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Code Issues Releases Activity

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

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

- Fix infinite loop if response from VideoCore never received
This commit is contained in:
Oleksandr Tymoshenko 2015-11-08 03:34:19 +00:00
parent 9da7d79f25
commit b805a8c3eb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=290533
1 changed files with 13 additions and 9 deletions
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22
sys/arm/broadcom/bcm2835/bcm2835_mbox.c
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@ -35,7 +35,6 @@ __FBSDID("$FreeBSD$");
#include <sys/module.h> #include <sys/module.h>
#include <sys/mutex.h> #include <sys/mutex.h>
#include <sys/rman.h> #include <sys/rman.h>
#include <sys/sema.h>
#include <machine/bus.h> #include <machine/bus.h>
#include <dev/ofw/ofw_bus.h> #include <dev/ofw/ofw_bus.h>
@ -83,7 +82,7 @@ struct bcm_mbox_softc {
bus_space_tag_t bst; bus_space_tag_t bst;
bus_space_handle_t bsh; bus_space_handle_t bsh;
int msg[BCM2835_MBOX_CHANS]; int msg[BCM2835_MBOX_CHANS];
struct sema sema[BCM2835_MBOX_CHANS]; int have_message[BCM2835_MBOX_CHANS];
}; };
#define mbox_read_4(sc, reg) \ #define mbox_read_4(sc, reg) \
@ -121,9 +120,11 @@ bcm_mbox_intr(void *arg)
struct bcm_mbox_softc *sc = arg; struct bcm_mbox_softc *sc = arg;
int chan; int chan;
MBOX_LOCK(sc);
while (!(mbox_read_4(sc, REG_STATUS) & STATUS_EMPTY)) while (!(mbox_read_4(sc, REG_STATUS) & STATUS_EMPTY))
if (bcm_mbox_read_msg(sc, &chan) == 0) if (bcm_mbox_read_msg(sc, &chan) == 0)
sema_post(&sc->sema[chan]); wakeup(&sc->have_message[chan]);
MBOX_UNLOCK(sc);
} }
static int static int
@ -175,7 +176,7 @@ bcm_mbox_attach(device_t dev)
mtx_init(&sc->lock, "vcio mbox", NULL, MTX_DEF); mtx_init(&sc->lock, "vcio mbox", NULL, MTX_DEF);
for (i = 0; i < BCM2835_MBOX_CHANS; i++) { for (i = 0; i < BCM2835_MBOX_CHANS; i++) {
sc->msg[i] = 0; sc->msg[i] = 0;
sema_init(&sc->sema[i], 0, "mbox"); sc->have_message[i] = 0;
} }
/* Read all pending messages */ /* 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); dprintf("bcm_mbox_write: chan %d, data %08x\n", chan, data);
MBOX_LOCK(sc); MBOX_LOCK(sc);
sc->have_message[chan] = 0;
while ((mbox_read_4(sc, REG_STATUS) & STATUS_FULL) && --limit) while ((mbox_read_4(sc, REG_STATUS) & STATUS_FULL) && --limit)
DELAY(5); DELAY(5);
if (limit == 0) { if (limit == 0) {
@ -222,11 +224,12 @@ bcm_mbox_read(device_t dev, int chan, uint32_t *data)
err = 0; err = 0;
MBOX_LOCK(sc); MBOX_LOCK(sc);
if (!cold) { if (!cold) {
while (sema_trywait(&sc->sema[chan]) == 0) { if (sc->have_message[chan] == 0) {
/* do not unlock sc while waiting for the mbox */ if (mtx_sleep(&sc->have_message[chan], &sc->lock, 0,
if (sema_timedwait(&sc->sema[chan], 10*hz) == 0) "mbox", 10*hz) != 0) {
break; device_printf(dev, "timeout waiting for message on chan %d\n", chan);
printf("timeout sema for chan %d\n", chan); err = ETIMEDOUT;
}
} }
} else { } else {
do { do {
@ -246,6 +249,7 @@ bcm_mbox_read(device_t dev, int chan, uint32_t *data)
*/ */
*data = MBOX_DATA(sc->msg[chan]); *data = MBOX_DATA(sc->msg[chan]);
sc->msg[chan] = 0; sc->msg[chan] = 0;
sc->have_message[chan] = 0;
out: out:
MBOX_UNLOCK(sc); MBOX_UNLOCK(sc);
dprintf("bcm_mbox_read: chan %d, data %08x\n", chan, *data); dprintf("bcm_mbox_read: chan %d, data %08x\n", chan, *data);