- Replace semaphore-base locking with sleep/wait synchronization:

    sema_trywait/sema_timedwait can't be used while holding
    non-sleepable mutex

- Fix infinite loop if response from VideoCore never received

diff --git a/sys/arm/broadcom/bcm2835/bcm2835_mbox.c b/sys/arm/broadcom/bcm2835/bcm2835_mbox.c
index dd2bb45a96804d536f82e22248d46996c6914c45..5f75fd4ae46b795b7a0b3dd831ecca8b4dbcd7ab 100644 (file)
--- a/sys/arm/broadcom/bcm2835/bcm2835_mbox.c
+++ b/sys/arm/broadcom/bcm2835/bcm2835_mbox.c
@@ -35,7 +35,6 @@ __FBSDID("$FreeBSD$");
 #include <sys/module.h>
 #include <sys/mutex.h>
 #include <sys/rman.h>
-#include <sys/sema.h>
 #include <machine/bus.h>
 
 #include <dev/ofw/ofw_bus.h>
@@ -83,7 +82,7 @@ struct bcm_mbox_softc {
        bus_space_tag_t         bst;
        bus_space_handle_t      bsh;
        int                     msg[BCM2835_MBOX_CHANS];
-       struct sema             sema[BCM2835_MBOX_CHANS];
+       int                     have_message[BCM2835_MBOX_CHANS];
 };
 
 #define        mbox_read_4(sc, reg)            \
@@ -121,9 +120,11 @@ bcm_mbox_intr(void *arg)
        struct bcm_mbox_softc *sc = arg;
        int chan;
 
+       MBOX_LOCK(sc);
        while (!(mbox_read_4(sc, REG_STATUS) & STATUS_EMPTY))
                if (bcm_mbox_read_msg(sc, &chan) == 0)
-                       sema_post(&sc->sema[chan]);
+                       wakeup(&sc->have_message[chan]);
+       MBOX_UNLOCK(sc);
 }
 
 static int
@@ -175,7 +176,7 @@ bcm_mbox_attach(device_t dev)
        mtx_init(&sc->lock, "vcio mbox", NULL, MTX_DEF);
        for (i = 0; i < BCM2835_MBOX_CHANS; i++) {
                sc->msg[i] = 0;
-               sema_init(&sc->sema[i], 0, "mbox");
+               sc->have_message[i] = 0;
        }
 
        /* Read all pending messages */
@@ -198,6 +199,7 @@ bcm_mbox_write(device_t dev, int chan, uint32_t data)
 
        dprintf("bcm_mbox_write: chan %d, data %08x\n", chan, data);
        MBOX_LOCK(sc);
+       sc->have_message[chan] = 0;
        while ((mbox_read_4(sc, REG_STATUS) & STATUS_FULL) && --limit)
                DELAY(5);
        if (limit == 0) {
@@ -222,11 +224,12 @@ bcm_mbox_read(device_t dev, int chan, uint32_t *data)
        err = 0;
        MBOX_LOCK(sc);
        if (!cold) {
-               while (sema_trywait(&sc->sema[chan]) == 0) {
-                       /* do not unlock sc while waiting for the mbox */
-                       if (sema_timedwait(&sc->sema[chan], 10*hz) == 0)
-                               break;
-                       printf("timeout sema for chan %d\n", chan);
+               if (sc->have_message[chan] == 0) {
+                       if (mtx_sleep(&sc->have_message[chan], &sc->lock, 0,
+                           "mbox", 10*hz) != 0) {
+                               device_printf(dev, "timeout waiting for message on chan %d\n", chan);
+                               err = ETIMEDOUT;
+                       }
                }
        } else {
                do {
@@ -246,6 +249,7 @@ bcm_mbox_read(device_t dev, int chan, uint32_t *data)
         */
        *data = MBOX_DATA(sc->msg[chan]);
        sc->msg[chan] = 0;
+       sc->have_message[chan] = 0;
 out:
        MBOX_UNLOCK(sc);
        dprintf("bcm_mbox_read: chan %d, data %08x\n", chan, *data);