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 */ 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 */ 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 */ 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 */ 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 } 106 107 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 * 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 } 134 135 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 } 155 156 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