source: mainline/uspace/drv/bus/usb/ohci/root_hub.c@ e65cd3c4

/*
 * Copyright (c) 2011 Jan Vesely
 * 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 drvusbohci
 * @{
 */
/** @file
 * @brief OHCI driver
 */
#include <assert.h>
#include <errno.h>
#include <str_error.h>
#include <fibril_synch.h>

#include <usb/debug.h>
#include <usb/dev/request.h>
#include <usb/classes/hub.h>

#include "root_hub.h"
#include <usb/classes/classes.h>
#include <usb/classes/hub.h>
#include <usb/dev/driver.h>
#include "ohci_regs.h"

/**
 * standart device descriptor for ohci root hub
 */
static const usb_standard_device_descriptor_t ohci_rh_device_descriptor = {
        .configuration_count = 1,
        .descriptor_type = USB_DESCTYPE_DEVICE,
        .device_class = USB_CLASS_HUB,
        .device_protocol = 0,
        .device_subclass = 0,
        .device_version = 0,
        .length = sizeof(usb_standard_device_descriptor_t),
        .max_packet_size = 64,
        .vendor_id = 0x16db, /* HelenOS does not have USB vendor ID assigned.*/
        .product_id = 0x0001,
        .str_serial_number = 0,
        .usb_spec_version = 0x110,
};

/**
 * standart configuration descriptor with filled common values
 * for ohci root hubs
 */
static const usb_standard_configuration_descriptor_t ohci_rh_conf_descriptor = {
        .attributes = 1 << 7,
        .configuration_number = 1,
        .descriptor_type = USB_DESCTYPE_CONFIGURATION,
        .interface_count = 1,
        .length = sizeof(usb_standard_configuration_descriptor_t),
        .max_power = 0, /* root hubs don't need no power */
        .str_configuration = 0,
};

/**
 * standart ohci root hub interface descriptor
 */
static const usb_standard_interface_descriptor_t ohci_rh_iface_descriptor = {
        .alternate_setting = 0,
        .descriptor_type = USB_DESCTYPE_INTERFACE,
        .endpoint_count = 1,
        .interface_class = USB_CLASS_HUB,
        .interface_number = 1,
        .interface_protocol = 0,
        .interface_subclass = 0,
        .length = sizeof(usb_standard_interface_descriptor_t),
        .str_interface = 0,
};

/**
 * standart ohci root hub endpoint descriptor
 */
static const usb_standard_endpoint_descriptor_t ohci_rh_ep_descriptor = {
        .attributes = USB_TRANSFER_INTERRUPT,
        .descriptor_type = USB_DESCTYPE_ENDPOINT,
        .endpoint_address = 1 + (1 << 7),
        .length = sizeof(usb_standard_endpoint_descriptor_t),
        .max_packet_size = 2,
        .poll_interval = 255,
};

static void create_serialized_hub_descriptor(rh_t *instance);
static void rh_init_descriptors(rh_t *instance);
static uint16_t create_interrupt_mask(const rh_t *instance);
static void get_status(const rh_t *instance, usb_transfer_batch_t *request);
static void get_descriptor(const rh_t *instance, usb_transfer_batch_t *request);
static void set_feature(const rh_t *instance, usb_transfer_batch_t *request);
static void clear_feature(const rh_t *instance, usb_transfer_batch_t *request);
static int set_feature_port(
    const rh_t *instance, uint16_t feature, uint16_t port);
static int clear_feature_port(
    const rh_t *instance, uint16_t feature, uint16_t port);
static void control_request(rh_t *instance, usb_transfer_batch_t *request);
static inline void interrupt_request(
    usb_transfer_batch_t *request, uint16_t mask, size_t size)
{
        assert(request);
        usb_transfer_batch_finish_error(request, &mask, size, EOK);
        usb_transfer_batch_destroy(request);
}

#define TRANSFER_END_DATA(request, data, bytes) \
do { \
        usb_transfer_batch_finish_error(request, data, bytes, EOK); \
        usb_transfer_batch_destroy(request); \
        return; \
} while (0)

#define TRANSFER_END(request, error) \
do { \
        usb_transfer_batch_finish_error(request, NULL, 0, error); \
        usb_transfer_batch_destroy(request); \
        return; \
} while (0)

/** Root Hub driver structure initialization.
 *
 * Reads info registers and prepares descriptors. Sets power mode.
 */
void rh_init(rh_t *instance, ohci_regs_t *regs)
{
        assert(instance);
        assert(regs);

        instance->registers = regs;
        instance->port_count =
            (instance->registers->rh_desc_a >> RHDA_NDS_SHIFT) & RHDA_NDS_MASK;
        if (instance->port_count > 15) {
                usb_log_warning("OHCI specification does not allow more than 15"
                    " ports. Max 15 ports will be used");
                instance->port_count = 15;
        }

        /* Don't forget the hub status bit and round up */
        instance->interrupt_mask_size = 1 + (instance->port_count / 8);
        instance->unfinished_interrupt_transfer = NULL;

#if defined OHCI_POWER_SWITCH_no
        /* Set port power mode to no power-switching. (always on) */
        instance->registers->rh_desc_a |= RHDA_NPS_FLAG;

        /* Set to no over-current reporting */
        instance->registers->rh_desc_a |= RHDA_NOCP_FLAG;

#elif defined OHCI_POWER_SWITCH_ganged
        /* Set port power mode to no ganged power-switching. */
        instance->registers->rh_desc_a &= ~RHDA_NPS_FLAG;
        instance->registers->rh_desc_a &= ~RHDA_PSM_FLAG;
        instance->registers->rh_status = RHS_CLEAR_GLOBAL_POWER;

        /* Set to global over-current */
        instance->registers->rh_desc_a &= ~RHDA_NOCP_FLAG;
        instance->registers->rh_desc_a &= ~RHDA_OCPM_FLAG;
#else
        /* Set port power mode to no per port power-switching. */
        instance->registers->rh_desc_a &= ~RHDA_NPS_FLAG;
        instance->registers->rh_desc_a |= RHDA_PSM_FLAG;

        /* Control all ports by global switch and turn them off */
        instance->registers->rh_desc_b &= (RHDB_PCC_MASK << RHDB_PCC_SHIFT);
        instance->registers->rh_status = RHS_CLEAR_GLOBAL_POWER;

        /* Return control to per port state */
        instance->registers->rh_desc_b |=
                ((1 << (instance->port_count + 1)) - 1) << RHDB_PCC_SHIFT;

        /* Set per port over-current */
        instance->registers->rh_desc_a &= ~RHDA_NOCP_FLAG;
        instance->registers->rh_desc_a |= RHDA_OCPM_FLAG;
#endif

        fibril_mutex_initialize(&instance->guard);
        rh_init_descriptors(instance);

        usb_log_info("Root hub (%zu ports) initialized.\n",
            instance->port_count);
}
/*----------------------------------------------------------------------------*/
/**
 * Process root hub request.
 *
 * @param instance Root hub instance
 * @param request Structure containing both request and response information
 * @return Error code
 */
void rh_request(rh_t *instance, usb_transfer_batch_t *request)
{
        assert(instance);
        assert(request);

        switch (request->ep->transfer_type)
        {
        case USB_TRANSFER_CONTROL:
                usb_log_debug("Root hub got CONTROL packet\n");
                control_request(instance, request);
                break;

        case USB_TRANSFER_INTERRUPT:
                usb_log_debug("Root hub got INTERRUPT packet\n");
                fibril_mutex_lock(&instance->guard);
                assert(instance->unfinished_interrupt_transfer == NULL);
                const uint16_t mask = create_interrupt_mask(instance);
                if (mask == 0) {
                        usb_log_debug("No changes...\n");
                        instance->unfinished_interrupt_transfer = request;
                } else {
                        usb_log_debug("Processing changes...\n");
                        interrupt_request(
                            request, mask, instance->interrupt_mask_size);
                }
                fibril_mutex_unlock(&instance->guard);
                break;

        default:
                usb_log_error("Root hub got unsupported request.\n");
                TRANSFER_END(request, ENOTSUP);
        }
}
/*----------------------------------------------------------------------------*/
/**
 * Process interrupt on a hub device.
 *
 * If there is no pending interrupt transfer, nothing happens.
 * @param instance
 */
void rh_interrupt(rh_t *instance)
{
        assert(instance);

        fibril_mutex_lock(&instance->guard);
        if (instance->unfinished_interrupt_transfer) {
                usb_log_debug("Finalizing interrupt transfer\n");
                const uint16_t mask = create_interrupt_mask(instance);
                interrupt_request(instance->unfinished_interrupt_transfer,
                    mask, instance->interrupt_mask_size);
                instance->unfinished_interrupt_transfer = NULL;
        }
        fibril_mutex_unlock(&instance->guard);
}
/*----------------------------------------------------------------------------*/
/**
 * Create hub descriptor.
 *
 * For descriptor format see USB hub specification (chapter 11.15.2.1, pg. 263)
 *
 * @param instance Root hub instance
 * @return Error code
 */
void create_serialized_hub_descriptor(rh_t *instance)
{
        assert(instance);

        /* 7 bytes + 2 port bit fields (port count + global bit) */
        const size_t size = 7 + (instance->interrupt_mask_size * 2);
        assert(size <= HUB_DESCRIPTOR_MAX_SIZE);
        instance->hub_descriptor_size = size;

        const uint32_t hub_desc = instance->registers->rh_desc_a;
        const uint32_t port_desc = instance->registers->rh_desc_b;

        /* bDescLength */
        instance->descriptors.hub[0] = size;
        /* bDescriptorType */
        instance->descriptors.hub[1] = USB_DESCTYPE_HUB;
        /* bNmbrPorts */
        instance->descriptors.hub[2] = instance->port_count;
        /* wHubCharacteristics */
        instance->descriptors.hub[3] = 0 |
            /* The lowest 2 bits indicate power switching mode */
            (((hub_desc & RHDA_PSM_FLAG)  ? 1 : 0) << 0) |
            (((hub_desc & RHDA_NPS_FLAG)  ? 1 : 0) << 1) |
            /* Bit 3 indicates device type (compound device) */
            (((hub_desc & RHDA_DT_FLAG)   ? 1 : 0) << 2) |
            /* Bits 4,5 indicate over-current protection mode */
            (((hub_desc & RHDA_OCPM_FLAG) ? 1 : 0) << 3) |
            (((hub_desc & RHDA_NOCP_FLAG) ? 1 : 0) << 4);

        /* Reserved */
        instance->descriptors.hub[4] = 0;
        /* bPwrOn2PwrGood */
        instance->descriptors.hub[5] =
            (hub_desc >> RHDA_POTPGT_SHIFT) & RHDA_POTPGT_MASK;
        /* bHubContrCurrent, root hubs don't need no power. */
        instance->descriptors.hub[6] = 0;

        /* Device Removable and some legacy 1.0 stuff*/
        instance->descriptors.hub[7] =
            (port_desc >> RHDB_DR_SHIFT) & RHDB_DR_MASK & 0xff;
        instance->descriptors.hub[8] = 0xff;
        if (instance->interrupt_mask_size == 2) {
                instance->descriptors.hub[8] =
                    (port_desc >> RHDB_DR_SHIFT) & RHDB_DR_MASK >> 8;
                instance->descriptors.hub[9]  = 0xff;
                instance->descriptors.hub[10] = 0xff;
        }
}
/*----------------------------------------------------------------------------*/
/** Initialize hub descriptors.
 *
 * A full configuration descriptor is assembled. The configuration and endpoint
 * descriptors have local modifications.
 * @param instance Root hub instance
 * @return Error code
 */
void rh_init_descriptors(rh_t *instance)
{
        assert(instance);

        instance->descriptors.configuration = ohci_rh_conf_descriptor;
        instance->descriptors.interface = ohci_rh_iface_descriptor;
        instance->descriptors.endpoint = ohci_rh_ep_descriptor;
        create_serialized_hub_descriptor(instance);

        instance->descriptors.endpoint.max_packet_size =
            instance->interrupt_mask_size;

        instance->descriptors.configuration.total_length =
            sizeof(usb_standard_configuration_descriptor_t) +
            sizeof(usb_standard_endpoint_descriptor_t) +
            sizeof(usb_standard_interface_descriptor_t) +
            instance->hub_descriptor_size;
}
/*----------------------------------------------------------------------------*/
/**
 * Create bitmap of changes to answer status interrupt.
 *
 * Result contains bitmap where bit 0 indicates change on hub and
 * bit i indicates change on i`th port (i>0). For more info see
 * Hub and Port status bitmap specification in USB specification
 * (chapter 11.13.4).
 * @param instance root hub instance
 * @return Mask of changes.
 */
uint16_t create_interrupt_mask(const rh_t *instance)
{
        assert(instance);
        uint16_t mask = 0;

        /* Only local power source change and over-current change can happen */
        if (instance->registers->rh_status & (RHS_LPSC_FLAG | RHS_OCIC_FLAG)) {
                mask |= 1;
        }
        for (size_t port = 1; port <= instance->port_count; ++port) {
                /* Write-clean bits are those that indicate change */
                if (RHPS_CHANGE_WC_MASK
                    & instance->registers->rh_port_status[port - 1]) {

                        mask |= (1 << port);
                }
        }
        /* USB is little endian */
        return host2uint32_t_le(mask);
}
/*----------------------------------------------------------------------------*/
/**
 * Create answer to status request.
 *
 * This might be either hub status or port status request. If neither,
 * ENOTSUP is returned.
 * @param instance root hub instance
 * @param request structure containing both request and response information
 * @return error code
 */
void get_status(const rh_t *instance, usb_transfer_batch_t *request)
{
        assert(instance);
        assert(request);


        const usb_device_request_setup_packet_t *request_packet =
            (usb_device_request_setup_packet_t*)request->setup_buffer;

        switch (request_packet->request_type)
        {
        case USB_HUB_REQ_TYPE_GET_HUB_STATUS:
        /* Hub status: just filter relevant info from rh_status reg */
                if (request->buffer_size < 4) {
                        usb_log_error("Buffer(%zu) too small for hub get "
                            "status request.\n", request->buffer_size);
                        TRANSFER_END(request, EOVERFLOW);
                } else {
                        const uint32_t data = instance->registers->rh_status &
                            (RHS_LPS_FLAG | RHS_LPSC_FLAG
                                | RHS_OCI_FLAG | RHS_OCIC_FLAG);
                        TRANSFER_END_DATA(request, &data, sizeof(data));
                }

        /* Copy appropriate rh_port_status register, OHCI designers were
         * kind enough to make those bit values match USB specification */
        case USB_HUB_REQ_TYPE_GET_PORT_STATUS:
                if (request->buffer_size < 4) {
                        usb_log_error("Buffer(%zu) too small for hub get "
                            "status request.\n", request->buffer_size);
                        TRANSFER_END(request, EOVERFLOW);
                } else {
                        const unsigned port = request_packet->index;
                        if (port < 1 || port > instance->port_count)
                                TRANSFER_END(request, EINVAL);

                        const uint32_t data =
                            instance->registers->rh_port_status[port - 1];
                        TRANSFER_END_DATA(request, &data, sizeof(data));
                }
        default:
                usb_log_error("Unsupported GET_STATUS request.\n");
                TRANSFER_END(request, ENOTSUP);
        }

}
/*----------------------------------------------------------------------------*/
/**
 * Create answer to a descriptor request.
 *
 * This might be a request for standard (configuration, device, endpoint or
 * interface) or device specific (hub) descriptor.
 * @param instance Root hub instance
 * @param request Structure containing both request and response information
 * @return Error code
 */
void get_descriptor(const rh_t *instance, usb_transfer_batch_t *request)
{
        assert(instance);
        assert(request);

        const usb_device_request_setup_packet_t *setup_request =
            (usb_device_request_setup_packet_t *) request->setup_buffer;
        size_t size;
        const void *descriptor = NULL;
        const uint16_t setup_request_value = setup_request->value_high;
        switch (setup_request_value)
        {
        case USB_DESCTYPE_HUB:
                usb_log_debug2("USB_DESCTYPE_HUB\n");
                /* Hub descriptor was generated locally */
                descriptor = instance->descriptors.hub;
                size = instance->hub_descriptor_size;
                break;

        case USB_DESCTYPE_DEVICE:
                usb_log_debug2("USB_DESCTYPE_DEVICE\n");
                /* Device descriptor is shared (No one should ask for it)*/
                descriptor = &ohci_rh_device_descriptor;
                size = sizeof(ohci_rh_device_descriptor);
                break;

        case USB_DESCTYPE_CONFIGURATION:
                usb_log_debug2("USB_DESCTYPE_CONFIGURATION\n");
                /* Start with configuration and add others depending on
                 * request size */
                descriptor = &instance->descriptors;
                size = instance->descriptors.configuration.total_length;
                break;

        case USB_DESCTYPE_INTERFACE:
                usb_log_debug2("USB_DESCTYPE_INTERFACE\n");
                /* Use local interface descriptor. There is one and it
                 * might be modified */
                descriptor = &instance->descriptors.interface;
                size = sizeof(instance->descriptors.interface);
                break;

        case USB_DESCTYPE_ENDPOINT:
                /* Use local endpoint descriptor. There is one
                 * it might have max_packet_size field modified*/
                usb_log_debug2("USB_DESCTYPE_ENDPOINT\n");
                descriptor = &instance->descriptors.endpoint;
                size = sizeof(instance->descriptors.endpoint);
                break;

        default:
                usb_log_debug2("USB_DESCTYPE_EINVAL %d \n"
                    "\ttype %d\n\trequest %d\n\tvalue "
                    "%d\n\tindex %d\n\tlen %d\n ",
                    setup_request->value,
                    setup_request->request_type, setup_request->request,
                    setup_request_value, setup_request->index,
                    setup_request->length);
                TRANSFER_END(request, EINVAL);
        }
        if (request->buffer_size < size) {
                size = request->buffer_size;
        }

        TRANSFER_END_DATA(request, descriptor, size);
}
/*----------------------------------------------------------------------------*/
/**
 * process feature-enabling request on hub
 *
 * @param instance root hub instance
 * @param feature feature selector
 * @param port port number, counted from 1
 * @param enable enable or disable the specified feature
 * @return error code
 */
int set_feature_port(const rh_t *instance, uint16_t feature, uint16_t port)
{
        assert(instance);

        if (port < 1 || port > instance->port_count)
                return EINVAL;

        switch (feature)
        {
        case USB_HUB_FEATURE_PORT_POWER:   //8
                /* No power switching */
                if (instance->registers->rh_desc_a & RHDA_NPS_FLAG)
                        return EOK;
                /* Ganged power switching */
                if (!(instance->registers->rh_desc_a & RHDA_PSM_FLAG)) {
                        instance->registers->rh_status = RHS_SET_GLOBAL_POWER;
                        return EOK;
                }
        case USB_HUB_FEATURE_PORT_ENABLE:  //1
        case USB_HUB_FEATURE_PORT_SUSPEND: //2
        case USB_HUB_FEATURE_PORT_RESET:   //4
                /* Nice thing is that these shifts correspond to the position
                 * of control bits in register */
                instance->registers->rh_port_status[port - 1] = (1 << feature);
                return EOK;
        default:
                return ENOTSUP;
        }
}
/*----------------------------------------------------------------------------*/
/**
 * Process feature clear request.
 *
 * @param instance root hub instance
 * @param feature feature selector
 * @param port port number, counted from 1
 * @param enable enable or disable the specified feature
 * @return error code
 */
int clear_feature_port(const rh_t *instance, uint16_t feature, uint16_t port)
{
        assert(instance);

        if (port < 1 || port > instance->port_count)
                return EINVAL;

        /* Enabled features to clear: see page 269 of USB specs */
        switch (feature)
        {
        case USB_HUB_FEATURE_PORT_POWER:          //8
                /* No power switching */
                if (instance->registers->rh_desc_a & RHDA_NPS_FLAG)
                        return ENOTSUP;
                /* Ganged power switching */
                if (!(instance->registers->rh_desc_a & RHDA_PSM_FLAG)) {
                        instance->registers->rh_status = RHS_CLEAR_GLOBAL_POWER;
                        return EOK;
                }
                instance->registers->rh_port_status[port - 1] =
                        RHPS_CLEAR_PORT_POWER;
                return EOK;

        case USB_HUB_FEATURE_PORT_ENABLE:         //1
                instance->registers->rh_port_status[port - 1] =
                        RHPS_CLEAR_PORT_ENABLE;
                return EOK;

        case USB_HUB_FEATURE_PORT_SUSPEND:        //2
                instance->registers->rh_port_status[port - 1] =
                        RHPS_CLEAR_PORT_SUSPEND;
                return EOK;

        case USB_HUB_FEATURE_C_PORT_CONNECTION:   //16
        case USB_HUB_FEATURE_C_PORT_ENABLE:       //17
        case USB_HUB_FEATURE_C_PORT_SUSPEND:      //18
        case USB_HUB_FEATURE_C_PORT_OVER_CURRENT: //19
        case USB_HUB_FEATURE_C_PORT_RESET:        //20
                /* Nice thing is that these shifts correspond to the position
                 * of control bits in register */
                instance->registers->rh_port_status[port - 1] = (1 << feature);
                return EOK;

        default:
                return ENOTSUP;
        }
}
/*----------------------------------------------------------------------------*/
/**
 * process one of requests that do not request nor carry additional data
 *
 * Request can be one of USB_DEVREQ_CLEAR_FEATURE, USB_DEVREQ_SET_FEATURE or
 * USB_DEVREQ_SET_ADDRESS.
 * @param instance root hub instance
 * @param request structure containing both request and response information
 * @return error code
 */
void set_feature(const rh_t *instance, usb_transfer_batch_t *request)
{
        assert(instance);
        assert(request);

        const usb_device_request_setup_packet_t *setup_request =
            (usb_device_request_setup_packet_t *) request->setup_buffer;
        switch (setup_request->request_type)
        {
        case USB_HUB_REQ_TYPE_SET_PORT_FEATURE:
                usb_log_debug("USB_HUB_REQ_TYPE_SET_PORT_FEATURE\n");
                const int ret = set_feature_port(instance,
                    setup_request->value, setup_request->index);
                TRANSFER_END(request, ret);

        case USB_HUB_REQ_TYPE_SET_HUB_FEATURE:
                /* Chapter 11.16.2 specifies that hub can be recipient
                 * only for C_HUB_LOCAL_POWER and C_HUB_OVER_CURRENT
                 * features. It makes no sense to SET either. */
                usb_log_error("Invalid HUB set feature request.\n");
                TRANSFER_END(request, ENOTSUP);
        default:
                usb_log_error("Invalid set feature request type: %d\n",
                    setup_request->request_type);
                TRANSFER_END(request, EINVAL);
        }
}
/*----------------------------------------------------------------------------*/
/**
 * process one of requests that do not request nor carry additional data
 *
 * Request can be one of USB_DEVREQ_CLEAR_FEATURE, USB_DEVREQ_SET_FEATURE or
 * USB_DEVREQ_SET_ADDRESS.
 * @param instance root hub instance
 * @param request structure containing both request and response information
 * @return error code
 */
void clear_feature(const rh_t *instance, usb_transfer_batch_t *request)
{
        assert(instance);
        assert(request);

        const usb_device_request_setup_packet_t *setup_request =
            (usb_device_request_setup_packet_t *) request->setup_buffer;

        switch (setup_request->request_type)
        {
        case USB_HUB_REQ_TYPE_CLEAR_PORT_FEATURE:
                usb_log_debug("USB_HUB_REQ_TYPE_CLEAR_PORT_FEATURE\n");
                const int ret = clear_feature_port(instance,
                    setup_request->value, setup_request->index);
                TRANSFER_END(request, ret);

        case USB_HUB_REQ_TYPE_CLEAR_HUB_FEATURE:
                usb_log_debug("USB_HUB_REQ_TYPE_CLEAR_HUB_FEATURE\n");
                /*
                 * Chapter 11.16.2 specifies that only C_HUB_LOCAL_POWER and
                 * C_HUB_OVER_CURRENT are supported.
                 * C_HUB_OVER_CURRENT is represented by OHCI RHS_OCIC_FLAG.
                 * C_HUB_LOCAL_POWER is not supported
                 * as root hubs do not support local power status feature.
                 * (OHCI pg. 127) */
                if (setup_request->value == USB_HUB_FEATURE_C_HUB_OVER_CURRENT) {
                        instance->registers->rh_status = RHS_OCIC_FLAG;
                        TRANSFER_END(request, EOK);
                }
        default:
                usb_log_error("Invalid clear feature request type: %d\n",
                    setup_request->request_type);
                TRANSFER_END(request, EINVAL);
        }
}
/*----------------------------------------------------------------------------*/
/**
 * Process hub control request.
 *
 * If needed, writes answer into the request structure.
 * Request can be one of
 * USB_DEVREQ_GET_STATUS,
 * USB_DEVREQ_GET_DESCRIPTOR,
 * USB_DEVREQ_GET_CONFIGURATION,
 * USB_DEVREQ_CLEAR_FEATURE,
 * USB_DEVREQ_SET_FEATURE,
 * USB_DEVREQ_SET_ADDRESS,
 * USB_DEVREQ_SET_DESCRIPTOR or
 * USB_DEVREQ_SET_CONFIGURATION.
 *
 * @param instance root hub instance
 * @param request structure containing both request and response information
 * @return error code
 */
void control_request(rh_t *instance, usb_transfer_batch_t *request)
{
        assert(instance);
        assert(request);

        if (!request->setup_buffer) {
                usb_log_error("Root hub received empty transaction!");
                TRANSFER_END(request, EBADMEM);
        }

        if (sizeof(usb_device_request_setup_packet_t) > request->setup_size) {
                usb_log_error("Setup packet too small\n");
                TRANSFER_END(request, EOVERFLOW);
        }

        usb_log_debug2("CTRL packet: %s.\n",
            usb_debug_str_buffer((uint8_t *) request->setup_buffer, 8, 8));
        const usb_device_request_setup_packet_t *setup_request =
            (usb_device_request_setup_packet_t *) request->setup_buffer;
        switch (setup_request->request)
        {
        case USB_DEVREQ_GET_STATUS:
                usb_log_debug("USB_DEVREQ_GET_STATUS\n");
                get_status(instance, request);
                break;

        case USB_DEVREQ_GET_DESCRIPTOR:
                usb_log_debug("USB_DEVREQ_GET_DESCRIPTOR\n");
                get_descriptor(instance, request);
                break;

        case USB_DEVREQ_GET_CONFIGURATION:
                usb_log_debug("USB_DEVREQ_GET_CONFIGURATION\n");
                if (request->buffer_size == 0)
                        TRANSFER_END(request, EOVERFLOW);
                static const uint8_t config = 1;
                TRANSFER_END_DATA(request, &config, sizeof(config));

        case USB_DEVREQ_CLEAR_FEATURE:
                usb_log_debug2("USB_DEVREQ_CLEAR_FEATURE\n");
                clear_feature(instance, request);
                break;

        case USB_DEVREQ_SET_FEATURE:
                usb_log_debug2("USB_DEVREQ_SET_FEATURE\n");
                set_feature(instance, request);
                break;

        case USB_DEVREQ_SET_ADDRESS:
                usb_log_debug("USB_DEVREQ_SET_ADDRESS\n");
                instance->address = setup_request->value;
                TRANSFER_END(request, EOK);

        case USB_DEVREQ_SET_CONFIGURATION:
                usb_log_debug("USB_DEVREQ_SET_CONFIGURATION\n");
                /* We don't need to do anything */
                TRANSFER_END(request, EOK);

        case USB_DEVREQ_SET_DESCRIPTOR: /* Not supported by OHCI RH */
        default:
                usb_log_error("Received unsupported request: %d.\n",
                    setup_request->request);
                TRANSFER_END(request, ENOTSUP);
        }
}
/**
 * @}
 */