribution and use in source and binary forms, with or without
   10  * modification, are permitted provided that the following conditions
   11  * are met:
   12  * 1. Redistributions of source code must retain the above copyright
   13  *    notice, this list of conditions and the following disclaimer.
   14  * 2. Redistributions in binary form must reproduce the above copyright
   15  *    notice, this list of conditions and the following disclaimer in the
   16  *    documentation and/or other materials provided with the distribution.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   28  * SUCH DAMAGE.
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD$");
   33 
   34 #include "opt_altera_sdcard.h"
   35 
   36 #include <sys/param.h>
   37 #include <sys/bus.h>
   38 #include <sys/condvar.h>
   39 #include <sys/conf.h>
   40 #include <sys/bio.h>
   41 #include <sys/kernel.h>
   42 #include <sys/lock.h>
   43 #include <sys/malloc.h>
   44 #include <sys/module.h>
   45 #include <sys/mutex.h>
   46 #include <sys/rman.h>
   47 #include <sys/systm.h>
   48 #include <sys/taskqueue.h>
   49 
   50 #include <machine/bus.h>
   51 #include <machine/resource.h>
   52 
   53 #include <geom/geom_disk.h>
   54 
   55 #include <dev/altera/sdcard/altera_sdcard.h>
   56 
   57 /*
   58  * Device driver for the Altera University Program Secure Data Card IP Core,
   59  * as described in the similarly named SOPC Builder IP Core specification.
   60  * This soft core is not a full SD host controller interface (SDHCI) but
   61  * instead provides a set of memory mapped registers and memory buffer that
   62  * mildly abstract the SD Card protocol, but without providing DMA or
   63  * interrupts.  However, it does hide the details of voltage and
   64  * communications negotiation.  This driver implements disk(9), but due to the
   65  * lack of interrupt support, must rely on timer-driven polling to determine
   66  * when I/Os have completed.
   67  *
   68  * TODO:
   69  *
   70  * 1. Implement DISKFLAG_CANDELETE / SD Card sector erase support.
   71  * 2. Implement d_ident from SD Card CID serial number field.
   72  * 3. Handle read-only SD Cards.
   73  * 4. Tune timeouts based on real-world SD Card speeds.
   74  */
   75 devclass_t      altera_sdcard_devclass;
   76 
   77 void
   78 altera_sdcard_attach(struct altera_sdcard_softc *sc)
   79 {
   80 
   81         ALTERA_SDCARD_LOCK_INIT(sc);
   82         ALTERA_SDCARD_CONDVAR_INIT(sc);
   83         sc->as_disk = NULL;
   84         bioq_init(&sc->as_bioq);
   85         sc->as_currentbio = NULL;
   86         sc->as_state = ALTERA_SDCARD_STATE_NOCARD;
   87         sc->as_taskqueue = taskqueue_create("altera_sdcardc taskq", M_WAITOK,
   88             taskqueue_thread_enqueue, &sc->as_taskqueue);
   89         taskqueue_start_threads(&sc->as_taskqueue, 1, PI_DISK,
   90             "altera_sdcardc%d taskqueue", sc->as_unit);
   91         TIMEOUT_TASK_INIT(sc->as_taskqueue, &sc->as_task, 0,
   92             altera_sdcard_task, sc);
   93 
   94         /*
   95          * Kick off timer-driven processing with a manual poll so that we
   96          * synchronously detect an already-inserted SD Card during the boot or
   97          * other driver attach point.
   98          */
   99         altera_sdcard_task(sc, 1);
  100 }
  101 
  102 void
  103 altera_sdcard_detach(struct altera_sdcard_softc *sc)
  104 {
  105 
  106         KASSERT(sc->as_taskqueue != NULL, ("%s: taskqueue not present",
  107             __func__));
  108 
  109         /*
  110          * Winding down the driver on detach is a bit complex.  Update the
  111          * flags to indicate that a detach has been requested, and then wait
  112          * for in-progress I/O to wind down before continuing.
  113          */
  114         ALTERA_SDCARD_LOCK(sc);
  115         sc->as_flags |= ALTERA_SDCARD_FLAG_DETACHREQ;
  116         while (sc->as_state != ALTERA_SDCARD_STATE_DETACHED)
  117                 ALTERA_SDCARD_CONDVAR_WAIT(sc);
  118         ALTERA_SDCARD_UNLOCK(sc);
  119 
  120         /*
  121          * Now wait for the possibly still executing taskqueue to drain.  In
  122          * principle no more events will be scheduled as we've transitioned to
  123          * a detached state, but there might still be a request in execution.
  124          */
  125         while (taskqueue_cancel_timeout(sc->as_taskqueue, &sc->as_task, NULL))
  126                 taskqueue_drain_timeout(sc->as_taskqueue, &sc->as_task);
  127 
  128         /*
  129          * Simulate a disk removal if one is present to deal with any pending
  130          * or queued I/O.
  131          */
  132         if (sc->as_disk != NULL)
  133                 altera_sdcard_disk_remove(sc);
  134         KASSERT(bioq_first(&sc->as_bioq) == NULL,
  135             ("%s: non-empty bioq", __func__));
  136 
  137         /*
  138          * Free any remaining allocated resources.
  139          */
  140         taskqueue_free(sc->as_taskqueue);
  141         sc->as_taskqueue = NULL;
  142         ALTERA_SDCARD_CONDVAR_DESTROY(sc);
  143         ALTERA_SDCARD_LOCK_DESTROY(sc);
  144 }
  145 
  146 /*
  147  * Set up and start the next I/O.  Transition to the I/O state, but allow the
  148  * caller to schedule the next timeout, as this may be called either from an
  149  * initial attach context, or from the task queue, which requires different
  150  * behaviour.
  151  */
  152 static void
  153 altera_sdcard_nextio(struct altera_sdcard_softc *sc)
  154 {
  155         struct bio *bp;
  156 
  157         ALTERA_SDCARD_LOCK_ASSERT(sc);
  158         KASSERT(sc->as_currentbio == NULL,
  159             ("%s: bio already active", __func__));
  160 
  161         bp = bioq_takefirst(&sc->as_bioq);
  162         if (bp == NULL)
  163                 panic("%s: bioq empty", __func__);
  164         altera_sdcard_io_start(sc, bp);
  165         sc->as_state = ALTERA_SDCARD_STATE_IO;
  166 }
  167 
  168 static void
  169 altera_sdcard_task_nocard(struct altera_sdcard_softc *sc)
  170 {
  171 
  172         ALTERA_SDCARD_LOCK_ASSERT(sc);
  173 
  174         /*
  175          * Handle device driver detach.
  176          */
  177         if (sc->as_flags & ALTERA_SDCARD_FLAG_DETACHREQ) {
  178                 sc->as_state = ALTERA_SDCARD_STATE_DETACHED;
  179                 return;
  180         }
  181 
  182         /*
  183          * If there is no card insertion, remain in NOCARD.
  184          */
  185         if (!(altera_sdcard_read_asr(sc) & ALTERA_SDCARD_ASR_CARDPRESENT))
  186                 return;
  187 
  188         /*
  189          * Read the CSD -- it may contain values that the driver can't handle,
  190          * either because of an unsupported version/feature, or because the
  191          * card is misbehaving.  This triggers a transition to
  192          * ALTERA_SDCARD_STATE_BADCARD.  We rely on the CSD read to print a
  193          * banner about how the card is problematic, since it has more
  194          * information.  The bad card state allows us to print that banner
  195          * once rather than each time we notice the card is there, and still
  196          * bad.
  197          */
  198         if (altera_sdcard_read_csd(sc) != 0) {
  199                 sc->as_state = ALTERA_SDCARD_STATE_BADCARD;
  200                 return;
  201         }
  202 
  203         /*
  204          * Process card insertion and upgrade to the IDLE state.
  205          */
  206         altera_sdcard_disk_insert(sc);
  207         sc->as_state = ALTERA_SDCARD_STATE_IDLE;
  208 }
  209 
  210 static void
  211 altera_sdcard_task_badcard(struct altera_sdcard_softc *sc)
  212 {
  213 
  214         ALTERA_SDCARD_LOCK_ASSERT(sc);
  215 
  216         /*
  217          * Handle device driver detach.
  218          */
  219         if (sc->as_flags & ALTERA_SDCARD_FLAG_DETACHREQ) {
  220                 sc->as_state = ALTERA_SDCARD_STATE_DETACHED;
  221                 return;
  222         }
  223 
  224         /*
  225          * Handle safe card removal -- no teardown is required, just a state
  226          * transition.
  227          */
  228         if (!(altera_sdcard_read_asr(sc) & ALTERA_SDCARD_ASR_CARDPRESENT))
  229                 sc->as_state = ALTERA_SDCARD_STATE_NOCARD;
  230 }
  231 
  232 static void
  233 altera_sdcard_task_idle(struct altera_sdcard_softc *sc)
  234 {
  235 
  236         ALTERA_SDCARD_LOCK_ASSERT(sc);
  237 
  238         /*
  239          * Handle device driver detach.
  240          */
  241         if (sc->as_flags & ALTERA_SDCARD_FLAG_DETACHREQ) {
  242                 sc->as_state = ALTERA_SDCARD_STATE_DETACHED;
  243                 return;
  244         }
  245 
  246         /*
  247          * Handle safe card removal.
  248          */
  249         if (!(altera_sdcard_read_asr(sc) & ALTERA_SDCARD_ASR_CARDPRESENT)) {
  250                 altera_sdcard_disk_remove(sc);
  251                 sc->as_state = ALTERA_SDCARD_STATE_NOCARD;
  252         }
  253 }
  254 
  255 static void
  256 altera_sdcard_task_io(struct altera_sdcard_softc *sc)
  257 {
  258         uint16_t asr;
  259 
  260         ALTERA_SDCARD_LOCK_ASSERT(sc);
  261         KASSERT(sc->as_currentbio != NULL, ("%s: no current I/O", __func__));
  262 
  263 #ifdef ALTERA_SDCARD_FAST_SIM
  264 recheck:
  265 #endif
  266         asr = altera_sdcard_read_asr(sc);
  267 
  268         /*
  269          * Check for unexpected card removal during an I/O.
  270          */
  271         if (!(asr & ALTERA_SDCARD_ASR_CARDPRESENT)) {
  272                 altera_sdcard_disk_remove(sc);
  273                 if (sc->as_flags & ALTERA_SDCARD_FLAG_DETACHREQ)
  274                         sc->as_state = ALTERA_SDCARD_STATE_DETACHED;
  275                 else
  276                         sc->as_state = ALTERA_SDCARD_STATE_NOCARD;
  277                 return;
  278         }
  279 
  280         /*
  281          * If the I/O isn't complete, remain in the IO state without further
  282          * action, even if DETACHREQ is in flight.
  283          */
  284         if (asr & ALTERA_SDCARD_ASR_CMDINPROGRESS)
  285                 return;
  286 
  287         /*
  288          * Handle various forms of I/O completion, successful and otherwise.
  289          * The I/O layer may restart the transaction if an error occurred, in
  290          * which case remain in the IO state and reschedule.
  291          */
  292         if (!altera_sdcard_io_complete(sc, asr))
  293                 return;
  294 
  295         /*
  296          * Now that I/O is complete, process detach requests in preference to
  297          * starting new I/O.
  298          */
  299         if (sc->as_flags & ALTERA_SDCARD_FLAG_DETACHREQ) {
  300                 sc->as_state = ALTERA_SDCARD_STATE_DETACHED;
  301                 return;
  302         }
  303 
  304         /*
  305          * Finally, either start the next I/O or transition to the IDLE state.
  306          */
  307         if (bioq_first(&sc->as_bioq) != NULL) {
  308                 altera_sdcard_nextio(sc);
  309 #ifdef ALTERA_SDCARD_FAST_SIM
  310                 goto recheck;
  311 #endif
  312         } else
  313                 sc->as_state = ALTERA_SDCARD_STATE_IDLE;
  314 }
  315 
  316 static void
  317 altera_sdcard_task_rechedule(struct altera_sdcard_softc *sc)
  318 {
  319         int interval;
  320 
  321         /*
  322          * Reschedule based on new state.  Or not, if detaching the device
  323          * driver.  Treat a bad card as though it were no card at all.
  324          */
  325         switch (sc->as_state) {
  326         case ALTERA_SDCARD_STATE_NOCARD:
  327         case ALTERA_SDCARD_STATE_BADCARD:
  328                 interval = ALTERA_SDCARD_TIMEOUT_NOCARD;
  329                 break;
  330 
  331         case ALTERA_SDCARD_STATE_IDLE:
  332                 interval = ALTERA_SDCARD_TIMEOUT_IDLE;
  333                 break;
  334 
  335         case ALTERA_SDCARD_STATE_IO:
  336                 if (sc->as_flags & ALTERA_SDCARD_FLAG_IOERROR)
  337                         interval = ALTERA_SDCARD_TIMEOUT_IOERROR;
  338                 else
  339                         interval = ALTERA_SDCARD_TIMEOUT_IO;
  340                 break;
  341 
  342         default:
  343                 panic("%s: invalid exit state %d", __func__, sc->as_state);
  344         }
  345         taskqueue_enqueue_timeout(sc->as_taskqueue, &sc->as_task, interval);
  346 }
  347 
  348 /*
  349  * Because the Altera SD Card IP Core doesn't support interrupts, we do all
  350  * asynchronous work from a timeout.  Poll at two different rates -- an
  351  * infrequent check for card insertion status changes, and a frequent one for
  352  * I/O completion.  The task should never start in DETACHED, as that would
  353  * imply that a previous instance failed to cancel rather than reschedule.
  354  */
  355 void
  356 altera_sdcard_task(void *arg, int pending)
  357 {
  358         struct altera_sdcard_softc *sc;
  359 
  360         sc = arg;
  361         KASSERT(sc->as_state != ALTERA_SDCARD_STATE_DETACHED,
  362             ("%s: already in detached", __func__));
  363 
  364         ALTERA_SDCARD_LOCK(sc);
  365         switch (sc->as_state) {
  366         case ALTERA_SDCARD_STATE_NOCARD:
  367                 altera_sdcard_task_nocard(sc);
  368                 break;
  369 
  370         case ALTERA_SDCARD_STATE_BADCARD:
  371                 altera_sdcard_task_badcard(sc);
  372                 break;
  373 
  374         case ALTERA_SDCARD_STATE_IDLE:
  375                 altera_sdcard_task_idle(sc);
  376                 break;
  377 
  378         case ALTERA_SDCARD_STATE_IO:
  379                 altera_sdcard_task_io(sc);
  380                 break;
  381 
  382         default:
  383                 panic("%s: invalid enter state %d", __func__, sc->as_state);
  384         }
  385 
  386         /*
  387          * If we have transitioned to DETACHED, signal the detach thread and
  388          * cancel the timeout-driven task.  Otherwise reschedule on an
  389          * appropriate timeout.
  390          */
  391         if (sc->as_state == ALTERA_SDCARD_STATE_DETACHED)
  392                 ALTERA_SDCARD_CONDVAR_SIGNAL(sc);
  393         else
  394                 altera_sdcard_task_rechedule(sc);
  395         ALTERA_SDCARD_UNLOCK(sc);
  396 }
  397 
  398 void
  399 altera_sdcard_start(struct altera_sdcard_softc *sc)
  400 {
  401 
  402         ALTERA_SDCARD_LOCK_ASSERT(sc);
  403 
  404         KASSERT(sc->as_state == ALTERA_SDCARD_STATE_IDLE,
  405             ("%s: starting when not IDLE", __func__));
  406 
  407         taskqueue_cancel_timeout(sc->as_taskqueue, &sc->as_task, NULL);
  408         altera_sdcard_nextio(sc);
  409 #ifdef ALTERA_SDCARD_FAST_SIM
  410         altera_sdcard_task_io(sc);
  411 #endif
  412         altera_sdcard_task_rechedule(sc);
  413 }

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