/****************************************************************************
* drivers/usbhost/usbhost_findclass.c
*
* Copyright (C) 2010 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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
* COPYRIGHT OWNER OR CONTRIBUTORS 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdbool.h>
#include <debug.h>
#include <nuttx/usb/usb.h>
#include <nuttx/usb/usbhost.h>
#include <arch/irq.h>
#include "usbhost_registry.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: usbhost_idmatch
*
* Description:
* Check if the class ID matches what the host controller found.
*
* Input Parameters:
* classid - ID info for the class under consideration.
* devid - ID info reported by the device.
*
* Returned Values:
* TRUE - the class will support this device.
*
****************************************************************************/
static bool usbhost_idmatch(const struct usbhost_id_s *classid,
const struct usbhost_id_s *devid)
{
uvdbg("Compare to class:%d subclass:%d protocol:%d vid:%04x pid:%04x\n",
classid->base, classid->subclass, classid->proto,
classid->vid, classid->pid);
/* The base class ID, subclass and protocol have to match up in any event */
if (devid->base == classid->base &&
devid->subclass == classid->subclass &&
devid->proto == classid->proto)
{
/* If this is a vendor-specific class ID, then the VID and PID have to
* match as well.
*/
if (devid->base == USB_CLASS_VENDOR_SPEC)
{
/* Vendor specific... do the VID and PID also match? */
if (devid->vid == classid->vid && devid->pid == classid->pid)
{
/* Yes.. then we have a match */
return true;
}
}
else
{
/* Not vendor specific? Then we have a match */
return true;
}
}
/* No match.. not supported */
return false;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: usbhost_findclass
*
* Description:
* Find a USB host class implementation previously registered by
* usbhost_registerclass(). On success, an instance of struct
* usbhost_registry_s will be returned. That instance will contain all of
* the information that will be needed to obtain and bind a struct
* usbhost_class_s instance for the device.
*
* Input Parameters:
* id - Identifies the USB device class that has connect to the USB host.
*
* Returned Values:
* On success this function will return a non-NULL instance of struct
* usbhost_registry_s. NULL will be returned on failure. This function
* can only fail if (1) id is NULL, or (2) no USB host class is registered
* that matches the device class ID.
*
****************************************************************************/
const struct usbhost_registry_s *usbhost_findclass(const struct usbhost_id_s *id)
{
struct usbhost_registry_s *class;
irqstate_t flags;
int ndx;
DEBUGASSERT(id);
uvdbg("Looking for class:%d subclass:%d protocol:%d vid:%04x pid:%04x\n",
id->base, id->subclass, id->proto, id->vid, id->pid);
/* g_classregistry is a singly-linkedlist of class ID information added by
* calls to usbhost_registerclass(). Since this list is accessed from USB
* host controller interrupt handling logic, accesses to this list must be
* protected by disabling interrupts.
*/
flags = irqsave();
/* Examine each register class in the linked list */
for (class = g_classregistry; class; class = class->flink)
{
/* If the registered class supports more than one ID, subclass, or
* protocol, then try each.
*/
uvdbg("Checking class:%p nids:%d\n", class, class->nids);
for (ndx = 0; ndx < class->nids; ndx++)
{
/* Did we find a matching ID? */
if (usbhost_idmatch(&class->id[ndx], id))
{
/* Yes.. restore interrupts and return the class info */
irqrestore(flags);
return class;
}
}
}
/* Not found... restore interrupts and return NULL */
irqrestore(flags);
return NULL;
}
