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/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include "usbaudio.h"
#include "helper.h"
/*
* combine bytes and get an integer value
*/
unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
{
switch (size) {
case 1: return *bytes;
case 2: return combine_word(bytes);
case 3: return combine_triple(bytes);
case 4: return combine_quad(bytes);
default: return 0;
}
}
/*
* parse descriptor buffer and return the pointer starting the given
* descriptor type.
*/
void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
{
u8 *p, *end, *next;
p = descstart;
end = p + desclen;
for (; p < end;) {
if (p[0] < 2)
return NULL;
next = p + p[0];
if (next > end)
return NULL;
if (p[1] == dtype && (!after || (void *)p > after)) {
return p;
}
p = next;
}
return NULL;
}
/*
* find a class-specified interface descriptor with the given subtype.
*/
void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
{
unsigned char *p = after;
while ((p = snd_usb_find_desc(buffer, buflen, p,
USB_DT_CS_INTERFACE)) != NULL) {
if (p[0] >= 3 && p[2] == dsubtype)
return p;
}
return NULL;
}
/*
* Wrapper for usb_control_msg().
* Allocates a temp buffer to prevent dmaing from/to the stack.
*/
int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
__u8 requesttype, __u16 value, __u16 index, void *data,
__u16 size, int timeout)
{
int err;
void *buf = NULL;
if (size > 0) {
buf = kmemdup(data, size, GFP_KERNEL);
if (!buf)
return -ENOMEM;
}
err = usb_control_msg(dev, pipe, request, requesttype,
value, index, buf, size, timeout);
if (size > 0) {
memcpy(data, buf, size);
kfree(buf);
}
return err;
}
unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
struct usb_host_interface *alts)
{
if (snd_usb_get_speed(chip->dev) == USB_SPEED_HIGH &&
get_endpoint(alts, 0)->bInterval >= 1 &&
get_endpoint(alts, 0)->bInterval <= 4)
return get_endpoint(alts, 0)->bInterval - 1;
else
return 0;
}
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