/*******************************************************************************
* drivers/usbhost/usbhost_devaddr.c
* Manage USB device addresses
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Authors: 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 <string.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/kmalloc.h>
#include <nuttx/usb/usbhost_devaddr.h>
/*******************************************************************************
* Pre-processor Definitions
*******************************************************************************/
/*******************************************************************************
* Private Functions
*******************************************************************************/
/****************************************************************************
* Name: usbhost_takesem and usbhost_givesem
*
* Description:
* This is just a wrapper to handle the annoying behavior of semaphore
* waits that return due to the receipt of a signal.
*
*******************************************************************************/
static void usbhost_takesem(FAR struct usbhost_devaddr_s *hcd)
{
/* Take the semaphore (perhaps waiting) */
while (sem_wait(&hcd->exclsem) != 0)
{
/* The only case that an error should occur here is if the wait was
* awakened by a signal.
*/
ASSERT(errno == EINTR);
}
}
#define usbhost_givesem(hcd) sem_post(&hcd->exclsem)
/*******************************************************************************
* Name: usbhost_devaddr_hash
*
* Description:
* Create a hash value from a device address.
*
*******************************************************************************/
static inline uint8_t usbhost_devaddr_hash(uint8_t devaddr)
{
uint8_t ret = devaddr;
ret ^= (devaddr >> 2);
ret ^= (devaddr >> 3);
return ret & USBHOST_DEVADDR_HASHMASK;
}
/*******************************************************************************
* Name: usbhost_devaddr_allocate
*
* Description:
* Allocate a new unique device address for this HCD.
*
* Assumptions:
* Caller hold the exclsem
*
*******************************************************************************/
static int usbhost_devaddr_allocate(FAR struct usbhost_devaddr_s *hcd)
{
uint8_t startaddr = hcd->next;
uint8_t devaddr;
int index;
int bitno;
/* Loop until we find a valid device address */
for (;;)
{
/* Try the next device address */
devaddr = hcd->next;
if (hcd->next >= 0x7f)
{
hcd->next = 1;
}
else
{
hcd->next++;
}
/* Is this address already allocated? */
index = devaddr >> 5;
bitno = devaddr & 0x1f;
if ((hcd->alloctab[index] & (1 << bitno)) == 0)
{
/* No... allocate it now */
hcd->alloctab[index] |= (1 << bitno);
return (int)devaddr;
}
/* This address has already been allocated. The followign logic will
* prevent (unexpected) infinite loops.
*/
if (startaddr == devaddr)
{
/* We are back where we started... the are no free device address */
return -ENOMEM;
}
}
}
/*******************************************************************************
* Public Functions
*******************************************************************************/
/*******************************************************************************
* Name: usbhost_devaddr_initialize
*
* Description:
* Initialize the caller provided struct usbhost_devaddr_s instance in
* preparation for the management of device addresses on behalf of an HCD.
*
*******************************************************************************/
void usbhost_devaddr_initialize(FAR struct usbhost_devaddr_s *hcd)
{
DEBUGASSERT(hcd);
memset(hcd, 0, sizeof(struct usbhost_devaddr_s));
sem_init(&hcd->exclsem, 0, 1);
hcd->next = 1;
}
/*******************************************************************************
* Name: usbhost_devaddr_create
*
* Description:
* Create a new unique device address for this HCD. Bind the void* arg to the
* the device address and return the newly allocated device address.
*
*******************************************************************************/
int usbhost_devaddr_create(FAR struct usbhost_devaddr_s *hcd,
FAR void *associate)
{
FAR struct usbhost_devhash_s *hentry;
uint8_t hvalue;
int devaddr;
/* Allocate a hash table entry */
hentry = (FAR struct usbhost_devhash_s *)kmm_malloc(sizeof(struct usbhost_devhash_s));
if (!hentry)
{
udbg("ERROR: Failed to allocate a hash table entry\n");
return -ENOMEM;
}
/* Get exclusive access to the HCD device address data */
usbhost_takesem(hcd);
/* Allocate a device address */
devaddr = usbhost_devaddr_allocate(hcd);
if (devaddr < 0)
{
udbg("ERROR: Failed to allocate a device address\n");
free(hentry);
}
else
{
/* Initialize the hash table entry */
hentry->devaddr = devaddr;
hentry->payload = associate;
/* Add the new device address to the hash table */
hvalue = usbhost_devaddr_hash(devaddr);
hentry->flink = hcd->hashtab[hvalue];
hcd->hashtab[hvalue] = hentry;
/* Try to re-use the lowest numbered device addresses */
if (hcd->next > devaddr)
{
hcd->next = devaddr;
}
}
usbhost_givesem(hcd);
return devaddr;
}
/*******************************************************************************
* Name: usbhost_devaddr_find
*
* Description:
* Given a device address, find the void* value that was bound to the device
* address by usbhost_devaddr_create() when the device address was allocated.
*
*******************************************************************************/
FAR void *usbhost_devaddr_find(FAR struct usbhost_devaddr_s *hcd,
uint8_t devaddr)
{
FAR struct usbhost_devhash_s *hentry;
uint8_t hvalue;
/* Get exclusive access to the HCD device address data */
hvalue = usbhost_devaddr_hash(devaddr);
usbhost_takesem(hcd);
/* Check each entry in the hash table */
for (hentry = hcd->hashtab[hvalue]; hentry; hentry = hentry->flink)
{
/* Is this the address we are looking for? */
if (hentry->devaddr == devaddr)
{
/* Yes.. return the payload from the hash table entry */
usbhost_givesem(hcd);
return hentry->payload;
}
}
/* Didn't find the device address */
usbhost_givesem(hcd);
return NULL;
}
/*******************************************************************************
* Name: usbhost_devaddr_destroy
*
* Description:
* Release a device address previously allocated by usbhost_devaddr_destroy()
* and destroy the association with the void* data.
*
*******************************************************************************/
void usbhost_devaddr_destroy(FAR struct usbhost_devaddr_s *hcd, uint8_t devaddr)
{
FAR struct usbhost_devhash_s *hentry;
FAR struct usbhost_devhash_s *prev;
uint8_t hvalue;
/* Get exclusive access to the HCD device address data */
hvalue = usbhost_devaddr_hash(devaddr);
usbhost_takesem(hcd);
/* Search the hast table for the matching entry */
for (hentry = hcd->hashtab[hvalue], prev = NULL;
hentry;
prev = hentry, hentry = hentry->flink)
{
/* Is this the address we are looking for? */
if (hentry->devaddr == devaddr)
{
/* Yes.. remove the entry from the hash list */
if (prev)
{
prev->flink = hentry->flink;
}
else
{
hcd->hashtab[hvalue] = hentry->flink;
}
/* And release the entry */
kmm_free(hentry);
break;
}
}
usbhost_givesem(hcd);
}
