// SPDX-License-Identifier: GPL-2.0-or-later
/*
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/usb.h>

#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;
}
EXPORT_SYMBOL_GPL(snd_usb_find_csint_desc);

/*
 * 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 (usb_pipe_type_check(dev, pipe))
                return -EINVAL;

        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_SUPER:
        case USB_SPEED_SUPER_PLUS:
                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;
}

struct usb_host_interface *
snd_usb_get_host_interface(struct snd_usb_audio *chip, int ifnum, int altsetting)
{
        struct usb_interface *iface;

        iface = usb_ifnum_to_if(chip->dev, ifnum);
        if (!iface)
                return NULL;
        return usb_altnum_to_altsetting(iface, altsetting);
}

int snd_usb_add_ctrl_interface_link(struct snd_usb_audio *chip, int ifnum,
                int ctrlif)
{
        struct usb_device *dev = chip->dev;
        struct usb_host_interface *host_iface;

        if (chip->num_intf_to_ctrl >= MAX_CARD_INTERFACES) {
                dev_info(&dev->dev, "Too many interfaces assigned to the single USB-audio card\n");
                return -EINVAL;
        }

        /* find audiocontrol interface */
        host_iface = &usb_ifnum_to_if(dev, ctrlif)->altsetting[0];

        chip->intf_to_ctrl[chip->num_intf_to_ctrl].interface = ifnum;
        chip->intf_to_ctrl[chip->num_intf_to_ctrl].ctrl_intf = host_iface;
        chip->num_intf_to_ctrl++;

        return 0;
}

struct usb_host_interface *snd_usb_find_ctrl_interface(struct snd_usb_audio *chip,
                                                        int ifnum)
{
        int i;

        for (i = 0; i < chip->num_intf_to_ctrl; ++i)
                if (chip->intf_to_ctrl[i].interface == ifnum)
                        return chip->intf_to_ctrl[i].ctrl_intf;

        /* Fallback to first audiocontrol interface */
        return chip->ctrl_intf;
}