diff options
Diffstat (limited to 'hw/usb')
| -rw-r--r-- | hw/usb/hcd-ehci.c | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c index 43a8f7abcc..b093db729c 100644 --- a/hw/usb/hcd-ehci.c +++ b/hw/usb/hcd-ehci.c @@ -2206,29 +2206,28 @@ static void ehci_advance_periodic_state(EHCIState *ehci) static void ehci_update_frindex(EHCIState *ehci, int uframes) { - int i; - if (!ehci_enabled(ehci) && ehci->pstate == EST_INACTIVE) { return; } - for (i = 0; i < uframes; i++) { - ehci->frindex++; - - if (ehci->frindex == 0x00002000) { - ehci_raise_irq(ehci, USBSTS_FLR); - } + /* Generate FLR interrupt if frame index rolls over 0x2000 */ + if ((ehci->frindex % 0x2000) + uframes >= 0x2000) { + ehci_raise_irq(ehci, USBSTS_FLR); + } - if (ehci->frindex == 0x00004000) { - ehci_raise_irq(ehci, USBSTS_FLR); - ehci->frindex = 0; - if (ehci->usbsts_frindex >= 0x00004000) { - ehci->usbsts_frindex -= 0x00004000; - } else { - ehci->usbsts_frindex = 0; - } + /* How many times will frindex roll over 0x4000 with this frame count? + * usbsts_frindex is decremented by 0x4000 on rollover until it reaches 0 + */ + int rollovers = (ehci->frindex + uframes) / 0x4000; + if (rollovers > 0) { + if (ehci->usbsts_frindex >= (rollovers * 0x4000)) { + ehci->usbsts_frindex -= 0x4000 * rollovers; + } else { + ehci->usbsts_frindex = 0; } } + + ehci->frindex = (ehci->frindex + uframes) % 0x4000; } static void ehci_frame_timer(void *opaque) |