epautoconf.c

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/*
 * epautoconf.c -- endpoint autoconfiguration for usb gadget drivers
 *
 * Copyright (C) 2004 David Brownell
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/device.h>

#include <linux/ctype.h>
#include <linux/string.h>

#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>

#include "gadget_chips.h"

/*
 * 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,
    struct usb_ss_ep_comp_descriptor *ep_comp
)
{
    u8      type;
    const char  *tmp;
    u16     max;

    int     num_req_streams = 0;

    /* 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;
                /* for now, avoid PXA "interrupt-in";
                 * it's documented as never using DATA1.
                 */
                if (gadget_is_pxa (gadget)
                        && 'i' == tmp [1])
                    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;
            }
        }
    }

    /*
     * Get the number of required streams from the EP companion
     * descriptor and see if the EP matches it
     */
    if (usb_endpoint_xfer_bulk(desc)) {
        if (ep_comp && gadget->max_speed >= USB_SPEED_SUPER) {
            num_req_streams = ep_comp->bmAttributes & 0x1f;
            if (num_req_streams > ep->max_streams)
                return 0;
        }

    }

    /*
     * If the protocol driver hasn't yet decided on wMaxPacketSize
     * and wants to know the maximum possible, provide the info.
     */
    if (desc->wMaxPacketSize == 0)
        desc->wMaxPacketSize = cpu_to_le16(ep->maxpacket);

    /* 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 & usb_endpoint_maxp(desc);
    switch (type) {
    case USB_ENDPOINT_XFER_INT:
        /* INT:  limit 64 bytes full speed, 1024 high/super speed */
        if (!gadget_is_dualspeed(gadget) && max > 64)
            return 0;
        /* FALLTHROUGH */

    case USB_ENDPOINT_XFER_ISOC:
        /* ISO:  limit 1023 bytes full speed, 1024 high/super speed */
        if (ep->maxpacket < max)
            return 0;
        if (!gadget_is_dualspeed(gadget) && max > 1023)
            return 0;

        /* BOTH:  "high bandwidth" works only at high speed */
        if ((desc->wMaxPacketSize & cpu_to_le16(3<<11))) {
            if (!gadget_is_dualspeed(gadget))
                return 0;
            /* configure your hardware with enough buffering!! */
        }
        break;
    }

    /* MATCH!! */

    /* report address */
    desc->bEndpointAddress &= USB_DIR_IN;
    if (isdigit (ep->name [2])) {
        u8  num = simple_strtoul (&ep->name [2], NULL, 10);
        desc->bEndpointAddress |= num;
    } else if (desc->bEndpointAddress & USB_DIR_IN) {
        if (++gadget->in_epnum > 15)
            return 0;
        desc->bEndpointAddress = USB_DIR_IN | gadget->in_epnum;
    } else {
        if (++gadget->out_epnum > 15)
            return 0;
        desc->bEndpointAddress |= gadget->out_epnum;
    }

    /* report (variable) full speed bulk maxpacket */
    if ((USB_ENDPOINT_XFER_BULK == type) && !ep_comp) {
        int size = ep->maxpacket;

        /* min() doesn't work on bitfields with gcc-3.5 */
        if (size > 64)
            size = 64;
        desc->wMaxPacketSize = cpu_to_le16(size);
    }
    ep->address = desc->bEndpointAddress;
    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;
}

struct usb_ep *usb_ep_autoconfig_ss(
    struct usb_gadget       *gadget,
    struct usb_endpoint_descriptor  *desc,
    struct usb_ss_ep_comp_descriptor *ep_comp
)
{
    struct usb_ep   *ep;
    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 (gadget_is_net2280 (gadget) && type == USB_ENDPOINT_XFER_INT) {
        /* ep-e, ep-f are PIO with only 64 byte fifos */
        ep = find_ep (gadget, "ep-e");
        if (ep && ep_matches(gadget, ep, desc, ep_comp))
            goto found_ep;
        ep = find_ep (gadget, "ep-f");
        if (ep && ep_matches(gadget, ep, desc, ep_comp))
            goto found_ep;

    } else if (gadget_is_goku (gadget)) {
        if (USB_ENDPOINT_XFER_INT == type) {
            /* single buffering is enough */
            ep = find_ep(gadget, "ep3-bulk");
            if (ep && ep_matches(gadget, ep, desc, ep_comp))
                goto found_ep;
        } else if (USB_ENDPOINT_XFER_BULK == type
                && (USB_DIR_IN & desc->bEndpointAddress)) {
            /* DMA may be available */
            ep = find_ep(gadget, "ep2-bulk");
            if (ep && ep_matches(gadget, ep, desc,
                          ep_comp))
                goto found_ep;
        }

#ifdef CONFIG_BLACKFIN
    } else if (gadget_is_musbhdrc(gadget)) {
        if ((USB_ENDPOINT_XFER_BULK == type) ||
            (USB_ENDPOINT_XFER_ISOC == type)) {
            if (USB_DIR_IN & desc->bEndpointAddress)
                ep = find_ep (gadget, "ep5in");
            else
                ep = find_ep (gadget, "ep6out");
        } else if (USB_ENDPOINT_XFER_INT == type) {
            if (USB_DIR_IN & desc->bEndpointAddress)
                ep = find_ep(gadget, "ep1in");
            else
                ep = find_ep(gadget, "ep2out");
        } else
            ep = NULL;
        if (ep && ep_matches(gadget, ep, desc, ep_comp))
            goto found_ep;
#endif
    }

    /* 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, ep_comp))
            goto found_ep;
    }

    /* Fail */
    return NULL;
found_ep:
    ep->desc = NULL;
    ep->comp_desc = NULL;
    return ep;
}
EXPORT_SYMBOL_GPL(usb_ep_autoconfig_ss);

struct usb_ep *usb_ep_autoconfig(
    struct usb_gadget       *gadget,
    struct usb_endpoint_descriptor  *desc
)
{
    return usb_ep_autoconfig_ss(gadget, desc, NULL);
}
EXPORT_SYMBOL_GPL(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;
    }
    gadget->in_epnum = 0;
    gadget->out_epnum = 0;
}
EXPORT_SYMBOL_GPL(usb_ep_autoconfig_reset);