usb: support for retrieving full configuration descriptors

In USB, the interface and endpoint descriptors, and possibly other
vendor-specific descriptors, are nested inside the configuration
descriptors. This makes it possible to retrieve the complete information
about a configuration in one single call.

Our drivers do this, and so does libusb (the Device Kit doesn't, it only
cares about individual descriptors and does not provide access to the
vendor-specific ones).

The driver did not expose the full descriptor, only the part that
belongs strictly to the configuration. libusb worked around this by
getting the descriptor from the device directly, using a control
transfer. This should be ok, but apparently some devices get confused
when you do this too often or at unexpected times.

These changes introduce a variation of the GET_CONFIGURATION_DESCRIPTOR
ioctl that allows the caller to specify a size. This way, one can get
the complete descriptor (after getting the configuration-only part to
figure out the size needed, most likely). The data is copied from
structures stored by the driver, so no further communication with the
device is necessary, making this safe to the problems mentioned above,
and faster.

Change-Id: Id97e40ea0d45b8c051ae8548486c4751fc6aad2a
Reviewed-on: https://review.haiku-os.org/453
Reviewed-by: Jérôme Duval <[email protected]>

src/add-ons/kernel/drivers/bus/usb/usb_raw.cpp

@@ -1,15 +1,17 @@
 /*
- * Copyright 2006-2010, Haiku Inc. All rights reserved.
+ * Copyright 2006-2018, Haiku Inc. All rights reserved.
  * Distributed under the terms of the MIT License.
  *
  * Authors:
  *		Michael Lotz <[email protected]>
+ *		Adrien Destugues <[email protected]>
  */
 
 #include "usb_raw.h"
 
 #include <KernelExport.h>
 #include <Drivers.h>
+#include <algorithm>
 #include <lock.h>
 #include <malloc.h>
 #include <stdio.h>
@@ -311,7 +313,12 @@ usb_raw_ioctl(void *cookie, uint32 op, void *buffer, size_t length)
 		}
 
 		case B_USB_RAW_COMMAND_GET_CONFIGURATION_DESCRIPTOR:
+		case B_USB_RAW_COMMAND_GET_CONFIGURATION_DESCRIPTOR_ETC:
 		{
+			if (op == B_USB_RAW_COMMAND_GET_CONFIGURATION_DESCRIPTOR_ETC
+					&& length < sizeof(command.config_etc))
+				return B_BUFFER_OVERFLOW;
+
 			if (length < sizeof(command.config))
 				return B_BUFFER_OVERFLOW;
 
@@ -322,10 +329,15 @@ usb_raw_ioctl(void *cookie, uint32 op, void *buffer, size_t length)
 			if (configurationInfo == NULL)
 				break;
 
+			size_t sizeToCopy = sizeof(usb_configuration_descriptor);
+			if (op == B_USB_RAW_COMMAND_GET_CONFIGURATION_DESCRIPTOR_ETC) {
+				sizeToCopy = std::min(command.config_etc.length,
+					(size_t)configurationInfo->descr->total_length);
+			}
+
 			if (!IS_USER_ADDRESS(command.config.descriptor)
 				|| user_memcpy(command.config.descriptor,
-					configurationInfo->descr,
-					sizeof(usb_configuration_descriptor)) != B_OK) {
+					configurationInfo->descr, sizeToCopy) != B_OK) {
 				return B_BAD_ADDRESS;
 			}
 

src/add-ons/kernel/drivers/bus/usb/usb_raw.h

@@ -25,6 +25,7 @@ typedef enum {
 	B_USB_RAW_COMMAND_GET_INTERFACE_DESCRIPTOR_ETC,
 	B_USB_RAW_COMMAND_GET_ENDPOINT_DESCRIPTOR_ETC,
 	B_USB_RAW_COMMAND_GET_GENERIC_DESCRIPTOR_ETC,
+	B_USB_RAW_COMMAND_GET_CONFIGURATION_DESCRIPTOR_ETC,
 
 	B_USB_RAW_COMMAND_SET_CONFIGURATION = 0x3000,
 	B_USB_RAW_COMMAND_SET_FEATURE,
@@ -74,6 +75,13 @@ typedef union {
 		uint32							config_index;
 	} config;
 
+	struct {
+		status_t						status;
+		usb_configuration_descriptor	*descriptor;
+		uint32							config_index;
+		size_t                          length;
+	} config_etc;
+
 	struct {
 		status_t						status;
 		uint32							alternate_info;