From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- sound/usb/helper.c | 132 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 132 insertions(+) create mode 100644 sound/usb/helper.c (limited to 'sound/usb/helper.c') diff --git a/sound/usb/helper.c b/sound/usb/helper.c new file mode 100644 index 000000000..51ed1ac82 --- /dev/null +++ b/sound/usb/helper.c @@ -0,0 +1,132 @@ +/* + * 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 +#include +#include + +#include "usbaudio.h" +#include "helper.h" +#include "quirks.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 err; + void *buf = NULL; + int timeout; + + if (size > 0) { + buf = kmemdup(data, size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + } + + if (requesttype & USB_DIR_IN) + timeout = USB_CTRL_GET_TIMEOUT; + else + timeout = USB_CTRL_SET_TIMEOUT; + + err = usb_control_msg(dev, pipe, request, requesttype, + value, index, buf, size, timeout); + + if (size > 0) { + memcpy(data, buf, size); + kfree(buf); + } + + snd_usb_ctl_msg_quirk(dev, pipe, request, requesttype, + value, index, data, size); + + return err; +} + +unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip, + struct usb_host_interface *alts) +{ + switch (snd_usb_get_speed(chip->dev)) { + case USB_SPEED_HIGH: + case USB_SPEED_WIRELESS: + case USB_SPEED_SUPER: + if (get_endpoint(alts, 0)->bInterval >= 1 && + get_endpoint(alts, 0)->bInterval <= 4) + return get_endpoint(alts, 0)->bInterval - 1; + break; + default: + break; + } + return 0; +} + -- cgit v1.2.3-54-g00ecf