path: root/drivers/usb/core/config.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Released under the GPLv2 only.
 */

#include <linux/usb.h>
#include <linux/usb/ch9.h>
#include <linux/usb/hcd.h>
#include <linux/usb/quirks.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/string_choices.h>
#include <linux/device.h>
#include <asm/byteorder.h>
#include "usb.h"


#define USB_MAXALTSETTING		128	/* Hard limit */

#define USB_MAXCONFIG			8	/* Arbitrary limit */

static int find_next_descriptor(unsigned char *buffer, int size,
    int dt1, int dt2, int *num_skipped)
{
	struct usb_descriptor_header *h;
	int n = 0;
	unsigned char *buffer0 = buffer;

	/* Find the next descriptor of type dt1 or dt2 */
	while (size > 0) {
		h = (struct usb_descriptor_header *) buffer;
		if (h->bDescriptorType == dt1 || h->bDescriptorType == dt2)
			break;
		buffer += h->bLength;
		size -= h->bLength;
		++n;
	}

	/* Store the number of descriptors skipped and return the
	 * number of bytes skipped */
	if (num_skipped)
		*num_skipped = n;
	return buffer - buffer0;
}

static void usb_parse_ssp_isoc_endpoint_companion(struct device *ddev,
		int cfgno, int inum, int asnum, struct usb_host_endpoint *ep,
		unsigned char *buffer, int size)
{
	struct usb_ssp_isoc_ep_comp_descriptor *desc;

	/*
	 * The SuperSpeedPlus Isoc endpoint companion descriptor immediately
	 * follows the SuperSpeed Endpoint Companion descriptor
	 */
	desc = (struct usb_ssp_isoc_ep_comp_descriptor *) buffer;
	if (desc->bDescriptorType != USB_DT_SSP_ISOC_ENDPOINT_COMP ||
	    size < USB_DT_SSP_ISOC_EP_COMP_SIZE) {
		dev_notice(ddev, "Invalid SuperSpeedPlus isoc endpoint companion"
			 "for config %d interface %d altsetting %d ep %d.\n",
			 cfgno, inum, asnum, ep->desc.bEndpointAddress);
		return;
	}
	memcpy(&ep->ssp_isoc_ep_comp, desc, USB_DT_SSP_ISOC_EP_COMP_SIZE);
}

static void usb_parse_eusb2_isoc_endpoint_companion(struct device *ddev,
		int cfgno, int inum, int asnum, struct usb_host_endpoint *ep,
		unsigned char *buffer, int size)
{
	struct usb_eusb2_isoc_ep_comp_descriptor *desc;
	struct usb_descriptor_header *h;

	/*
	 * eUSB2 isochronous endpoint companion descriptor for this endpoint
	 * shall be declared before the next endpoint or interface descriptor
	 */
	while (size >= USB_DT_EUSB2_ISOC_EP_COMP_SIZE) {
		h = (struct usb_descriptor_header *)buffer;

		if (h->bDescriptorType == USB_DT_EUSB2_ISOC_ENDPOINT_COMP) {
			desc = (struct usb_eusb2_isoc_ep_comp_descriptor *)buffer;
			ep->eusb2_isoc_ep_comp = *desc;
			return;
		}
		if (h->bDescriptorType == USB_DT_ENDPOINT ||
		    h->bDescriptorType == USB_DT_INTERFACE)
			break;

		buffer += h->bLength;
		size -= h->bLength;
	}

	dev_notice(ddev, "No eUSB2 isoc ep %d companion for config %d interface %d altsetting %d\n",
		   ep->desc.bEndpointAddress, cfgno, inum, asnum);
}

static void usb_parse_ss_endpoint_companion(struct device *ddev, int cfgno,
		int inum, int asnum, struct usb_host_endpoint