/*
 * 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;
}

/**
 * usb_ep_autoconfig_ss() - choose an endpoint matching the ep
 * descriptor and ep companion 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.
 * @ep_comp: Endpoint companion descriptor, with the required
 *    number of streams. Will be modified when the chosen EP
 *    supports a different number of streams.
 *
 * This routine replaces the usb_ep_autoconfig when needed
 * superspeed enhancments. If such enhancemnets are required,
 * the FD should call usb_ep_autoconfig_ss directly and provide
 * the additional ep_comp parameter.
 *
 * 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 and
 * the bmAttribute field in the ep companion descriptor is
 * updated with the assigned number of streams if it is
 * different from the original value. 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_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);

/**
 * 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
)
{
        return usb_ep_autoconfig_ss(gadget, desc, NULL);
}
EXPORT_SYMBOL_GPL(usb_ep_autoconfig);

/**
 * 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;
        }
        gadget->in_epnum = 0;
        gadget->out_epnum = 0;
}
EXPORT_SYMBOL_GPL(usb_ep_autoconfig_reset);