diff options
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/core/hub.c | 32 | ||||
| -rw-r--r-- | drivers/usb/core/hub.h | 7 |
2 files changed, 30 insertions, 9 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 9f54e8330f7..758c7f0ed15 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -627,19 +627,33 @@ static int hub_configure(struct usb_hub *hub, break; } + /* Note 8 FS bit times == (8 bits / 12000000 bps) ~= 666ns */ switch (hub->descriptor->wHubCharacteristics & HUB_CHAR_TTTT) { - case 0x00: - if (hdev->descriptor.bDeviceProtocol != 0) - dev_dbg(hub_dev, "TT requires at most 8 FS bit times\n"); + case HUB_TTTT_8_BITS: + if (hdev->descriptor.bDeviceProtocol != 0) { + hub->tt.think_time = 666; + dev_dbg(hub_dev, "TT requires at most %d " + "FS bit times (%d ns)\n", + 8, hub->tt.think_time); + } break; - case 0x20: - dev_dbg(hub_dev, "TT requires at most 16 FS bit times\n"); + case HUB_TTTT_16_BITS: + hub->tt.think_time = 666 * 2; + dev_dbg(hub_dev, "TT requires at most %d " + "FS bit times (%d ns)\n", + 16, hub->tt.think_time); break; - case 0x40: - dev_dbg(hub_dev, "TT requires at most 24 FS bit times\n"); + case HUB_TTTT_24_BITS: + hub->tt.think_time = 666 * 3; + dev_dbg(hub_dev, "TT requires at most %d " + "FS bit times (%d ns)\n", + 24, hub->tt.think_time); break; - case 0x60: - dev_dbg(hub_dev, "TT requires at most 32 FS bit times\n"); + case HUB_TTTT_32_BITS: + hub->tt.think_time = 666 * 4; + dev_dbg(hub_dev, "TT requires at most %d " + "FS bit times (%d ns)\n", + 32, hub->tt.think_time); break; } diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h index 53bf5649621..e7fa9b5a521 100644 --- a/drivers/usb/core/hub.h +++ b/drivers/usb/core/hub.h @@ -157,6 +157,12 @@ enum hub_led_mode { struct usb_device; +/* Transaction Translator Think Times, in bits */ +#define HUB_TTTT_8_BITS 0x00 +#define HUB_TTTT_16_BITS 0x20 +#define HUB_TTTT_24_BITS 0x40 +#define HUB_TTTT_32_BITS 0x60 + /* * As of USB 2.0, full/low speed devices are segregated into trees. * One type grows from USB 1.1 host controllers (OHCI, UHCI etc). @@ -170,6 +176,7 @@ struct usb_device; struct usb_tt { struct usb_device *hub; /* upstream highspeed hub */ int multi; /* true means one TT per port */ + unsigned think_time; /* think time in ns */ /* for control/bulk error recovery (CLEAR_TT_BUFFER) */ spinlock_t lock; |