hw/usb-desc.c - third_party/qemu - Git at Google

 #include "usb.h"
 #include "usb-desc.h"
 #include "trace.h"

 /* ------------------------------------------------------------------ */

 static uint8_t usb_lo(uint16_t val)
 {
     return val & 0xff;
 }

 static uint8_t usb_hi(uint16_t val)
 {
     return (val >> 8) & 0xff;
 }

 int usb_desc_device(const USBDescID *id, const USBDescDevice *dev,
                     uint8_t *dest, size_t len)
 {
     uint8_t bLength = 0x12;

     if (len < bLength) {
         return -1;
     }

     dest[0x00] = bLength;
     dest[0x01] = USB_DT_DEVICE;

     dest[0x02] = usb_lo(dev->bcdUSB);
     dest[0x03] = usb_hi(dev->bcdUSB);
     dest[0x04] = dev->bDeviceClass;
     dest[0x05] = dev->bDeviceSubClass;
     dest[0x06] = dev->bDeviceProtocol;
     dest[0x07] = dev->bMaxPacketSize0;

     dest[0x08] = usb_lo(id->idVendor);
     dest[0x09] = usb_hi(id->idVendor);
     dest[0x0a] = usb_lo(id->idProduct);
     dest[0x0b] = usb_hi(id->idProduct);
     dest[0x0c] = usb_lo(id->bcdDevice);
     dest[0x0d] = usb_hi(id->bcdDevice);
     dest[0x0e] = id->iManufacturer;
     dest[0x0f] = id->iProduct;
     dest[0x10] = id->iSerialNumber;

     dest[0x11] = dev->bNumConfigurations;

     return bLength;
 }

 int usb_desc_device_qualifier(const USBDescDevice *dev,
                               uint8_t *dest, size_t len)
 {
     uint8_t bLength = 0x0a;

     if (len < bLength) {
         return -1;
     }

     dest[0x00] = bLength;
     dest[0x01] = USB_DT_DEVICE_QUALIFIER;

     dest[0x02] = usb_lo(dev->bcdUSB);
     dest[0x03] = usb_hi(dev->bcdUSB);
     dest[0x04] = dev->bDeviceClass;
     dest[0x05] = dev->bDeviceSubClass;
     dest[0x06] = dev->bDeviceProtocol;
     dest[0x07] = dev->bMaxPacketSize0;
     dest[0x08] = dev->bNumConfigurations;
     dest[0x09] = 0; /* reserved */

     return bLength;
 }

 int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len)
 {
     uint8_t  bLength = 0x09;
     uint16_t wTotalLength = 0;
     int i, rc;

     if (len < bLength) {
         return -1;
     }

     dest[0x00] = bLength;
     dest[0x01] = USB_DT_CONFIG;
     dest[0x04] = conf->bNumInterfaces;
     dest[0x05] = conf->bConfigurationValue;
     dest[0x06] = conf->iConfiguration;
     dest[0x07] = conf->bmAttributes;
     dest[0x08] = conf->bMaxPower;
     wTotalLength += bLength;

     /* handle grouped interfaces if any*/
     for (i = 0; i < conf->nif_groups; i++) {
         rc = usb_desc_iface_group(&(conf->if_groups[i]),
                                   dest + wTotalLength,
                                   len - wTotalLength);
         if (rc < 0) {
             return rc;
         }
         wTotalLength += rc;
     }

     /* handle normal (ungrouped / no IAD) interfaces if any */
     for (i = 0; i < conf->nif; i++) {
         rc = usb_desc_iface(conf->ifs + i, dest + wTotalLength, len - wTotalLength);
         if (rc < 0) {
             return rc;
         }
         wTotalLength += rc;
     }

     dest[0x02] = usb_lo(wTotalLength);
     dest[0x03] = usb_hi(wTotalLength);
     return wTotalLength;
 }

 int usb_desc_iface_group(const USBDescIfaceAssoc *iad, uint8_t *dest,
                          size_t len)
 {
     int pos = 0;
     int i = 0;

     /* handle interface association descriptor */
     uint8_t bLength = 0x08;

     if (len < bLength) {
         return -1;
     }

     dest[0x00] = bLength;
     dest[0x01] = USB_DT_INTERFACE_ASSOC;
     dest[0x02] = iad->bFirstInterface;
     dest[0x03] = iad->bInterfaceCount;
     dest[0x04] = iad->bFunctionClass;
     dest[0x05] = iad->bFunctionSubClass;
     dest[0x06] = iad->bFunctionProtocol;
     dest[0x07] = iad->iFunction;
     pos += bLength;

     /* handle associated interfaces in this group */
     for (i = 0; i < iad->nif; i++) {
         int rc = usb_desc_iface(&(iad->ifs[i]), dest + pos, len - pos);
         if (rc < 0) {
             return rc;
         }
         pos += rc;
     }

     return pos;
 }

 int usb_desc_iface(const USBDescIface *iface, uint8_t *dest, size_t len)
 {
     uint8_t bLength = 0x09;
     int i, rc, pos = 0;

     if (len < bLength) {
         return -1;
     }

     dest[0x00] = bLength;
     dest[0x01] = USB_DT_INTERFACE;
     dest[0x02] = iface->bInterfaceNumber;
     dest[0x03] = iface->bAlternateSetting;
     dest[0x04] = iface->bNumEndpoints;
     dest[0x05] = iface->bInterfaceClass;
     dest[0x06] = iface->bInterfaceSubClass;
     dest[0x07] = iface->bInterfaceProtocol;
     dest[0x08] = iface->iInterface;
     pos += bLength;

     for (i = 0; i < iface->ndesc; i++) {
         rc = usb_desc_other(iface->descs + i, dest + pos, len - pos);
         if (rc < 0) {
             return rc;
         }
         pos += rc;
     }

     for (i = 0; i < iface->bNumEndpoints; i++) {
         rc = usb_desc_endpoint(iface->eps + i, dest + pos, len - pos);
         if (rc < 0) {
             return rc;
         }
         pos += rc;
     }

     return pos;
 }

 int usb_desc_endpoint(const USBDescEndpoint *ep, uint8_t *dest, size_t len)
 {
     uint8_t bLength = 0x07;

     if (len < bLength) {
         return -1;
     }

     dest[0x00] = bLength;
     dest[0x01] = USB_DT_ENDPOINT;
     dest[0x02] = ep->bEndpointAddress;
     dest[0x03] = ep->bmAttributes;
     dest[0x04] = usb_lo(ep->wMaxPacketSize);
     dest[0x05] = usb_hi(ep->wMaxPacketSize);
     dest[0x06] = ep->bInterval;

     return bLength;
 }

 int usb_desc_other(const USBDescOther *desc, uint8_t *dest, size_t len)
 {
     int bLength = desc->length ? desc->length : desc->data[0];

     if (len < bLength) {
         return -1;
     }

     memcpy(dest, desc->data, bLength);
     return bLength;
 }

 /* ------------------------------------------------------------------ */

 static void usb_desc_setdefaults(USBDevice *dev)
 {
     const USBDesc *desc = dev->info->usb_desc;

     assert(desc != NULL);
     switch (dev->speed) {
     case USB_SPEED_LOW:
     case USB_SPEED_FULL:
         dev->device = desc->full;
         break;
     case USB_SPEED_HIGH:
         dev->device = desc->high;
         break;
     }
     dev->config = dev->device->confs;
 }

 void usb_desc_init(USBDevice *dev)
 {
     const USBDesc *desc = dev->info->usb_desc;

     assert(desc != NULL);
     dev->speed = USB_SPEED_FULL;
     dev->speedmask = 0;
     if (desc->full) {
         dev->speedmask |= USB_SPEED_MASK_FULL;
     }
     if (desc->high) {
         dev->speedmask |= USB_SPEED_MASK_HIGH;
     }
     usb_desc_setdefaults(dev);
 }

 void usb_desc_attach(USBDevice *dev)
 {
     const USBDesc *desc = dev->info->usb_desc;

     assert(desc != NULL);
     if (desc->high && (dev->port->speedmask & USB_SPEED_MASK_HIGH)) {
         dev->speed = USB_SPEED_HIGH;
     } else if (desc->full && (dev->port->speedmask & USB_SPEED_MASK_FULL)) {
         dev->speed = USB_SPEED_FULL;
     } else {
         fprintf(stderr, "usb: port/device speed mismatch for \"%s\"\n",
                 dev->info->product_desc);
         return;
     }
     usb_desc_setdefaults(dev);
 }

 void usb_desc_set_string(USBDevice *dev, uint8_t index, const char *str)
 {
     USBDescString *s;

     QLIST_FOREACH(s, &dev->strings, next) {
         if (s->index == index) {
             break;
         }
     }
     if (s == NULL) {
         s = qemu_mallocz(sizeof(*s));
         s->index = index;
         QLIST_INSERT_HEAD(&dev->strings, s, next);
     }
     qemu_free(s->str);
     s->str = qemu_strdup(str);
 }

 const char *usb_desc_get_string(USBDevice *dev, uint8_t index)
 {
     USBDescString *s;

     QLIST_FOREACH(s, &dev->strings, next) {
         if (s->index == index) {
             return s->str;
         }
     }
     return NULL;
 }

 int usb_desc_string(USBDevice *dev, int index, uint8_t *dest, size_t len)
 {
     uint8_t bLength, pos, i;
     const char *str;

     if (len < 4) {
         return -1;
     }

     if (index == 0) {
         /* language ids */
         dest[0] = 4;
         dest[1] = USB_DT_STRING;
         dest[2] = 0x09;
         dest[3] = 0x04;
         return 4;
     }

     str = usb_desc_get_string(dev, index);
     if (str == NULL) {
         str = dev->info->usb_desc->str[index];
         if (str == NULL) {
             return 0;
         }
     }

     bLength = strlen(str) * 2 + 2;
     dest[0] = bLength;
     dest[1] = USB_DT_STRING;
     i = 0; pos = 2;
     while (pos+1 < bLength && pos+1 < len) {
         dest[pos++] = str[i++];
         dest[pos++] = 0;
     }
     return pos;
 }

 int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len)
 {
     const USBDesc *desc = dev->info->usb_desc;
     const USBDescDevice *other_dev;
     uint8_t buf[256];
     uint8_t type = value >> 8;
     uint8_t index = value & 0xff;
     int ret = -1;

     if (dev->speed == USB_SPEED_HIGH) {
         other_dev = dev->info->usb_desc->full;
     } else {
         other_dev = dev->info->usb_desc->high;
     }

     switch(type) {
     case USB_DT_DEVICE:
         ret = usb_desc_device(&desc->id, dev->device, buf, sizeof(buf));
         trace_usb_desc_device(dev->addr, len, ret);
         break;
     case USB_DT_CONFIG:
         if (index < dev->device->bNumConfigurations) {
             ret = usb_desc_config(dev->device->confs + index, buf, sizeof(buf));
         }
         trace_usb_desc_config(dev->addr, index, len, ret);
         break;
     case USB_DT_STRING:
         ret = usb_desc_string(dev, index, buf, sizeof(buf));
         trace_usb_desc_string(dev->addr, index, len, ret);
         break;

     case USB_DT_DEVICE_QUALIFIER:
         if (other_dev != NULL) {
             ret = usb_desc_device_qualifier(other_dev, buf, sizeof(buf));
         }
         trace_usb_desc_device_qualifier(dev->addr, len, ret);
         break;
     case USB_DT_OTHER_SPEED_CONFIG:
         if (other_dev != NULL && index < other_dev->bNumConfigurations) {
             ret = usb_desc_config(other_dev->confs + index, buf, sizeof(buf));
             buf[0x01] = USB_DT_OTHER_SPEED_CONFIG;
         }
         trace_usb_desc_other_speed_config(dev->addr, index, len, ret);
         break;

     case USB_DT_DEBUG:
         /* ignore silently */
         break;

     default:
         fprintf(stderr, "%s: %d unknown type %d (len %zd)\n", __FUNCTION__,
                 dev->addr, type, len);
         break;
     }

     if (ret > 0) {
         if (ret > len) {
             ret = len;
         }
         memcpy(dest, buf, ret);
     }
     return ret;
 }

 int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
         int request, int value, int index, int length, uint8_t *data)
 {
     const USBDesc *desc = dev->info->usb_desc;
     int i, ret = -1;

     assert(desc != NULL);
     switch(request) {
     case DeviceOutRequest | USB_REQ_SET_ADDRESS:
         dev->addr = value;
         trace_usb_set_addr(dev->addr);
         ret = 0;
         break;

     case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
         ret = usb_desc_get_descriptor(dev, value, data, length);
         break;

     case DeviceRequest | USB_REQ_GET_CONFIGURATION:
         data[0] = dev->config->bConfigurationValue;
         ret = 1;
         break;
     case DeviceOutRequest | USB_REQ_SET_CONFIGURATION:
         for (i = 0; i < dev->device->bNumConfigurations; i++) {
             if (dev->device->confs[i].bConfigurationValue == value) {
                 dev->config = dev->device->confs + i;
                 ret = 0;
             }
         }
         trace_usb_set_config(dev->addr, value, ret);
         break;

     case DeviceRequest | USB_REQ_GET_STATUS:
         data[0] = 0;
         if (dev->config->bmAttributes & 0x40) {
             data[0] |= 1 << USB_DEVICE_SELF_POWERED;
         }
         if (dev->remote_wakeup) {
             data[0] |= 1 << USB_DEVICE_REMOTE_WAKEUP;
         }
         data[1] = 0x00;
         ret = 2;
         break;
     case DeviceOutRequest | USB_REQ_CLEAR_FEATURE:
         if (value == USB_DEVICE_REMOTE_WAKEUP) {
             dev->remote_wakeup = 0;
             ret = 0;
         }
         trace_usb_clear_device_feature(dev->addr, value, ret);
         break;
     case DeviceOutRequest | USB_REQ_SET_FEATURE:
         if (value == USB_DEVICE_REMOTE_WAKEUP) {
             dev->remote_wakeup = 1;
             ret = 0;
         }
         trace_usb_set_device_feature(dev->addr, value, ret);
         break;
     }
     return ret;
 }
	#include "usb.h"
	#include "usb-desc.h"
	#include "trace.h"

	/* ------------------------------------------------------------------ */

	static uint8_t usb_lo(uint16_t val)
	{
	return val & 0xff;
	}

	static uint8_t usb_hi(uint16_t val)
	{
	return (val >> 8) & 0xff;
	}

	int usb_desc_device(const USBDescID id, const USBDescDevice dev,
	uint8_t *dest, size_t len)
	{
	uint8_t bLength = 0x12;

	if (len < bLength) {
	return -1;
	}

	dest[0x00] = bLength;
	dest[0x01] = USB_DT_DEVICE;

	dest[0x02] = usb_lo(dev->bcdUSB);
	dest[0x03] = usb_hi(dev->bcdUSB);
	dest[0x04] = dev->bDeviceClass;
	dest[0x05] = dev->bDeviceSubClass;
	dest[0x06] = dev->bDeviceProtocol;
	dest[0x07] = dev->bMaxPacketSize0;

	dest[0x08] = usb_lo(id->idVendor);
	dest[0x09] = usb_hi(id->idVendor);
	dest[0x0a] = usb_lo(id->idProduct);
	dest[0x0b] = usb_hi(id->idProduct);
	dest[0x0c] = usb_lo(id->bcdDevice);
	dest[0x0d] = usb_hi(id->bcdDevice);
	dest[0x0e] = id->iManufacturer;
	dest[0x0f] = id->iProduct;
	dest[0x10] = id->iSerialNumber;

	dest[0x11] = dev->bNumConfigurations;

	return bLength;
	}

	int usb_desc_device_qualifier(const USBDescDevice *dev,
	uint8_t *dest, size_t len)
	{
	uint8_t bLength = 0x0a;

	if (len < bLength) {
	return -1;
	}

	dest[0x00] = bLength;
	dest[0x01] = USB_DT_DEVICE_QUALIFIER;

	dest[0x02] = usb_lo(dev->bcdUSB);
	dest[0x03] = usb_hi(dev->bcdUSB);
	dest[0x04] = dev->bDeviceClass;
	dest[0x05] = dev->bDeviceSubClass;
	dest[0x06] = dev->bDeviceProtocol;
	dest[0x07] = dev->bMaxPacketSize0;
	dest[0x08] = dev->bNumConfigurations;
	dest[0x09] = 0; /* reserved */

	return bLength;
	}

	int usb_desc_config(const USBDescConfig conf, uint8_t dest, size_t len)
	{
	uint8_t bLength = 0x09;
	uint16_t wTotalLength = 0;
	int i, rc;

	if (len < bLength) {
	return -1;
	}

	dest[0x00] = bLength;
	dest[0x01] = USB_DT_CONFIG;
	dest[0x04] = conf->bNumInterfaces;
	dest[0x05] = conf->bConfigurationValue;
	dest[0x06] = conf->iConfiguration;
	dest[0x07] = conf->bmAttributes;
	dest[0x08] = conf->bMaxPower;
	wTotalLength += bLength;

	/* handle grouped interfaces if any*/
	for (i = 0; i < conf->nif_groups; i++) {
	rc = usb_desc_iface_group(&(conf->if_groups[i]),
	dest + wTotalLength,
	len - wTotalLength);
	if (rc < 0) {
	return rc;
	}
	wTotalLength += rc;
	}

	/* handle normal (ungrouped / no IAD) interfaces if any */
	for (i = 0; i < conf->nif; i++) {
	rc = usb_desc_iface(conf->ifs + i, dest + wTotalLength, len - wTotalLength);
	if (rc < 0) {
	return rc;
	}
	wTotalLength += rc;
	}

	dest[0x02] = usb_lo(wTotalLength);
	dest[0x03] = usb_hi(wTotalLength);
	return wTotalLength;
	}

	int usb_desc_iface_group(const USBDescIfaceAssoc iad, uint8_t dest,
	size_t len)
	{
	int pos = 0;
	int i = 0;

	/* handle interface association descriptor */
	uint8_t bLength = 0x08;

	if (len < bLength) {
	return -1;
	}

	dest[0x00] = bLength;
	dest[0x01] = USB_DT_INTERFACE_ASSOC;
	dest[0x02] = iad->bFirstInterface;
	dest[0x03] = iad->bInterfaceCount;
	dest[0x04] = iad->bFunctionClass;
	dest[0x05] = iad->bFunctionSubClass;
	dest[0x06] = iad->bFunctionProtocol;
	dest[0x07] = iad->iFunction;
	pos += bLength;

	/* handle associated interfaces in this group */
	for (i = 0; i < iad->nif; i++) {
	int rc = usb_desc_iface(&(iad->ifs[i]), dest + pos, len - pos);
	if (rc < 0) {
	return rc;
	}
	pos += rc;
	}

	return pos;
	}

	int usb_desc_iface(const USBDescIface iface, uint8_t dest, size_t len)
	{
	uint8_t bLength = 0x09;
	int i, rc, pos = 0;

	if (len < bLength) {
	return -1;
	}

	dest[0x00] = bLength;
	dest[0x01] = USB_DT_INTERFACE;
	dest[0x02] = iface->bInterfaceNumber;
	dest[0x03] = iface->bAlternateSetting;
	dest[0x04] = iface->bNumEndpoints;
	dest[0x05] = iface->bInterfaceClass;
	dest[0x06] = iface->bInterfaceSubClass;
	dest[0x07] = iface->bInterfaceProtocol;
	dest[0x08] = iface->iInterface;
	pos += bLength;

	for (i = 0; i < iface->ndesc; i++) {
	rc = usb_desc_other(iface->descs + i, dest + pos, len - pos);
	if (rc < 0) {
	return rc;
	}
	pos += rc;
	}

	for (i = 0; i < iface->bNumEndpoints; i++) {
	rc = usb_desc_endpoint(iface->eps + i, dest + pos, len - pos);
	if (rc < 0) {
	return rc;
	}
	pos += rc;
	}

	return pos;
	}

	int usb_desc_endpoint(const USBDescEndpoint ep, uint8_t dest, size_t len)
	{
	uint8_t bLength = 0x07;

	if (len < bLength) {
	return -1;
	}

	dest[0x00] = bLength;
	dest[0x01] = USB_DT_ENDPOINT;
	dest[0x02] = ep->bEndpointAddress;
	dest[0x03] = ep->bmAttributes;
	dest[0x04] = usb_lo(ep->wMaxPacketSize);
	dest[0x05] = usb_hi(ep->wMaxPacketSize);
	dest[0x06] = ep->bInterval;

	return bLength;
	}

	int usb_desc_other(const USBDescOther desc, uint8_t dest, size_t len)
	{
	int bLength = desc->length ? desc->length : desc->data[0];

	if (len < bLength) {
	return -1;
	}

	memcpy(dest, desc->data, bLength);
	return bLength;
	}

	/* ------------------------------------------------------------------ */

	static void usb_desc_setdefaults(USBDevice *dev)
	{
	const USBDesc *desc = dev->info->usb_desc;

	assert(desc != NULL);
	switch (dev->speed) {
	case USB_SPEED_LOW:
	case USB_SPEED_FULL:
	dev->device = desc->full;
	break;
	case USB_SPEED_HIGH:
	dev->device = desc->high;
	break;
	}
	dev->config = dev->device->confs;
	}

	void usb_desc_init(USBDevice *dev)
	{
	const USBDesc *desc = dev->info->usb_desc;

	assert(desc != NULL);
	dev->speed = USB_SPEED_FULL;
	dev->speedmask = 0;
	if (desc->full) {
	dev->speedmask \|= USB_SPEED_MASK_FULL;
	}
	if (desc->high) {
	dev->speedmask \|= USB_SPEED_MASK_HIGH;
	}
	usb_desc_setdefaults(dev);
	}

	void usb_desc_attach(USBDevice *dev)
	{
	const USBDesc *desc = dev->info->usb_desc;

	assert(desc != NULL);
	if (desc->high && (dev->port->speedmask & USB_SPEED_MASK_HIGH)) {
	dev->speed = USB_SPEED_HIGH;
	} else if (desc->full && (dev->port->speedmask & USB_SPEED_MASK_FULL)) {
	dev->speed = USB_SPEED_FULL;
	} else {
	fprintf(stderr, "usb: port/device speed mismatch for \"%s\"\n",
	dev->info->product_desc);
	return;
	}
	usb_desc_setdefaults(dev);
	}

	void usb_desc_set_string(USBDevice dev, uint8_t index, const char str)
	{
	USBDescString *s;

	QLIST_FOREACH(s, &dev->strings, next) {
	if (s->index == index) {
	break;
	}
	}
	if (s == NULL) {
	s = qemu_mallocz(sizeof(*s));
	s->index = index;
	QLIST_INSERT_HEAD(&dev->strings, s, next);
	}
	qemu_free(s->str);
	s->str = qemu_strdup(str);
	}

	const char usb_desc_get_string(USBDevice dev, uint8_t index)
	{
	USBDescString *s;

	QLIST_FOREACH(s, &dev->strings, next) {
	if (s->index == index) {
	return s->str;
	}
	}
	return NULL;
	}

	int usb_desc_string(USBDevice dev, int index, uint8_t dest, size_t len)
	{
	uint8_t bLength, pos, i;
	const char *str;

	if (len < 4) {
	return -1;
	}

	if (index == 0) {
	/* language ids */
	dest[0] = 4;
	dest[1] = USB_DT_STRING;
	dest[2] = 0x09;
	dest[3] = 0x04;
	return 4;
	}

	str = usb_desc_get_string(dev, index);
	if (str == NULL) {
	str = dev->info->usb_desc->str[index];
	if (str == NULL) {
	return 0;
	}
	}

	bLength = strlen(str) * 2 + 2;
	dest[0] = bLength;
	dest[1] = USB_DT_STRING;
	i = 0; pos = 2;
	while (pos+1 < bLength && pos+1 < len) {
	dest[pos++] = str[i++];
	dest[pos++] = 0;
	}
	return pos;
	}

	int usb_desc_get_descriptor(USBDevice dev, int value, uint8_t dest, size_t len)
	{
	const USBDesc *desc = dev->info->usb_desc;
	const USBDescDevice *other_dev;
	uint8_t buf[256];
	uint8_t type = value >> 8;
	uint8_t index = value & 0xff;
	int ret = -1;

	if (dev->speed == USB_SPEED_HIGH) {
	other_dev = dev->info->usb_desc->full;
	} else {
	other_dev = dev->info->usb_desc->high;
	}

	switch(type) {
	case USB_DT_DEVICE:
	ret = usb_desc_device(&desc->id, dev->device, buf, sizeof(buf));
	trace_usb_desc_device(dev->addr, len, ret);
	break;
	case USB_DT_CONFIG:
	if (index < dev->device->bNumConfigurations) {
	ret = usb_desc_config(dev->device->confs + index, buf, sizeof(buf));
	}
	trace_usb_desc_config(dev->addr, index, len, ret);
	break;
	case USB_DT_STRING:
	ret = usb_desc_string(dev, index, buf, sizeof(buf));
	trace_usb_desc_string(dev->addr, index, len, ret);
	break;

	case USB_DT_DEVICE_QUALIFIER:
	if (other_dev != NULL) {
	ret = usb_desc_device_qualifier(other_dev, buf, sizeof(buf));
	}
	trace_usb_desc_device_qualifier(dev->addr, len, ret);
	break;
	case USB_DT_OTHER_SPEED_CONFIG:
	if (other_dev != NULL && index < other_dev->bNumConfigurations) {
	ret = usb_desc_config(other_dev->confs + index, buf, sizeof(buf));
	buf[0x01] = USB_DT_OTHER_SPEED_CONFIG;
	}
	trace_usb_desc_other_speed_config(dev->addr, index, len, ret);
	break;

	case USB_DT_DEBUG:
	/* ignore silently */
	break;

	default:
	fprintf(stderr, "%s: %d unknown type %d (len %zd)\n", __FUNCTION__,
	dev->addr, type, len);
	break;
	}

	if (ret > 0) {
	if (ret > len) {
	ret = len;
	}
	memcpy(dest, buf, ret);
	}
	return ret;
	}

	int usb_desc_handle_control(USBDevice dev, USBPacket p,
	int request, int value, int index, int length, uint8_t *data)
	{
	const USBDesc *desc = dev->info->usb_desc;
	int i, ret = -1;

	assert(desc != NULL);
	switch(request) {
	case DeviceOutRequest \| USB_REQ_SET_ADDRESS:
	dev->addr = value;
	trace_usb_set_addr(dev->addr);
	ret = 0;
	break;

	case DeviceRequest \| USB_REQ_GET_DESCRIPTOR:
	ret = usb_desc_get_descriptor(dev, value, data, length);
	break;

	case DeviceRequest \| USB_REQ_GET_CONFIGURATION:
	data[0] = dev->config->bConfigurationValue;
	ret = 1;
	break;
	case DeviceOutRequest \| USB_REQ_SET_CONFIGURATION:
	for (i = 0; i < dev->device->bNumConfigurations; i++) {
	if (dev->device->confs[i].bConfigurationValue == value) {
	dev->config = dev->device->confs + i;
	ret = 0;
	}
	}
	trace_usb_set_config(dev->addr, value, ret);
	break;

	case DeviceRequest \| USB_REQ_GET_STATUS:
	data[0] = 0;
	if (dev->config->bmAttributes & 0x40) {
	data[0] \|= 1 << USB_DEVICE_SELF_POWERED;
	}
	if (dev->remote_wakeup) {
	data[0] \|= 1 << USB_DEVICE_REMOTE_WAKEUP;
	}
	data[1] = 0x00;
	ret = 2;
	break;
	case DeviceOutRequest \| USB_REQ_CLEAR_FEATURE:
	if (value == USB_DEVICE_REMOTE_WAKEUP) {
	dev->remote_wakeup = 0;
	ret = 0;
	}
	trace_usb_clear_device_feature(dev->addr, value, ret);
	break;
	case DeviceOutRequest \| USB_REQ_SET_FEATURE:
	if (value == USB_DEVICE_REMOTE_WAKEUP) {
	dev->remote_wakeup = 1;
	ret = 0;
	}
	trace_usb_set_device_feature(dev->addr, value, ret);
	break;
	}
	return ret;
	}