cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

helper.c (2826B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 */
      4
      5#include <linux/init.h>
      6#include <linux/slab.h>
      7#include <linux/usb.h>
      8
      9#include "usbaudio.h"
     10#include "helper.h"
     11#include "quirks.h"
     12
     13/*
     14 * combine bytes and get an integer value
     15 */
     16unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
     17{
     18	switch (size) {
     19	case 1:  return *bytes;
     20	case 2:  return combine_word(bytes);
     21	case 3:  return combine_triple(bytes);
     22	case 4:  return combine_quad(bytes);
     23	default: return 0;
     24	}
     25}
     26
     27/*
     28 * parse descriptor buffer and return the pointer starting the given
     29 * descriptor type.
     30 */
     31void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
     32{
     33	u8 *p, *end, *next;
     34
     35	p = descstart;
     36	end = p + desclen;
     37	for (; p < end;) {
     38		if (p[0] < 2)
     39			return NULL;
     40		next = p + p[0];
     41		if (next > end)
     42			return NULL;
     43		if (p[1] == dtype && (!after || (void *)p > after)) {
     44			return p;
     45		}
     46		p = next;
     47	}
     48	return NULL;
     49}
     50
     51/*
     52 * find a class-specified interface descriptor with the given subtype.
     53 */
     54void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
     55{
     56	unsigned char *p = after;
     57
     58	while ((p = snd_usb_find_desc(buffer, buflen, p,
     59				      USB_DT_CS_INTERFACE)) != NULL) {
     60		if (p[0] >= 3 && p[2] == dsubtype)
     61			return p;
     62	}
     63	return NULL;
     64}
     65
     66/*
     67 * Wrapper for usb_control_msg().
     68 * Allocates a temp buffer to prevent dmaing from/to the stack.
     69 */
     70int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
     71		    __u8 requesttype, __u16 value, __u16 index, void *data,
     72		    __u16 size)
     73{
     74	int err;
     75	void *buf = NULL;
     76	int timeout;
     77
     78	if (usb_pipe_type_check(dev, pipe))
     79		return -EINVAL;
     80
     81	if (size > 0) {
     82		buf = kmemdup(data, size, GFP_KERNEL);
     83		if (!buf)
     84			return -ENOMEM;
     85	}
     86
     87	if (requesttype & USB_DIR_IN)
     88		timeout = USB_CTRL_GET_TIMEOUT;
     89	else
     90		timeout = USB_CTRL_SET_TIMEOUT;
     91
     92	err = usb_control_msg(dev, pipe, request, requesttype,
     93			      value, index, buf, size, timeout);
     94
     95	if (size > 0) {
     96		memcpy(data, buf, size);
     97		kfree(buf);
     98	}
     99
    100	snd_usb_ctl_msg_quirk(dev, pipe, request, requesttype,
    101			      value, index, data, size);
    102
    103	return err;
    104}
    105
    106unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
    107					 struct usb_host_interface *alts)
    108{
    109	switch (snd_usb_get_speed(chip->dev)) {
    110	case USB_SPEED_HIGH:
    111	case USB_SPEED_WIRELESS:
    112	case USB_SPEED_SUPER:
    113	case USB_SPEED_SUPER_PLUS:
    114		if (get_endpoint(alts, 0)->bInterval >= 1 &&
    115		    get_endpoint(alts, 0)->bInterval <= 4)
    116			return get_endpoint(alts, 0)->bInterval - 1;
    117		break;
    118	default:
    119		break;
    120	}
    121	return 0;
    122}
    123
    124struct usb_host_interface *
    125snd_usb_get_host_interface(struct snd_usb_audio *chip, int ifnum, int altsetting)
    126{
    127	struct usb_interface *iface;
    128
    129	iface = usb_ifnum_to_if(chip->dev, ifnum);
    130	if (!iface)
    131		return NULL;
    132	return usb_altnum_to_altsetting(iface, altsetting);
    133}