diff options
Diffstat (limited to 'drivers/usb/host/ehci-timer.c')
| -rw-r--r-- | drivers/usb/host/ehci-timer.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c index f6279e2883a8..ecd3296157c6 100644 --- a/drivers/usb/host/ehci-timer.c +++ b/drivers/usb/host/ehci-timer.c @@ -16,6 +16,28 @@ /*-------------------------------------------------------------------------*/ +/* Set a bit in the USBCMD register */ +static void ehci_set_command_bit(struct ehci_hcd *ehci, u32 bit) +{ + ehci->command |= bit; + ehci_writel(ehci, ehci->command, &ehci->regs->command); + + /* unblock posted write */ + ehci_readl(ehci, &ehci->regs->command); +} + +/* Clear a bit in the USBCMD register */ +static void ehci_clear_command_bit(struct ehci_hcd *ehci, u32 bit) +{ + ehci->command &= ~bit; + ehci_writel(ehci, ehci->command, &ehci->regs->command); + + /* unblock posted write */ + ehci_readl(ehci, &ehci->regs->command); +} + +/*-------------------------------------------------------------------------*/ + /* * EHCI timer support... Now using hrtimers. * @@ -45,6 +67,8 @@ * the event types indexed by enum ehci_hrtimer_event in ehci.h. */ static unsigned event_delays_ns[] = { + 1 * NSEC_PER_MSEC, /* EHCI_HRTIMER_POLL_PSS */ + 10 * NSEC_PER_MSEC, /* EHCI_HRTIMER_DISABLE_PERIODIC */ }; /* Enable a pending hrtimer event */ @@ -67,12 +91,68 @@ static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event, } +/* Poll the STS_PSS status bit; see when it agrees with CMD_PSE */ +static void ehci_poll_PSS(struct ehci_hcd *ehci) +{ + unsigned actual, want; + + /* Don't do anything if the controller isn't running (e.g., died) */ + if (ehci->rh_state != EHCI_RH_RUNNING) + return; + + want = (ehci->command & CMD_PSE) ? STS_PSS : 0; + actual = ehci_readl(ehci, &ehci->regs->status) & STS_PSS; + + if (want != actual) { + + /* Poll again later, but give up after about 20 ms */ + if (ehci->PSS_poll_count++ < 20) { + ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true); + return; + } + ehci_warn(ehci, "Waited too long for the periodic schedule status, giving up\n"); + } + ehci->PSS_poll_count = 0; + + /* The status is up-to-date; restart or stop the schedule as needed */ + if (want == 0) { /* Stopped */ + free_cached_lists(ehci); + if (ehci->periodic_count > 0) { + + /* make sure ehci_work scans these */ + ehci->next_uframe = ehci_read_frame_index(ehci) + & ((ehci->periodic_size << 3) - 1); + ehci_set_command_bit(ehci, CMD_PSE); + } + + } else { /* Running */ + if (ehci->periodic_count == 0) { + + /* Turn off the schedule after a while */ + ehci_enable_event(ehci, EHCI_HRTIMER_DISABLE_PERIODIC, + true); + } + } +} + +/* Turn off the periodic schedule after a brief delay */ +static void ehci_disable_PSE(struct ehci_hcd *ehci) +{ + ehci_clear_command_bit(ehci, CMD_PSE); + + /* Poll to see when it actually stops */ + ehci_enable_event(ehci, EHCI_HRTIMER_POLL_PSS, true); +} + + /* * Handler functions for the hrtimer event types. * Keep this array in the same order as the event types indexed by * enum ehci_hrtimer_event in ehci.h. */ static void (*event_handlers[])(struct ehci_hcd *) = { + ehci_poll_PSS, /* EHCI_HRTIMER_POLL_PSS */ + ehci_disable_PSE, /* EHCI_HRTIMER_DISABLE_PERIODIC */ }; static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t) |