message.c

ReactOs中的USB驱动

			}
		}
	}
}

/**
 * usb_clear_halt - tells device to clear endpoint halt/stall condition
 * @dev: device whose endpoint is halted
 * @pipe: endpoint "pipe" being cleared
 * Context: !in_interrupt ()
 *
 * This is used to clear halt conditions for bulk and interrupt endpoints,
 * as reported by URB completion status.  Endpoints that are halted are
 * sometimes referred to as being "stalled".  Such endpoints are unable
 * to transmit or receive data until the halt status is cleared.  Any URBs
 * queued for such an endpoint should normally be unlinked by the driver
 * before clearing the halt condition, as described in sections 5.7.5
 * and 5.8.5 of the USB 2.0 spec.
 *
 * Note that control and isochronous endpoints don't halt, although control
 * endpoints report "protocol stall" (for unsupported requests) using the
 * same status code used to report a true stall.
 *
 * This call is synchronous, and may not be used in an interrupt context.
 *
 * Returns zero on success, or else the status code returned by the
 * underlying usb_control_msg() call.
 */
int usb_clear_halt(struct usb_device *dev, int pipe)
{
	int result;
	int endp = usb_pipeendpoint(pipe);
	
	if (usb_pipein (pipe))
		endp |= USB_DIR_IN;

	/* we don't care if it wasn't halted first. in fact some devices
	 * (like some ibmcam model 1 units) seem to expect hosts to make
	 * this request for iso endpoints, which can't halt!
	 */
	result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
		USB_REQ_CLEAR_FEATURE, USB_RECIP_ENDPOINT, 0, endp, NULL, 0,
		HZ * USB_CTRL_SET_TIMEOUT);

	/* don't un-halt or force to DATA0 except on success */
	if (result < 0)
		return result;

	/* NOTE:  seems like Microsoft and Apple don't bother verifying
	 * the clear "took", so some devices could lock up if you check...
	 * such as the Hagiwara FlashGate DUAL.  So we won't bother.
	 *
	 * NOTE:  make sure the logic here doesn't diverge much from
	 * the copy in usb-storage, for as long as we need two copies.
	 */

	/* toggle was reset by the clear, then ep was reactivated */
	usb_settoggle(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe), 0);
	usb_endpoint_running(dev, usb_pipeendpoint(pipe), usb_pipeout(pipe));

	return 0;
}

/**
 * usb_set_interface - Makes a particular alternate setting be current
 * @dev: the device whose interface is being updated
 * @interface: the interface being updated
 * @alternate: the setting being chosen.
 * Context: !in_interrupt ()
 *
 * This is used to enable data transfers on interfaces that may not
 * be enabled by default.  Not all devices support such configurability.
 * Only the driver bound to an interface may change its setting.
 *
 * Within any given configuration, each interface may have several
 * alternative settings.  These are often used to control levels of
 * bandwidth consumption.  For example, the default setting for a high
 * speed interrupt endpoint may not send more than 64 bytes per microframe,
 * while interrupt transfers of up to 3KBytes per microframe are legal.
 * Also, isochronous endpoints may never be part of an
 * interface's default setting.  To access such bandwidth, alternate
 * interface settings must be made current.
 *
 * Note that in the Linux USB subsystem, bandwidth associated with
 * an endpoint in a given alternate setting is not reserved until an URB
 * is submitted that needs that bandwidth.  Some other operating systems
 * allocate bandwidth early, when a configuration is chosen.
 *
 * This call is synchronous, and may not be used in an interrupt context.
 * Also, drivers must not change altsettings while urbs are scheduled for
 * endpoints in that interface; all such urbs must first be completed
 * (perhaps forced by unlinking).
 *
 * Returns zero on success, or else the status code returned by the
 * underlying usb_control_msg() call.
 */
int usb_set_interface(struct usb_device *dev, int interface, int alternate)
{
	struct usb_interface *iface;
	struct usb_host_interface *iface_as;
	int i, ret;
	void (*disable)(struct usb_device *, int) = dev->bus->op->disable;

	iface = usb_ifnum_to_if(dev, interface);
	if (!iface) {
		warn("selecting invalid interface %d", interface);
		return -EINVAL;
	}

	/* 9.4.10 says devices don't need this, if the interface
	   only has one alternate setting */
	if (iface->num_altsetting == 1) {
		dbg("ignoring set_interface for dev %d, iface %d, alt %d",
			dev->devnum, interface, alternate);
		return 0;
	}

	if (alternate < 0 || alternate >= iface->num_altsetting)
		return -EINVAL;

	if ((ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
				   USB_REQ_SET_INTERFACE, USB_RECIP_INTERFACE,
				   iface->altsetting[alternate]
				   	.desc.bAlternateSetting,
				   interface, NULL, 0, HZ * 5)) < 0)
		return ret;

	/* FIXME drivers shouldn't need to replicate/bugfix the logic here
	 * when they implement async or easily-killable versions of this or
	 * other "should-be-internal" functions (like clear_halt).
	 * should hcd+usbcore postprocess control requests?
	 */

	/* prevent submissions using previous endpoint settings */
	iface_as = iface->altsetting + iface->act_altsetting;
	for (i = 0; i < iface_as->desc.bNumEndpoints; i++) {
		u8	ep = iface_as->endpoint [i].desc.bEndpointAddress;
		int	out = !(ep & USB_DIR_IN);

		/* clear out hcd state, then usbcore state */
		if (disable)
			disable (dev, ep);
		ep &= USB_ENDPOINT_NUMBER_MASK;
		(out ? dev->epmaxpacketout : dev->epmaxpacketin ) [ep] = 0;
	}
	iface->act_altsetting = alternate;

	/* 9.1.1.5: reset toggles for all endpoints affected by this iface-as
	 *
	 * Note:
	 * Despite EP0 is always present in all interfaces/AS, the list of
	 * endpoints from the descriptor does not contain EP0. Due to its
	 * omnipresence one might expect EP0 being considered "affected" by
	 * any SetInterface request and hence assume toggles need to be reset.
	 * However, EP0 toggles are re-synced for every individual transfer
	 * during the SETUP stage - hence EP0 toggles are "don't care" here.
	 * (Likewise, EP0 never "halts" on well designed devices.)
	 */

	iface_as = &iface->altsetting[alternate];
	for (i = 0; i < iface_as->desc.bNumEndpoints; i++) {
		u8	ep = iface_as->endpoint[i].desc.bEndpointAddress;
		int	out = !(ep & USB_DIR_IN);

		ep &= USB_ENDPOINT_NUMBER_MASK;
		usb_settoggle (dev, ep, out, 0);
		(out ? dev->epmaxpacketout : dev->epmaxpacketin) [ep]
			= iface_as->endpoint [i].desc.wMaxPacketSize;
		usb_endpoint_running (dev, ep, out);
	}

	return 0;
}

/**
 * usb_set_configuration - Makes a particular device setting be current
 * @dev: the device whose configuration is being updated
 * @configuration: the configuration being chosen.
 * Context: !in_interrupt ()
 *
 * This is used to enable non-default device modes.  Not all devices
 * support this kind of configurability.  By default, configuration
 * zero is selected after enumeration; many devices only have a single
 * configuration.
 *
 * USB devices may support one or more configurations, which affect
 * power consumption and the functionality available.  For example,
 * the default configuration is limited to using 100mA of bus power,
 * so that when certain device functionality requires more power,
 * and the device is bus powered, that functionality will be in some
 * non-default device configuration.  Other device modes may also be
 * reflected as configuration options, such as whether two ISDN
 * channels are presented as independent 64Kb/s interfaces or as one
 * bonded 128Kb/s interface.
 *
 * Note that USB has an additional level of device configurability,
 * associated with interfaces.  That configurability is accessed using
 * usb_set_interface().
 *
 * This call is synchronous, and may not be used in an interrupt context.
 *
 * Returns zero on success, or else the status code returned by the
 * underlying usb_control_msg() call.
 */
int usb_set_configuration(struct usb_device *dev, int configuration)
{
	int i, ret;
	struct usb_host_config *cp = NULL;
	void (*disable)(struct usb_device *, int) = dev->bus->op->disable;
	
	for (i=0; i<dev->descriptor.bNumConfigurations; i++) {
		if (dev->config[i].desc.bConfigurationValue == configuration) {
			cp = &dev->config[i];
			break;
		}
	}
	if ((!cp && configuration != 0) || (cp && configuration == 0)) {
		warn("selecting invalid configuration %d", configuration);
		return -EINVAL;
	}

	/* if it's already configured, clear out old state first. */
	if (dev->state != USB_STATE_ADDRESS && disable) {
		for (i = 1 /* skip ep0 */; i < 15; i++) {
			disable (dev, i);
			disable (dev, USB_DIR_IN | i);
		}
	}
	dev->toggle[0] = dev->toggle[1] = 0;
	dev->halted[0] = dev->halted[1] = 0;
	dev->state = USB_STATE_ADDRESS;

	if ((ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			USB_REQ_SET_CONFIGURATION, 0, configuration, 0,
			NULL, 0, HZ * USB_CTRL_SET_TIMEOUT)) < 0)
		return ret;
	if (configuration)
		dev->state = USB_STATE_CONFIGURED;
	dev->actconfig = cp;

	/* reset more hc/hcd endpoint state */
	usb_set_maxpacket(dev);

	return 0;
}


/**
 * usb_string - returns ISO 8859-1 version of a string descriptor
 * @dev: the device whose string descriptor is being retrieved
 * @index: the number of the descriptor
 * @buf: where to put the string
 * @size: how big is "buf"?
 * Context: !in_interrupt ()
 * 
 * This converts the UTF-16LE encoded strings returned by devices, from
 * usb_get_string_descriptor(), to null-terminated ISO-8859-1 encoded ones
 * that are more usable in most kernel contexts.  Note that all characters
 * in the chosen descriptor that can't be encoded using ISO-8859-1
 * are converted to the question mark ("?") character, and this function
 * chooses strings in the first language supported by the device.
 *
 * The ASCII (or, redundantly, "US-ASCII") character set is the seven-bit
 * subset of ISO 8859-1. ISO-8859-1 is the eight-bit subset of Unicode,
 * and is appropriate for use many uses of English and several other
 * Western European languages.  (But it doesn't include the "Euro" symbol.)
 *
 * This call is synchronous, and may not be used in an interrupt context.
 *
 * Returns length of the string (>= 0) or usb_control_msg status (< 0).
 */
int usb_string(struct usb_device *dev, int index, char *buf, size_t size)
{
	unsigned char *tbuf;
	int err, len;
	unsigned int u, idx;

	if (size <= 0 || !buf || !index)
		return -EINVAL;
	buf[0] = 0;
	tbuf = kmalloc(256, GFP_KERNEL);
	if (!tbuf)
		return -ENOMEM;

	/* get langid for strings if it's not yet known */
	if (!dev->have_langid) {
		err = usb_get_string(dev, 0, 0, tbuf, 4);
		if (err < 0) {
			err("error getting string descriptor 0 (error=%d)", err);
			goto errout;
		} else if (tbuf[0] < 4) {
			err("string descriptor 0 too short");
			err = -EINVAL;
			goto errout;
		} else {
			dev->have_langid = -1;
			dev->string_langid = tbuf[2] | (tbuf[3]<< 8);
				/* always use the first langid listed */
			dbg("USB device number %d default language ID 0x%x",
				dev->devnum, dev->string_langid);
		}
	}

	/*
	 * ask for the length of the string 
	 */

	err = usb_get_string(dev, dev->string_langid, index, tbuf, 2);
	if(err<2)
		goto errout;
	len=tbuf[0];	
	
	err = usb_get_string(dev, dev->string_langid, index, tbuf, len);
	if (err < 0)
		goto errout;

	size--;		/* leave room for trailing NULL char in output buffer */
	for (idx = 0, u = 2; u < err; u += 2) {
		if (idx >= size)
			break;
		if (tbuf[u+1])			/* high byte */
			buf[idx++] = '?';  /* non ISO-8859-1 character */
		else
			buf[idx++] = tbuf[u];
	}
	buf[idx] = 0;
	err = idx;

 errout:
	kfree(tbuf);
	return err;
}

// synchronous request completion model
EXPORT_SYMBOL(usb_control_msg);
EXPORT_SYMBOL(usb_bulk_msg);

EXPORT_SYMBOL(usb_sg_init);
EXPORT_SYMBOL(usb_sg_cancel);
EXPORT_SYMBOL(usb_sg_wait);

// synchronous control message convenience routines
EXPORT_SYMBOL(usb_get_descriptor);
EXPORT_SYMBOL(usb_get_device_descriptor);
EXPORT_SYMBOL(usb_get_status);
EXPORT_SYMBOL(usb_get_string);
EXPORT_SYMBOL(usb_string);
EXPORT_SYMBOL(usb_clear_halt);
EXPORT_SYMBOL(usb_set_configuration);
EXPORT_SYMBOL(usb_set_interface);