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// SPDX-License-Identifier: GPL-2.0+
/*
* epautoconf.c -- endpoint autoconfiguration for usb gadget drivers
*
* Copyright (C) 2004 David Brownell
*
* Ported to U-Boot by: Thomas Smits <ts.smits@gmail.com> and
* Remy Bohmer <linux@bohmer.net>
*/
#include <linux/usb/ch9.h>
#include <linux/errno.h>
#include <linux/usb/gadget.h>
#include <asm/unaligned.h>
#define isdigit(c) ('0' <= (c) && (c) <= '9')
/* we must assign addresses for configurable endpoints (like net2280) */
static unsigned epnum;
/* #define MANY_ENDPOINTS */
#ifdef MANY_ENDPOINTS
/* more than 15 configurable endpoints */
static unsigned in_epnum;
#endif
/*
* This should work with endpoints from controller drivers sharing the
* same endpoint naming convention. By example:
*
* - ep1, ep2, ... address is fixed, not direction or type
* - ep1in, ep2out, ... address and direction are fixed, not type
* - ep1-bulk, ep2-bulk, ... address and type are fixed, not direction
* - ep1in-bulk, ep2out-iso, ... all three are fixed
* - ep-* ... no functionality restrictions
*
* Type suffixes are "-bulk", "-iso", or "-int". Numbers are decimal.
* Less common restrictions are implied by gadget_is_*().
*
* NOTE: each endpoint is unidirectional, as specified by its USB
* descriptor; and isn't specific to a configuration or altsetting.
*/
static int ep_matches(
struct usb_gadget *gadget,
struct usb_ep *ep,
struct usb_endpoint_descriptor *desc
)
{
u8 type;
const char *tmp;
u16 max;
/* endpoint already claimed? */
if (NULL != ep->driver_data)
return 0;
/* only support ep0 for portable CONTROL traffic */
type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
if (USB_ENDPOINT_XFER_CONTROL == type)
return 0;
/* some other naming convention */
if ('e' != ep->name[0])
return 0;
/* type-restriction: "-iso", "-bulk", or "-int".
* direction-restriction: "in", "out".
*/
if ('-' != ep->name[2]) {
tmp = strrchr(ep->name, '-');
if (tmp) {
switch (type) {
case USB_ENDPOINT_XFER_INT:
/* bulk endpoints handle interrupt transfers,
* except the toggle-quirky iso-synch kind
*/
if ('s' == tmp[2]) /* == "-iso" */
return 0;
break;
case USB_ENDPOINT_XFER_BULK:
if ('b' != tmp[1]) /* != "-bulk" */
return 0;
break;
case USB_ENDPOINT_XFER_ISOC:
if ('s' != tmp[2]) /* != "-iso" */
return 0;
}
} else {
tmp = ep->name + strlen(ep->name);
}
/* direction-restriction: "..in-..", "out-.." */
tmp--;
if (!isdigit(*tmp)) {
if (desc->bEndpointAddress & USB_DIR_IN) {
if ('n' != *tmp)
return 0;
} else {
if ('t' != *tmp)
return 0;
}
}
}
/* endpoint maxpacket size is an input parameter, except for bulk
* where it's an output parameter representing the full speed limit.
* the usb spec fixes high speed bulk maxpacket at 512 bytes.
*/
max = 0x7ff & le16_to_cpu(get_unaligned(&desc->wMaxPacketSize));
switch (type) {
case USB_ENDPOINT_XFER_INT:
/* INT: limit 64 bytes full speed, 1024 high speed */
if (!gadget->is_dualspeed && max > 64)
return 0;
/* FALLTHROUGH */
case USB_ENDPOINT_XFER_ISOC:
/* ISO: limit 1023 bytes full speed, 1024 high speed */
if (ep->maxpacket < max)
return 0;
if (!gadget->is_dualspeed && max > 1023)
return 0;
/* BOTH: "high bandwidth" works only at high speed */
if ((get_unaligned(&desc->wMaxPacketSize) &
__constant_cpu_to_le16(3<<11))) {
if (!gadget->is_dualspeed)
return 0;
/* configure your hardware with enough buffering!! */
}
break;
}
/* MATCH!! */
/* report address */
if (isdigit(ep->name[2])) {
u8 num = dectoul(&ep->name[2], NULL);
desc->bEndpointAddress |= num;
#ifdef MANY_ENDPOINTS
} else if (desc->bEndpointAddress & USB_DIR_IN) {
if (++in_epnum > 15)
return 0;
desc->bEndpointAddress = USB_DIR_IN | in_epnum;
#endif
} else {
if (++epnum > 15)
return 0;
desc->bEndpointAddress |= epnum;
}
/* report (variable) full speed bulk maxpacket */
if (USB_ENDPOINT_XFER_BULK == type) {
int size = ep->maxpacket;
/* min() doesn't work on bitfields with gcc-3.5 */
if (size > 64)
size = 64;
put_unaligned(cpu_to_le16(size), &desc->wMaxPacketSize);
}
if (gadget->ops->ep_conf)
return gadget->ops->ep_conf(gadget, ep, desc);
return 1;
}
static struct usb_ep *
find_ep(struct usb_gadget *gadget, const char *name)
{
struct usb_ep *ep;
list_for_each_entry(ep, &gadget->ep_list, ep_list) {
if (0 == strcmp(ep->name, name))
return ep;
}
return NULL;
}
/**
* usb_ep_autoconfig - choose an endpoint matching the descriptor
* @gadget: The device to which the endpoint must belong.
* @desc: Endpoint descriptor, with endpoint direction and transfer mode
* initialized. For periodic transfers, the maximum packet
* size must also be initialized. This is modified on success.
*
* By choosing an endpoint to use with the specified descriptor, this
* routine simplifies writing gadget drivers that work with multiple
* USB device controllers. The endpoint would be passed later to
* usb_ep_enable(), along with some descriptor.
*
* That second descriptor won't always be the same as the first one.
* For example, isochronous endpoints can be autoconfigured for high
* bandwidth, and then used in several lower bandwidth altsettings.
* Also, high and full speed descriptors will be different.
*
* Be sure to examine and test the results of autoconfiguration on your
* hardware. This code may not make the best choices about how to use the
* USB controller, and it can't know all the restrictions that may apply.
* Some combinations of driver and hardware won't be able to autoconfigure.
*
* On success, this returns an un-claimed usb_ep, and modifies the endpoint
* descriptor bEndpointAddress. For bulk endpoints, the wMaxPacket value
* is initialized as if the endpoint were used at full speed. To prevent
* the endpoint from being returned by a later autoconfig call, claim it
* by assigning ep->driver_data to some non-null value.
*
* On failure, this returns a null endpoint descriptor.
*/
struct usb_ep *usb_ep_autoconfig(
struct usb_gadget *gadget,
struct usb_endpoint_descriptor *desc
)
{
struct usb_ep *ep = NULL;
u8 type;
type = desc->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK;
/* First, apply chip-specific "best usage" knowledge.
* This might make a good usb_gadget_ops hook ...
*/
if (!IS_ENABLED(CONFIG_SPL_BUILD) &&
IS_ENABLED(CONFIG_USB_DWC3_GADGET) &&
!strcmp("dwc3-gadget", gadget->name)) {
const char *name = NULL;
/*
* First try standard, common configuration: ep1in-bulk,
* ep2out-bulk, ep3in-int to match other udc drivers to avoid
* confusion in already deployed software (endpoint numbers
* hardcoded in userspace software/drivers)
*/
if ((desc->bEndpointAddress & USB_DIR_IN) &&
type == USB_ENDPOINT_XFER_BULK)
name = "ep1in";
else if ((desc->bEndpointAddress & USB_DIR_IN) == 0 &&
type == USB_ENDPOINT_XFER_BULK)
name = "ep2out";
else if ((desc->bEndpointAddress & USB_DIR_IN) &&
type == USB_ENDPOINT_XFER_INT)
name = "ep3in";
if (name)
ep = find_ep(gadget, name);
if (ep && ep_matches(gadget, ep, desc))
return ep;
}
if (gadget->ops->match_ep) {
ep = gadget->ops->match_ep(gadget, desc, NULL);
if (ep && ep_matches(gadget, ep, desc))
return ep;
}
/* Second, look at endpoints until an unclaimed one looks usable */
list_for_each_entry(ep, &gadget->ep_list, ep_list) {
if (ep_matches(gadget, ep, desc))
return ep;
}
/* Fail */
return NULL;
}
/**
* usb_ep_autoconfig_reset - reset endpoint autoconfig state
* @gadget: device for which autoconfig state will be reset
*
* Use this for devices where one configuration may need to assign
* endpoint resources very differently from the next one. It clears
* state such as ep->driver_data and the record of assigned endpoints
* used by usb_ep_autoconfig().
*/
void usb_ep_autoconfig_reset(struct usb_gadget *gadget)
{
struct usb_ep *ep;
list_for_each_entry(ep, &gadget->ep_list, ep_list) {
ep->driver_data = NULL;
}
#ifdef MANY_ENDPOINTS
in_epnum = 0;
#endif
epnum = 0;
}