/*
* Copyright (c) 2011 Jan Vesely
* Copyright (c) 2018 Ondrej Hlavaty
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup libusbhost
* @{
*/
/** @file
*
* Bandwidth calculation functions. Shared among uhci, ohci and ehci drivers.
*/
#include <assert.h>
#include <stdlib.h>
#include "endpoint.h"
#include "bus.h"
#include "bandwidth.h"
/** Bytes per second in FULL SPEED */
#define BANDWIDTH_TOTAL_USB11 (12000000 / 8)
/** 90% of total bandwidth is available for periodic transfers */
#define BANDWIDTH_AVAILABLE_USB11 ((BANDWIDTH_TOTAL_USB11 * 9) / 10)
/**
* Calculate bandwidth that needs to be reserved for communication with EP.
* Calculation follows USB 1.1 specification.
*
* @param ep An endpoint for which the bandwidth is to be counted
*/
static size_t bandwidth_count_usb11(endpoint_t *ep)
{
assert(ep);
assert(ep->device);
const usb_transfer_type_t type = ep->transfer_type;
/* We care about bandwidth only for interrupt and isochronous. */
if ((type != USB_TRANSFER_INTERRUPT) &&
(type != USB_TRANSFER_ISOCHRONOUS)) {
return 0;
}
const size_t max_packet_size = ep->max_packet_size;
const size_t packet_count = ep->packets_per_uframe;
/*
* TODO: It may be that ISO and INT transfers use only one packet per
* transaction, but I did not find text in USB spec to confirm this
*/
/* NOTE: All data packets will be considered to be max_packet_size */
switch (ep->device->speed) {
case USB_SPEED_LOW:
assert(type == USB_TRANSFER_INTERRUPT);
/*
* Protocol overhead 13B
* (3 SYNC bytes, 3 PID bytes, 2 Endpoint + CRC bytes, 2
* CRC bytes, and a 3-byte interpacket delay)
* see USB spec page 45-46.
*/
/* Speed penalty 8: low speed is 8-times slower */
return packet_count * (13 + max_packet_size) * 8;
case USB_SPEED_FULL:
/*
* Interrupt transfer overhead see above
* or page 45 of USB spec
*/
if (type == USB_TRANSFER_INTERRUPT)
return packet_count * (13 + max_packet_size);
assert(type == USB_TRANSFER_ISOCHRONOUS);
/*
* Protocol overhead 9B
* (2 SYNC bytes, 2 PID bytes, 2 Endpoint + CRC bytes, 2 CRC
* bytes, and a 1-byte interpacket delay)
* see USB spec page 42
*/
return packet_count * (9 + max_packet_size);
default:
return 0;
}
}
const bandwidth_accounting_t bandwidth_accounting_usb11 = {
.available_bandwidth = BANDWIDTH_AVAILABLE_USB11,
.count_bw = &bandwidth_count_usb11,
};
/** Number of nanoseconds in one microframe */
#define BANDWIDTH_TOTAL_USB2 (125000)
/** 90% of total bandwidth is available for periodic transfers */
#define BANDWIDTH_AVAILABLE_USB2 ((BANDWIDTH_TOTAL_USB2 * 9) / 10)
/**
* Calculate bandwidth that needs to be reserved for communication with EP.
* Calculation follows USB 2.0 specification, chapter 5.11.3.
*
* FIXME: Interrupt transfers shall be probably divided by their polling interval.
*
* @param ep An endpoint for which the bandwidth is to be counted
* @return Number of nanoseconds transaction with @c size bytes payload will
* take.
*/
static size_t bandwidth_count_usb2(endpoint_t *ep)
{
assert(ep);
assert(ep->device);
const usb_transfer_type_t type = ep->transfer_type;
/* We care about bandwidth only for interrupt and isochronous. */
if ((type != USB_TRANSFER_INTERRUPT) &&
(type != USB_TRANSFER_ISOCHRONOUS)) {
return 0;
}
// FIXME: Come up with some upper bound for these (in ns).
const size_t host_delay = 0;
const size_t hub_ls_setup = 0;
// Approx. Floor(3.167 + BitStuffTime(Data_bc))
const size_t base_time = (ep->max_transfer_size * 8 + 19) / 6;
switch (ep->device->speed) {
case USB_SPEED_LOW:
if (ep->direction == USB_DIRECTION_IN)
return 64060 + (2 * hub_ls_setup) +
(677 * base_time) + host_delay;
else
return 64107 + (2 * hub_ls_setup) +
(667 * base_time) + host_delay;
case USB_SPEED_FULL:
if (ep->transfer_type == USB_TRANSFER_INTERRUPT)
return 9107 + 84 * base_time + host_delay;
if (ep->direction == USB_DIRECTION_IN)
return 7268 + 84 * base_time + host_delay;
else
return 6265 + 84 * base_time + host_delay;
case USB_SPEED_HIGH:
if (ep->transfer_type == USB_TRANSFER_INTERRUPT)
return (3648 + 25 * base_time + 11) / 12 + host_delay;
else
return (5280 + 25 * base_time + 11) / 12 + host_delay;
default:
return 0;
}
}
const bandwidth_accounting_t bandwidth_accounting_usb2 = {
.available_bandwidth = BANDWIDTH_AVAILABLE_USB2,
.count_bw = &bandwidth_count_usb2,
};