Name
usb_calc_bus_time —
approximate periodic transaction time in nanoseconds
Synopsis
long usb_calc_bus_time (int speed, int is_input, int isoc, int bytecount);
Arguments
speed
from dev->speed; USB_SPEED_{LOW,FULL,HIGH}
is_input
true iff the transaction sends data to the host
isoc
true for isochronous transactions, false for interrupt ones
bytecount
how many bytes in the transaction.
Description
Returns approximate bus time in nanoseconds for a periodic transaction.
See USB 2.0 spec section 5.11.3; only periodic transfers need to be
scheduled in software, this function is only used for such scheduling.