// SPDX-License-Identifier: GPL-2.0+
/*
* usb/gadget/config.c -- simplify building config descriptors
*
* Copyright (C) 2003 David Brownell
*/
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/device.h>
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb/composite.h>
#include <linux/usb/otg.h>
/**
* usb_descriptor_fillbuf - fill buffer with descriptors
* @buf: Buffer to be filled
* @buflen: Size of buf
* @src: Array of descriptor pointers, terminated by null pointer.
*
* Copies descriptors into the buffer, returning the length or a
* negative error code if they can't all be copied. Useful when
* assembling descriptors for an associated set of interfaces used
* as part of configuring a composite device; or in other cases where
* sets of descriptors need to be marshaled.
*/
int
usb_descriptor_fillbuf(void *buf, unsigned buflen,
const struct usb_descriptor_header **src)
{
u8 *dest = buf;
if (!src)
return -EINVAL;
/* fill buffer from src[] until null descriptor ptr */
for (; NULL != *src; src++) {
unsigned len = (*src)->bLength;
if (len > buflen)
return -EINVAL;
memcpy(dest, *src, len);
buflen -= len;
dest += len;
}
return dest - (u8 *)buf;
}
EXPORT_SYMBOL_GPL(usb_descriptor_fillbuf);
/**
* usb_gadget_config_buf - builts a complete configuration descriptor
* @config: Header for the descriptor, including characteristics such
* as power requirements and number of interfaces.
* @desc: Null-terminated vector of pointers to the descriptors (interface,
* endpoint, etc) defining all functions in this device configuration.
* @buf: Buffer for the resulting configuration descriptor.
* @length: Length of buffer. If this is not big enough to hold the
* entire configuration descriptor, an error code will be returned.
*
* This copies descriptors into the response buffer, building a descriptor
* for that configuration. It returns the buffer length or a negative
* status code. The config.wTotalLength field is set to match the length
* of the result, but other descriptor fields (including power usage and
* interface count) must be set by the caller.
*
* Gadget drivers could use this when constructing a config descriptor
* in response to USB_REQ_GET_DESCRIPTOR. They will need to patch the
* resulting bDescriptorType value if USB_DT_OTHER_SPEED_CONFIG is needed.
*/
int usb_gadget_config_buf(
const struct usb_config_descriptor *config,
void *buf,
unsigned length,
const struct usb_descriptor_header **desc
)
{
struct usb_config_descriptor *cp = buf;
int len;
/* config descriptor first */
if (length < USB_DT_CONFIG_SIZE || !desc)
return -EINVAL;
*cp = *config;
/* then interface/endpoint/class/vendor/... */
len = usb_descriptor_fillbuf(USB_DT_CONFIG_SIZE + (u8 *)buf,
length - USB_DT_CONFIG_SIZE, desc);
if (len < 0)
return len;
len += USB_DT_CONFIG_SIZE;
if (len > 0xffff)
return -EINVAL;
/* patch up the config descriptor */
cp->bLength = USB_DT_CONFIG_SIZE;
cp->bDescriptorType = USB_DT_CONFIG;
cp->wTotalLength = cpu_to_le16(len);
cp->bmAttributes |= USB_CONFIG_ATT_ONE;
return len;
}
EXPORT_SYMBOL_GPL(usb_gadget_config_buf);
/**
* usb_copy_descriptors - copy a vector of USB descriptors
* @src: null-terminated vector to copy
* Context: initialization code, which may sleep
*
* This makes a copy of a vector of USB descriptors. Its primary use
* is to support usb_function objects which can have multiple copies,
* each needing different descriptors. Functions may have static
* tables of descriptors, which are used as templates and customized
* with identifiers (for interfaces, strings, endpoints, and more)
* as needed by a given function instance.
*/
struct usb_descriptor_header **
usb_copy_descriptors(struct usb_descriptor_header **src)
{
struct usb_descriptor_header **tmp;
unsigned bytes;
unsigned n_desc;
void *mem;
struct usb_descriptor_header **ret;
/* count descriptors and their sizes; then add vector size */
for (bytes = 0, n_desc = 0, tmp = src; *tmp; tmp++, n_desc++)
bytes += (*tmp)->bLength;
bytes += (n_desc + 1) * sizeof(*tmp);
mem = kmalloc(bytes, GFP_KERNEL);
if (!mem)
return NULL;
/* fill in pointers starting at "tmp",
* to descriptors copied starting at "mem";
* and return "ret"
*/
tmp = mem;
ret = mem;
mem += (n_desc + 1) * sizeof(*tmp);
while (*src) {
memcpy(mem, *src, (*src)->bLength);
*tmp = mem;
tmp++;
mem += (*src)->bLength;
src++;
}
*tmp = NULL;
return ret;
}
EXPORT_SYMBOL_GPL(usb_copy_descriptors);
int usb_assign_descriptors(struct usb_function *f,
struct usb_descriptor_header **fs,
struct usb_descriptor_header **hs,
struct usb_descriptor_header **ss,
struct usb_descriptor_header **ssp)
{
/* super-speed-plus descriptor falls back to super-speed one,
* if such a descriptor was provided, thus avoiding a NULL
* pointer dereference if a 5gbps capable gadget is used with
* a 10gbps capable config (device port + cable + host port)
*/
if (!ssp)
ssp = ss;
if (fs) {
f->fs_descriptors = usb_copy_descriptors(fs);
if (!f->fs_descriptors)
goto err;
}
if (hs) {
f->hs_descriptors = usb_copy_descriptors(hs);
if (!f->hs_descriptors)
goto err;
}
if (ss) {
f->ss_descriptors = usb_copy_descriptors(ss);
if (!f->ss_descriptors)
goto err;
}
if (ssp) {
f->ssp_descriptors = usb_copy_descriptors(ssp);
if (!f->ssp_descriptors)
goto err;
}
return 0;
err:
usb_free_all_descriptors(f);
return -ENOMEM;
}
EXPORT_SYMBOL_GPL(usb_assign_descriptors);
void usb_free_all_descriptors(struct usb_function *f)
{
usb_free_descriptors(f->fs_descriptors);
f->fs_descriptors = NULL;
usb_free_descriptors(f->hs_descriptors);
f->hs_descriptors = NULL;
usb_free_descriptors(f->ss_descriptors);
f->ss_descriptors = NULL;
usb_free_descriptors(f->ssp_descriptors);
f->ssp_descriptors = NULL;
}
EXPORT_SYMBOL_GPL(usb_free_all_descriptors);
struct usb_descriptor_header *usb_otg_descriptor_alloc(
struct usb_gadget *gadget)
{
struct usb_descriptor_header *otg_desc;
unsigned length = 0;
if (gadget->otg_caps && (gadget->otg_caps->otg_rev >= 0x0200))
length = sizeof(struct usb_otg20_descriptor);
else
length = sizeof(struct usb_otg_descriptor);
otg_desc = kzalloc(length, GFP_KERNEL);
return otg_desc;
}
EXPORT_SYMBOL_GPL(usb_otg_descriptor_alloc);
int usb_otg_descriptor_init(struct usb_gadget *gadget,
struct usb_descriptor_header *otg_desc)
{
struct usb_otg_descriptor *otg1x_desc;
struct usb_otg20_descriptor *otg20_desc;
struct usb_otg_caps *otg_caps = gadget->otg_caps;
u8 otg_attributes = 0;
if (!otg_desc)
return -EINVAL;
if (otg_caps && otg_caps->otg_rev) {
if (otg_caps->hnp_support)
otg_attributes |= USB_OTG_HNP;
if (otg_caps->srp_support)
otg_attributes |= USB_OTG_SRP;
if (otg_caps->adp_support && (otg_caps->otg_rev >= 0x0200))
otg_attributes |= USB_OTG_ADP;
} else {
otg_attributes = USB_OTG_SRP | USB_OTG_HNP;
}
if (otg_caps && (otg_caps->otg_rev >= 0x0200)) {
otg20_desc = (struct usb_otg20_descriptor *)otg_desc;
otg20_desc->bLength = sizeof(struct usb_otg20_descriptor);
otg20_desc->bDescriptorType = USB_DT_OTG;
otg20_desc->bmAttributes = otg_attributes;
otg20_desc->bcdOTG = cpu_to_le16(otg_caps->otg_rev);
} else {
otg1x_desc = (struct usb_otg_descriptor *)otg_desc;
otg1x_desc->bLength = sizeof(struct usb_otg_descriptor);
otg1x_desc->bDescriptorType = USB_DT_OTG;
otg1x_desc->bmAttributes = otg_attributes;
}
return 0;
}
EXPORT_SYMBOL_GPL(usb_otg_descriptor_init);
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