// SPDX-License-Identifier: GPL-2.0
/*
 * Wireless USB Host Controller
 * Root Hub operations
 *
 *
 * Copyright (C) 2005-2006 Intel Corporation
 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
 *
 * We fake a root hub that has fake ports (as many as simultaneous
 * devices the Wireless USB Host Controller can deal with). For each
 * port we keep an state in @wusbhc->port[index] identical to the one
 * specified in the USB2.0[ch11] spec and some extra device
 * information that complements the one in 'struct usb_device' (as
 * this lacs a hcpriv pointer).
 *
 * Note this is common to WHCI and HWA host controllers.
 *
 * Through here we enable most of the state changes that the USB stack
 * will use to connect or disconnect devices. We need to do some
 * forced adaptation of Wireless USB device states vs. wired:
 *
 *        USB:                 WUSB:
 *
 * Port   Powered-off          port slot n/a
 *        Powered-on           port slot available
 *        Disconnected         port slot available
 *        Connected            port slot assigned device
 *                             device sent DN_Connect
 *                             device was authenticated
 *        Enabled              device is authenticated, transitioned
 *                             from unauth -> auth -> default address
 *                             -> enabled
 *        Reset                disconnect
 *        Disable              disconnect
 *
 * This maps the standard USB port states with the WUSB device states
 * so we can fake ports without having to modify the USB stack.
 *
 * FIXME: this process will change in the future
 *
 *
 * ENTRY POINTS
 *
 * Our entry points into here are, as in hcd.c, the USB stack root hub
 * ops defined in the usb_hcd struct:
 *
 * wusbhc_rh_status_data()      Provide hub and port status data bitmap
 *
 * wusbhc_rh_control()          Execution of all the major requests
 *                              you can do to a hub (Set|Clear
 *                              features, get descriptors, status, etc).
 *
 * wusbhc_rh_[suspend|resume]() That
 *
 * wusbhc_rh_start_port_reset() ??? unimplemented
 */
#include <linux/slab.h>
#include <linux/export.h>
#include "wusbhc.h"

/*
 * Reset a fake port
 *
 * Using a Reset Device IE is too heavyweight as it causes the device
 * to enter the UnConnected state and leave the cluster, this can mean
 * that when the device reconnects it is connected to a different fake
 * port.
 *
 * Instead, reset authenticated devices with a SetAddress(0), followed
 * by a SetAddresss(AuthAddr).
 *
 * For unauthenticated devices just pretend to reset but do nothing.
 * If the device initialization continues to fail it will eventually
 * time out after TrustTimeout and enter the UnConnected state.
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked.
 *
 * Supposedly we are the only thread accesing @wusbhc->port; in any
 * case, maybe we should move the mutex locking from
 * wusbhc_devconnect_auth() to here.
 *
 * @port_idx refers to the wusbhc's port index, not the USB port number
 */
static int wusbhc_rh_port_reset(struct wusbhc *wusbhc, u8 port_idx)
{
        int result = 0;
        struct wusb_port *port = wusb_port_by_idx(wusbhc, port_idx);
        struct wusb_dev *wusb_dev = port->wusb_dev;

        if (wusb_dev == NULL)
                return -ENOTCONN;

        port->status |= USB_PORT_STAT_RESET;
        port->change |= USB_PORT_STAT_C_RESET;

        if (wusb_dev->addr & WUSB_DEV_ADDR_UNAUTH)
                result = 0;
        else
                result = wusb_dev_update_address(wusbhc, wusb_dev);

        port->status &= ~USB_PORT_STAT_RESET;
        port->status |= USB_PORT_STAT_ENABLE;
        port->change |= USB_PORT_STAT_C_RESET | USB_PORT_STAT_C_ENABLE; 

        return result;
}

/*
 * Return the hub change status bitmap
 *
 * The bits in the change status bitmap are cleared when a
 * ClearPortFeature request is issued (USB2.0[11.12.3,11.12.4].
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked.
 *
 * WARNING!! This gets called from atomic context; we cannot get the
 *           mutex--the only race condition we can find is some bit
 *           changing just after we copy it, which shouldn't be too
 *           big of a problem [and we can't make it an spinlock
 *           because other parts need to take it and sleep] .
 *
 *           @usb_hcd is refcounted, so it won't disappear under us
 *           and before killing a host, the polling of the root hub
 *           would be stopped anyway.
 */
int wusbhc_rh_status_data(struct usb_hcd *usb_hcd, char *_buf)
{
        struct wusbhc *wusbhc = usb_hcd_to_wusbhc(usb_hcd);
        size_t cnt, size, bits_set = 0;

        /* WE DON'T LOCK, see comment */
        /* round up to bytes.  Hub bit is bit 0 so add 1. */
        size = DIV_ROUND_UP(wusbhc->ports_max + 1, 8);

        /* clear the output buffer. */
        memset(_buf, 0, size);
        /* set the bit for each changed port. */
        for (cnt = 0; cnt < wusbhc->ports_max; cnt++) {

                if (wusb_port_by_idx(wusbhc, cnt)->change) {
                        const int bitpos = cnt+1;

                        _buf[bitpos/8] |= (1 << (bitpos % 8));
                        bits_set++;
                }
        }

        return bits_set ? size : 0;
}
EXPORT_SYMBOL_GPL(wusbhc_rh_status_data);

/*
 * Return the hub's descriptor
 *
 * NOTE: almost cut and paste from ehci-hub.c
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked
 */
static int wusbhc_rh_get_hub_descr(struct wusbhc *wusbhc, u16 wValue,
                                   u16 wIndex,
                                   struct usb_hub_descriptor *descr,
                                   u16 wLength)
{
        u16 temp = 1 + (wusbhc->ports_max / 8);
        u8 length = 7 + 2 * temp;

        if (wLength < length)
                return -ENOSPC;
        descr->bDescLength = 7 + 2 * temp;
        descr->bDescriptorType = USB_DT_HUB; /* HUB type */
        descr->bNbrPorts = wusbhc->ports_max;
        descr->wHubCharacteristics = cpu_to_le16(
                HUB_CHAR_COMMON_LPSM    /* All ports power at once */
                | 0x00                  /* not part of compound device */
                | HUB_CHAR_NO_OCPM      /* No overcurrent protection */
                | 0x00                  /* 8 FS think time FIXME ?? */
                | 0x00);                /* No port indicators */
        descr->bPwrOn2PwrGood = 0;
        descr->bHubContrCurrent = 0;
        /* two bitmaps:  ports removable, and usb 1.0 legacy PortPwrCtrlMask */
        memset(&descr->u.hs.DeviceRemovable[0], 0, temp);
        memset(&descr->u.hs.DeviceRemovable[temp], 0xff, temp);
        return 0;
}

/*
 * Clear a hub feature
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked.
 *
 * Nothing to do, so no locking needed ;)
 */
static int wusbhc_rh_clear_hub_feat(struct wusbhc *wusbhc, u16 feature)
{
        int result;

        switch (feature) {
        case C_HUB_LOCAL_POWER:
                /* FIXME: maybe plug bit 0 to the power input status,
                 * if any?
                 * see wusbhc_rh_get_hub_status() */
        case C_HUB_OVER_CURRENT:
                result = 0;
                break;
        default:
                result = -EPIPE;
        }
        return result;
}

/*
 * Return hub status (it is always zero...)
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked.
 *
 * Nothing to do, so no locking needed ;)
 */
static int wusbhc_rh_get_hub_status(struct wusbhc *wusbhc, u32 *buf,
                                    u16 wLength)
{
        /* FIXME: maybe plug bit 0 to the power input status (if any)? */
        *buf = 0;
        return 0;
}

/*
 * Set a port feature
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked.
 */
static int wusbhc_rh_set_port_feat(struct wusbhc *wusbhc, u16 feature,
                                   u8 selector, u8 port_idx)
{
        struct device *dev = wusbhc->dev;

        if (port_idx > wusbhc->ports_max)
                return -EINVAL;

        switch (feature) {
                /* According to USB2.0[11.24.2.13]p2, these features
                 * are not required to be implemented. */
        case USB_PORT_FEAT_C_OVER_CURRENT:
        case USB_PORT_FEAT_C_ENABLE:
        case USB_PORT_FEAT_C_SUSPEND:
        case USB_PORT_FEAT_C_CONNECTION:
        case USB_PORT_FEAT_C_RESET:
                return 0;
        case USB_PORT_FEAT_POWER:
                /* No such thing, but we fake it works */
                mutex_lock(&wusbhc->mutex);
                wusb_port_by_idx(wusbhc, port_idx)->status |= USB_PORT_STAT_POWER;
                mutex_unlock(&wusbhc->mutex);
                return 0;
        case USB_PORT_FEAT_RESET:
                return wusbhc_rh_port_reset(wusbhc, port_idx);
        case USB_PORT_FEAT_ENABLE:
        case USB_PORT_FEAT_SUSPEND:
                dev_err(dev, "(port_idx %d) set feat %d/%d UNIMPLEMENTED\n",
                        port_idx, feature, selector);
                return -ENOSYS;
        default:
                dev_err(dev, "(port_idx %d) set feat %d/%d UNKNOWN\n",
                        port_idx, feature, selector);
                return -EPIPE;
        }

        return 0;
}

/*
 * Clear a port feature...
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked.
 */
static int wusbhc_rh_clear_port_feat(struct wusbhc *wusbhc, u16 feature,
                                     u8 selector, u8 port_idx)
{
        int result = 0;
        struct device *dev = wusbhc->dev;

        if (port_idx > wusbhc->ports_max)
                return -EINVAL;

        mutex_lock(&wusbhc->mutex);
        switch (feature) {
        case USB_PORT_FEAT_POWER:       /* fake port always on */
                /* According to USB2.0[11.24.2.7.1.4], no need to implement? */
        case USB_PORT_FEAT_C_OVER_CURRENT:
                break;
        case USB_PORT_FEAT_C_RESET:
                wusb_port_by_idx(wusbhc, port_idx)->change &= ~USB_PORT_STAT_C_RESET;
                break;
        case USB_PORT_FEAT_C_CONNECTION:
                wusb_port_by_idx(wusbhc, port_idx)->change &= ~USB_PORT_STAT_C_CONNECTION;
                break;
        case USB_PORT_FEAT_ENABLE:
                __wusbhc_dev_disable(wusbhc, port_idx);
                break;
        case USB_PORT_FEAT_C_ENABLE:
                wusb_port_by_idx(wusbhc, port_idx)->change &= ~USB_PORT_STAT_C_ENABLE;
                break;
        case USB_PORT_FEAT_SUSPEND:
        case USB_PORT_FEAT_C_SUSPEND:
                dev_err(dev, "(port_idx %d) Clear feat %d/%d UNIMPLEMENTED\n",
                        port_idx, feature, selector);
                result = -ENOSYS;
                break;
        default:
                dev_err(dev, "(port_idx %d) Clear feat %d/%d UNKNOWN\n",
                        port_idx, feature, selector);
                result = -EPIPE;
                break;
        }
        mutex_unlock(&wusbhc->mutex);

        return result;
}

/*
 * Return the port's status
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked.
 */
static int wusbhc_rh_get_port_status(struct wusbhc *wusbhc, u16 port_idx,
                                     u32 *_buf, u16 wLength)
{
        __le16 *buf = (__le16 *)_buf;

        if (port_idx > wusbhc->ports_max)
                return -EINVAL;

        mutex_lock(&wusbhc->mutex);
        buf[0] = cpu_to_le16(wusb_port_by_idx(wusbhc, port_idx)->status);
        buf[1] = cpu_to_le16(wusb_port_by_idx(wusbhc, port_idx)->change);
        mutex_unlock(&wusbhc->mutex);

        return 0;
}

/*
 * Entry point for Root Hub operations
 *
 * @wusbhc is assumed referenced and @wusbhc->mutex unlocked.
 */
int wusbhc_rh_control(struct usb_hcd *usb_hcd, u16 reqntype, u16 wValue,
                      u16 wIndex, char *buf, u16 wLength)
{
        int result = -ENOSYS;
        struct wusbhc *wusbhc = usb_hcd_to_wusbhc(usb_hcd);

        switch (reqntype) {
        case GetHubDescriptor:
                result = wusbhc_rh_get_hub_descr(
                        wusbhc, wValue, wIndex,
                        (struct usb_hub_descriptor *) buf, wLength);
                break;
        case ClearHubFeature:
                result = wusbhc_rh_clear_hub_feat(wusbhc, wValue);
                break;
        case GetHubStatus:
                result = wusbhc_rh_get_hub_status(wusbhc, (u32 *)buf, wLength);
                break;

        case SetPortFeature:
                result = wusbhc_rh_set_port_feat(wusbhc, wValue, wIndex >> 8,
                                                 (wIndex & 0xff) - 1);
                break;
        case ClearPortFeature:
                result = wusbhc_rh_clear_port_feat(wusbhc, wValue, wIndex >> 8,
                                                   (wIndex & 0xff) - 1);
                break;
        case GetPortStatus:
                result = wusbhc_rh_get_port_status(wusbhc, wIndex - 1,
                                                   (u32 *)buf, wLength);
                break;

        case SetHubFeature:
        default:
                dev_err(wusbhc->dev, "%s (%p [%p], %x, %x, %x, %p, %x) "
                        "UNIMPLEMENTED\n", __func__, usb_hcd, wusbhc, reqntype,
                        wValue, wIndex, buf, wLength);
                /* dump_stack(); */
                result = -ENOSYS;
        }
        return result;
}
EXPORT_SYMBOL_GPL(wusbhc_rh_control);

int wusbhc_rh_start_port_reset(struct usb_hcd *usb_hcd, unsigned port_idx)
{
        struct wusbhc *wusbhc = usb_hcd_to_wusbhc(usb_hcd);
        dev_err(wusbhc->dev, "%s (%p [%p], port_idx %u) UNIMPLEMENTED\n",
                __func__, usb_hcd, wusbhc, port_idx);
        WARN_ON(1);
        return -ENOSYS;
}
EXPORT_SYMBOL_GPL(wusbhc_rh_start_port_reset);

static void wusb_port_init(struct wusb_port *port)
{
        port->status |= USB_PORT_STAT_HIGH_SPEED;
}

/*
 * Alloc fake port specific fields and status.
 */
int wusbhc_rh_create(struct wusbhc *wusbhc)
{
        int result = -ENOMEM;
        size_t port_size, itr;
        port_size = wusbhc->ports_max * sizeof(wusbhc->port[0]);
        wusbhc->port = kzalloc(port_size, GFP_KERNEL);
        if (wusbhc->port == NULL)
                goto error_port_alloc;
        for (itr = 0; itr < wusbhc->ports_max; itr++)
                wusb_port_init(&wusbhc->port[itr]);
        result = 0;
error_port_alloc:
        return result;
}

void wusbhc_rh_destroy(struct wusbhc *wusbhc)
{
        kfree(wusbhc->port);
}