167 lines · c
1// SPDX-License-Identifier: GPL-2.0-or-later2/*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 value15 */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 given29 * 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 else90 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_SUPER:112 case USB_SPEED_SUPER_PLUS:113 if (get_endpoint(alts, 0)->bInterval >= 1 &&114 get_endpoint(alts, 0)->bInterval <= 4)115 return get_endpoint(alts, 0)->bInterval - 1;116 break;117 default:118 break;119 }120 return 0;121}122 123struct usb_host_interface *124snd_usb_get_host_interface(struct snd_usb_audio *chip, int ifnum, int altsetting)125{126 struct usb_interface *iface;127 128 iface = usb_ifnum_to_if(chip->dev, ifnum);129 if (!iface)130 return NULL;131 return usb_altnum_to_altsetting(iface, altsetting);132}133 134int snd_usb_add_ctrl_interface_link(struct snd_usb_audio *chip, int ifnum,135 int ctrlif)136{137 struct usb_device *dev = chip->dev;138 struct usb_host_interface *host_iface;139 140 if (chip->num_intf_to_ctrl >= MAX_CARD_INTERFACES) {141 dev_info(&dev->dev, "Too many interfaces assigned to the single USB-audio card\n");142 return -EINVAL;143 }144 145 /* find audiocontrol interface */146 host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];147 148 chip->intf_to_ctrl[chip->num_intf_to_ctrl].interface = ifnum;149 chip->intf_to_ctrl[chip->num_intf_to_ctrl].ctrl_intf = host_iface;150 chip->num_intf_to_ctrl++;151 152 return 0;153}154 155struct usb_host_interface *snd_usb_find_ctrl_interface(struct snd_usb_audio *chip,156 int ifnum)157{158 int i;159 160 for (i = 0; i < chip->num_intf_to_ctrl; ++i)161 if (chip->intf_to_ctrl[i].interface == ifnum)162 return chip->intf_to_ctrl[i].ctrl_intf;163 164 /* Fallback to first audiocontrol interface */165 return chip->ctrl_intf;166}167