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 */
snd_usb_combine_bytes(unsigned char * bytes,int size)16 unsigned 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 */
snd_usb_find_desc(void * descstart,int desclen,void * after,u8 dtype)31 void *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 */
snd_usb_find_csint_desc(void * buffer,int buflen,void * after,u8 dsubtype)54 void *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 EXPORT_SYMBOL_GPL(snd_usb_find_csint_desc);
66
67 /*
68 * Wrapper for usb_control_msg().
69 * Allocates a temp buffer to prevent dmaing from/to the stack.
70 */
snd_usb_ctl_msg(struct usb_device * dev,unsigned int pipe,__u8 request,__u8 requesttype,__u16 value,__u16 index,void * data,__u16 size)71 int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
72 __u8 requesttype, __u16 value, __u16 index, void *data,
73 __u16 size)
74 {
75 int err;
76 void *buf = NULL;
77 int timeout;
78
79 if (usb_pipe_type_check(dev, pipe))
80 return -EINVAL;
81
82 if (size > 0) {
83 buf = kmemdup(data, size, GFP_KERNEL);
84 if (!buf)
85 return -ENOMEM;
86 }
87
88 if (requesttype & USB_DIR_IN)
89 timeout = USB_CTRL_GET_TIMEOUT;
90 else
91 timeout = USB_CTRL_SET_TIMEOUT;
92
93 err = usb_control_msg(dev, pipe, request, requesttype,
94 value, index, buf, size, timeout);
95
96 if (size > 0) {
97 memcpy(data, buf, size);
98 kfree(buf);
99 }
100
101 snd_usb_ctl_msg_quirk(dev, pipe, request, requesttype,
102 value, index, data, size);
103
104 return err;
105 }
106
snd_usb_parse_datainterval(struct snd_usb_audio * chip,struct usb_host_interface * alts)107 unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,
108 struct usb_host_interface *alts)
109 {
110 switch (snd_usb_get_speed(chip->dev)) {
111 case USB_SPEED_HIGH:
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
124 struct usb_host_interface *
snd_usb_get_host_interface(struct snd_usb_audio * chip,int ifnum,int altsetting)125 snd_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 }
134
snd_usb_add_ctrl_interface_link(struct snd_usb_audio * chip,int ifnum,int ctrlif)135 int snd_usb_add_ctrl_interface_link(struct snd_usb_audio *chip, int ifnum,
136 int ctrlif)
137 {
138 struct usb_device *dev = chip->dev;
139 struct usb_host_interface *host_iface;
140
141 if (chip->num_intf_to_ctrl >= MAX_CARD_INTERFACES) {
142 dev_info(&dev->dev, "Too many interfaces assigned to the single USB-audio card\n");
143 return -EINVAL;
144 }
145
146 /* find audiocontrol interface */
147 host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];
148
149 chip->intf_to_ctrl[chip->num_intf_to_ctrl].interface = ifnum;
150 chip->intf_to_ctrl[chip->num_intf_to_ctrl].ctrl_intf = host_iface;
151 chip->num_intf_to_ctrl++;
152
153 return 0;
154 }
155
snd_usb_find_ctrl_interface(struct snd_usb_audio * chip,int ifnum)156 struct usb_host_interface *snd_usb_find_ctrl_interface(struct snd_usb_audio *chip,
157 int ifnum)
158 {
159 int i;
160
161 for (i = 0; i < chip->num_intf_to_ctrl; ++i)
162 if (chip->intf_to_ctrl[i].interface == ifnum)
163 return chip->intf_to_ctrl[i].ctrl_intf;
164
165 /* Fallback to first audiocontrol interface */
166 return chip->ctrl_intf;
167 }
168