/* increment the counter for # of contexts accessing the device. */
void gdev_access_start(struct gdev_device *gdev)
{
struct gdev_device *phys = gdev_phys_get(gdev);
retry:
if (phys) {
gdev_lock(&phys->global_lock);
if (phys->blocked) {
gdev_unlock(&phys->global_lock);
SCHED_YIELD();
goto retry;
}
phys->accessed++;
gdev_unlock(&phys->global_lock);
}
else {
gdev_lock(&gdev->global_lock);
if (gdev->blocked) {
gdev_unlock(&gdev->global_lock);
SCHED_YIELD();
goto retry;
}
gdev->accessed++;
gdev_unlock(&gdev->global_lock);
}
}
/* set the flag to block any access to the device. */
void gdev_block_start(struct gdev_device *gdev)
{
struct gdev_device *phys = gdev->parent;
/* we have to spin while some context is accessing the GPU. */
retry:
if (phys) {
gdev_lock(&phys->global_lock);
if (phys->accessed) {
gdev_unlock(&phys->global_lock);
goto retry;
}
phys->blocked = 1;
gdev_unlock(&phys->global_lock);
}
else {
gdev_lock(&gdev->global_lock);
if (gdev->accessed) {
gdev_unlock(&gdev->global_lock);
goto retry;
}
gdev->blocked = 1;
gdev_unlock(&gdev->global_lock);
}
}
/* set the flag to block any access to the device. */
void gdev_block_start(struct gdev_device *gdev)
{
struct gdev_device *phys = gdev_phys_get(gdev);
/* we have to spin while some context is accessing the GPU. */
retry:
if (phys) {
gdev_lock(&phys->global_lock);
if (phys->accessed || phys->blocked) {
gdev_unlock(&phys->global_lock);
SCHED_YIELD();
goto retry;
}
phys->blocked++;
gdev_unlock(&phys->global_lock);
}
else {
gdev_lock(&gdev->global_lock);
if (gdev->accessed || gdev->blocked) {
gdev_unlock(&gdev->global_lock);
SCHED_YIELD();
goto retry;
}
gdev->blocked++;
gdev_unlock(&gdev->global_lock);
}
}
/* decrement the counter for # of contexts accessing the device. */
void gdev_access_end(struct gdev_device *gdev)
{
struct gdev_device *phys = gdev->parent;
if (phys) {
gdev_lock(&phys->global_lock);
phys->accessed--;
gdev_unlock(&phys->global_lock);
}
else {
gdev_lock(&gdev->global_lock);
gdev->accessed--;
gdev_unlock(&gdev->global_lock);
}
}
/* clear the flag to unlock any access to the device. */
void gdev_block_end(struct gdev_device *gdev)
{
struct gdev_device *phys = gdev->parent;
if (phys) {
gdev_lock(&phys->global_lock);
phys->blocked = 0;
gdev_unlock(&phys->global_lock);
}
else {
gdev_lock(&gdev->global_lock);
gdev->blocked = 0;
gdev_unlock(&gdev->global_lock);
}
}
