diff options
| author | david-b@pacbell.net <david-b@pacbell.net> | 2005-08-14 01:41:04 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2005-09-08 23:28:35 (GMT) |
| commit | e09711aef4180002241c7f2eab37390ddf40d6a0 (patch) | |
| tree | 9a537e417df8b8ab0d8e121f6a3e596898ec8ec0 /drivers/usb/core | |
| parent | 090ffa9d0e904e1ed0f86c84dcf20684a8ac1a5a (diff) | |
| download | linux-e09711aef4180002241c7f2eab37390ddf40d6a0.tar.xz | |
[PATCH] ehci: add think_time
This adds think_time to the usb_tt struct and sets it appropriately
(measured in ns); this can help us implement better split transaction
scheduling.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/core')
| -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 9f54e83..758c7f0 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 53bf564..e7fa9b5 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; |