#define EHCI_IAA_MSECS 10 /* arbitrary */
#define EHCI_IO_JIFFIES (HZ/10) /* io watchdog > irq_thresh */
-#define EHCI_ASYNC_JIFFIES (HZ/20) /* async idle timeout */
#define EHCI_SHRINK_JIFFIES (DIV_ROUND_UP(HZ, 200) + 1)
/* 5-ms async qh unlink delay */
* SHRINK were pending, OFF would never be requested.
*/
if (timer_pending(&ehci->watchdog)
- && ((BIT(TIMER_ASYNC_SHRINK) | BIT(TIMER_ASYNC_OFF))
+ && (BIT(TIMER_ASYNC_SHRINK)
& ehci->actions))
return;
return;
t = EHCI_IO_JIFFIES;
break;
- case TIMER_ASYNC_OFF:
- t = EHCI_ASYNC_JIFFIES;
- break;
/* case TIMER_ASYNC_SHRINK: */
default:
t = EHCI_SHRINK_JIFFIES;
spin_lock_irqsave(&ehci->lock, flags);
- /* stop async processing after it's idled a bit */
- if (test_bit (TIMER_ASYNC_OFF, &ehci->actions))
- start_unlink_async (ehci, ehci->async);
-
/* ehci could run by timer, without IRQs ... */
ehci_work (ehci);
if (ehci->scanning)
return;
ehci->scanning = 1;
- scan_async (ehci);
+ if (ehci->async_count)
+ scan_async(ehci);
if (ehci->next_uframe != -1)
scan_periodic (ehci);
ehci->scanning = 0;
/*-------------------------------------------------------------------------*/
+static void enable_async(struct ehci_hcd *ehci)
+{
+ if (ehci->async_count++)
+ return;
+
+ /* Stop waiting to turn off the async schedule */
+ ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_DISABLE_ASYNC);
+
+ /* Don't start the schedule until ASS is 0 */
+ ehci_poll_ASS(ehci);
+}
+
+static void disable_async(struct ehci_hcd *ehci)
+{
+ if (--ehci->async_count)
+ return;
+
+ /* The async schedule and async_unlink list are supposed to be empty */
+ WARN_ON(ehci->async->qh_next.qh || ehci->async_unlink);
+
+ /* Don't turn off the schedule until ASS is 1 */
+ ehci_poll_ASS(ehci);
+}
+
/* move qh (and its qtds) onto async queue; maybe enable queue. */
static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh)
WARN_ON(qh->qh_state != QH_STATE_IDLE);
- /* (re)start the async schedule? */
- head = ehci->async;
- timer_action_done (ehci, TIMER_ASYNC_OFF);
- if (!head->qh_next.qh) {
- if (!(ehci->command & CMD_ASE)) {
- /* in case a clear of CMD_ASE didn't take yet */
- (void)handshake(ehci, &ehci->regs->status,
- STS_ASS, 0, 150);
- ehci->command |= CMD_ASE;
- ehci_writel(ehci, ehci->command, &ehci->regs->command);
- /* posted write need not be known to HC yet ... */
- }
- }
-
/* clear halt and/or toggle; and maybe recover from silicon quirk */
qh_refresh(ehci, qh);
/* splice right after start */
+ head = ehci->async;
qh->qh_next = head->qh_next;
qh->hw->hw_next = head->hw->hw_next;
wmb ();
qh->xacterrs = 0;
qh->qh_state = QH_STATE_LINKED;
/* qtd completions reported later by interrupt */
+
+ enable_async(ehci);
}
/*-------------------------------------------------------------------------*/
qh_completions (ehci, qh);
- if (!list_empty(&qh->qtd_list) && ehci->rh_state == EHCI_RH_RUNNING) {
+ if (!list_empty(&qh->qtd_list) && ehci->rh_state == EHCI_RH_RUNNING)
qh_link_async (ehci, qh);
- } else {
- /* it's not free to turn the async schedule on/off; leave it
- * active but idle for a while once it empties.
- */
- if (ehci->rh_state == EHCI_RH_RUNNING
- && ehci->async->qh_next.qh == NULL)
- timer_action (ehci, TIMER_ASYNC_OFF);
- }
+
+ disable_async(ehci);
if (next) {
ehci->async_unlink = NULL;
BUG ();
#endif
- /* stop async schedule right now? */
- if (unlikely (qh == ehci->async)) {
- /* can't get here without STS_ASS set */
- if (ehci->rh_state != EHCI_RH_HALTED
- && !ehci->async_unlink) {
- /* ... and CMD_IAAD clear */
- ehci->command &= ~CMD_ASE;
- ehci_writel(ehci, ehci->command, &ehci->regs->command);
- wmb ();
- // handshake later, if we need to
- timer_action_done (ehci, TIMER_ASYNC_OFF);
- }
- return;
- }
-
qh->qh_state = QH_STATE_UNLINK;
ehci->async_unlink = qh;
if (!qh->unlink_next)
* the event types indexed by enum ehci_hrtimer_event in ehci.h.
*/
static unsigned event_delays_ns[] = {
+ 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_ASS */
1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_PSS */
10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */
+ 15 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_ASYNC */
};
/* Enable a pending hrtimer event */
}
+/* Poll the STS_ASS status bit; see when it agrees with CMD_ASE */
+static void ehci_poll_ASS(struct ehci_hcd *ehci)
+{
+ unsigned actual, want;
+
+ /* Don't enable anything if the controller isn't running (e.g., died) */
+ if (ehci->rh_state != EHCI_RH_RUNNING)
+ return;
+
+ want = (ehci->command & CMD_ASE) ? STS_ASS : 0;
+ actual = ehci_readl(ehci, &ehci->regs->status) & STS_ASS;
+
+ if (want != actual) {
+
+ /* Poll again later, but give up after about 20 ms */
+ if (ehci->ASS_poll_count++ < 20) {
+ ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true);
+ return;
+ }
+ ehci_warn(ehci, "Waited too long for the async schedule status, giving up\n");
+ }
+ ehci->ASS_poll_count = 0;
+
+ /* The status is up-to-date; restart or stop the schedule as needed */
+ if (want == 0) { /* Stopped */
+ if (ehci->async_count > 0)
+ ehci_set_command_bit(ehci, CMD_ASE);
+
+ } else { /* Running */
+ if (ehci->async_count == 0) {
+
+ /* Turn off the schedule after a while */
+ ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_ASYNC,
+ true);
+ }
+ }
+}
+
+/* Turn off the async schedule after a brief delay */
+static void ehci_disable_ASE(struct ehci_hcd *ehci)
+{
+ ehci_clear_command_bit(ehci, CMD_ASE);
+}
+
+
/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */
static void ehci_poll_PSS(struct ehci_hcd *ehci)
{
* enum ehci_hrtimer_event in ehci.h.
*/
static void (*event_handlers[])(struct ehci_hcd *) = {
+ ehci_poll_ASS, /* EHCI_HRTIMER_POLL_ASS */
ehci_poll_PSS, /* EHCI_HRTIMER_POLL_PSS */
ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */
+ ehci_disable_ASE, /* EHCI_HRTIMER_DISABLE_ASYNC */
};
static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t)
* ehci-timer.c) in parallel with this list.
*/
enum ehci_hrtimer_event {
+ EHCI_HRTIMER_POLL_ASS, /* Poll for async schedule off */
EHCI_HRTIMER_POLL_PSS, /* Poll for periodic schedule off */
EHCI_HRTIMER_DISABLE_PERIODIC, /* Wait to disable periodic sched */
+ EHCI_HRTIMER_DISABLE_ASYNC, /* Wait to disable async sched */
EHCI_HRTIMER_NUM_EVENTS /* Must come last */
};
#define EHCI_HRTIMER_NO_EVENT 99
struct hrtimer hrtimer;
int PSS_poll_count;
+ int ASS_poll_count;
/* glue to PCI and HCD framework */
struct ehci_caps __iomem *caps;
struct ehci_qh *async_unlink_last;
struct ehci_qh *qh_scan_next;
unsigned scanning : 1;
+ unsigned async_count; /* async activity count */
/* periodic schedule support */
#define DEFAULT_I_TDPS 1024 /* some HCs can do less */
enum ehci_timer_action {
TIMER_IO_WATCHDOG,
TIMER_ASYNC_SHRINK,
- TIMER_ASYNC_OFF,
};
static inline void
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